OBJECTIVETo examine the association between Ponderal index (PI) at birth and metabolic syndrome during middle age.

METHODSTotally, 975 adults (494 men and 481 women) aged 41-52 from the study cohort of Fetal Origin of Adult Disease were recruited in the study for clinic examinations, involving anthropometry and measurements of blood pressure, fasting and 2 hr plasma levels of glucose and insulin, serum lipid profile. Their HOMA-insulin resistance (IR) index was estimated. Metabolic syndrome (MS) was diagnosed according to 1999 WHO definition. Multivariate logistic regression analysis was used to estimate the effect of PI on MS and the interaction between PI at birth and body mass index (BMI) in adulthood.

RESULTSPrevalence of MS was 18.7% in this mid-aged population, 24.8%, 19.4%, 16.3% and 14.0% in those with less than the 25th percentile, the 25th to less than the 50th percentile, the 50th to less than the 75th percentile and more than 75th percentile of PI at birth, respectively, in a decreasing trend (chi2 M-H for trend=9.938 adjusted for gender, P=0.002). Logistic regression analysis showed that both PI at birth and BMI during adulthood could influence their occurrence of MS (beta=-0.125, P=0.002, for PI; and beta=0.430, P=0.000, for BMI). A synergistic effect between PI at birth and BMI in adulthood was observed in this population. Persons who were thin at birth with PI less than the 25th percentile, and became overweight with BMI greater than or equal to 24 kg/m2 later in their life, were at higher risk of suffering from metabolic syndrome (OR=29.1, 95% CI=13.6-62.1), in comparison with those who became overweight during adulthood from a higher PI at birth (OR=16.0, 95% CI=7.9-32.3) and those who were thin at birth and remained a appropriate BMI during their adulthood (OR=2.0, 95% CI=0.7-5.7). Attributable fraction of the interaction to MS was 34.6%.

CONCLUSIONSThin at birth was a predictor for later occurrence of metabolic syndrome, as well as an effect modifier for the association between of later BMI and metabolic syndrome, i.e., overweight later in his life was most deleterious for a person with growth retardation at birth.