Vitamin D and Health

Serum/plasma 25(OH)D concentration
10.42 In the DNSIYC and NDNS annualised 109 mean plasma 25(OH)D concentrations in the UK were: 64-
69 nmol/L for ages 5-18m; 58 nmol/L for ages 1.5-3y 110 ; 50 nmol/L for ages 4-10y; 43-45 nmol/L for
ages 11-65+y. The percentage with plasma 25(OH)D concentrations < 25 nmol/L was: 5-11m, 6%; 12-
18m, 2%; 1.5-3y, 7.5%; 4-10y, 12-16%; 11-18y, 20-24%; 19-64y, 22-24%; 65+y, 17-24%. 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.
10.43 For low income groups, annualised mean plasma 25(OH)D concentrations were 40-44 nmol/L in
children aged 11-18y 111 and 43-53 nmol/L in adults aged ≥ 19y. The percentage with plasma 25(OH)D
concentration < 25 nmol/L was: 8% of boys and 23% of girls aged 11-18y and 14-25% of adults aged
≥19y.
10.44 For all age groups in the NDNS, mean plasma 25(OH)D concentrations were lowest in the winter
months (January-March) and highest in the summer months (July-September). The proportion with
plasma 25(OH)D concentration < 25 nmol/L in winter was: children (4-10y), 31%; older children and
adolescents (11-18y), 40%; adults aged 19-64y, 39%; and adults aged ≥ 65y, 29%. The proportion in
the summer was: 2% of children (4-10y); 13% of older children and adolescents (11-18y); 8% of adults
aged 19-64y; and 4% of adults aged ≥ 65y.
10.45 Data from the HSE, SHS and cohort studies show that a proportion of the following population groups
do not achieve serum 25(OH)D concentrations ≥ 25 nmol/L in summer: 17% of adults in Scotland; 16%
of adults in London; 53% of women of South Asian ethnic origin in Southern England; and 29% of
pregnant women in north west London. Data from UK based cohort studies in pregnant women have
reported mean/median serum 25(OH)D concentrations of 34-53 nmol/L in summer and 26-34 nmol/L
in winter. The percentage with concentrations < 25 nmol/L ranged from 25-29% in the summer to 49-
76% in the winter.
10.46 An HSE analysis by ethnicity showed that annualised mean serum 25(OH)D concentration was higher
in white adults aged ≥ 16y (45.8 nmol/L) compared to Asian (20.5 nmol/L) and black (27.7 nmol/L)
adults. The 1996 Asian Infant Feeding Survey (age 2y) reported that the mean serum 25(OH)D
concentration (October-November) was 42 nmol/L in Bangladeshi infants (20% < 25 nmol/L), 36 nmol
in Pakistani infants (34% < 25 nmol/L and 42 nmol/L in Indian infants (with 25% < 25 nmol/L). A study
in Southern England reported lower mean serum 25(OH)D concentrations (in every season) in South
Asian women compared to white women and a higher percentage with serum 25(OH)D concentration
< 25 nmol/L throughout the year (53% in summer, 75% in winter) compared with white women (0.4%
in summer, 9.7% in winter).
109 Average of reports from different months of the year.
110 Based on small sample size (n=42).
111 Sample size in boys aged 8-10 years was too small (n=8) to be representative.
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