A number of research papers have been published in peer-reviewed journals and elsewhere, based on Alberta’s Tomorrow Project data:
Csizmadi I, Boucher B, Lo Siou G, Massarrelli I, Rondeau I, Garriguet D, Koushik A, Elenko J, Subar AF. Using national dietary intake data to evaluate and adapt the US Diet History Questionnaire: the stepwise tailoring of an FFQ for Canadian populations. Public Health Nutr 2016; Jun 28:1-9.
Anand S, Tu J, Awadalla P, Black S, Boileau C, Busseuil D, Desai D, Despres J-P, de Souza R, Dummer T, Jacquemont S, Knoppers B, Larose E, Lear S, Marcotte F, Moody A, Parker L, Poirier P, Robson P, Smith E, Spinelli J, Tardiff J-C, Teo K, Tuevljak N, Friedrich M. Rationale, Design, and Methods for Canadian Alliance for Healthy Hearts and Minds Cohort Study (CAHHM) – A Pan Canadian Cohort Study BMC Public Health 2016 Jul 27;16:650. doi: 10.1186/s12889-016-3310-8.
Robson PJ, Solbak NM, Haig TR, Whelan HK, Vena JE, Akawung AK, Rosner WK, Brenner DA, Cook LS, Csizmadi I, Kopciuk KA, McGregor SE, Friedenreich CM. Design, methods and demographics from phase I of Alberta’s Tomorrow Project cohort: a prospective cohort profile CMAJ Open 2016 Sep 29;4(3):E515-E527.
Labonté MÈ, Kirkpatrick SI, Bell RC, Boucher BA Csizmadi I, Koushik A, L’Abbé MR, Massarelli I, Robson PJ, Rondeau I, Shatenstein B, Subar AF, Lamarche B. Dietary assessment is a critical element of health research – Perspective from the Partnership for Advancing Nutritional and Dietary Assessment in Canada. Appl Physiol Nutr Metab 2016; Jul 20:1-4. [Epub ahead of print]
Nicholas JA, Lo Siou G, Lynch BM, Robson PJ, Friedenreich CM, Csizmadi I. Leisure-time Physical Activity Does Not Attenuate the Association Between Occupational Sedentary Behaviour and Obesity: Results From the Tomorrow Project in Alberta, Canada. J Phys Act Health 2015; 12(12):1589-1600 .
Sedentary behaviour has been proposed as a risk factor for obesity that is distinct from physical inactivity. This study aimed to examine the association between occupational sedentary behaviour and obesity, and to determine if this association is independent of leisure-time physical activity (LTPA).
Fully-employed participants enrolled between 2001 and 2008 to the Tomorrow Project, a prospective cohort study in Alberta, Canada, were studied (n=12,409). Associations between occupational sedentary behaviour and waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) were examined using multiple binary and multinomial logistic regressions.
In men, a positive association was observed between daily occupational sedentary hours and WC, WHR, BMI and with high risk profiles that incorporated both BMI and WC (P<0.01). Controlling for vigorous-intensity LTPA in all models strengthened associations between sedentary behaviour and measures of obesity. In contrast, inverse associations were observed for occupational sedentary hours and WHR for women (P<0.05).
In fully-employed men, occupational sedentary behaviour was positively associated with obesity risk that was not attenuated by physical activity. In women, an increase in obesity risk was not observed with sedentary behaviour. Gender differences in the health effects of sedentary behavior require further study.
Csizmadi I, Kelemen LE, Speidel T, Yuan Y, Dale LC, Friedenreich CM, Robson PJ. Are physical activity levels linked to nutrient adequacy? Implications for cancer risk. Nutr Cancer 2014;66(2):214-24.
Cancer prevention guidelines recommend a healthy body mass index, physical activity, and nutrient intake from food rather than supplements. Sedentary individuals may restrict energy intake to prevent weight gain and in so doing may compromise nutritional intake. We conducted a cross-sectional analysis to determine if adequacy of micronutrients is linked to physical activity levels (PALs) in healthy-weight adults. Tomorrow Project participants in Alberta, Canada (n = 5333), completed past-year diet and physical activity questionnaires. The percent meeting Dietary Reference Intakes (DRIs) was reported across low and high PAL groups, and the relation between PAL and percent achieved DRI was determined using multiple linear regression analyses. Overall, <50% of healthy-weight participants met DRIs for folate, calcium, and vitamin D. Percent achieved DRI increased linearly with increasing PAL in both genders (P < 0.01). A hypothetical increase in PAL from 1.4 to 1.9 was associated with a DRI that was 8%-13% higher for folate and vitamin C (men) and 5%-15% higher for calcium and iron (women). Healthy-weight adults at higher PALs appear more likely to meet DRIs for potential cancer-preventing nutrients. The benefits of higher PALs may extend beyond the usual benefits attributed to physical activityto include having a more favorable impact on nutrient adequacy.
Kelemen LE, Brenton JD, Parkinson C, C Whittaker H, Piskorz AM, Csizmadi I, Robson PJ. Conditions associated with circulating tumor-associated folate receptor 1 protein in healthy men and women. PLoS One 2014; 9(5): e96542
Serum concentrations of the tumor-associated folate receptor 1 (FOLR1) protein may be a marker for early cancer detection, yet concentrations have also been detected in cancer-free women. We investigated the conditions associated with circulating FOLR1 protein in healthy individuals and sought to clarify the range of normal serum values.
Sera of cancer-free men and women (N = 60) enrolled in a population-based cohort study in Alberta, Canada were analyzed for FOLR1 protein using an electrochemical luminescence immunoassay. Dietary, lifestyle, medical and reproductive history information was collected by questionnaires. Differences in serum FOLR1 concentrations between groups were assessed by non-parametric tests, and predictors of serum FOLR1 concentrations were estimated using multivariable linear regression.
Median serum FOLR1 concentration was higher in women (491 pg/ml, range = 327-693 pg/ml) than in men (404 pg/ml, range = 340-682 pg/ml), P = 0.001. FOLR1 concentration was also positively associated with vitamin A intake (P = 0.02), and showed positive trends with age and with oral contraceptive hormone use among women and an inverse trend with body mass index. All variables examined explained almost half of the variation in serum FOLR1 (model R2 = 0.44, P = 0.04); however, the retention of gender (P = 0.003) and vitamin A intake (P = 0.03) together explained 20% (P = 0.001) of serum FOLR1 variation. No other predictor was significant at P<0.05.
The positive association between serum FOLR1 concentration and female gender independent of an age effect suggests caution against statements to exploit serum FOLR1 for early cancer detection without further understanding the biological underpinnings of these observations. Serum FOLR1 concentrations may be influenced by the steroid retinoic acid (vitamin A) but do not appear to be associated with folate nutritional status. These findings require confirmation in larger independent studies.
Csizmadi I, Neilson HK,Kopciuk KA,Khandwala F,Liu A,Friedenreich CM,Yasui Y,Rabasa-Lhoret R,Bryant HE,Lau DC, Robson PJ. The Sedentary Time and Activity Reporting Questionnaire (STAR-Q): reliability and validity against doubly labeled water and 7-day activity diaries. Am J Epidemiol 2014 180(4):424-35. doi: 10.1093/aje/kwu150.
