Vitamin D and Health

Adults 65y and above
8.40 In the NDNS, mean plasma 25(OH)D concentration was 47 nmol/L in men and 42.5 nmol/L in women;
16.9% of men and 24.1% of women had a plasma 25(OH)D concentration < 25 nmol/L.
8.41 For institutionalised adults the mean plasma 25(OH)D concentration was 33.7 nmol/L in men and
32.5 nmol/L in women; 38% of men and 37% of women had a concentration < 25 nmol/L.
8.42 In the HSE 2005 mean serum 25(OH)D concentration was 53 nmol/L for men and 48 nmol/L for
women.
8.43 In the LIDNS, mean serum 25(OH)D concentration) was 52.8 nmol/L in men and 44.2 nmol/L in
women; 14% of men and women had a serum 25(OH)D concentration < 25 nmol/L.
Serum/plasma 25(OH)D concentration by season
8.44 For all age groups in the NDNS, mean plasma 25(OH)D concentrations were lowest during the winter
months (January-March) and highest in the summer months (July-September). For children (4-10y)
mean plasma 25(OH)D concentration was 37 nmol/L in the winter months and 66 nmol/L in the
summer months. For older children and adolescents (11-18y) mean plasma 25(OH)D concentration
was 31.5 nmol/L in the winter and 52.3 nmol/L in the summer. For adults aged 19-64y, the mean
25(OH)D concentration was 34.8 nmol/L in the winter and 57.5 nmol/L in the summer. For adults
aged ≥ 65y the mean plasma 25(OH)D concentration was 40.5 nmol/L in winter and 50.5 nmol/L in the
summer.
8.45 The proportion of the population with a plasma 25(OH)D concentration < 25 nmol/L in the winter
months was 4-10y, 31%; 11-18y, 40%; 19-64y, 39%; ≥ 65y, 29%. The proportion with plasma 25(OH)D
concentration < 25 nmol/L in the summer months was: 4-10y, 2%; 11-18y, 13%; 19-64y, 8%; and
≥ 65y, 4%.
8.46 Serum 25(OH)D concentration was also measured by season in the HSE (2010) and the SHS. For ages
≥ 16y, concentration was lowest in the winter months compared to the summer months in both
England and Scotland; it was also lower in Scotland compared to England in all seasons. In the winter
months mean serum 25(OH)D concentration was 33.1 nmol/L in England and 27.9 nmol/L in Scotland,
increasing in the summer months to 60.1 nmol/L in England and 51.3 nmol/L in Scotland. In England,
the proportion with serum 25(OH)D concentration < 25 nmol/L was 42% in winter and 7% in summer;
in Scotland, the proportion with plasma 25(OH)D concentration < 25 nmol/L was 54% in winter and
17% in summer.
8.47 A cohort study of South Asian women (n=35) living in Southern England (Darling et al., 2013) found
that 81% and 53% had a plasma 25(OH)D concentration < 25nmol/L in winter and summer
respectively. Another cohort study of pregnant women in North West London (n=346) (McAree et al.,
2013) reported that the proportion with a plasma 25(OH)D concentration < 25 nmol/L was 49% in
winter and 29% in summer.
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