Growing obesity rate in the USA

Childhood obesity has been shown to predict adult obesity, indicating that early life factors may be important risk factors for adult obesity (Bray and Bouchard, 4-9). A number of American studies have shown that overweight children become overweight adults, with a five- to ninefold increase in adult obesity for individuals obese at age 9-13 years. About one-third of obese preschoolers, half of obese school-age children, and 70 percent of obese adolescents were obese as adults. Recent surveys report a higher predictive rate of 65 to 84 percent, which may be reflective of recent trends of increasing obesity, or a redefinition of body mass index (BMI) cutoff points used to classify obesity. Although a higher proportion of obese children become obese adults, only a small proportion of obese adults were obese as children. (Obesity: The Real Cause)

Early childhood factors that may affect the propensity to develop obesity in adulthood include birth weight, early feeding patterns, adiposity rebound, early maturation, genetic predisposition, parental obesity, and socioeconomic status. Adiposity rebound is the point at which the BMI inflection occurs in the BMI-for-age curve, usually at about 5-7 years of age. Adults who had adiposity rebound after age 8 had 40 percent lower incidence of obesity compared to those who had adiposity rebound before 5 years of age. (Freedman, Serdula, and Khan, 44-55)

The risk of an overweight child becoming an obese adult rises with age. Among preschoolers, the risk of becoming an obese adult is twice as likely if the preschooler was obese, while among adolescents, the risk is 18 times more likely for an obese adolescent becoming an obese adult. The higher the BMI is in childhood, the greater the probability of persistence to adulthood. Tracking of obesity is greatest when both parents are obese. Obesity runs in families, a reflection of shared genes, environment, and culture. However, the relative contribution of genes and inherited lifestyle factors contributing to the parent-child obesity association is unknown.

The velocity of BMI has been shown to be an important predictor of adult obesity. Rapid weight gain in infancy and childhood is associated with development of obesity in childhood and adulthood. Adults with BMI in the upper quartile by age seven had threefold increase in obesity compared to their counterparts with a BMI in the lower quartile.

An association between birth weight and adult obesity has been documented. The relationship is not linear, but a ...