The 77% level of infants ever breastfed represents an important public health milestone, as the rate exceeded the Healthy People 2010 target of 75%. Children from some population subgroups are more likely to be breastfed than others, though all groups have made notable progress. Mexican American and non-Hispanic white children were significantly more likely to have been breastfed compared with non-Hispanic black children. However, the percentage of non-Hispanic black infants who were ever breastfed increased from 36% for those born in 1993-1994 to 65% for those born in 2005-2006. This significant increase is particularly good news, because black women have historically had lower breastfeeding rates.

While definite strides have been made in breastfeeding initiation rates, there is room for improvement in breastfeeding duration. Overall breastfeeding rates at age 6 months did not reach the Healthy People 2010 goal of 50%, nor did any race-ethnicity group achieve the target goal.

Breastfeeding rates differ by other sociodemographic characteristics as well. Rates continue to be lower for infants in low income families, and infants whose mothers were younger were less likely to have been breastfed. Breastfeeding rates have increased as mother’s age increased: mothers under 20 years initiated breastfeeding at 43%, with mothers 20 to 29 initiating at 65%. Mothers age 30 years and older initiated breastfeeding at 75%.

Recent research reveals that long-term, exclusive breastfeeding appears to improve children’s cognitive development, according to a report in the May 2008 issue of Archives of General Psychiatry. While several previous studies have reported children and adults who were breastfed as infants have higher scores in thinking, learning and memory development, the current research followed over 14,000 children-mother dyads from birth to age 6.5 years. Additionally, teachers’ ratings found the breastfed children significantly higher academically than the control children – in both reading and writing.

It remains unclear why the benefits exist – it may be due to some ingredient of breast milk, such as essential long-chain fatty acids or a compound known as insulinlike growth factor 1. Or it could be due to the physical or emotional component of breastfeeding that leads to permanent changes affecting brain development.

Although breastfeeding initiation rates are up in the past 30 years, the authors note that more work needs to be done in "increasing the exclusivity and duration of breastfeeding." They endorse "further public health efforts to promote, protect and support breastfeeding."

Another recent study found that breastfeeding helps explain racial and socioeconomic status (SES) disparities in adolescent adiposity. The authors found that having been breastfed for longer than four months was associated with lower adolescent BMI levels and lower odds of having a BMI in the overweight or obese categories – independent of race or parental education. Additionally, this work suggests that being breastfed for longer than four months partially explains the relationship between social disadvantage and increased adiposity. The authors conclude that "increasing breastfeeding duration could result in lower adolescent adiposity for all racial and SES status groups."