Glomerular number and size in autopsy kidneys: the relationship to birth weight.
BACKGROUND
In the Southeast United States, African Americans have an estimated incidence of hypertension and end-stage renal disease (ESRD) that is five times greater than Caucasians. Higher rates of low birth weight (LBW) among African Americans is suggested to predispose African Americans to the higher risk, possibly by reducing the number of glomeruli that develop in the kidney. This study investigates the relationships between age, race, gender, total glomerular number (Nglom), mean glomerular volume (Vglom), body surface area (BSA), and birth weight.


METHODS
Stereologic estimates of Nglom and Vglom were obtained using the physical disector/fractionator combination for autopsy kidneys from 37 African Americans and 19 Caucasians.


RESULTS
Nglom was normally distributed and ranged from 227,327 to 1,825,380, an 8.0-fold difference. A direct linear relationship was observed between Nglom and birth weight (r = 0.423, P = 0.0012) with a regression coefficient that predicted an increase of 257,426 glomeruli per kilogram increase in birth weight (alpha = 0.050:0.908). Among adults there was a 4.9-fold range in Vglom, and in adults, Vglom was strongly and inversely correlated with Nglom (r =-0.640, P = 0.000002). Adult Vglom showed no significant correlation with BSA for males (r = -0.0150, P = 0.936), although it did for females (r = 0.606, P = 0.022). No racial differences in average Nglom or Vglom were observed.


CONCLUSIONS
Birth weight is a strong determinant of Nglom and thereby of glomerular size in the postnatal kidney. The findings support the hypothesis that LBW by impairing nephron development is a risk factor for hypertension and ESRD in adulthood.
Hughson
Michael
M
University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA. mhughsn@pathology.umsmed.edu
Farris
Alton B
AB
Douglas-Denton
Rebecca
R
Hoy
Wendy E
WE
Bertram
John F
JF
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D001161:Arteriosclerosis / Q000208:ethnology / Q000473:pathology; D001724:Birth Weight; D001824:Body Constitution; D005260:Female; D005355:Fibrosis; D006801:Humans; D006977:Hypertension, Renal / Q000208:ethnology / Q000473:pathology; D007231:Infant, Newborn; D007676:Kidney Failure, Chronic / Q000208:ethnology* / Q000473:pathology*; D007678:Kidney Glomerulus / Q000473:pathology*; D008297:Male; D012307:Risk Factors; D044465:White People / Q000706:statistics & numerical data