Predictors of body size in the first 2 y of life: a high-risk study of human obesity.

OBJECTIVE

To ascertain the predictors of body size at 2 y of age.

DESIGN

: Prospective, longitudinal study of risk factors for weight gain of infants at high or low risk of obesity by virtue of their mothers' obesity or leanness.

SUBJECTS

A total of 40 infants of obese mothers and 38 infants of lean mothers, equally divided among boys and girls.

METHODS

Measurement of dependent variables: weight, length and skinfold thicknesses at 3, 6, 9, 12, 18 and 24 months and percent body fat at 3, 12 and 24 months. Measurement of independent variables: average daily caloric consumption at 3, 6, 9, 12, 18 and 24 months; and, at 3 months, nutritive sucking behavior during a test meal, total energy expenditure (TEE), sleeping energy expenditure (SEE), estimation of nonsleeping energy expenditure (TEE-SEE) and socioeconomic status. Parental weights and heights were obtained by self-report at the time of recruitment. Partial correlation and mixed effects linear regression analyses were performed.

RESULTS

Measures of body size (weight, length, skinfold thicknesses) and percent of body fat were almost identical between high- and low-risk groups at all times. Energy intake during six occasions over the 2 y, sucking behavior, family income and TEE predicted weight gain, controlling for body length. Parental body mass index was not associated with the child's body size during the first 2 y. During the first year, there were strong lagged correlations between energy intake and body weight and smaller correlations between protein intake and body weight.

CONCLUSION

Energy intake, and not energy expenditure, was the determinant of body size in these infants at 2 y of age, as it had been at 1 y. Sucking behavior and TEE (positively) and family income (negatively) also contributed to body weight at 2 y. The novel finding of a lagged correlation between energy intake and body weight early in life suggests that energy intake is programmed for future growth and development.