25-Hydroxyvitamin D in Canadian adults: biological, environmental, and behavioral correlates.
CONCLUSIONS
We assessed vitamin D status and its correlates in the population-based Canadian Multicentre Osteoporosis Study (CaMos). Results showed that serum 25-hydroxyvitamin D levels <75 nmol/L were common. Given Canada's high latitude, attention should be given to strategies for enhancing vitamin D status in the population.


BACKGROUND
Inadequate vitamin D has been implicated as a risk factor for several clinical disorders. We assessed, in a Canadian cohort, vitamin D status and its correlates, based on serum 25-hydroxyvitamin D [25(OH)D], the best functional indicator of vitamin D status.


METHODS
We studied 577 men and 1,335 women 35+ years from seven cities across Canada in the randomly selected, population-based Canadian Multicentre Osteoporosis Study (CaMos). Participants completed a comprehensive questionnaire. Serum 25(OH)D was measured by immunoassay. Multivariate linear regression modeling assessed the association between 25(OH)D and determinants of vitamin D status.


RESULTS
Participants (2.3%) were deficient in 25(OH)D (<27.5 nmol/L); a further 18.1% exhibited 25(OH)D insufficiency (27.5-50 nmol/L). Levels <75 nmol/L were evident in 57.5% of men and 60.7% of women and rose to 73.5% in spring (men) and 77.5% in winter (women); 25(OH)D <50 nmol/L was ≤10% year round for those supplementing with ≥400 IU vitamin D/day but was 43.9% among those not supplementing in winter and spring. The strongest predictors of reduced 25(OH)D for both men and women were winter and spring season, BMI ≥30, non-white ethnicity, and lower vitamin D supplementation and its modification by fall and winter.


CONCLUSIONS
In this national Canadian cohort, vitamin D levels <75 nmol/L were common, particularly among non-white and obese individuals, and in winter and spring. Vitamin D intake through diet and supplementation and maintenance of normal weight are key modifiable factors for enhancing vitamin D status and thus potentially influencing susceptibility to common chronic diseases.
Greene-Finestone
L S
LS
Public Health Agency of Canada, Ottawa, Ontario, Canada. linda.greene-finestone@phac-aspc.gc.ca
Berger
C
C
de Groh
M
M
Hanley
D A
DA
Hidiroglou
N
N
Sarafin
K
K
Poliquin
S
S
Krieger
J
J
Richards
J B
JB
Goltzman
D
D
D000328:Adult; D017677:Age Distribution; D000368:Aged; D015992:Body Mass Index; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004032:Diet / Q000706:statistics & numerical data; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D012621:Seasons; D017678:Sex Distribution; D012880:Skin Pigmentation / Q000502:physiology; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology
D014807:Vitamin D; C104450:25-hydroxyvitamin D