Reduced nephron number and glomerulomegaly in Australian Aborigines: A group at high risk for renal disease and hypertension

• DOI: 10.1038/sj.ki.5000397
• Publication Date: 2006-05-24T14:21:17Z
• Authors: W.E. Hoy; M.D. Hughson; G.R. Singh; R. Douglas-Denton; J.F. Bertram
• Keywords: Adult; Male; Indigenous Australians; hypertension; Hypertension, Renal; Native Hawaiian or Other Pacific Islander; Body Surface Area; Kidney Glomerulus; Community; Kidney; Intrauterine Growth-retardation; glomerular number; Body Mass Index; 03 medical and health sciences; C1; Size; renal disease; 616; 730115 Urogenital system and disorders; Humans; Renal Insufficiency; 321012 Nephrology and Urology; Australian Aborigines; 0303 health sciences; Volume; Body Weight; Glomerular Number; Australia; 1103 Clinical Sciences; Nephrons; Organ Size; Urology & Nephrology; Middle Aged; 15. Life on land; Body Height; 3. Good health; Nephrology; Hypertension; Low-birth-weight; Disease Susceptibility; Renal Disease; CX; Blood-pressure; Cardiovascular Risk

Aborigines in remote areas of Australia have much higher rates of renal disease, as well as hypertension and cardiovascular disease, than non-Aboriginal Australians. We compared kidney findings in Aboriginal and non-Aboriginal people in one remote region. Glomerular number and mean glomerular volume were estimated with the disector/fractionator combination in the right kidney of 19 Aborigines and 24 non-Aboriginal people undergoing forensic autopsy for sudden or unexpected death in the Top End of the Northern Territory. Aborigines had 30% fewer glomeruli than non-Aborigines--202,000 fewer glomeruli per kidney, or an estimated 404,000 fewer per person (P=0.036). Their mean glomerular volume was 27% larger (P=0.016). Glomerular number was significantly correlated with adult height, inferring a relationship with birthweight, which, on average, is much lower in Aboriginal than non-Aboriginal people. Aboriginal people with a history of hypertension had 30% fewer glomeruli than those without--250,000 fewer per kidney (P=0.03), or 500,000 fewer per person, and their mean glomerular volume was about 25% larger. The lower nephron number in Aboriginal people is compatible with their susceptibility to renal failure. The additional nephron deficit associated with hypertension is compatible with other reports. Lower nephron numbers are probably due in part to reduced nephron endowment, which is related to a suboptimal intrauterine environment. Compensatory glomerular hypertrophy in people with fewer nephrons, while minimizing loss of total filtering surface area, might be exacerbating nephron loss. Optimization of fetal growth should ultimately reduce the florid epidemic of renal disease, hypertension, and cardiovascular disease.