Serum leptin concentrations and body adipose measures in older black and white adults.
BACKGROUND
Among US adults, serum leptin concentrations are higher in women than in men and are higher in blacks than in whites independent of anthropometric measures of body fatness.


OBJECTIVE
Using radiographic measures of body fat, we determined the best correlates of leptin and whether adiposity can explain sex and race differences in leptin concentrations in older adults.


METHODS
This was a cross-sectional analysis of fasting serum leptin concentrations and body fat measured by dual-energy X-ray absorptiometry (DXA), abdominal computed tomography, and standard anthropometry in 3026 well-functioning 70-79-y-old participants (42% black, 51% women) of the Health, Aging, and Body Composition Study.


RESULTS
Geometric mean (+/-SE) leptin concentrations (ng/mL) were higher in the women than in the men (16.5 +/- 0.3 and 5.7 +/- 0.1, respectively) and in the black women than in the white women (20.2 +/- 0.6 and 13.9 +/- 0.4, respectively), but did not differ significantly between the white and black men (5.8 +/- 0.2 and 5.5 +/- 0.2, respectively). Percentage fat estimated from DXA showed the highest correlation with leptin (R(2) = 0.56 for both sexes). Addition of abdominal visceral fat minimally increased the correlation. In the multivariate analysis, the association with sex was eliminated after adjustment for percentage fat and visceral fat in both whites (P = 0.051) and blacks (P = 0.34). Among women, higher leptin concentrations in blacks remained after adjustment for percentage fat and visceral fat (mean race difference = 4.95 ng/mL; P < 0.001). Among men, an association with black race emerged after adjustment for these factors (mean race difference = 1.42 ng/mL; P < 0.001).


CONCLUSIONS
Among older adults, higher serum leptin concentrations in women are explained by a greater percentage of body fat. Higher leptin concentrations in blacks are not explained by percentage of body fat.
Ruhl
Constance E
CE
Social and Scientific Systems, Inc., 8758 Georgia Avenue, Silver Spring, MD 20910, USA. cruhl@s-3.com
Everhart
James E
JE
Ding
Jingzhong
J
Goodpaster
Bret H
BH
Kanaya
Alka M
AM
Simonsick
Eleanor M
EM
Tylavsky
Frances A
FA
Harris
Tamara B
TB
D000005:Abdomen; D015502:Absorptiometry, Photon / Q000379:methods; D000273:Adipose Tissue / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000378:metabolism*; D000367:Age Factors; D000368:Aged; D000886:Anthropometry; D044383:Black People; D001823:Body Composition / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005215:Fasting; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D044465:White People
D020738:Leptin