The role of sunlight exposure in determining the vitamin D status of the UK white Caucasian adult population

School of Earth Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK.
British Journal of Dermatology (Impact Factor: 4.28). 11/2010; 163(5):1050-5. DOI: 10.1111/j.1365-2133.2010.09975.x
Source: PubMed


Vitamin D is necessary for bone health and is potentially protective against a range of malignancies. Opinions are divided on whether the proposed optimal circulating 25-hydroxyvitamin D [25(OH)D] level (≥ 32 ng mL⁻¹) is an appropriate and feasible target at population level.
We examined whether personal sunlight exposure levels can provide vitamin D sufficient (≥ 20 ng mL⁻¹) and optimal status in the U.K. public.
This prospective cohort study measured circulating 25(OH)D monthly for 12 months in 125 white adults aged 20-60 years in Greater Manchester. Dietary vitamin D and personal ultraviolet radiation (UVR) exposure were assessed over 1-2 weeks in each season. The primary analysis determined the post-summer peak 25(OH)D required to maintain sufficiency in wintertime.
Dietary vitamin D remained low in all seasons (median 3·27 μg daily, range 2·76-4·15) while personal UVR exposure levels were high in spring and summer, low in autumn and negligible in winter. Mean 25(OH)D levels were highest in September [28·4 ng mL⁻¹; 28% optimal, zero deficient (<5 ng mL⁻¹)], and lowest in February (18·3 ng mL⁻¹; 7% optimal, 5% deficient). A February 25(OH)D level of 20 ng mL⁻¹ was achieved following a mean (95% confidence interval) late summer level of 30·4 (25·6-35·2) and 34·9 (27·9-41·9) ng mL⁻¹ in women and men, respectively, with 62% of variance explained by gender and September levels.
Late summer 25(OH)D levels approximating the optimal range are required to retain sufficiency throughout the U.K. winter. Currently the majority of the population fails to reach this post-summer level and becomes vitamin D insufficient during the winter.

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    • "Both forms are hydroxylated in the liver to 25-hydroxyvi- tamin D (25-OH-D) and serum levels are used as a measure of vitamin D status. If sunlight exposure is limited, there is increased dependence on dietary sources to provide adequate intakes (Webb et al., 2010), especially in vulnerable groups, during winter months (Glerup, 2000; Webb et al., 2010). However, there are only a few foods that are naturally rich in vitamin D; good sources include liver and fatty fish such as salmon, mackerel and sardines, whereas other foods such as red meat and eggs provide marginal amounts (O'Connor & Benelam, 2011). "
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    ABSTRACT: Background Dietary intakes of vitamin D are very low in the UK. Dietary calcium is also necessary to promote bone health. The fortification of foods with vitamin D could be a safe and effective way of increasing intake.Methods Diets of preschool children, 755 at 18 months and 3.5 years, from the Avon Longitudinal Study of Parents and Children were assessed using dietary records completed by parents. Energy, vitamin D and calcium intakes were calculated. Multinomial logistic regression was used to estimate the odds ratio for being in the highest/lowest quartile of intake. Intakes were recalculated to test different fortification regimes.ResultsVitamin D intakes were low; all children were below the UK and US dietary recommendations. Calcium intakes decreased between the two ages as a result of reduced milk consumption. Children in the lowest quartile for vitamin D intake at 18 months were twice as likely to remain in that quartile at 3.5 years (odds ratio = 2.35; 95% confidence interval = 1.56–3.55). The majority of foods provide no vitamin D with fat spreads and milk as the main sources. The contribution from breakfast cereals increased, from 6% to 12%, as a result of the increased consumption of fortified cereals. Dairy foods provided the highest contribution to calcium at 18 months but were less important at 3.5 years. Theoretical intakes from different fortification regimens suggest that milk fortified at 2 μg 100 g–1 vitamin D would provide most children with adequate but not excessive intakes.Conclusions Dietary vitamin D intakes were very low and calcium intakes were mostly adequate. Fortification of milk with vitamin D could be a good way to boost intakes.
    Journal of Human Nutrition and Dietetics 09/2014; DOI:10.1111/jhn.12277 · 1.99 Impact Factor
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    • "In this group ultraviolet light may not be the only key in the prevention of different condition but the role of dietary vitamin D intake, supplement vitamin D and calcium come into play [62-64]. In our study, the highest levels of serum 25OHD3 were seen during the summer and in the autumn and these are in agreement with previous studies [65-69]. This is also to be expected as during this season the solar UV radiation reaches adequate levels to have a sufficient vitamin D production (ibid). "
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    ABSTRACT: Low blood levels of vitamin D (25-hydroxy D3, 25OHD3) in women have been associated with an increased risk of several diseases. A large part of the population may have suboptimal 25OHD3 levels but high-risk groups are not well known. The aim of the present study was to identify determinants for serum levels of 25OHD3 in women, i.e. factors such as lifestyle, menopausal status, diet and selected biochemical variables. The study was based on women from the Malmo Diet and Cancer Study (MDCS), a prospective, population-based cohort study in Malmo, Sweden. In a previous case--control study on breast cancer, 25OHD3 concentrations had been measured in 727 women. In these, quartiles of serum 25OHD3 were compared with regard to age at baseline, BMI (Body Max Index), menopausal status, use of oral contraceptives or menopausal hormone therapy (MHT) , life-style (e.g. smoking and alcohol consumption), socio-demographic factors, season, biochemical variables (i.e. calcium, PTH, albumin, creatinine, and phosphate), and dietary intake of vitamin D and calcium. In order to test differences in mean vitamin D concentrations between different categories of the studied factors, an ANOVA test was used followed by a t-test. The relation between different factors and 25OHD3 was further investigated using multiple linear regression analysis and a logistic regression analysis. We found a positive association between serum levels of 25OHD3 and age, oral contraceptive use, moderate alcohol consumption, blood collection during summer/ autumn, creatinine, phosphate, calcium, and a high intake of vitamin D. Low vitamin D levels were associated with obesity, being born outside Sweden and high PTH levels. The present population-based study found a positive association between serum levels of 25OHD3 and to several socio-demographic, life-style and biochemical factors. The study may have implications e. g. for dietary recommendations. However, the analysis is a cross-sectional and it is difficult to suggest Lifestyle changes as cause- effect relationships are difficult to assess.
    BMC Women's Health 08/2013; 13(1):33. DOI:10.1186/1472-6874-13-33 · 1.50 Impact Factor
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    • "Hamilton, Grantham, Racinais, & Chalabi (2010) reported that 91% of middle eastern athletes tested demonstrated vitamin D concentrations of 550 nmol Á l 71 . There is, however , a lack of data on the vitamin D concentration of UK7based athletes that is surprising given that the majority of the UK population may be deficient during the winter months (Webb et al., 2010). "
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    ABSTRACT: Abstract The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day(-1) vitamin D(3) supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l(-1), deficient 12.5-30 nmol · l(-1) and inadequate 30-50 nmol · l(-1). We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l(-1). Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l(-1), P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l(-1), P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l(-1)). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.
    Journal of Sports Sciences 10/2012; 31(4). DOI:10.1080/02640414.2012.733822 · 2.25 Impact Factor
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