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

摘要

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