Objective: We studied whether the serum leptin concentration at age 2 years predicts changes in relative body weight by age 8 and whether the serum leptin concentration is associated with intake of energy and nutrients at age 5.
Methods: A total of 156 8-year-old participants of the Special Turku Coronary Risk Factor Intervention Project were chosen to represent children whose relative weight decreased, was stable, or increased during the preceding 6 years. Their serum leptin concentrations were measured in samples collected when they were 2 years. Serum leptin was also measured in 100 5-year-old children in the Special Turku Coronary Risk Factor Intervention Project whose energy and nutrient intakes were analyzed using 4-day food records.
Results: The boys whose relative weight decreased (n = 25), was stable (n = 28), or increased (n = 26) between 2 and 8 years of age had similar serum leptin concentrations at the age of 2 years. The girls whose relative weight decreased (n = 27) had higher serum leptin concentrations at 2 years than the girls whose relative weight remained stable (n = 26) but only when the leptin values were not adjusted for body mass index. The serum leptin concentration was higher in 5-year-old girls than in 5-year-old boys even when adjusted for body mass index. Serum leptin correlated with relative weight in girls and boys (r = 0.65 and r = 0.45, respectively). Serum leptin concentration adjusted for relative weight correlated poorly with intakes of energy, fat, saturated fat, carbohydrates, sucrose, and protein.
Conclusions: Serum leptin concentrations at age 2 poorly predicted changes in relative body weight during the following 6 years and poorly reflected the intake of energy or major nutrients at age 5.