Association between alcohol and tobacco use and primary open-angle glaucoma: the Eyes of Africa study

Abstract Background Primary open-angle glaucoma (POAG) is the most prevalent glaucoma subtype globally and has disproportionately high rates in Africa. While smoking and alcohol consumption are established risk factors for several ocular conditions, their associations with POAG remain unclear. This study examined substance use patterns among individuals with and without POAG in sub-Saharan Africa. Methods This cross-sectional study included 9,418 participants aged ≥ 40 years (5,189 POAG cases and 4,229 controls) from the Eyes of Africa: Genetics of Blindness study conducted across Nigeria, Ghana, and Malawi between 2017 and 2023. Comprehensive ocular examinations were performed, and POAG was diagnosed according to the International Society of Geographical and Epidemiologic Ophthalmology criteria. Sociodemographic data and detailed information on the use of substances including alcohol, tobacco, pharmaceutical substances, and illicit drugs, were collected through structured interviews. Chi-squared tests were used to examine the associations between variables, and multivariable logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for substance use and POAG status. Results Alcohol consumption and tobacco smoking were strongly and independently associated with POAG ( P < 0.001). Former (OR = 1.49; 95% CI: 1.33–1.66; P < 0.001) and current drinkers (OR = 1.15; 95% CI: 1.00–1.31; P = 0.04) had higher odds than never-drinkers. Lifetime heavy episodic drinking (> 2 drinks per occasion) was associated with 40% higher odds of POAG (95% CI: 1.20–1.65; P < 0.001) than having ≤ 2 drinks. Tobacco use was also independently associated with POAG among both former (OR = 1.38; 95% CI: 1.13–1.68; P = 0.002) and current smokers (OR = 1.46; 95% CI: 1.12–1.91; P = 0.005). In addition, older age, male sex, higher educational level, and unemployment (all P < 0.001) were independently associated with POAG. Conclusion Cigarette smoking and alcohol use are significantly associated with increased risk of POAG in this African population, representing potentially modifiable risk factors. Confirmatory longitudinal studies are needed to establish causality. If validated, public health strategies for POAG prevention in Africa should incorporate substance use reduction as a key component of primary prevention.