Correlates of breastfeeding and infant growth in Kenya

Abstract

The benefits of breast milk for infant nutrition are well established. Breastfeeding has been shown to reduce infant morbidity and promote optimal growth during infancy. However, the uptake of breastfeeding globally remains low. The objective of this study was to understand the factors that influence a mother’s decision to breastfeed, and how breastfeeding impacts infant growth. We used data from a cross sectional survey of mother-infant pairs attending week 6 and month 9 infant immunizations at 140 clinics across Kenya. Self-reported breastfeeding practices were collected by standardized questionnaire and infant weight, length, and mid-upper arm circumference were measured. Exclusive breastfeeding was the outcome at 6-week immunizations, while currently breastfeeding and exclusive breastfeeding during the first 6 months of life were outcomes at the 9-month visit. Infant growth was analyzed using weight and length measurements z-scores. Among 1,662 mothers at 6 week and 1,180 at 9-months, the breastfeeding prevalence was 100% and 93% respectively. In multivariable analysis, younger maternal age (<25 years) at 6-weeks postpartum was associated with a 4% (adjusted Prevalence Ratio (aPR)=0.96, 95% CI: 0.93, 0.99, p=0.02) lower prevalence of exclusive breastfeeding compared to older maternal age. HIV-infected mothers had a 5% higher prevalence of exclusive breastfeeding at 6-weeks postpartum (aPR=1.05, 95% CI: 1.01, 1.09, p=0.008) and a 27% higher prevalence (aPR=1.27, 95% CI: 1.17, 1.37, p<0.001) of exclusively breastfeeding during the first six months of life compared to HIV-uninfected mothers. Among HIV-unexposed infants at 6-week visit, exclusive breastfeeding was associated with a 59% (aPR=0.41, 95% CI: 0.22, 0.75, p=0.01) lower prevalence of underweight compared to HIV-unexposed infants that were not exclusively breastfed. Our findings suggest that uptake of breastfeeding is high among mothers in Kenya. HIV-infected mothers had higher prevalence of exclusive breastfeeding at 6-weeks and during the first 6-months of an infants life, but lower prevalence of continued breastfeeding at 9-months postpartum, Lower education and maternal depression were associated with lower prevalence of exclusive breastfeeding for the first 6-month of life in both HIV-infected and HIV-uninfected mothers. Intervention studies to reduce barriers and increase support of breastfeeding among mothers, and longitudinal studies on the effect of breastfeeding on infant growth are needed.