BACKGROUND:

Obesity is increasing in the United States. Evidence-based prevention is a public health priority and should target well-defined risk factors and critical periods.

OBJECTIVE:

We tested the hypothesis that rapid weight gain during early infancy is associated with obesity in African American young adults, a group at increased risk of obesity.

DESIGN:

A cohort of 300 African Americans born at full term was followed from birth to 20 y of age. A pattern of rapid weight gain was defined as an increase in weight-for-age > or = 1 SD between birth and 4 mo.

RESULTS:

About 29% of subjects had a pattern of rapid weight gain during infancy; 8% were obese [body mass index (in kg/m(2)) > or = 30] at age 20 y. One-third of the obesity at age 20 y could be attributed to rapid weight gain in the first 4 mo of life. After adjustment for confounding factors, subjects with rapid weight gain during early infancy were more likely to become obese at age 20 y (odds ratio = 5.22; 95% CI: 1.55, 17.6; P = 0.008). The results were confirmed by using a combination of body mass index and skinfold thickness (odds ratio = 6.72; 95% CI: 1.93, 23.4; P = 0.003).

CONCLUSIONS:

The results of the present study provide evidence that a pattern of rapid weight gain during early infancy is associated with obesity not only in childhood but also in young adulthood. We propose that early infancy constitutes a critical period for the development of obesity. Mechanisms of action and prevention strategies require further investigation.