The association between age and nephrosclerosis on renal biopsy among healthy adults

Background: Chronic kidney disease is common with older age and is characterized on renal biopsy by global glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriosclerosis. Objective: To see whether the prevalence of these histologic abnormalities in the kidney increases with age in healthy adults and whether histologic findings are explained by age-related differences in kidney function or chronic kidney disease risk factors. Design: Cross-sectional study. Setting: Mayo Clinic, Rochester, Minnesota, from 1999 to 2009. Patients: 1203 adult living kidney donors. Measurements: Core-needle biopsy of the renal cortex obtained during surgical implantation of the kidney, and medical record data of kidney function and risk factors obtained before donation. Results: The prevalence of nephrosclerosis (≥2 chronic histologic abnormalities) was 2.7% (95% CI, 1.1% to 6.7%) for patients aged 18 to 29 years, 16% (CI, 12% to 20%) for patients aged 30 to 39 years, 28% (CI, 24% to 32%) for patients aged 40 to 49 years, 44% (CI, 38% to 50%) for patients aged 50 to 59 years, 58% (CI, 47% to 67%) for patients aged 60 to 69 years, and 73% (CI, 43% to 90%) for patients aged 70 to 77 years. Adjustment for kidney function and risk factor covariates did not explain the age-related increase in the prevalence of nephrosclerosis. Limitation: Kidney donors are selected for health and lack the spectrum or severity of renal pathologic findings in the general population. Conclusion: Kidney function and chronic kidney disease risk factors do not explain the strong association between age and nephrosclerosis in healthy adults.