Potentially modifiable determinants of vitamin D status in an older population in the Netherlands: the Hoorn Study.
BACKGROUND
Inadequate vitamin D status is common in many populations around the world.


OBJECTIVE
The aim was to evaluate potentially modifiable determinants of vitamin D status in an older population.


METHODS
This was a cross-sectional study from a population-based cohort including 538 white Dutch men and women aged 60-87 y. Vitamin D status was assessed by plasma 25-hydroxyvitamin D [25(OH)D] concentrations.


RESULTS
In the winter period, 51% of the subjects had 25(OH)D concentrations <50.0 nmol/L. Greater body fatness and less time spent on outdoor physical activity were associated with worse vitamin D status. Regular use of vitamin D-fortified margarine products [odds ratio (OR) in a comparison of intake of >or=20 g/d with none: 0.41; 95% CI: 0.20, 0.86; P for trend < 0.001], fatty fish (OR for servings of >or=2/mo versus none: 0.41; 95% CI: 0.16, 1.04; P for trend = 0.01), and vitamin D-containing supplements (OR for >or= 1/d versus none: 0.33; 95% CI: 0.17, 0.63; P for trend < 0.001) were inversely associated with vitamin D inadequacy [25(OH)D <50.0 nmol/L]. We estimated that combined use of margarine products (20 g/d), fatty fish (100 g/wk), and vitamin D supplements (>or=1/d) was associated with a 16.8 nmol/L higher 25(OH)D concentration than was the use of none of these. However, none of the participants reached these intakes for all 3 factors.


CONCLUSIONS
Because few foods are vitamin D-fortified and the amounts of vitamin D in supplements are low, it is difficult to achieve adequate vitamin D status through increasing intakes in the Netherlands and in countries with similar policies.
van Dam
Rob M
RM
Institute for Health Sciences, Vrije Universiteit Amsterdam, Netherlands. rvandam@hsph.harvard.edu
Snijder
Marieke B
MB
Dekker
Jacqueline M
JM
Stehouwer
Coen D A
CD
Bouter
Lex M
LM
Heine
Robert J
RJ
Lips
Paul
P
D000273:Adipose Tissue / Q000033:anatomy & histology; D000368:Aged; D000369:Aged, 80 and over; D002112:Calcifediol / Q000097:blood*; D004032:Diet; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D009765:Obesity / Q000097:blood / Q000378:metabolism; D012907:Smoking; D014807:Vitamin D / Q000378:metabolism*
D014807:Vitamin D; D002112:Calcifediol