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Seasonal Changes in Vitamin D-Effective UVB Availability in Europe and Associations with Population Serum 25-Hydroxyvitamin D

View Article: PubMed Central - PubMed

ABSTRACT

Low vitamin D status is common in Europe. The major source of vitamin D in humans is ultraviolet B (UVB)-induced dermal synthesis of cholecalciferol, whereas food sources are believed to play a lesser role. Our objectives were to assess UVB availability (Jm−2) across several European locations ranging from 35° N to 69° N, and compare these UVB data with representative population serum 25-hydroxyvitamin D (25(OH)D) data from Ireland (51–54° N), Iceland (64° N) and Norway (69° N), as exemplars. Vitamin D-effective UVB availability was modelled for nine European countries/regions using a validated UV irradiance model. Standardized serum 25(OH)D data was accessed from the EC-funded ODIN project. The results showed that UVB availability decreased with increasing latitude (from 35° N to 69° N), while all locations exhibited significant seasonal variation in UVB. The UVB data suggested that the duration of vitamin D winters ranged from none (at 35° N) to eight months (at 69° N). The large seasonal fluctuations in serum 25(OH)D in Irish adults was much dampened in Norwegian and Icelandic adults, despite considerably lower UVB availability at these northern latitudes but with much higher vitamin D intakes. In conclusion, increasing the vitamin D intake can ameliorate the impact of low UVB availability on serum 25(OH)D status in Europe.

No MeSH data available.


Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) on a monthly basis in a typical year (mean of 2003–2012) in Ireland (51–54° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–84 years) in the National Adult Nutrition Survey in Ireland [21] (A); in Tromsø, Northern Norway (69° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–83 years) in the regionally representative Tromsø sixth cycle cohort [17] (solid line) and adolescents (15–18 years) in the Tromsø—Fit Futures study [18] (dotted black line) (B); and in Reykjavik, Iceland (64° N) and mean (SD) monthly serum 25(OH)D measured in adults (aged 66–96 years) in the regionally representative AGES-Reykjavik cohort in Iceland [19] (C). Note: Data on serum 25(OH)D for the four summer months (May to August) are absent in Tromsø—Fit Futures study as the adolescents were not sampled in this period due to school summer vacation. Dotted line reflects a threshold of 1000 Jm−2 as a guide to a dose below which dermal synthesis of pre-vitamin D3 is relatively low. Black bars and error bars represent mean and SD monthly UVB doses, respectively.
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nutrients-08-00533-f004: Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) on a monthly basis in a typical year (mean of 2003–2012) in Ireland (51–54° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–84 years) in the National Adult Nutrition Survey in Ireland [21] (A); in Tromsø, Northern Norway (69° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–83 years) in the regionally representative Tromsø sixth cycle cohort [17] (solid line) and adolescents (15–18 years) in the Tromsø—Fit Futures study [18] (dotted black line) (B); and in Reykjavik, Iceland (64° N) and mean (SD) monthly serum 25(OH)D measured in adults (aged 66–96 years) in the regionally representative AGES-Reykjavik cohort in Iceland [19] (C). Note: Data on serum 25(OH)D for the four summer months (May to August) are absent in Tromsø—Fit Futures study as the adolescents were not sampled in this period due to school summer vacation. Dotted line reflects a threshold of 1000 Jm−2 as a guide to a dose below which dermal synthesis of pre-vitamin D3 is relatively low. Black bars and error bars represent mean and SD monthly UVB doses, respectively.

Mentions: The mean (and SD) for the monthly standardized serum 25(OH)D values in the Irish adults (aged 18–84 years) from the nationally representative NANS [20] have been superimposed onto the graph of monthly mean modeled UVB doses in Ireland (51–54° N) (Figure 4A). There was a clear seasonal variation in serum 25(OH)D concentration of Irish adults (p < 0.0001) with a late summer peak and late winter nadir, separated by ~25 nmol/L. The seasonal fluctuations in serum 25(OH)D concentrations broadly tracks, albeit with a slight lag, that of the UVB availability for Ireland.


