Vitamin D status in postmenopausal women living at higher latitudes in the UK in relation to bone health, overweight, sunlight exposure and dietary vitamin D

Helen M. Macdonald (Lead / Corresponding author), Alexandra Mavroeidi, Rebecca J. Barr, Alison J. Black, William D. Fraser, David M. Reid

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    123 Citations (Scopus)

    Abstract

    For 5 months a year the UK has insufficient sunlight for cutaneous synthesis of vitamin D and winter requirements are met from stores made the previous summer. Although there are few natural dietary sources, dietary intake may help maintain vitamin D status. We investigated the relationship between 25-hydroxyvitamin D (25(OH)D), bone health, overweight, sunlight exposure and dietary vitamin D in 3113 women (age 54.8 [SD 2.3] years) living at latitude 57°N between 1998-2000. Serum 25(OH)D was measured by high performance liquid chromatography (HPLC), dietary intakes (food frequency questionnaire, n = 2598), sunlight exposure (questionnaire, n = 2402) and bone markers were assessed. Bone mineral density (BMD) was measured by dual x-ray absorptiometry in all women at the sampling visit and 6 years before. Seasonal variation in 25(OH)D was not substantial with a peak in the autumn (23.7 [9.9] ng/ml) and a nadir in spring (19.7 [7.6] ng/ml). Daily intake of vitamin D was 4.2 [2.5] μg from food only and 5.8 [4.0] μg including vitamin D from cod liver oil and multivitamins. The latter was associated with 25(OH)D at each season whereas vitamin D simply from food was associated with 25(OH)D in winter and spring only. Sunlight exposure was associated with 25(OH)D in summer and autumn. 25(OH)D was negatively associated with increased bone resorption and bone loss (P < 0.05) remaining significant after adjustment for confounders (age, weight, height, menopausal status/HRT use, physical activity and socio-economic status). Using an insufficiency cut-off of < 28 ng/ml 25(OH)D, showed lower concentrations of bone resorption markers in the upper category (fDPD/Cr 5.1 [1.7] nmol/mmol compared to 5.3 [2.1] nmol/mmol, P = 0.03) and no difference in BMD or bone loss. 25(OH)D was lower (P < 0.01) and parathyroid hormone higher (P < 0.01) in the top quintile of body mass index. In conclusion, low vitamin D status is associated with greater bone turnover, bone loss and obesity. Diet appears to attenuate the seasonal variation of vitamin D status in early postmenopausal women at northerly latitude where quality of sunlight for production of vitamin D is diminished.

    Original languageEnglish
    Pages (from-to)996-1003
    Number of pages8
    JournalBone
    Volume42
    Issue number5
    Early online date9 Feb 2008
    DOIs
    Publication statusPublished - May 2008

    Keywords

    • 25-hydroxy vitamin D
    • Bone loss
    • Dietary vitamin D
    • Postmenopausal women
    • Sunlight exposure

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism
    • Physiology
    • Histology

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