We determined measurement properties of the Sedentary Time and Activity Reporting Questionnaire (STAR-Q), which was designed to estimate past-month activity energy expenditure (AEE). STAR-Q validity and reliability were assessed in 102 adults in Alberta, Canada (2009-2011), who completed 14-day doubly labeled water (DLW) protocols, 7-day activity diaries on day 15, and the STAR-Q on day 14 and again at 3 and 6 months. Three-month reliability was substantial for total energy expenditure (TEE) and AEE (intraclass correlation coefficients of 0.84 and 0.73, respectively), while 6-month reliability was moderate. STAR-Q-derived TEE and AEE were moderately correlated with DLW estimates (Spearman’s ρs of 0.53 and 0.40, respectively; P < 0.001), and on average, the STAR-Q overestimated TEE and AEE (median differences were 367 kcal/day and 293 kcal/day, respectively). Body mass index-, age-, sex-, and season-adjusted concordance correlation coefficients (CCCs) were 0.24 (95% confidence interval (CI): 0.07, 0.36) and 0.21 (95% CI: 0.11, 0.32) for STAR-Q-derived versus DLW-derived TEE and AEE, respectively. Agreement between the diaries and STAR-Q (metabolic equivalent-hours/day) was strongest for occupational sedentary time (adjusted CCC = 0.76, 95% CI: 0.64, 0.85) and overall strenuous activity (adjusted CCC = 0.64, 95% CI: 0.49, 0.76). The STAR-Q demonstrated substantial validity for estimating occupational sedentary time and strenuous activity and fair validity for ranking individuals by AEE.
Aparicio-Ting FE, Friedenreich CM, Plotnikoff RC, Bryant HE.Intrapersonal and Social Environment Correlates of Leisure-Time Physical Activity for Cancer Prevention: A Cross-Sectional Study Among Canadian Adults. J Phys Act Health 2013.
Little is known about the intrapersonal and social factors associated with sufficient physical activity (PA) for cancer prevention, which is greater than for cardiovascular health.
1087 and 1684 randomly selected men and women, age 35-64, completed self-administered questionnaires on PA behavior and psycho-social characteristics. Using gender-stratified logistic regression, we investigated correlates of compliance with Canadian Society for Exercise Physiology PA guidelines for general health (150 min/wk), and the American Cancer Society (ACS; 225 min/wk) and World Cancer Research Fund/American Institute for Cancer Research (WCRF/AIRC; 420 min/wk) guidelines for cancer prevention.
Only 39% and 19% of men and women met ACS and WCRF/AICR guidelines, respectively. Self-efficacy, scheduling PA and friend social support were positively correlated with recommended PA for cancer prevention. In men, poor self-rated health and perceived negative outcomes were negatively correlated and hypertension was positively correlated with meeting cancer prevention guidelines. For women, not being married and having a companion for PA were positively correlated with meeting cancer prevention guidelines.
Few adults participate in sufficient PA for cancer risk reduction. Multidimensional public health strategies that incorporate intrapersonal and social factors and are tailored for each gender are needed to promote PA for cancer prevention.
Doiron D, Raina P, Fortier I. Linking Canadian population health data: maximizing the potential of cohort and administrative data. Can J Public Health 2013;104(3): e258-e261
Full free text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880355/
Linkage of data collected by large Canadian cohort studies with provincially managed administrative health databases can offer very interesting avenues for multidisciplinary and cost-effective health research in Canada. Successfully co-analyzing cohort data and administrative health data (AHD) can lead to research results capable of improving the health and well-being of Canadians and enhancing the delivery of health care services. However, such an endeavour will require strong coordination and long-term commitment between all stakeholders involved. The challenges and opportunities of a pan-Canadian cohort-to-AHD data linkage program have been considered by cohort study investigators and data custodians from each Canadian province. Stakeholders acknowledge the important public health benefits of establishing such a program and have established an action plan to move forward.
Hajiloo M, Damavandi B, HooshSadat M, Sangi F, Mackey JR, Cass CE, Greiner R, and Damaraju S. Breast cancer prediction using genome wide single nucleotide polymorphism data. BMC Bioinformatics 2013;14 Suppl 13:S3.
Full free text: http://www.biomedcentral.com/1471-2105/14/S13/S3
This paper introduces and applies a genome wide predictive study to learn a model that predicts whether a new subject will develop breast cancer or not, based on her SNP profile.
We first genotyped 696 female subjects (348 breast cancer cases and 348 apparently healthy controls), predominantly of Caucasian origin from Alberta, Canada using Affymetrix Human SNP 6.0 arrays. Then, we applied EIGENSTRAT population stratification correction method to remove 73 subjects not belonging to the Caucasian population. Then, we filtered any SNP that had any missing calls, whose genotype frequency was deviated from Hardy-Weinberg equilibrium, or whose minor allele frequency was less than 5%. Finally, we applied a combination of MeanDiff feature selection method and KNN learning method to this filtered dataset to produce a breast cancer prediction model. LOOCV accuracy of this classifier is 59.55%. Random permutation tests show that this result is significantly better than the baseline accuracy of 51.52%. Sensitivity analysis shows that the classifier is fairly robust to the number of MeanDiff-selected SNPs. External validation on the CGEMS breast cancer dataset, the only other publicly available breast cancer dataset, shows that this combination of MeanDiff and KNN leads to a LOOCV accuracy of 60.25%, which is significantly better than its baseline of 50.06%. We then considered a dozen different combinations of feature selection and learning method, but found that none of these combinations produces a better predictive model than our model. We also considered various biological feature selection methods like selecting SNPs reported in recent genome wide association studies to be associated with breast cancer, selecting SNPs in genes associated with KEGG cancer pathways, or selecting SNPs associated with breast cancer in the F-SNP database to produce predictive models, but again found that none of these models achieved accuracy better than baseline.
We anticipate producing more accurate breast cancer prediction models by recruiting more study subjects, providing more accurate labelling of phenotypes (to accommodate the heterogeneity of breast cancer), measuring other genomic alterations such as point mutations and copy number variations, and incorporating non-genetic information about subjects such as environmental and lifestyle factors.
Hajiloo M, Sapkota Y, Mackey JR, Robson P, Greiner R, and Damaraju S. ETHNOPRED: a novel machine learning method for accurate continental and sub-continental ancestry identification and population stratification correction. BMC Bioinformatics 2013, 14:61
Full free text: http://www.biomedcentral.com/1471-2105/14/61
Population stratification is a systematic difference in allele frequencies between subpopulations. This can lead to spurious association findings in the case-control genome wide association studies (GWASs) used to identify single nucleotide polymorphisms (SNPs) associated with disease-linked phenotypes. Methods such as self-declared ancestry, ancestry informative markers, genomic control, structured association, and principal component analysis are used to assess and correct population stratification but each has limitations. We provide an alternative technique to address population stratification.
