Association between Renal Tubular Dysfunction and Mortality among Residents in a Cadmium-Polluted Area, Nagasaki, Japan.

Abstract

A retrospective cohort study was carried out to clarify the effect of exposure to environmental cadmium (Cd) on mortality. A total of 256 residents aged 50 years or older, living in Sasu, a Cd-polluted area in Tsushima Island in Nagasaki Prefecture, Japan, were followed from July 1979 to February 1989. The expected number of deaths calculated was based on the sex- and age- specific mortality rate in Tsushima Island in 1985. In Sasu residents of both sexes with urinary beta 2-microglobulin (beta 2-m) concentration greater than 1,000 microgram/g creatinine in 1979, observed deaths were greater than expected. However, the p value of the difference was less than 0.05 only in men. The relationships of age, mean blood pressure, urinary beta 2-m and urinary Cd concentration to mortality were examined using Cox's proportional hazards model. Urinary beta 2-m was independently and significantly related to mortality in men but not in women. The results suggest an association between Cd-induced renal tubular dysfunction and mortality.