<b>Objective: </b>The evidence regarding vitamin D status and
mortality among diabetes is scarce. This study aimed to examine the association
of serum 25-hydroxyvitamin D [25(OH)D] concentrations with all-cause and cause-specific
mortality among adults with <a>diabetes mellitus</a>.
<p><b>Research Design and Methods: </b>This
study included 6329 adults with diabetes from the Third National Health and
Nutrition Examination Survey (NHANES III) and NHANES 2001-2014. Death outcomes were
ascertained by linkage to National Death Index records through 31 December 2015. Cox proportional hazard models were used to estimate
hazard ratios (HR) and 95% confidence (CIs) for mortality from all
causes, cardiovascular disease (CVD), and cancer.</p>
<p><b>Results:</b> The weighted mean (95% CI) level of serum 25(OH)D
was 57.7 (56.6, 58.8) nmol/L, and 46.6% had deficient vitamin D (<50 nmol/L [20 ng/mL]). <a>Higher </a>serum
25(OH)D
levels
were significantly associated with lower levels of glucose, insulin, HOMA-IR, HbA1c,
blood lipids, and C-reactive protein at baseline (all <i>P</i><sub>trend</sub><0.05).
During 55126 person-years of follow-up, 2056 deaths were documented, including 605 CVD deaths and 309 cancer deaths. <a>After multivariate adjustment, higher </a>serum 25(OH)D levels were significantly
and linearly associated with lower all-cause and CVD mortality: there was a 31% reduced risk of all-cause
mortality and a 38% reduced risk
of CVD mortality per one unit increment in natural log-transformed 25(OH)D (both <i>P</i><0.001). Compared with participants with 25(OH)D <25 nmol/L, the multivariate-adjusted HRs and 95% CI for participants
with 25(OH)D >75
nmol/L were 0.59 (0.43, 0.83) for
all-cause mortality (<i>P</i><sub>trend</sub>=0.003), 0.50 (0.29, 0.86) for CVD mortality (<i>P</i><sub>trend</sub>=0.02), and 0.49 (0.23, 1.04) for cancer mortality (<i>P</i><sub>trend</sub>=0.12). </p>
<p><b>Conclusions: </b>In a nationally
representative sample of US adults with diabetes, higher serum 25(OH)D levels
were significantly associated with lower all-cause and CVD mortality. These
findings suggest that maintaining adequate vitamin D status may lower mortality
risk in individuals with diabetes.</p>
Circulating 25-hydroxyvitamin D concentration and cause-specific mortality in the Melbourne Collaborative Cohort Study