We propose a novel machine learning method, ETHNOPRED, which uses the genotype and ethnicity data from the HapMap project to learn ensembles of disjoint decision trees, capable of accurately predicting an individual’s continental and sub-continental ancestry. To predict an individual’s continental ancestry, ETHNOPRED produced an ensemble of 3 decision trees involving a total of 10 SNPs, with 10-fold cross validation accuracy of 100% using HapMap II dataset. We extended this model to involve 29 disjoint decision trees over 149 SNPs, and showed that this ensemble has an accuracy of ≥ 99.9%, even if some of those 149 SNP values were missing. On an independent dataset, predominantly of Caucasian origin, our continental classifier showed 96.8%
accuracy and improved genomic control’s λ from 1.22 to 1.11. We next used the HapMap III dataset to learn classifiers to distinguish European subpopulations (North-Western vs. Southern), East Asian subpopulations (Chinese vs. Japanese), African subpopulations (Eastern vs. Western), North American subpopulations (European vs. Chinese vs. African vs. Mexican vs. Indian), and Kenyan subpopulations (Luhya vs. Maasai). In these cases, ETHNOPRED produced ensembles of 3, 39, 21, 11, and 25 disjoint decision trees, respectively involving 31, 502, 526, 242 and 271 SNPs, with 10-fold cross validation accuracy of 86.5% ± 2.4%, 95.6% ± 3.9%, 95.6% ± 2.1%, 98.3% ± 2.0%, and 95.9% ± 1.5%. However, ETHNOPRED was unable to produce a classifier that can accurately distinguish Chinese in Beijing vs. Chinese in Denver.
ETHNOPRED is a novel technique for producing classifiers that can identify an individual’s continental and sub-continental heritage, based on a small number of SNPs. We show that its learned classifiers are simple, cost-efficient, accurate, transparent, flexible, fast, applicable to large scale GWASs, and robust to missing values.
Neilson HK, Ullman R, Robson PJ, Friedenreich CM, Csizmadi I. Cognitive testing of the STAR-Q: insights in activity and sedentary time reporting. J Phys Act Health 2013 10(3):379-89.
The qualitative attributes and quantitative measurement properties of physical activity questionnaires are equally important considerations in questionnaire appraisal, yet fundamental aspects such as question comprehension are not often described in the literature. Here we describe the use of cognitive interviewing to evaluate the Sedentary Time and Activity Reporting Questionnaire (STAR-Q), a self-administered questionnaire designed to assess overall activity energy expenditure and sedentary behavior.
Several rounds of one-on-one interviews were conducted by an interviewer trained in qualitative research methods. Interviewees included a convenience sample of volunteers and participants in the Tomorrow Project, a large cohort study in Alberta, Canada. Following each round of interviews the STAR-Q was revised and cognitively tested until saturation was achieved.
Six rounds of cognitive interviewing in 22 adults (5 males, 17 females) age 23-74 years, led to revisions involving 1) use of recall aids; 2) ambiguous terms; and 3) specific tasks, such as averaging across multiple routines, reporting time asleep and self-care, and reporting by activity domain.
Cognitive interviewing is a critical step in questionnaire development. Knowledge gained in this study led to revisions that improved respondent acceptability and comprehension of the STAR-Q and will complement ongoing validity testing.
Sapkota Y, Yasui Y, Lai R, Sridharan M, Robson PJ, Cass CE, Mackey JR, Damaraju S. Identification of a breast cancer susceptibility locus at 4q31.22 using a genome-wide association study paradigm. PLoS One 2013 8(5): e62550.
More than 40 single nucleotide polymorphisms (SNPs) for breast cancer susceptibility were identified by genome-wide association studies (GWASs). However, additional SNPs likely contribute to breast cancer susceptibility and overall genetic risk, prompting this investigation for additional variants. Six putative breast cancer susceptibility SNPs identified in a two-stage GWAS that we reported earlier were replicated in a follow-up stage 3 study using an independent set of breast cancer cases and controls from Canada, with an overall cumulative sample size of 7,219 subjects across all three stages. The study design also encompassed the 11 variants from GWASs previously reported by various consortia between the years 2007-2009 to (i) enable comparisons of effect sizes, and (ii) identify putative prognostic variants across studies. All SNP associations reported with breast cancer were also adjusted for body mass index (BMI). We report a strong association with 4q31.22-rs1429142 (combined per allele odds ratio and 95% confidence interval = 1.28 [1.17-1.41] and Pcombined = 1.5×10−7), when adjusted for BMI. Ten of the 11 breast cancer susceptibility loci reported by consortia also showed associations in our predominantly Caucasian study population, and the associations were independent of BMI; four FGFR2 SNPs and TNRC9-rs3803662 were among the most notable associations. Since the original report by Garcia-Closas et al. 2008, this is the second study to confirm the association of 8q24.21-rs13281615 with breast cancer outcomes.
Sapkota Y, Mackey JR, Lai R, Franco-Villalobos C, Lupichuk S, Robson PJ, Kopciuk K, Cass CE, Yasui Y, and Damaraju S.Assessing SNP-SNP interactions among DNA repair, modification and metabolism related pathway genes in breast cancer susceptibility. PLoS One 2013 8(6): e64896.
Genome-wide association studies (GWASs) have identified low-penetrance common variants (i.e., single nucleotide polymorphisms, SNPs) associated with breast cancer susceptibility. Although GWASs are primarily focused on single-locus effects, gene-gene interactions (i.e., epistasis) are also assumed to contribute to the genetic risks for complex diseases including breast cancer. While it has been hypothesized that moderately ranked (P value based) weak single-locus effects in GWASs could potentially harbor valuable information for evaluating epistasis, we lack systematic efforts to investigate SNPs showing consistent associations with weak statistical significance across independent discovery and replication stages. The objectives of this study were i) to select SNPs showing single-locus effects with weak statistical significance for breast cancer in a GWAS and/or candidate-gene studies; ii) to replicate these SNPs in an independent set of breast cancer cases and controls; and iii) to explore their potential SNP-SNP interactions contributing to breast cancer susceptibility. A total of 17 SNPs related to DNA repair, modification and metabolism pathway genes were selected since these pathways offer a priori knowledge for potential epistatic interactions and an overall role in breast carcinogenesis. The study design included predominantly Caucasian women (2,795 cases and 4,505 controls) from Alberta, Canada. We observed two two-way SNP-SNP interactions (APEX1-rs1130409 and RPAP1-rs2297381; MLH1-rs1799977 andMDM2-rs769412) in logistic regression that conferred elevated risks for breast cancer ( Pinteraction<7.3×10−3). Logic regression identified an interaction involving four SNPs (MBD2-rs4041245, MLH1-rs1799977, MDM2-rs769412, BRCA2-rs1799943) (Ppermutation = 2.4×10−3). SNPs involved in SNP-SNP interactions also showed single-locus effects with weak statistical significance, while BRCA2-rs1799943 showed stronger statistical significance (Pcorrelation/trend= 3.2×10−4) than the others. These single-locus effects were independent of body mass index. Our results provide a framework for evaluating SNPs showing statistically weak but reproducible single-locus effects for epistatic effects contributing to disease susceptibility.
