Vitamin D and all-cause mortality among adults in USA: findings from the National Health and Nutrition Examination Survey Linked Mortality Study.
BACKGROUND
Whether concentrations of vitamin D are related to mortality remains unresolved. Our objective was to examine the relationship between serum concentrations of 25-hydroxyvitamin D and all-cause mortality in a national sample of US adults.


METHODS
We used data from the National Health and Nutrition Examination Survey Mortality Study from 2001 to 2004 with mortality compiled through 2006. Mortality status was established through a match to the National Death Index.


RESULTS
Of the 7531 participants, 347 died. Median follow-up was 3.8 years. The mean unadjusted concentrations of vitamin D were 54.1 nmol/l (21.7 ng/ml) among participants who died and 60.7 nmol/l (24.3 ng/ml) among participants who survived (P = 0.002). After adjustment for socio-demographic factors, the hazard ratios (HR) for all-cause mortality were 1.65 [95% confidence interval (CI): 95% CI: 1.13-2.40] for participants with a concentration <50 nmol/l (<20 ng/ml) and 1.02 (95% CI: 0.74-1.41) for participants with a concentration of 50 to <75 nmol/l (20 to <30 ng/ml) compared with participants who had a concentration of ≥ 75 nmol/l (≥ 30 ng/ml). After more extensive adjustment, the HRs were 1.28 (95% CI: 0.86-1.90) and 0.91 (95% CI: 0.63-1.33), respectively. The fully adjusted HR per 10 nmol/l of vitamin D was 0.93 (95% CI: 0.86-1.01). The HRs did not vary by gender (P = 0.80) or among the three major racial or ethnic groups (P = 0.46).


CONCLUSIONS
Concentrations of vitamin D were weakly and inversely related to all-cause mortality in this sample of US adults.
Division of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA. eford@cdc.gov
Earl S
ES
Ford
Guixiang
G
Zhao
James
J
Tsai
Chaoyang
C
Li
D000328:Adult; D003625:Data Collection; D005260:Female; D006801:Humans; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D009313:National Health Programs; D016016:Proportional Hazards Models; D011863:Radioimmunoassay; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
D014807:Vitamin D; C104450:25-hydroxyvitamin D