Objectives To identify the sociodemographic factors associated with variation in area-based breastfeeding in England; to calculate the predicted breastfeeding rates adjusted for sociodemographic variations.

Design Ecological analysis of routine data using random effects logistic regression.

Setting All 151 primary care trusts (PCTs) in England 2010–2011.

Outcome measures PCT level data on breastfeeding: initiation, any and exclusive breastfeeding at 6–8 weeks.

Results There was considerable variation in breastfeeding across PCTs (breastfeeding initiation mean 72%, range 39–93%; any breastfeeding at 6–8 weeks mean 45%, range 19–83%; exclusive breastfeeding at 6–8 weeks mean 32%, range 14–58%), with London PCTs reporting markedly higher rates. Maternal age was strongly associated with area-based breastfeeding, with a 4–6% increase in odds of breastfeeding associated with a unit increase in the percentage of older mothers. Outside London, the proportion of the local population from a Black and Minority Ethnic (BME) background, compared with those from a White British background, was associated with higher breastfeeding (1–3% increase in odds per unit increase in the proportion from a BME background). Area-based deprivation was associated with reduced odds of breastfeeding (21–32% reduced odds comparing most deprived quintile to least deprived quintile). Weaker associations were observed between sociodemographic factors and breastfeeding in London PCTs. Very few PCTs reported breastfeeding figures substantially above or below the national average, having adjusted for variations in sociodemographic factors.

Conclusions Our results show striking associations between sociodemographic factors and breastfeeding at the area level, with much of the variation in breastfeeding rates explained by the sociodemographic profile. The sociodemographic context of breastfeeding is clearly important at the area level as well as the individual level. Our findings can be used to inform decision-making relating to local priorities and service provision.