Aparicio-Ting FE, Friedenreich CM, Kopciuk KA, Plotnikoff RC, Bryant HE. Prevalence of meeting physical activity guidelines for cancer prevention in Alberta. Chronic Dis Inj Can 2012 32(4):216-26.
Guidelines for recommended physical activity (PA) levels have been developed by the Canadian Society for Exercise Physiology (CSEP) and the U.S. Department of Health and Human Services (USDHHS) for health benefits and by the American Cancer Society (ACS) and the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) for cancer prevention benefits.
We examined if these guidelines were met using a sample of 14 294 Albertan participants of the Tomorrow Project, aged 35 to 64 years, enrolled from 2001 to 2005. We used logistic regression to examine correlates of leisure PA behaviour.
An estimated 55%, 42%, 26% and 23% of participants met CSEP, ACS, USDHHS, and WCRF/AICR guidelines, respectively. Women were less likely than men to meet ACS (Odds Ratio [OR] = 0.72, 95% confidence interval [CI]: 0.55-0.93), USDHHS (OR = 0.67, 95% CI: 0.50-0.89) and WCRF/AICR (OR = 0.63, 95% CI: 0.47-0.85) guidelines, and being obese was correlated with not meeting USDHHS (OR = 0.45, 95% CI: 0.32-0.65) and WCRF/AICR guidelines (OR = 0.79, 95% CI: 0.63-0.98).
Albertans, particularly women and obese individuals, are not sufficiently active for cancer prevention benefits.
Sapkota Y, Robson P, Lai R, Cass CE, Mackey JR, Damaraju S. A two-stage association study identifies methyl-CpG-binding domain protein 2 gene polymorphisms as candidates for breast cancer susceptibility. Eur J Hum Genet 2012 20(6):682-9.
Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3355265/
Genome-wide association studies for breast cancer have identified over 40 single-nucleotide polymorphisms (SNPs), a subset of which remains statistically significant after genome-wide correction. Improved strategies for mining of genome-wide association data have been suggested to address heritable component of genetic risk in breast cancer. In this study, we attempted a two-stage association design using markers from a genome-wide study (stage 1, Affymetrix Human SNP 6.0 array, cases=302, controls=321). We restricted our analysis to DNA repair/modifications/metabolism pathway related gene polymorphisms for their obvious role in carcinogenesis in general and for their known protein-protein interactions vis-à-vis, potential epistatic effects. We selected 22 SNPs based on linkage disequilibrium patterns and high statistical significance. Genotyping assays in an independent replication study of 1178 cases and 1314 controls were attempted using Sequenom iPLEX Gold platform (stage 2). Six SNPs (rs8094493, rs4041245, rs7614, rs13250873, rs1556459 and rs2297381) showed consistent and statistically significant associations with breast cancer risk in both stages, with allelic odds ratios (and P-values) of
0.85 (0.0021), 0.86 (0.0026), 0.86 (0.0041), 1.17 (0.0043), 1.20 (0.0103) and 1.13 (0.0154), respectively, in combined analysis (N=3115). Of these, three polymorphisms were located in methyl-CpG-binding domain protein 2 gene regions and were in strong linkage disequilibrium. The remaining three SNPs were in proximity to RAD21homolog (S. pombe), O-6-methylguanine-DNA methyltransferase and RNA polymerase II-associated protein 1. The identified markers may be relevant to breast cancer susceptibility in populations if these findings are confirmed in independent cohorts.
Boffetta P, Colditz GA, Potter JD, Kolonel L, Robson PJ, Malekzadeh R, Seminara D, Goode EL, Yoo KY, Demers P, Gallagher R, Prentice R, Yasui Y, O’Doherty K, Petersen GM, Ulrich CM, Csizmadi I, Amankwah EK, Brockton NT, Kopciuk K, McGregor SE, and Kelemen LE. Cohorts and consortia conference: a summary report (Banff, Canada, June 17-19, 2009). Cancer Causes Control 2011 22(3):463-8.
Epidemiologic studies have adapted to the genomics era by forming large international consortia to overcome issues of large data volume and small sample size. Whereas both cohort and well-conducted case-control studies can inform disease risk from genetic susceptibility, cohort studies offer the additional advantages of assessing lifestyle and environmental exposure-disease time sequences often over a life course. Consortium involvement poses several logistical and ethical issues to investigators, some of which are unique to cohort studies, including the challenge to harmonize prospectively collected lifestyle and environmental exposures validly across individual studies. An open forum to discuss the opportunities and challenges of large-scale cohorts and their consortia was held in June 2009 in Banff, Canada, and is summarized in this report.
Csizmadi I, Lo Siou G, Friedenreich CM, Owen N, Robson PJ. Hours spent and energy expended in physical activity domains: results from the Tomorrow Project cohort in Alberta, Canada. Int J Behav Nutr Phys Act 2011;8:110.
Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3215175/
Knowledge of adult activity patterns across domains of physical activity is essential for the planning of population-based strategies that will increase overall energy expenditure and reduce the risk of obesity and related chronic diseases. We describe domain-specific hours ofactivity and energy expended among participants in a prospective cohort in Alberta, Canada.
The Past Year Total Physical Activity Questionnaire was completed by 15,591 Tomorrow Project® participants, between 2001 and 2005 detailing physical activity type, duration, frequency and intensity. Domain-specific hours of activity and activity-related energy expenditure, expressed as a percent of total energy expenditure (TEE) (Mean (SD); Median (IQR)) are reported across inactive (<1.4), low active (1.4 to 1.59), active (1.6 to 1.89) and very active (≥ 1.9) Physical Activity Level (PAL = TEE:REE) categories.
In very active women and amongst all men except those classified as inactive, activity-related energy expenditure comprised primarily occupational activity. Amongst inactive men and women in active, low active and inactive groups, activity-related energy expenditure from householdactivity was comparable to, or exceeded that for occupational activity. Leisure-time activity-related energy expenditure decreased with decreasing PAL categories; however, even amongst the most active men and women it accounted for less than 10 percent of TEE. When stratified by employment status, leisure-time activity-related energy expenditure was greatest for retired men [mean (SD): 10.8 (8.5) percent of TEE], compared with those who were fully employed, employed part-time or not employed. Transportation-related activity was negligible across all categories of PAL and employment status.
For the inactive portion of this population, active non-leisure activities, specifically in the transportation and occupational domains, need to be considered for inclusion in daily routines as a means of increasing population-wide activity levels. Environmental and policy changes to promote active transport and workplace initiatives could increase overall daily energy expenditure through reducing prolonged sitting time.
Lo Siou G, Yasui Y, Csizmadi I, McGregor SE, Robson PJ.Exploring statistical approaches to diminish subjectivity of cluster analysis to derive dietary patterns: The Tomorrow Project. Am J Epidemiol 2011 173(8):956-67.
