Vitamin D: data

The 2010 and 2011 Scottish Health Surveys collected samples of blood from participants, which were subsequently analysed by the Food Standards Agency Scotland to assess vitamin D levels in the population. This showed that the mean serum vitamin D level for the Scottish population was 37.5 nmol/L, but that there was substantial variation across the population. Table 1 shows that individuals from more deprived areas have lower mean vitamin D levels than those from less deprived areas.  The proportion of the population with suboptimal levels (<25 nmol/L) increases with area deprivation level: nearly half of those in the most deprived areas (47%) had insufficient vitamin D to protect their musculoskeletal health, compared with a quarter of those in the least deprived areas.

Table 1 – Vitamin D status in Scottish Health Survey respondents aged 16 years and over by Scottish Index of Multiple Deprivation quintile, 2010 and 2011 (Source: Purdon et al. 2013).
Scottish Index of Multiple Deprivation (SIMD) quintile 5 (least deprived)  1 (most deprived) 
Mean vitamin D serum concentration (nmol/L)  45.7  40.9  38.7  31.5  31.3 
Percentage of population with suboptimal vitamin D (<25 nmol/L)  25 26 29 38 47
95% confidence interval  (19-33)  (21-32)  (22-38)  (31-46)  (39-55) 

 

A 2007 study based on 7,430 adults from the 1958 British birth cohort found that vitamin D levels in Scottish individuals were lower than in those living in other parts of the UK (Table 2; Hypponen and Power, 2007).  The prevalence of vitamin D deficiency, based on the <25 nmol/L and <75 nmol/L thresholds, was higher in Scotland than elsewhere.

Table 2 – Mean vitamin D serum concentration and prevalence of vitamin D deficiency at two thresholds (adapted from Hypponen and Power, 2007).Table 2 – Mean vitamin D serum concentration and prevalence of vitamin D deficiency at two thresholds (adapted from Hypponen and Power, 2007).
Region of residence (and season) Subjects (n) Mean vitamin D serum concentration (95% confidence intervals) (nmol/L) % sample under threshold
< 25 nmol/L < 75 nmol/L
Winter and spring        
Southern England 1,226 42.6 (41.5, 43.7) 12.5 86.2
Midlands and Wales 690 40.6 (39.3, 42.0) 16.1 87.9
Northern England 676 41.2 (39.7, 42.7) 17.5 85.9
Scotland 256 35.4 (33.4, 37.5) 23.5 92.2
Summer and autumn        
Southern England 1,627 62.4 (61.2, 63.6) 2.7 56.7
Midlands and Wales 1,238 60.4 (59.1, 61.8) 2.1 62.4
Northern England 1,261 60.9 (59.5, 62.3) 3.3 60.0
Scotland 456 50.9 (48.9, 53.0) 8.3 74.9

 

Although there are plausible reasons why vitamin D levels may be lower in the Scottish population than in other countries (e.g., latitude and climate), there are little data for comparison. Deficiency has also been reported to be common in countries where the population experiences more sunlight than in the UK; for example the US National Health and Nutrition Examination Survey of healthy adults reported that 41.6% of the participants were vitamin D deficient (i.e., serum concentrations of less than 50 nmol/L) (Forrest and Stuhldreher 2011).

Please note: If you require the most up-to-date data available, please check the data sources directly as new data may have been published since these data pages were last updated. Although we endeavour to ensure that the data pages are kept up-to-date, there may be a time lag between new data being published and the relevant ScotPHO web pages being updated.