A child's risk of becoming obese may begin before birth and continue throughout infancy

A child's risk of becoming obese may begin before birth and continue throughout infancy and early childhood - critical periods for cellular growth and development, according to research results discussed during a national conference and outlined in the October supplement to Pediatrics.

The conference, "Preventing Childhood Obesity: A National Conference Focusing on Pregnancy, Infancy, and Early Childhood Factors," was organized by the non-profit organization Shape Up America! The Washington, DC, conference was held in December 2003.

During the last 30 years, the number of obese children and adults has grown rapidly. The percentage of children ages 6 to 11 who are overweight increased from 4 percent in the 1970s to 15 percent in 1999-2000.

Studies presented at the conference showed that a child's size at birth and early eating habits may affect body mass and weight gain. Such critical periods, according to researchers, should be the focus of childhood obesity prevention efforts.

While large for gestational age (LGA) infants (generally greater than the 90th percentile of weight at birth) are more susceptible to high weight or high body mass index (BMI) later in life, these infants have a greater proportion of lean tissue relative to body fat and a lower risk of cardiovascular disease, stroke, hypertension, and type 2 diabetes at a given BMI.

Conversely, small for gestational age (SGA) infants have a greater percentage of body fat and a higher risk of obesity-related conditions and diseases.

Rapid infant weight gain during the first year of life increases the risk of high adult BMI, particularly for SGA infants. An early "adiposity rebound," the time in childhood when body fat reaches a minimum and then rises - usually between ages 5 and 6 - also increases adult obesity risk.

Breastfeeding may prevent obesity later in life, according to the supplement, as can a parent's encouragement of healthy eating during the toddler and early childhood years. Increased activity and decreased television viewing were also encouraged.

The conference recommended more research on the effects of breastfeeding and formula, early exposure to flavors and food groups, and parental feeding styles on later child behavior, food choices and body weight. Increased monitoring of pediatric weight and improved tools for measuring and defining obesity and body mass were also encouraged.