Free full text: http://aje.oxfordjournals.org/content/173/8/956.long
Dietary patterns derived by cluster analysis are commonly reported with little information describing how decisions are made at each step of the analytical process. Using food frequency questionnaire data obtained in 2001-2007 on Albertan men (n = 6,445) and women (n = 10,299) aged 35-69 years, the authors explored the use of statistical approaches to diminish the subjectivity inherent in cluster analysis. Reproducibility of cluster solutions, defined as agreement between 2 cluster assignments, by 3 clustering methods (Ward’s minimum variance, flexible beta, K means) was evaluated. Ratios of between- versus within-cluster variances were examined, and health-related variables across clusters in the final solution were described. K means produced cluster solutions with the highest reproducibility. For men, 4 clusters were chosen on the basis of ratios of between- versus within-cluster variances, but for women, 3 clusters were chosen on the basis of interpretability of cluster labels and descriptive statistics. In comparison with those in other clusters, men and women in the “healthy” clusters by greater proportions reported normal body mass index, smaller waist circumference, and lower energy intakes. The authors’ approach appeared helpful when choosing the clustering method for both sexes and the optimal number of clusters for men, but additional analyses are required to understand why it performed differently for women.
Sehrawat B, Sridharan M, Ghosh S, Robson PJ, Cass CE, Mackey JR, Greiner R, and Damaraju S. Potential novel candidate polymorphisms identified in genome-wide association study for breast cancer susceptibility. Hum Genet 2011 130(4):529-37.
Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3178778/
Previous genome-wide association studies (GWAS) have shown several risk alleles to be associated with breast cancer. However, the variants identified so far contribute to only a small proportion of disease risk. The objective of our GWAS was to identify additional novel breast cancersusceptibility variants and to replicate these findings in an independent cohort. We performed a two-stage association study in a cohort of 3,064 women from Alberta, Canada. In Stage I, we interrogated 906,600 single nucleotide polymorphisms (SNPs) on Affymetrix SNP 6.0 arrays using 348 breast cancer cases and 348 controls. We used single-locus association tests to determine statistical significance for the observed differences in allele frequencies between cases and controls. In Stage II, we attempted to replicate 35 significant markers identified in Stage I in an independent study of 1,153 cases and 1,215 controls. Genotyping of Stage II samples was done using Sequenom Mass-ARRAY iPlex platform. Six loci from four different gene regions (chromosomes 4, 5, 16 and 19) showed statistically significant differences between cases and controls in both Stage I and Stage II testing, and also in joint analysis. The identified variants were from EDNRA, ROPN1L, C16orf61 and ZNF577 gene regions. The presented joint analyses from the two-stage study design were not significant after genome-wide correction. The SNPs identified in this study may serve as potential candidate loci for breast cancer risk in a further replication study in Stage III from Alberta population or independent validation in Caucasian cohorts elsewhere.
Borugian MJ, Robson P,Fortier I,Parker L,McLaughlin J,Knoppers BM,Bédard K,Gallagher RP,Sinclair S,Ferretti V,Whelan H,Hoskin D, andPotter JD. The Canadian Partnership for Tomorrow Project: building a pan-Canadian research platform for disease prevention. CMAJ 2010 182(11):1197-201.
Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2917932/
(NB: There is no abstract for this article: these are the first two paragraphs:)
As the proportion of the population over age 65 increases in Western countries, the burden of cancer 1 and other chronic diseases is also increasing. If advances in preventing these diseases are to be realized, better information is needed about their causes and the antecedents of the causes. For example, although it is known that many sporadic cancers are caused by a combination of lifestyle factors, exposure to environmental carcinogens and individual genetic makeup,2,3 detailed knowledge about the interplay among these factors is lacking.
Much of our current knowledge about the causes of cancer and most relatively rare chronic diseases has come from retrospective case-control studies, in which the characteristics of patients (cases) are compared with those of age- and sex-matched people who do not have the disease (controls). This design has strengths but also a number of weakneses, including potential recall bias and selection bias4 ( Table 1). To address some of these weaknesses, in particular recall bias and the temporal relation between risk factors and outcomes, prospective cohorts are helpful because participants are enrolled before the onset of disease. In studies with a prospective cohort design, large numbers of participants, who generally have not had cancer or any other significant diagnosis, are recruited and followed over a long time, periodically providing updated health and lifestyle information and biologic samples. Layers of data and samples accumulate over time, allowing an exploration of why cancer develops in some people within the cohort but not others.6 The disadvantages of such a design ( Table 1) are cost and time, as it may be a decade or more efore major results are obtained. Fortunately, many shorter-term results are also available, such as information on screening attendance and information on the frequency of major risk factors and health states, as well as environmental and individual determinants of these risk factors, all of which are useful for planning various health services. Furthermore, because many diseases can be studied simultaneously, the cost over time per health outcome studied is substantially lower than the cost of case-control studies for a comparable number of participants.
Fortier I, Burton PR,Robson PJ,Ferretti V,Little J,L’Heureux F,Deschênes M,Knoppers BM,Doiron D,Keers JC,Linksted P,Harris JR,Lachance G,Boileau C,Pedersen NL,Hamilton CM,Hveem K,Borugian MJ,Gallagher RP,McLaughlin J,Parker L,Potter JD,Gallacher J,Kaaks R,Liu B,Sprosen T,Vilain A,Atkinson SA,Rengifo A,Morton R,Metspalu A,Wichmann HE,Tremblay M,Chisholm RL,Garcia-Montero A,Hillege H,Litton JE,Palmer LJ,Perola M,Wolffenbuttel BH,Peltonen L,Hudson TJ. Quality, quantity and harmony: the DataSHaPER approach to integrating data across bioclinical studies. Int J Epidemiol 2010 39(5):1383-93.
Free full text:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2972444/
Vast sample sizes are often essential in the quest to disentangle the complex interplay of the genetic, lifestyle, environmental and social factors that determine the aetiology and progression of chronic diseases. The pooling of information between studies is therefore of central importance to contemporary bioscience. However, there are many technical, ethico-legal and scientific challenges to be overcome if an effective, valid, pooled analysis is to be achieved. Perhaps most critically, any data that are to be analysed in this way must be adequately ‘harmonized’. This implies that the collection and recording of information and data must be done in a manner that is sufficiently similar in the different studies to allow valid synthesis to take place.
This conceptual article describes the origins, purpose and scientific foundations of the DataSHaPER (DataSchema and Harmonization Platform for Epidemiological Research; http://www.datashaper.org), which has been created by a multidisciplinary consortium of experts that was pulled together and coordinated by three international organizations: P³G (Public Population Project in Genomics), PHOEBE (Promoting Harmonization of Epidemiological Biobanks in Europe) and CPT (Canadian Partnership for Tomorrow Project).
The DataSHaPER provides a flexible, structured approach to the harmonization and pooling of information between studies. Its two primary components, the ‘DataSchema’ and ‘Harmonization Platforms’, together support the preparation of effective data-collection protocols and provide a central reference to facilitate harmonization. The DataSHaPER supports both ‘prospective’ and ‘retrospective’ harmonization.
It is hoped that this article will encourage readers to investigate the project further: the more the research groups and studies are actively involved, the more effective the DataSHaPER programme will ultimately be.
Linder J, McLaren L, Lo Siou G, Csizmadi I, Robson PJ.The epidemiology of weight perception: perceived versus self-reported actual weight status among Albertan adults. Can J Public Health 2010 101(1):56-60.
