Risk Factors for Pterygium in Ilam Province, Iran

Purpose: To evaluate the risk factors for pterygium in the dry, high altitude province of Ilam, Iran. Methods: The study included patients who presented to ophthalmology clinic. The patients were divided into two groups: 210 diagnosed with pterygium or pinguecula (unilateral or bilateral), and 210 healthy controls. Demographic variables, living environment, disease type, disease laterality, family history of pterygium as well as history of smoking, working outdoors, baking, welding, ocular conditions (trachoma keratopathy, glaucoma, refractive error, and dry eye), use of glasses, ultraviolet light exposure, and systemic conditions were collected from both groups and compared for risk assessment. Results: Univariate analysis revealed that age (P = 0.001), sex (P = 0.001), family history of pterygium (P = 0.001), positive history of smoking (P < 0.001), history of baking (P = 0.045), welding experience (P < 0.001), severe blepharitis (P < 0.001), hyperopia (P < 0.001), dry eye (P < 0.001), hypertension (P < 0.001), ischemic heart disease (P < 0.001), obesity (P = 0.038), and primary residential area (P = 0.025) had significant associations with increased incidence of pterygium. However, in multivariate analysis, only family history of pterygium, cigarette smoking, history of baking, age, and severe blepharitis were significantly associated with the incidence of pterygium (P<0.001, P<0.001, P = 0.002, P = 0.023 and P = 0.002, respectively). Conclusion: This study tested more risk factors related to the prevalence of pterygium compared to previous studies. It also confirmed previously established risk factors. Family history of pterygium and blepharitis were risk factors that have not been reported in previous studies and were found to be significantly associated with the development of pterygium in this study.