Epidemiology and Associated Morbidity of Pterygium: A Large, Community-Based Case-Control Study

Background: To evaluate the prevalence and risk factors of various conditions among patients with pterygium. Methods: A retrospective observational case control study of 4,037 patients who were diagnosed with pterygium in the Central District of Clalit Health Services in Israel from 2000–2009. A total of 16,054 randomly selected controls from the district HMO members. Personal, medical, and demographic information were extracted from patients’ files. We calculated the prevalence of various ocular, systemic, and demographic conditions as risk factors for pterygium. Results: The average age of pterygium patients was 58.4 ± 14 years; 56.9% were male. A significant tendency to develop pterygium was found among individuals of lower socioeconomic status (p < 0.001) and in populations living in rural areas (p < 0.001). A logistic regression model adjusted to marital status, socio-economic class, and area of living was performed. The following conditions were significantly associated with pterygium: blepharitis (OR = 1.71; 99.9% CI: 1.53–1.93), chalazia (OR = 1.46; 99.9% CI: (1.19–1.78)), anxiety (OR = 1.14, 99.9% CI: 0.98–1.33), and G₆PD deficiency (OR = 1.85; 99.9% CI: 1.11–3.07). Schizophrenia (OR 0.31; 99.9% CI: 0.19–0.50) and smoking (OR 0.82; 99.9% CI: 0.76–0.89) were significantly less prevalent among pterygium patients. Conclusions: Pterygium etiology is multifactorial. Some demographic, systemic, and periocular conditions are significantly more prevalent and some are less prevalent among pterygium patients. Better understanding of the pathophysiological association between those diseases and pterygium may help in its prevention and treatment.