The socioeconomic gradient of secondhand smoke exposure in children: evidence from 26 low-income and middle-income countries.
To provide the first analysis of socioeconomic inequalities in children's daily exposure to indoor smoking in households in 26 low-income and middle-income countries (LMICs).



We used nationally representative household samples (n=369 654) collected through the Demographic Health Surveys between 2010 and 2014 to calculate daily exposure to secondhand smoke (ESHS) among children aged 0-5 years. The relative and absolute concentration (RC and AC) indices were used to quantify wealth-based inequalities in daily ESHS in each country and in urban and rural areas in each country. We decomposed total socioeconomic inequalities in ESHS into within-group and between-group (rural-urban) inequalities to identify the sources of wealth-based inequality in ESHS in LMICs.



We observed substantial variation across countries in the prevalence of daily ESHS among children. Children's ESHS was higher in rural areas compared to urban areas in the majority of the countries. The RC and AC demonstrated that daily ESHS was concentrated among poorer children in almost all countries (RC, median=-0.179, IQR=0.186 and AC, median=-0.040, IQR=0.055). The concentration of ESHS among poorer children was greater in urban relative to rural areas. The decomposition of the overall socioeconomic inequality in daily ESHS revealed that wealth-based differences in ESHS within urban and rural areas were the main contributor to socioeconomic inequalities in most countries (median=46%, IQR=32%).



Special attention should be given to reduce ESHS among children from rural and socioeconomically disadvantaged households as social inequalities in ESHS might contribute to social inequalities in health over the life course.
Faculty of Health Professions, School of Health Administration, Dalhousie University, Halifax, Nova Scotia, Canada.
Mohammad
M
Hajizadeh
Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada.|Institute for Health and Social Policy, McGill University, Montreal, Quebec, Canada.
Arijit
A
Nandi
D000067576:Child Health / Q000706:statistics & numerical data*; D002675:Child, Preschool; D003906:Developing Countries; D005260:Female; D054624:Health Status Disparities; D006306:Health Surveys; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011203:Poverty; D015995:Prevalence; D012423:Rural Health / Q000706:statistics & numerical data; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*; D014504:Urban Health / Q000706:statistics & numerical data
D014028:Tobacco Smoke Pollution
Disparities; Low/Middle income country; Secondhand smoke; Socioeconomic status