Relationship of infant feeding to recurrent wheezing at age 6 years.

OBJECTIVES

To investigate the relationship of infant feeding to recurrent wheezing at age 6 years and to assess whether this relationship is altered by a history of wheezing lower respiratory tract illnesses.

DESIGN

Prospective, longitudinal study of healthy infants followed up from birth to 6 years of age.

SETTING

Nonselected health maintenance organization population in Tucson, Arizona.

PARTICIPANTS

There were 1246 healthy infants enrolled at birth, 988 of whom had data on both infant feeding and wheezing at age 6 years.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Recurrent wheeze (four or more episodes in the past year) was assessed by a questionnaire that was completed by parents when the children were 6 years old. Children were classified by atopic status on the basis of skin prick tests.

RESULTS

Breast-feeding information was collected prospectively, and lower respiratory tract illnesses in the first 3 years of life were diagnosed by the pediatrician. Being breast-fed was associated with lower rates of recurrent wheeze at age 6 years (3.1% vs 9.7%, P < .01) for nonatopic children; this relationship was not significant for atopic children. The relationship of breast-feeding with recurrent wheeze was apparent among nonatopic children both with and without a wheezing lower respiratory tract illness in the first 6 months of life. When potential confounders, including early wheezing lower respiratory tract illness, were included in a multivariate model, nonatopic children who had not been breast-fed had three times the odds of wheezing recurrently (odds ratio, 3.03; confidence interval, 1.06 to 8.69). Eleven percent of recurrent wheeze among nonatopic children could be attributed to not breast-feeding.

CONCLUSIONS

Recurrent wheeze at age 6 years is less common among nonatopic children who were breast-fed as infants. This effect is independent of whether the child wheezed with a lower respiratory tract illness in the first 6 months of life.