Hyperuricemia is associated with all-cause mortality among males and females: Findings from a study on Japanese community-dwelling individuals

BACKGROUND: Serum uric acid (SUA) is a key determinant of cardiovascular diseases (CVDs). Studies have also shown that SUA independently impacts age-related health outcomes, although their findings differ between males and females. Furthermore, predictive data on all-cause mortality remain limited, particularly for the Japanese population. Thus, this study examined the association between SUA and survival prognosis among males and females based on a follow-up period of 7 or 19 years. METHODS: The study was based on 1,573 male (63 ± 14 years) and 1,980 female (65 ± 12 years) participants who participated in a Nomura Cohort Study in 2002 (Cohort 1) and 2014 (Cohort 2), and continued throughout the follow-up period. A basic resident register was referenced to derive the adjusted relative risk estimates for all-cause mortality. Finally, a Cox proportional hazards model analysis was conducted and was adjusted for possible confounders to estimate hazard ratios (HRs). 95% confidence intervals (CIs) were computed separately for male and female participants. RESULTS: Of the total 3,553 participants, 905 (25.5%) were deceased. Of these, 473 were male (30.1% of all males) and 432 were female (21.8% of all females). Hyperuricemia was defined in males with SUA levels of 8.5 mg/dL or higher, and in females with SUA levels of 7.5 mg/dL or higher, and was associated with a significantly increased HR for all-cause mortality (males: 1.67; 95% CI: 1.06–2.63; females: 2.17; 95% CI: 1.20–3.94). The data were further stratified based on age (< 65 years or ≥ 65 years), body mass index (BMI) (< 25.0 kg/m(2) or ≥ 25.0 kg/m(2)), History of cardiovascular disease, estimated glomerular filtration rate (< 60 mL/min/1.73 m(2) or ≥ 60 mL/min/1.73 m(2)), and presence of SUA-lowering medication. All stratified groups demonstrated a similar trend. The hyperuricemia group in particular reported a significant increase in HR. On the other hand, a U-shaped increase in HR was observed in those with BMI greater than 25 kg/m(2) and SUA-lowering medication, but interaction effect was not significant. CONCLUSIONS: Hyperuricemia is a key risk indicator for all-cause mortality in male and female community-dwelling individuals in Japan.