Association between cigarette smoking prevalence and income level: a systematic review and meta-analysis

Article type
Year
Authors
Bardach A1, Ciapponi A1, Casetta B2, Videla A3, Morello P1, Soto N1, Lee K4, Camacho PA5, Hermoza Moquillaza RV6
1Argentine Cochrane Center, Institute for Clinical Effectiveness and Health Policy (IECS), Argentina
2Direction of Non-Communicable Diseases, Ministry of Health, Buenos Aires , Argentina
3Direction of Non-Communicable Diseases, Ministry of Health, Buenos Aires, Argentina
4Deakin University, Melbourne, Australia
5Dirección de investigaciones, Fundación Oftalmológica de Santander. Bucaramanga, Colombia
6Facultad de Salud Pública y Administración de la Universidad Peruana Cayetano Heredia, Lima, Perú
Abstract
Background: Previous evidence has associated socioeconomic status and smoking.

Objective: To assess the association between socioeconomic status and smoking prevalence worldwide.

Methods: Systematic review and meta-analysis of observational studies (Mantel-Haenszel random-effects models) summarizing adjusted odds ratios (ORs) and 95% confidence intervals (CI). Heterogeneity was assessed by the I2 statistic. We performed subgroup analyses for continents, World Health Organization (WHO) regions, country mortality, gender, age, risk of bias and study decade. Independent reviewers selected studies, assessed potential bias and extracted data. We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), SocINDEX, African Index Medicus, and LILACS, and other sources for studies from 1989 to 2013 reporting direct measurements of income and current cigarette smoking. Funding: WHO.

Results: We retrieved 13,583 articles, included 201 and meta-analyzed 93. Median smoking prevalence: 17.8% (95% CI 3% to 70%). Lower income was associated with higher smoking prevalence. The direction of the association was consistent across all subgroups and was statistically significant for most of them (Table 1). Analyzing three categories of income, prevalence was highest in the lowest income levels compared to the middle, followed by the middle level compared to the highest either considering all studies or subgroups by gender and age group (Table 2).

Conclusions: Our results show that current cigarette smoking is significantly associated with lower income worldwide and across subgroups with a dose-response relationship.