BREASTFEEDING FULLY FOR 6 MONTHS VS 4 MONTHS DECREASES RISK OF RESPIRATORY TRACT INFECTION Caroline J Chantry ¹, Cynthia R Howard ² and Peggy Auinger ³. ¹Pediatrics, University of California Davis Medical Center, Sacramento, CA; ²Pediatrics, University of Rochester, Rochester, NY; and ³Center for Child Health Research, American Academy of Pediatrics, Rochester, NY.

BACKGROUND: The AAP recommends exclusive breastfeeding for 6 months. Evidence suggests 6 vs. 4 mos of exclusive breastfeeding further protects against gastrointestinal infections, but greater protection against respiratory tract infection has not been demonstrated.

OBJECTIVE: To ascertain if full breastfeeding for 6 vs. 4 mos provides greater protection for US children against respiratory tract infection.

DESIGN/METHODS: Data regarding 2,277 children 6 to <24 mos from NHANES III, a nationally representative cross-sectional survey conducted from 1988-94, were analyzed. Percent of children w/ pneumonia (pnx), 3 episodes of cold/flu (cold), 3 episodes OM (ROM), or wheezing (whz) in past 12 mos; or 1st OM <12 mos age (OM<12), were compared for 5 groups: formula fed only (n=1149), or full breastfeeding for: <1 month "FullBF<1" (n=426), 1 to <4 months "FullBF1-3+" (n=343), 4 to <6 months "FullBF4-5+" (n=223), and 6 months "FullBF6+" (n=136). Median durations of full breastfeeding in the 4 breastfed groups were 5, 61, 122 and 182 days. Children requiring NICU care were excluded. SUDAAN software was used to account for the complex sampling design. Logistic regression controlled for confounding factors. Data were also analyzed for ages 6 to <72 mos.

RESULTS: In unadjusted analyses, "FullBF6+" children were at less risk for pnx than "FullBF4-5+", (1.6% vs. 6.5%, p=.02), but not for cold (41% vs. 45%), whz (24% vs. 23%), ROM (20% vs. 27%), or OM<12 (47% vs. 49%). Adjusting for age, birthweight, ethnicity, poverty, 2 parent household, parental education, family size, childcare, and prenatal smoke exposure revealed significantly decreased risk in "FullBF6+" vs. "FullBF4-5+" for both pnx (p=.02, OR 0.2, CI 0.1,0.8) and ROM (p=.03, OR 0.5, CI 0.3,0.9); but no significant difference in risk of cold, whz, or OM<12. Adjusted risk for pnx but not ROM remained lower in "FullBF6+" than "FullBF4-5+" in the 6 to <72 mos age group; additionally, "FullBF6+" but not "FullBF4-5+" had lower odds of OM<12 than "FullBF1-3+".

CONCLUSIONS: This study of a nationally representative sample is the first to document decreased risk for respiratory tract infection including pnx and ROM in children fully breastfed for 6 vs. 4 mos. Our findings add to a mounting body of evidence that breastfeeding benefits are dose responsive.