PLASMA LEPTIN IN NONDIABETIC ASIAN INDIANS - ASSOCIATION WITH ABDOMINAL ADIPOSITY

Plasma leptin concentrations were measured in 144 non-diabetic men and women (age 21-73 years, BMI 14.8-37.7 kg m(-2)), in fasting samples c ollected during a population survey for diabetes mellitus. Leptin, fas ting and 2-h post-glucose load plasma concentrations of glucose and im munoreactive insulin were measured. In a subset of 50 normoglycaemic i ndividuals, subcutaneous fat (SF) and visceral fat (VF) areas at L4-L5 level were also measured by CT. As in other populations, women had si gnificantly higher plasma leptin concentrations than men (p < 0.001) b ut the values were similar in normal (NGT) and impaired glucose tolera nce (IGT). Geometric mean concentrations of leptin in men and women wi th NGT were 4.8 and 17.7 ng ml(-1), respectively, and the correspondin g values in IGT were 6.2 and 19.0 ng ml(-1). Multiple regression analy sis in the total group showed that the leptin concentration (log-trans formed) was strongly dependent on sex (R-2 = 53.4 %), BMI (R-2 = 17.4 %), and to a lesser degree on the 2-h plasma insulin (R-2 = 2.4 %) and the WHR (R-2 = 0.8 %) In men, the total abdominal fat showed a strong association with leptin (R-2 = 49.3 %) and in women the subcutaneous fat area showed a similar effect (R-2 = 39.5 %). It is likely that sub cutaneous and not visceral fat may be a determinant of plasma leptin i n Asian Indians, and the correlation between leptin and insulin resist ance may be less strong than in other ethnic groups. (C) 1997 by John Wiley & Sons, Ltd.