摘要：Objectives. We sought to determine whether increased duration of breast-feeding was associated with decreased risk of overweight among 4-year-old children in Kansas families with limited means. Methods. We linked data on Kansas families from the Pediatric Nutrition Surveillance System and Pregnancy Nutrition Surveillance System, 1998 to 2002, to determine breastfeeding duration and weight status at age 4 years. Overweight among 4-year-old children was defined as body mass index–for-age at the 95th percentile and above. Linked analysis included 3692 children. Logistic regression was applied to determine odds of being overweight at each duration of breastfeeding. Results. Breastfeeding duration considered independently showed a significant protective association with childhood overweight at age 4 years for all non-Hispanics (odds ratio [OR]=0.72; 95% confidence interval [CI]=0.55, 0.94) and for Whites only (OR=0.68; CI=0.50, 0.92). When we controlled for other significant risk factors for childhood overweight, the association diminished and was not statistically significant. Conclusions. Although breastfeeding for longer duration appeared to be protective against overweight among 4-year-old non-Hispanic children, cultural and environmental factors may override this protective benefit. Childhood overweight may be the most significant health issue facing American children today. The number of children who are overweight in the United States has risen dramatically since the 1970s, and the prevalence of excess weight in US children continues to increase. 1 Excess weight has negative effects on children from early childhood throughout life; therefore, research regarding causes as well as prevention and treatment of childhood overweight is needed. Childhood overweight reflects the convergence of many biological, economic, and social factors. Each of these factors affects family food choices, food preparation, and food consumption, and together they contribute to the complex problem of overweight in children. No single intervention is likely to produce large reductions in the prevalence of overweight children, 2 but choosing to breastfeed an infant rather than use formula is one factor that may prevent subsequent overweight. 3 Recent studies have reported that longer breastfeeding is protective against childhood overweight. 4 – 9 In 2004, Howell Wechsler, acting director of the Centers for Disease Control and Prevention Division of Adolescent and School Health, testified before a congressional subcommittee that the “promotion of breastfeeding and efforts to increase its duration” is one behavioral strategy for reducing rates of overweight and obesity in children and adolescents. 10 Data from 2002 revealed that breastfeeding rates among recipients of benefits from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) lagged behind those of non-WIC recipients by more than 20% in the hospital and at 6 months of age. 11 Kansas data showed similar disparity between in-hospital breastfeeding rates (initiation) and breastfeeding rates at 6 months (duration) for WIC infants, with only 19.6% still breastfeeding at 6 months, below even the national rate for WIC infants of 22.1%. 12 Breastfeeding is initiated in this population, but it is not continued. Grummer-Strawn and Mei reported that prolonged breastfeeding was associated with a reduced risk of overweight in non-Hispanic White children. 4 Their study analyzed linked data from the Pediatric Nutrition Surveillance System (PedNSS) and the Pregnancy Nutrition Surveillance System (PNSS) for 7 states. The PedNSS and PNSS receive data from publicly funded health and nutrition programs, including WIC. Little was known about breastfeeding and childhood overweight among Kansans, particularly low-income Kansans. Kansas was not included in the 2004 study by Grummer-Strawn and Mei. 4 Therefore, we designed our study to address the paucity of data for Kansas by analyzing linked data from the PedNSS and PNSS to determine whether longer breastfeeding was associated with decreased incidence of childhood overweight at the age of 4 years among a Kansas WIC population.