To understand, prevent, and manage weight-related health issues, researchers and clinicians rely on the ability to identify those atrisk. Prevention and management strategies may also rely on accurate self-perception of weight and body composition in the general population.
We analyzed data from The Tomorrow Project (n = 7,436), a prospective cohort study enrolling adults aged 35-69 years, in Alberta, Canada. Weight perception accuracy was defined based on body mass index (BMI), waist circumference (WC), and a combined (BMI and WC) riskprofile.
The majority of participants correctly perceived themselves as overweight. Women were more accurate than men in identifying themselves as overweight. In terms of inaccuracy, more normal-weight women than men perceived themselves to be overweight, while more overweight men than women perceived themselves as about the right weight. When using the combined risk profile, all men with normal weight (BMI) but higher risk WC perceived their weight as about right whereas just under half of men who were overweight (BMI) but lower risk WC perceived their weight as about right. For women, a much higher proportion recognized their weight status as overweight when only BMI was elevated compared to when only WC indicated higher risk.
Adults in our sample showed reasonable accuracy in weight perception. Gender differences reveal that women were more accurate than men in identifying themselves as overweight. Incongruence between weight status indicators was noted, indicating the importance of using both BMI and waist circumference as health status measures.
Robson PJ, Lo Siou, G, Ullman R, Bryant HE.Sociodemographic, health and lifestyle characteristics reported by discrete groups of adult dietary supplement users in Alberta, Canada: findings from The Tomorrow Project. Public Health Nutr 2008 11(12):1238-47.
To determine the extent to which differences in sociodemographic, dietary and lifestyle characteristics exist between users of different types of dietary supplements and supplement non-users.
Design: We analysed cross-sectional data obtained from self-administered questionnaires completed at baseline by participants in The Tomorrow Project; a prospective cohort study in Alberta, Canada. Participants who used at least one type of dietary supplement at least weekly in the year prior to questionnaire completion were defined as supplement users, while the remainder were classified as non-users. Seven discrete user categories were created: multivitamins (1/2 minerals) only, specific nutritional supplements only, herbal/other supplements only, and all possible combinations. Differences in sociodemographic, dietary and lifestyle characteristics between different groups of supplement users and non-users were analysed using Rao-Scott x2 tests and multinomial logistic regression.
Subjects and setting:
Subjects were 5067 men and 7439 women, aged 35-69 years, recruited by random digit dialling throughout Alberta. Results: Supplement use was extensive in this study population (69.8 %). Users of herbal/other supplements only, and women who used multivitamins only, tended to report dietary and lifestyle characteristics that were not significantly different from non-users. In contrast, those who reported using a combination of multivitamins, specific nutritional and herbal/other supplements were more likely than non-users to report behaviours and characteristics consistent with current health guidelines.
Conclusions: Dichotomizing participants as supplement users or non-users is likely to mask further differences in sociodemographic, dietary and lifestyle characteristics among users of different types of supplements. This may have implications for analysis and interpretation of observational studies.
Csizmadi I, Kahle L,Ullman R,Dawe U,Zimmerman TP,Friedenreich CM,Bryant H,Subar AF.Adaptation and evaluation of the National Cancer Institute’s Diet History Questionnaire and nutrient database for Canadian populations. Public Health Nutr 2007 10(1):88-96.
BACKGROUND AND OBJECTIVE:
Despite assumed similarities in Canadian and US dietary habits, some differences in food availability and nutrientfortification exist. Food-frequency questionnaires designed for the USA may therefore not provide the most accurate estimates of dietary intake in Canadian populations. Hence, we undertook to evaluate and modify the National Cancer Institute’s Diet History Questionnaire (DHQ) and nutrientdatabase.
Of the foods queried on the DHQ, those most likely to differ in nutrient composition were identified. Where possible these foods were matched to comparable foods in the Canadian Nutrient File. Nutrient values were examined and modified to reflect the Canadian content of minerals (calcium, iron, zinc) and vitamins (A, C, D, thiamin, riboflavin, niacin, B6, folate and B12). DHQs completed by 13 181 Alberta Cohort Study participants aged 35-69 years were analysed to estimate nutrient intakes using the original US and modified versions of the DHQ databases. Misclassification of intake for meeting the Dietary Reference Intake (DRI) was determined following analysis with the US nutrient database.
Twenty-five per cent of 2411 foods deemed most likely to differ in nutrient profile were subsequently modified for folate, 11% for vitamin D, 10% for calcium and riboflavin, and between 7 and 10% for the remaining nutrients of interest. Misclassification with respect to meeting the DRI varied but was highest for folate (7%) and vitamin A (7%) among men, and for vitamin D (7%) among women over 50 years of age.
Errors in nutrient intake estimates owing to differences in food fortification between the USA and Canada can be reduced in Canadian populations by using nutrient databases that reflect Canadian fortification practices.
Richardson H, Aronson KJ, James A, McGregor ES, Bryant H. Factors related to use of prostate cancer screening: the Alberta Tomorrow Project. Open Med 2007 1(1):e3-e12.
Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2801912/
Very few data are available on the determinants of PSA testing in Canada, and it is a matter of debate whether prostate-specific antigen (PSA) screening in asymptomatic men age 50 and older with no risk factors for prostate cancer is useful. If PSA screening is introduced into the periodic health examination, it will be important to know what factors influence its use.
The purpose of this study is to determine the factors associated with PSA testing among asymptomatic men age 50 and older participating in the Tomorrow Project in Alberta.
The Tomorrow Project is a population-based cohort study with over 11,000 participants accrued in Alberta since February 2003. Information was collected on medical history, sociodemographic factors, health status and lifestyle characteristics. This analysis includes 2136 men 50 years of age and older. The independent association between various factors and recent PSA screening is estimated using logistic regression.
Approximately 50% of of the study group had received one or more PSA tests in their lifetime. Of these, 58% were asymptomatic for prostate disease at the time of their most recent PSA test. Variables independently associated with recent PSA screening for prostate cancer in this population include older age (>/= 65 versus < 55 years: adjusted odds ratio [OR] 2.60; 95% confidence interval [CI] 1.77-3.83), higher income (>/= $80,000 versus < $20,000, OR 1.97; 95% CI 1.09-3.55), region of health care delivery, perception of health status (good versus excellent health status; OR 0.65, CI 0.43-0.96], increased number of chronic health conditions (OR 1.73, 95% CI 1.10-2.71), and history of colorectal cancerscreening with fecal occult blood test (OR 2.21; 95% CI 1.73-2.83).
An increasing proportion of men in Alberta are receiving a PSA test. A number of significant predictors of having a PSA test were identified, suggesting that factors other than having a clinical indication for prostate disease can influence decisions about PSA screening.
Alberta Cancer Board. An Overview of Modifiable Health Risks in Alberta. 2006.
Bryant H, Robson PJ, Ullman R, Friedenreich C, Dawe U. Population-based cohort development in Alberta, Canada: a feasibility study. Chronic Dis Can 2006 27(2):51-9.
