Is individual smoking behaviour influenced by area level ethnic density? A cross-sectional electronic health database study of inner south east London

smoking remains one of the greatest public health problems facing the UK today. It varies significantly by ethnic group. This study aimed to determine whether ethnic differences in smoking behaviour are related to neighbourhood level own-group ethnic density across south and east London. The association between ethnic density and individual smoking behaviour was assessed by multilevel logistic regression using the electronic health records of 688,397 GP registered patients. Restricted cubic splines were created to explore whether the effect of ethnic density on smoking behaviour was non-linear. Increasing own-group ethnic density was found to be associated with a significant reduction in the odds of being a current smoker in all ethnic groups, except for Caribbean women. The relationship between ethnic density and current smoking was found to be non-linear, with the strength of association varying significantly by gender and ethnic group. These novel findings point to a complex relationship between culture, neighbourhood level experience of adversity or social support and smoking behaviour, and will allow us to target smoking cessation services differentially to individuals/groups living in relative ethnic isolation, who do not benefit from the potential cultural/social factors associated with reduced tobacco consumption.This study was funded by a grant from The Curriers Company.The project was supported by a Curriers' Company Millennium Healthcare Bursary