Association Between Serum Vitamin D and All-Cause and Cause-Specific Death in a General Japanese Population - The Hisayama Study.

Background: Few studies have investigated the association between serum vitamin D levels and mortality in general Asian populations.

Methods and results: We examined the association of serum 1,25-dihydroxyvitamin D (1,25(OH)D) levels with the risk of all-cause and cause-specific death in an average 9.5-year follow-up study of 3,292 community-dwelling Japanese subjects aged ≥40 years (2002-2012). The multivariable-adjusted hazard ratio (HR) for all-cause death increased significantly with lower serum 1,25(OH)D levels (HR 1.54 [95% confidence interval, 1.18-2.01] for the lowest quartile, 1.31 [0.99-1.73] for the 2nd quartile, 0.94 [0.70-1.25] for the 3rd quartile, 1.00 [Ref.] for highest quartile; P for trend <0.001). A similar association was observed for cardiovascular and respiratory infection death (both P for trend <0.01), but not for cancer death or death from other causes. In the stratified analysis, the association between lower serum 1,25(OH)D levels and the risk of respiratory infection death was stronger in subjects with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 mthan in those with eGFR ≥60 mL/min/1.73 m; there was a significant heterogeneity in the association between eGFR levels (P for heterogeneity=0.04).

Conclusions: The findings suggested that a lower serum 1,25(OH)D level is a potential risk factor for all-cause death, especially cardiovascular and respiratory infection death, in the general Japanese population, and that lower serum 1,25(OH)D levels greatly increase the risk of respiratory infection death in subjects with kidney dysfunction.