Sunlight and dietary contributions to the seasonal vitamin D status of cohorts of healthy postmenopausal women living at northerly latitudes: a major cause for concern?
- H. M. MacdonaldAffiliated withUniversity of AberdeenMusculoskeletal Research, Health Sciences Building, University of Aberdeen Email author
- , A. MavroeidiAffiliated withUniversity of Aberdeen
- , W. D. FraserAffiliated withDepartment of Musculoskeletal Biology, University of Liverpool
- , A. L. DarlingAffiliated withNutritional Sciences Division, Faculty of Health and Medical Sciences, University of Surrey
- , A. J. BlackAffiliated withUniversity of Aberdeen
- , L. AucottAffiliated withUniversity of Aberdeen
- , F. O’NeillAffiliated withUniversity of Aberdeen
- , K. HartAffiliated withNutritional Sciences Division, Faculty of Health and Medical Sciences, University of Surrey
- , J. L. BerryAffiliated withVitamin D Research Group, Department of Medicine, Manchester Royal Infirmary
- and 2 more
- , S. A. Lanham-NewAffiliated withNutritional Sciences Division, Faculty of Health and Medical Sciences, University of Surrey
- , D. M. ReidAffiliated withUniversity of Aberdeen
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We assessed sunlight and dietary contributions to vitamin D status in British postmenopausal women. Our true longitudinal 25-hydroxyvitamin D (25(OH)D) measurements varied seasonally, being lower in the north compared to the south and lower in Asian women. Sunlight exposure in summer and spring provided 80% total annual intake of vitamin D.
Vitamin D deficiency is highlighted as a potential problem for countries at high latitude, but there are few true longitudinal, seasonal data to allow regional comparisons. We aimed to directly compare seasonal variation in vitamin D status (25(OH)D) in postmenopausal women at two northerly latitudes and to assess the relative contributions of sunlight exposure and diet.
Vitamin D status was assessed in 518 postmenopausal women (age 55–70 years) in a two-centre cohort study with serum collected at fixed three-monthly intervals from summer 2006 for immunoassay measurement of 25(OH)D and parathyroid hormone. At 57° N (Aberdeen, Scotland, UK), there were 338 Caucasian women; at 51° N (Surrey, South of England, UK), there were 144 Caucasian women and 35 Asian women. UVB exposure (polysulphone film badges) and dietary vitamin D intakes (food diaries) were also estimated.
Caucasian women had lower 25(OH)D (p < 0.001) at 57° N compared to 51° N. Median (interquartile range) in nanomoles per litre for summer (June–August) at 57° N was 43.0 (20.9) and at 51° N was 62.5 (26.6) and for winter (December–February) at 57° N was 28.3 (18.9) and at 51° N was 39.9 (24.0). For Asian women at 51° N, median 25(OH)D was 24.0 (15.8) nmol/L in summer and 16.9 (15.9) nmol/L in winter. Median dietary vitamin D intakes were 80–100 IU for Caucasians and 50–65 IU for the Asian women. Sunlight was the main contributor to 25(OH)D with spring and summer providing >80% total annual intake.
These longitudinal data show significant regional and ethnic differences in UVB exposure and vitamin D status for postmenopausal women at northerly latitudes. The numbers of women who are vitamin D deficient is a major concern and public health problem.
KeywordsDietary vitamin D Longitudinal study Postmenopausal women Regional vitamin D status Seasonal 25-hydroxyvitamin D Sunlight exposure
- Sunlight and dietary contributions to the seasonal vitamin D status of cohorts of healthy postmenopausal women living at northerly latitudes: a major cause for concern?
Volume 22, Issue 9 , pp 2461-2472
- Cover Date
- Print ISSN
- Online ISSN
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- Dietary vitamin D
- Longitudinal study
- Postmenopausal women
- Regional vitamin D status
- Seasonal 25-hydroxyvitamin D
- Sunlight exposure
- Industry Sectors
- Author Affiliations
- 1. University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- 5. Musculoskeletal Research, Health Sciences Building, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- 2. Department of Musculoskeletal Biology, University of Liverpool, Liverpool, L69 3GA, UK
- 3. Nutritional Sciences Division, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
- 4. Vitamin D Research Group, Department of Medicine, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL, UK