In a climate of increasing privacy concerns, the feasibility of establishing new cohorts to examine chronic disease etiology has been debated. Our primary aim was to ascertain the feasibility of enrolling a geographically dispersed, population-based cohort in Alberta. We also examined whether enrolees would grant access to provincial health care utilization data and consider providing blood for future analysis. Using random digit dialling, 22,652 men and women aged 35 to 69 years, without diagnosed cancer, were recruited. Of these, 52.4 percent (N=11,865) enrolled; 84 percent of Alberta communities were represented. Approximately 97 percent of enrolees consented to linkage with health care data, and 91 percent indicated willingness to consider future blood sampling. Comparisons between the cohort and the Canadian Community Health Survey (Cycle 1.1) for Alberta demonstrated similarities in marital status and income. However, the cohort had a smaller proportion who had not finished high school, a greater proportion of nonsmokers and a higher prevalence of obesity. These findings indicate that establishment of a geographically dispersed cohort is feasible in the Canadian context, and that data linkage and biomarker studies may be viable.
Friedenreich CM, Courneya KS,Neilson HK,Matthews CE,Willis G,Irwin M,Troiano R,Ballard-Barbash R. Reliability and validity of the Past Year Total Physical Activity Questionnaire. Am J Epidemiol 2006 163(10):959-70.
The authors determined the validity and reliability of their Past Year Total Physical Activity Questionnaire (PYTPAQ), which assesses the frequency, duration, and intensity of occupational, household, and recreational activities performed over the past year. The PYTPAQ was completed twice at baseline, 9 weeks apart (on average), by 154 healthy Canadian men and women aged 35-65 years for assessment of reliability. The PYTPAQ was completed again 1 year later as a self-administered questionnaire. Four times during the year, participants wore an accelerometer for 7 days and completed 7-day physical activity logs.
The authors assessed validity by comparing PYTPAQ summary values with 1-year averages of the physicalactivity logs and accelerometer data and with physical fitness and anthropometric data measured at baseline and 1 year. Spearman correlations for reliability (metabolic equivalent-hours/week) were 0.64 for total activity, 0.70 for occupational activity, 0.73 for recreational activity, and 0.65 for household activity. For total activity, the intraclass correlation coefficient for correlation between the PYTPAQ and the 7-day physical activity logs was 0.42 (95% confidence interval: 0.28, 0.54), and for the accelerometer data it was 0.18 (95% confidence interval: 0.03, 0.32). Spearman correlations between PYTPAQ hours/week of vigorous activity and maximal oxygen uptake were 0.37 and 0.32 at baseline and follow-up, respectively. In general, the PYTPAQ has acceptable reliability and validity for measurement of past-year physical activity that is comparable to that of similar questionnaires.
McGregor SE, Bryant HE. Predictors of colorectal cancer screening: a comparison of men and women. Can J Gastroenterol. 2005 Jun;19(6):343-9.
New Canadian guidelines recommend screening average-risk adults to reduce mortality from colorectal cancer, the second most common cause of cancer death among Canadians. The present study examined the self-reported prevalence of colorectal cancer testing and sex-specific predictors of having had a fecal occult blood (FOB) test for screening, among a cohort of Alberta residents aged 50 to 69 years.
Subjects (n=5009) enrolled in a geographically based cohort study completed a Health and Lifestyle Questionnaire between October 2000 and June 2002 that ascertained their colorectal cancer detection practices, as well as demographic and other health and lifestyle characteristics.
Patterns of FOB testing, and sigmoidoscopy or colonoscopy, were similar for men and women. The majority of subjects (83.3%) reported no first-degree family history of colorectal cancer or bowel conditions, and they were considered to be at average risk. Few average-risk subjects reported having a screening FOB test within the past two years (7.7% [95% CI 6.7% to 8.7%] of subjects aged 50 to 59 years and 12.5% [95% CI 10.9% to 14.3%] of subjects aged 60 to 69 years). In men, the strongest predictors of having a screening FOB test in the past two years were a recent history of prostate-specific antigen testing and educational attainment. Among women, the strongest predictors were a recent history of having had a Pap test, a recent mammogram, employment status and educational attainment.
Screening for colorectal cancer in average-risk adults was infrequent in this sample and lagged behind screening for other cancers. Screening of average-risk adults occurred primarily in people already accessing the health care system, suggesting that public education programs will be required to increase screening rates.
Other Publications and Presentations:
Wray D, Rosner W, Powell WA, Monga D, Whelan HK, Robson PJ. The Tomorrow Project: Creation of mobile laboratories to support collection and storage of high quality biological samples for epidemiologic research. Poster: International Society for Biological and Environmental Repositories, Vancouver, BC, Canada, 2012.
Sapkota Y, Sehrawat BS, Ghosh S, Robson P, Cass CE, Mackey JR, Damaraju S. Genome-wide analysis of germline copy number variations and association with breast cancer susceptibility. Poster: Annual Meeting of the American Society of Human Genetics, San Francisco, CA, USA, 2012.
Sapkota Y, Cass CE, Mackey J, Ghosh S, Robson P, Lai R, Damaraju S. DNA repair gene variants association with luminal A breast cancer.
Oral presentation: Keystone Symposia on Molecular and Cellular Biology, Keystone, CO, USA, 2011.
Sharma AM. Why Leisure-Time Physical Activity Is Irrelevant. http://www.drsharma.ca/obesitywhy-leisure-time-physical-activity-levels-are-irrelevant
Damaraju S, Sapkota Y, Sridharan M, Robson P, Cass C, Mackey J. Genome-wide and candidate gene association studies identify chromosome 5 breast cancer susceptibility loci in Alberta women. Oral presentation: Annual Canadian Human Genetics Conference, Banff, AB, Canada, 2011.
Csizmadi I, Lo Siou G, Friedenreich CM, Robson PJ. Recreational activities reported by middle aged and older adults in the Tomorrow Project. Oral presentation: International Academy on Nutrition and Aging, Albuquerque, NM, USA, 2010. Journal of Nutrition Health and Aging, 2010, 14:500.
Hearps SJ. Self-reported anthropometric data. Can J Public Health 2010;101:345. http://journal.cpha.ca/index.php/cjph/article/view/2338/2195 )
Robson PJ, Whelan HK, Powell W, Spurrell J on behalf of the Tomorrow Project investigator team (in alphabetical order: Brockton N, Csizmadi I, Friedenreich CM, Kelemen L, Kopciuk K, McGregor SE). The Alberta Tomorrow Project in the Canadian Partnership for Tomorrow Project. Poster: Cohorts and Consortia: From Biotechnology to Populations, Banff, AB, Canada, 2009.
Robson PJ, Baracos V, Mackey JR, Cass CE, Greiner R, Yasui Y, Wishart D, Damaraju S. Establishing population based cohorts with urinary metabolome profiles, diet and lifestyle variables for comprehensive analysis to define health and disease status. Poster presentation: Annual Metabolomics Conference, Edmonton, AB, Canada, 2009.
Sridharan M, Sehrawit B, Ghosh S, Robson P, Cass C, Mackey J, Greiner R, Carandang D, Dufour J, Damaraju S. An evaluation of recently identified single nucleoside polymorphisms from whole genome association studies in breast cancer. Are risk alleles specific to populations?Alberta Cancer Research Institute Annual Meeting, Banff, AB, Canada, 2009.
