Associations of glomerular number and birth weight with clinicopathological features of African Americans and whites

BACKGROUND: Hypertension and its cardiovascular complications affect African Americans more severely than whites, a disparity variously ascribed to low birth weight, low glomerular number, an exaggerated arteriolonephrosclerotic blood pressure response, and inflammation-induced oxidative stress. STUDY DESIGN: Case series. SETTING AND PARTICIPANTS: Autopsy kidneys of 107 African Americans and 87 whites aged 18 to 65 years at a single medical center between 1998 and 2005. Excluded were persons with known premorbid kidney disease; pathological findings of severe arterioarteriolonephrosclerosis, nodular and diffuse diabetic glomerulosclerosis, or nonischemic cardiomyopathy. PREDICTORS OUTCOMES: Associations of: (1) race, age, sex, birth weight, obesity, and glomerular number (predictors) with hypertension and death from coronary artery (CAD) and cerebrovascular disease (CVD; outcomes); and (2) age, blood pressure, and race (predictors) with arteriolonephrosclerotic changes, including chronic tubulointerstitial inflammation (outcomes). MEASUREMENTS: Hypertension ascertained from chart review and heart weight. Cause of death determined from chart review and autopsy findings. Birth weight obtained from birth records (115 persons). Total glomerular number (N(glom)) estimated by using the dissector/fractionator technique. Arteriolosclerosis, glomerulosclerosis, cortical fibrosis, and chronic inflammation by using CD68 density were measured morphometrically. RESULTS: 59 African Americans (55 ) and 32 whites (37 ) were classified as hypertensive. CAD and CVD were the cause of death in 64 (33 ) and 18 persons (9 ), respectively. By using multiple linear regression, birth weight (P <0.001) and sex (P <0.01), but not race (P = 0.3) or age (P = 0.2), predicted N(glom) (P <0.001; adjusted r(2) = 0.176). Hypertension was associated with African American race (P = 0.04), older age (P <...