Seasonal Changes in Vitamin D-Effective UVB Availability in Europe and Associations with Population Serum 25-Hydroxyvitamin D
Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) on a monthly basis in a typical year (mean of 2003–2012) in Ireland (51–54° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–84 years) in the National Adult Nutrition Survey in Ireland [21] (A); in Tromsø, Northern Norway (69° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–83 years) in the regionally representative Tromsø sixth cycle cohort [17] (solid line) and adolescents (15–18 years) in the Tromsø—Fit Futures study [18] (dotted black line) (B); and in Reykjavik, Iceland (64° N) and mean (SD) monthly serum 25(OH)D measured in adults (aged 66–96 years) in the regionally representative AGES-Reykjavik cohort in Iceland [19] (C). Note: Data on serum 25(OH)D for the four summer months (May to August) are absent in Tromsø—Fit Futures study as the adolescents were not sampled in this period due to school summer vacation. Dotted line reflects a threshold of 1000 Jm−2 as a guide to a dose below which dermal synthesis of pre-vitamin D3 is relatively low. Black bars and error bars represent mean and SD monthly UVB doses, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037520&req=5

nutrients-08-00533-f004: Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) on a monthly basis in a typical year (mean of 2003–2012) in Ireland (51–54° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–84 years) in the National Adult Nutrition Survey in Ireland [21] (A); in Tromsø, Northern Norway (69° N) and mean (SD) monthly serum 25(OH)D measured in adults (18–83 years) in the regionally representative Tromsø sixth cycle cohort [17] (solid line) and adolescents (15–18 years) in the Tromsø—Fit Futures study [18] (dotted black line) (B); and in Reykjavik, Iceland (64° N) and mean (SD) monthly serum 25(OH)D measured in adults (aged 66–96 years) in the regionally representative AGES-Reykjavik cohort in Iceland [19] (C). Note: Data on serum 25(OH)D for the four summer months (May to August) are absent in Tromsø—Fit Futures study as the adolescents were not sampled in this period due to school summer vacation. Dotted line reflects a threshold of 1000 Jm−2 as a guide to a dose below which dermal synthesis of pre-vitamin D3 is relatively low. Black bars and error bars represent mean and SD monthly UVB doses, respectively.
Mentions: The mean (and SD) for the monthly standardized serum 25(OH)D values in the Irish adults (aged 18–84 years) from the nationally representative NANS [20] have been superimposed onto the graph of monthly mean modeled UVB doses in Ireland (51–54° N) (Figure 4A). There was a clear seasonal variation in serum 25(OH)D concentration of Irish adults (p < 0.0001) with a late summer peak and late winter nadir, separated by ~25 nmol/L. The seasonal fluctuations in serum 25(OH)D concentrations broadly tracks, albeit with a slight lag, that of the UVB availability for Ireland.

View Article: PubMed Central - PubMed

ABSTRACT

Low vitamin D status is common in Europe. The major source of vitamin D in humans is ultraviolet B (UVB)-induced dermal synthesis of cholecalciferol, whereas food sources are believed to play a lesser role. Our objectives were to assess UVB availability (Jm&minus;2) across several European locations ranging from 35&deg; N to 69&deg; N, and compare these UVB data with representative population serum 25-hydroxyvitamin D (25(OH)D) data from Ireland (51&ndash;54&deg; N), Iceland (64&deg; N) and Norway (69&deg; N), as exemplars. Vitamin D-effective UVB availability was modelled for nine European countries/regions using a validated UV irradiance model. Standardized serum 25(OH)D data was accessed from the EC-funded ODIN project. The results showed that UVB availability decreased with increasing latitude (from 35&deg; N to 69&deg; N), while all locations exhibited significant seasonal variation in UVB. The UVB data suggested that the duration of vitamin D winters ranged from none (at 35&deg; N) to eight months (at 69&deg; N). The large seasonal fluctuations in serum 25(OH)D in Irish adults was much dampened in Norwegian and Icelandic adults, despite considerably lower UVB availability at these northern latitudes but with much higher vitamin D intakes. In conclusion, increasing the vitamin D intake can ameliorate the impact of low UVB availability on serum 25(OH)D status in Europe.

No MeSH data available.