Reliability of self-reported sun exposure in Canadian women and estimation of lifetime exposure to vitamin D from sun and diet

Abstract

Objective: To assess the inter-method reliability of the Ovarian Cancer in Alberta (OVAL) survey developed to estimate adult vitamin D exposure from sun and diet for every tenth year, against the longer Geraldton Skin Cancer Prevention Survey (the assumed 'gold standard'). We also estimated total vitamin D exposure using the OVAL survey. Design: A randomized crossover design to assess the inter-method reliability of sun exposure (OVAL v. Geraldton survey), using intra-class correlation and estimated total vitamin D exposure from sun and diet. Setting: Calgary, Alberta, Canada. Subjects: Randomly selected women (n 90) aged 40-79 years. Results: The average lifetime sun exposure of 13 913 h (average 411 h/year) from the Geraldton survey was not significantly different from the 13 034 h (average 385 h/year) from the OVAL survey for periods with sufficient UV radiation to stimulate vitamin D production. The intra-class correlation coefficient for average lifetime sun exposure was 0?77 (95 % CI 0?69, 0?86); the annual average was 0?60 (95 % CI 0?47, 0?74). Estimated vitamin D from diet and supplements increased with age. Conclusions: Our OVAL survey reliably estimated adult sun exposure relative to the Geraldton survey, suggesting that assessing sun exposure every tenth year is a reliable and efficient method for estimating sun contributions to lifetime vitamin D exposure.

An Inter-Method Reliability Study Comparing Interview Information on Sunlight, Tanning Beds, Food, and Supplement Exposures with Serum 25-Hydroxy Vitamin D Levels

“…There is substantial variation in the ascertainment of vitamin D related foods across studies. We attempted to capture all major sources of vitamin D from food in our study and only included those foods that were consumed by at least 5% of the population in our previous reliability study (16). Outdoor sunlight exposures explained a consistent but small level of the variation in serum 25(OH)D levels.…”

“…The telephone interview was extensive and included personal health history, reproductive and menstrual history, exogenous hormone use, family history of cancer, physical activity patterns (for a subset of women only), adult lifetime caffeine and alcohol consumption, smoking habits, demographic characteristics and adult height and weight at each decade from age 20 years onward. Additionally, four vitamin D related exposures over adult life were ascertained (16) and are described below. For the purposes of this analysis, we used the most recently reported exposures relative to the reference date.…”

“…We developed a questionnaire designed to capture self-reported adult life-time vitamin-D related sun, tanning bed, diet, and supplement exposures for a case-control study (16). Retrospective serum samples from age 20 years forwards for our study participants were not available, but we did have a serum samples as well as self-reported vitamin D related exposures near to the reference date, i.e., an assigned month/year for controls that had the same distribution as the diagnosis dates of ovarian cancer cases.…”

The Breast Cancer to Bone (B2B) Metastases Research Program: a multi-disciplinary investigation of bone metastases from breast cancer

“…Also, large disease-free prospective cohorts, such as the Canadian Partnership for Tomorrow Project [ 104 ], could not deliver the necessary number of outcomes within a reasonable period and are not currently configured to collect epidemiologic data and biologic samples specifically during the crucial peri-diagnostic period or conduct disease-specific follow-up. Although previous studies have conducted population-based recruitment of cancer patients in Alberta [ 94 , 105 ], there was no existing mechanism to comprehensively identify, contact, obtain consent and track breast cancer patients. Furthermore, the increasingly stringent privacy requirements demanded the development of a system that could accomplish the recruitment and biospecimen collection targets whilst being sensitive to the circumstances of the patients and complying with all relevant privacy regulations.…”

“…The Past Year Dietary Worksheets collect data regarding food intake and frequency in the 12 months prior to breast cancer diagnosis, and was developed to assess intake of certain foods and supplements that have high vitamin D and calcium content, consumed at a reasonable frequency by female study participants in Alberta [ 94 ]. The sun exposure, dietary, and supplement data will be used to estimate levels of vitamin D during the relevant exposure period.…”