Abstract
BACKGROUND: Although the prevalence of kidney disease is higher in those with reduced lung function, the longitudinal relationship between low lung function and future risk of chronic kidney disease (CKD) has not been widely explored. METHODS: Baseline lung function was assessed in 20,700 men and 7325 women from 1974 to 1992. Mean age was 43.4 (±6.6) and 47.5 (±7.9) for men and women respectively. Sex-specific quartiles of FEV(1) and FVC (L) were created (Q4: highest, reference) and the cohort was also divided by the FEV(1)/FVC ratio (≥ or < 0.70). Cox proportional hazards regression was used to determine the risk of incident CKD events (inpatient or outpatient hospital diagnosis of CKD) in relation to baseline lung function after adjustment for various confounding factors. RESULTS: Over 41 years of follow-up there were 710 and 165 incident CKD events (main diagnosis) in men and women respectively. Low FEV(1) was strongly associated with future risk of CKD in men (Q1 vs Q4 adjusted HR: 1.46 (CI:1.14-1.89), p-trend 0.002). Similar findings were observed for FVC in men (1.51 (CI:1.16-1.95), p-trend 0.001). The adjusted risks were not found to be significant in women, for either FEV(1) or FVC. FEV(1)/FVC < 0.70 was not associated with increased incidence of CKD in men or women. CONCLUSION: Low FEV(1) and FVC levels at baseline are a risk factor for the development of future incident CKD in men. Monitoring kidney function in those with reduced vital capacity in early life could help with identifying those at increased risk of future CKD.