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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) in Norway (mean of Oslo (60° N) and Tromsø (69° N)), Iceland (Reykjavik (64° N)) and Finland (60–70° N) (A); Ireland (51–54° N), the UK (50–59° N), Netherlands (Amsterdam, (52° N)), and Denmark (mean of Copenhagen and Aarhus (56° N)) (B); and Thessaloniki (40° N), Athens (37° N) and Crete (35° N) (C) on a monthly basis in a typical year (mean of 2003–2012). 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.
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nutrients-08-00533-f002: Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) in Norway (mean of Oslo (60° N) and Tromsø (69° N)), Iceland (Reykjavik (64° N)) and Finland (60–70° N) (A); Ireland (51–54° N), the UK (50–59° N), Netherlands (Amsterdam, (52° N)), and Denmark (mean of Copenhagen and Aarhus (56° N)) (B); and Thessaloniki (40° N), Athens (37° N) and Crete (35° N) (C) on a monthly basis in a typical year (mean of 2003–2012). 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.

Mentions: The mean monthly modeled UVB doses for Norway, Iceland, and Finland, all above 60° N, are shown in Figure 2A. Relative to that in Germany (spanning ~47–54° N), the monthly mean modeled UVB doses were lower in each of these three Northern European countries (Table 1). Maximum monthly mean modeled UVB doses was close to only 4000 Jm−2 in these three countries compared to 5600 Jm−2 in Germany. In general, Finland had slightly higher mean monthly modeled UVB doses than either Norway or Iceland, with only relatively small differences between these latter two countries (Figure 2A). This is also reflected in a significantly higher mean yearly modeled UVB dose for Finland than either Iceland or Norway (p < 0.02 in both cases), with no significant difference in these latter two countries (p = 0.2) (Table 1). November through to February, inclusive, had mean monthly modeled UVB doses < 100 Jm−2 in all three countries. The “vitamin D winter” lasted for six months in both Norway and Finland, and extended to a seventh month in Iceland (Figure 2 and Table 1). However, within Norway, Oslo (60° N) and Tromsø (69° N) had 51% and 64% of the year with mean daily modeled UVB doses < 1000 Jm−2, respectively, leading to “vitamin D winters” lasting for six and eight months, respectively.


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) in Norway (mean of Oslo (60° N) and Tromsø (69° N)), Iceland (Reykjavik (64° N)) and Finland (60–70° N) (A); Ireland (51–54° N), the UK (50–59° N), Netherlands (Amsterdam, (52° N)), and Denmark (mean of Copenhagen and Aarhus (56° N)) (B); and Thessaloniki (40° N), Athens (37° N) and Crete (35° N) (C) on a monthly basis in a typical year (mean of 2003–2012). 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.
© Copyright Policy
Related In: Results  -  Collection

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

nutrients-08-00533-f002: Mean modeled UVB doses effective for pre-vitamin D3 synthesis (Jm−2) in Norway (mean of Oslo (60° N) and Tromsø (69° N)), Iceland (Reykjavik (64° N)) and Finland (60–70° N) (A); Ireland (51–54° N), the UK (50–59° N), Netherlands (Amsterdam, (52° N)), and Denmark (mean of Copenhagen and Aarhus (56° N)) (B); and Thessaloniki (40° N), Athens (37° N) and Crete (35° N) (C) on a monthly basis in a typical year (mean of 2003–2012). 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.
Mentions: The mean monthly modeled UVB doses for Norway, Iceland, and Finland, all above 60° N, are shown in Figure 2A. Relative to that in Germany (spanning ~47–54° N), the monthly mean modeled UVB doses were lower in each of these three Northern European countries (Table 1). Maximum monthly mean modeled UVB doses was close to only 4000 Jm−2 in these three countries compared to 5600 Jm−2 in Germany. In general, Finland had slightly higher mean monthly modeled UVB doses than either Norway or Iceland, with only relatively small differences between these latter two countries (Figure 2A). This is also reflected in a significantly higher mean yearly modeled UVB dose for Finland than either Iceland or Norway (p < 0.02 in both cases), with no significant difference in these latter two countries (p = 0.2) (Table 1). November through to February, inclusive, had mean monthly modeled UVB doses < 100 Jm−2 in all three countries. The “vitamin D winter” lasted for six months in both Norway and Finland, and extended to a seventh month in Iceland (Figure 2 and Table 1). However, within Norway, Oslo (60° N) and Tromsø (69° N) had 51% and 64% of the year with mean daily modeled UVB doses < 1000 Jm−2, respectively, leading to “vitamin D winters” lasting for six and eight months, respectively.

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.