Malay Glaucoma Eye Study: cigarette smoking and primary angle closure glaucoma

Abstract

Introduction: The detrimental effects of cigarette smoking include impairment of optic nerve head perfusion and elevation of oxidative stress levels, which are believed to be part of the pathogenesis of glaucoma. However, there is no evidence on the effect of cigarette smoking as a risk for primary angle-closure glaucoma (PACG). Purpose: To determine the association between cigarette smoking and PACG in Malay patients. Study design: Case control study. Materials and methods: Two-hundred Malay PACG patients and 250 controls from  three tertiary hospitals in Malaysia were involved in this study. PACG patients were diagnosed based on the World Glaucoma Association consensus. The smoking status was documented using validated questionnaire adopted from Singapore Malays Eye Study through face-to-face interview. Smoking status was divided into active smokers, ex-smokers, passive smokers, and non-smokers. The association of smoking and PACG was analysed with multiple logistic regression. Confounders such as age, gender, education status, and body mass index (BMI) were considered in the analysis. Results: There was female preponderance in PACG with 3:1 ratio. Active smokers (p = 0.656) and ex-smokers (0.073) were not significantly associated with PACG in Malays. Passive smoking significantly increased the risk of PACG by 6.8-fold (95% CI 2.49,18.67; p < 0.001). Number of cigarettes/day (p = 0.144) and duration of smoking (p = 0.176) were also not significantly associated with PACG (p = 0.144). No formal education, primary and secondary education level increased the risk of PACG (p < 0.001). Each unit increment of BMI increased the risk of PACG by 1.14-fold (95% CI 1.03, 1.27; p = 0.014). A year increased in age increased the risk by 1.05 times (95% CI 1.00, 1.09; p = 0.026). Conclusions: There is no significant association between active smoking and PACG. Passive smoking is a potential risk factor for PACG. The preponderance of women may contribute to this result. However, quantification of exposure to passive smoking is not possible in this study.