Dueck J, Lo Siou G, Robson PJ, Csizmadi I. Evaluation of the Canadian Diet History Questionnaire (DHQ) for food list and portion size categories using the Canadian Community Health Survey (Nutrition Cycle 2.2). Poster: American Institute for Cancer Research Annual Research Conference on Food, Nutrition, Physical Activity and Cancer, Washington, DC, USA, 2009.
Robson PJ, Pachnowski CA. Carrying out leading research while complying with privacy expectations. Oral presentation: National Access and
Privacy Conference, Edmonton, AB, Canada, 2009.
Lo Siou G, Csizmadi I, McGregor SE, Kopciuk KA, Robson PJ. Use of cluster analyses to assess dietary patterns: a comparison of unsupervised clustering methods. Poster: Statistical Society of Canada Annual Meeting, Ottawa, ON, Canada, 2008.
Robson PJ, on behalf of the CPTP Investigator group. The Canadian Partnership for Tomorrow Project: Canada’s cancer cohort study. Oral
presentation: Southern Alberta Cancer Research Institute Annual Research Meeting, Banff, AB, Canada, 2008.
Csizmadi I, Kelemen LE, Robson PJ. Evaluation of nutrient intakes of men and women at lower risk of cancer identified by level of physical activity (PAL) and body mass index (BMI). Poster: Society for Epidemiologic Research Annual Meeting, Chicago, IL, USA, 2008.
Csizmadi I, Robson PJ, Friedenreich CM, Lo Siou G, Neilson H, Vallance J, Bryant H. Energy expenditure from recreational physical activity in The Tomorrow Project. Poster: Canadian Society for Epidemiology and Biostatistics Meeting, Calgary, AB, 2007.
Csizmadi I, Robson PJ, McGregor SE, Lo Siou G, Gregory J, Bryant HE . Evaluation of diet quality using the Healthy Eating Index in The Tomorrow Project. Poster: Canadian Society for Epidemiology and Biostatistics, Calgary, AB, Canada, 2007.
Robson PJ. The Alberta cohort study: What does tomorrow hold? Oral presentation: Annual Canadian Genetic Epidemiology and Statistical
Genetics Meeting, Toronto, ON, Canada, 2007. Csizmadi I, Robson PJ, Friedenreich CM, Lo Siou G, Neilson HK, Bryant H.
Recreational physical activity energy expenditure estimated from self-reported past-year activity in adults participating in The Tomorrow Project. Poster: American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research, Philadelphia, PA, USA, 2007.
Robson PJ, McLaren L, Lo Siou G, Csizmadi I, Bryant HE. The epidemiology of weight perception: Perceived versus self-reported actual weight status among Albertan adults. Oral presentation: Canadian Society for Epidemiology and Biostatistics, Calgary, AB, Canada, 2007.
McGregor SE, Lewin AM, Bryant HE. Uptake of colorectal cancer screening among a cohort of adults aged 50-69 in Alberta, Canada. Poster:
Canadian Society for Epidemiology and Biostatistics, Calgary, AB, Canada, 2007.
Bryant H, Robson P, Lo Siou G, Chen Y, Qiu Z. Effect of HRT cessation patterns on future cancer risk. Oral presentation: North American
Association of Central Cancer Registries Annual Conference, Detroit, MI, USA, 2007.
Robson PJ, Ullman R, Lo Siou G, Rosner W, Bryant HE. Use of dietary supplements and pharmaceutical products in a sub-sample of women participating in The Tomorrow Project, Alberta, Canada. Poster: Canadian Society for Epidemiology and Biostatistics, Calgary, AB, Canada, 2007.
Robson PJ. The Alberta cohort study: What does Tomorrow hold? Oral presentation: Southern Alberta Cancer Research Institute Annual
Research Meeting, Banff, AB, Canada, 2006.
Robson PJ, Bryant HE. The Alberta cohort study (The Tomorrow Project): Progress and plans. Oral presentation: Canadian Cancer Research
Alliance Conference, Toronto, ON, Canada, 2006.
Robson PJ, Csizmadi I, Bryant H. The Alberta Cohort Study: Characteristics of sub-categories of dietary supplement users. Poster:
International Conference on Dietary Assessment Methods, Copenhagen, Denmark, 2006.
Robson PJ, Csizmadi I, Bryant H. Self-perception of overweight status in adults, based on body mass index and waist circumference. Poster:
North American Association for the Study of Obesity Annual Scientific Meeting, Boston, MA, USA, 2006. Supplement to Obesity, 2006; 14:A262.
Bryant HE, Dover D, Csizmadi I, Robson P. Colorectal cancer in peri- and post-menopausal women: Predictions of an increasing secular trend. Oral presentation: North American Association of Central Cancer Registries Annual Conference, Cambridge, MA, USA, 2005.
Csizmadi I, Friedenreich CM, Robson PJ, Bryant H. Using reported physical activity to identify invalid reporting of energy intake (EI) in the Alberta Cohort Study. Poster: The Society for Epidemiological Research – Canadian Society for Epidemiology and Biostatistics Meeting, Toronto, ON, Canada, 2005. American Journal of Epidemiology, 2005;
Robson PJ, Csizmadi I, Bryant H. Characteristics of nutritional supplement users in the Alberta Cohort Study: A prospective study of diet, lifestyle and cancer. Poster:
The Society for Epidemiological Research – Canadian Society for Epidemiology and Biostatistics Meeting, Toronto, ON, Canada, 2005. American Journal of
Epidemiology, 2005; 161(11):S80.
Csizmadi I, Subar A, Kahle L, Ullman R, Dawe U, Zimmerman T, Friedenreich CM, Bryant HE. Adaptation of the National Cancer Institute’s Dietary History Questionnaire (DHQ) and nutrient database for Canadian populations. Poster: International Research Conference on Food, Nutrition and Cancer (World Cancer Research Fund/American Institute for Cancer Research), Washington, DC, USA, 2004. Journal of Nutrition, 2004; 134(suppl):3532S.
Bryant H. Alberta cohort study. Oral presentation, Canadian Cohort Studies Symposium, Canadian Society for Epidemiology and Biostatistics
Meeting, Halifax, NS, Canada, 2003.
Bryant H, Dawe U, Ullman R. Collection of whole blood samples from geographically dispersed Alberta Cancer Board cohort participants.
Poster: Canadian Society for Epidemiology and Biostatistics Meeting, Halifax, NS, Canada, 2003.
Bryant H, Dawe U, Ullman R. Subject recruitment for the Alberta Cancer Board cohort study using random digit dialling. Poster: Canadian
Society for Epidemiology and Biostatistics Meeting, Halifax, NS, Canada, 2003.
Csizmadi I, Subar A, Kahle L, Ullman R, Dawe U, Zimmerman T, Friedenreich C, Bryant H . Adaptation of the national cancer institute’s (NCI) diet history questionnaire and nutrient database for use in Canadian populations. Oral presentation: Canadian Society for Epidemiology and Biostatistics Meeting, Halifax, NS, Canada, 2003.