Cognitive testing of the STAR-Q: insights in activity and sedentary time reporting.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Sociodemographic, health and lifestyle characteristics reported by discrete groups of adult dietary supplement users in Alberta, Canada: findings from The Tomorrow Project.

OBJECTIVE: 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 (+/- 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 chi2 tests and multinomial logistic regression. SUBJECTS AND SETTING: Subjects were 5,067 men and 7,439 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.

Adaptation and evaluation of the National Cancer Institute's Diet History Questionnaire and nutrient database for Canadian populations.

BACKGROUND AND OBJECTIVE: Despite assumed similarities in Canadian and US dietary habits, some differences in food availability and nutrient fortification 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 nutrient database. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Population-based cohort development in Alberta, Canada: a feasibility study.

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.