Vitamin C status and mortality in US adults

Background: Low vitamin C status may increase the risk of mortality from ca ncer and cardiovascular disease. Objective: The objective was to test whether an association existed between serum ascorbate concentrations and mortality and whether the association w as modified by cigarette smoking status or sex. Design: Serum ascorbate concentrations were measured in adults as part of t he second National Health and Nutrition Examination Survey (1976-1980). Vit al status was ascertained 12-16 y later. Results: The relative risk (RR) of death, adjusted for potential confounder s, was estimated by using Cox proportional hazards models. Men in the lowes t (<28.4 mu mol/L) compared with the highest (greater than or equal to 73.8 mu mol/L) serum ascorbate quartile had a 57% higher risk of dying from any cause (RR: 1.57; 95% CI: 1.21, 2.03) and a 62% higher risk of dying from c ancer (RR: 1.62; 95% CI: 1.01, 2.59). In contrast, there was no increased r isk among men in the middle 2 quartiles for these outcomes and no increased risk of cardiovascular disease mortality in any quartile. There was no ass ociation between serum ascorbate quartile and mortality among women. These findings were consistent when analyses were limited to nonsmokers or furthe r to adults who never smoked, suggesting that the observed relations were n ot due to cigarette smoking. Conclusions: These data suggest that men with low serum ascorbate concentra tions may have an increased risk of mortality, probably because of an incre ased risk of dying from cancer. In contrast, serum ascorbate concentrations were not related to mortality among women.