That U.S. breastfeeding rates vary significantly from state to state is well known. What is less apparent (and the subject of a recent analysis) is why.

Western and northwestern states consistently boast the highest breastfeeding rates (duration as well as exclusivity), while southern and southeastern states lag well behind. Studies show that demographic and socioeconomic characteristics such as increasing maternal age, education, income, non-Hispanic White race, being foreign born, and being a non-smoker are associated with higher rates of breastfeeding.

In an effort to determine which (if any) of the characteristics account for the state to state differences, Michael Kogan, PhD and colleagues conducted a multivariate analysis. Data was taken from the National Survey of Children’s Health (NSCH), a nationally representative cross-sectional study of more than 100,000 children ages newborn to 18 years. The NCSH survey was conducted by telephone in all 50 states and the District of Columbia from January 2003 through July 2004. The person who knew the child best (mother, father or grandparent) was asked to participate in the survey.

For the purpose of Kogan’s study, participants were limited to children between the ages of 6 and 71 months (a total of 33,121 children). Two outcome measures were examined: (1) whether the child was ever breastfed and (2) whether the child was breastfed for at least 6 months.

The variables used in the analysis included:

• Family’s poverty level
• Child’s race/ethnicity
• Child’s gender
• Family structure
• Primary language spoken in the home
• Nativity status (child or parents foreign born)
• Smoker in the household
• Exercise behavior of mother
• General health (physical and mental) of mother

An added feature of the study was a look at whether state breastfeeding legislation is associated with breastfeeding rates.

Location, location, location
After adjusting for all the variables, where a child lived still had a strong association with whether he/she was breastfed and for how long. But before you pack up your kids, pets, and possessions, consider that a woman’s decision to breastfeed (or not) is influenced by a multitude of factors, key among them being the culture in which she lives.

In those states with more than one piece of breastfeeding promotion legislation, more children (76 percent) were breastfeed, compared to states with one or no pieces of legislation (63.7 percent). Additional research is needed to better understand the association between breastfeeding legislation and breastfeeding rates. One theory is that states with multiple pieces of breastfeeding legislation exemplify cultures in which breastfeeding is valued and supported.

“We can’t tell whether the legislation affected breastfeeding practices or whether the culture in the state was such that it influenced the legislature to promote breastfeeding legislation,” said Dr. Kogan.