Risk Factors Associated with Cataracts in Middle-Aged People, an Incidence-Based Case-Control Study in Shiraz, Iran

Background: Cataracts is the most common cause of blindness worldwide. Factors that influence the development of cataracts in middle-aged people have not been thoroughly investigated. Objectives: The purpose of this study was to explore risk factors associated with cataracts among middle-aged patients attended an outpatient clinic in Shiraz, Iran. Methods: This was a case-control study of patients aged 40 to 59 years who were attended Motahari outpatient clinic from February to June 2017. The case subjects were 140 patients who were found to have incident cataracts and controls were 140 age- and sex-matched healthy patients with a normal eye examination. Data were collected by an interviewer-administered questionnaire, an ophthalmologic examination, and the measurement of HbA1c levels. Univariate and conditional logistic regression analyses were used to identify factors that independently predicted the risk of middle-aged cataracts. Results: Our findings showed that a middle-aged cataracts was associated with myopia (odds ratio [OR] = 2.66, P = 0.001), a history of cataracts before age 60 years in patient’s first degree relatives (OR = 2.12, P = 0.009), a low educational level (OR = 1.89, P = 0.020), and overweight or obesity (OR = 1.80, P = 0.039). Prediabetes and diabetes status were not independently associated with the outcome of interest in this age group. Conclusions: A hereditary predisposition may play a primary role in the development of cataracts in middle-aged people. Myopia and cataracts may share a genetic predisposition in this age group. Further genetic studies are recommended to elucidate the pos-sible role of specific genes in the development of middle-aged cataracts.