Cataract incidence was higher among patients diagnosed with pneumoconiosis in a nationwide Taiwanese cohort, according to a recent study.
In a nationwide retrospective cohort study from Taiwan, researchers compared nearly 20,000 adults with pneumoconiosis and more than 79,000 matched controls to evaluate whether occupational lung disease was associated with subsequent cataract development. After adjustment for age, sex, comorbidities, and medication use, pneumoconiosis was associated with a 22% increased risk of cataract. The association was consistent across sex and age strata and remained evident among patients without major comorbidities. Systemic corticosteroid exposure was not significantly associated with cataract development.
Researchers used data from Taiwan's National Health Insurance database, which covers more than 99% of the population, to identify 19,841 adults newly diagnosed with pneumoconiosis between 2001 and 2020. Each patient was matched with four patients without pneumoconiosis by age, sex, and diagnostic date, yielding a comparison cohort of 79,364 patients. Patients with a history of cataract before the index date were excluded. Pneumoconiosis and cataract were identified using validated International Classification of Diseases diagnostic codes, defined by one inpatient or two outpatient diagnoses. Follow-up continued until cataract diagnosis, death, withdrawal from the insurance system, or December 31, 2021.
The primary outcome was incident cataract. Covariates included age, sex, hypertension, diabetes mellitus, hyperlipidemia, and asthma or chronic obstructive pulmonary disease (COPD). Group characteristics at baseline were evaluated using chi-square analyses for categorical measures and t tests for continuous measures. Kaplan-Meier analyses were used to estimate cumulative cataract incidence, and Cox proportional hazards models were applied to calculate crude and adjusted hazard ratios. Given the higher mortality among patients with pneumoconiosis, Fine-Gray competing risk models were used to account for death as a competing event.
During a mean follow-up of approximately 7.5 years, cataract incidence was higher in the pneumoconiosis cohort than in controls, at 39 vs 35 per 1,000 person-years. Increased cataract risk was observed in both men and women. All age groups demonstrated elevated risk, with the highest estimate among patients aged 75 years or older. Among patients with pneumoconiosis and no comorbidities, cataract risk remained higher than in controls. In a secondary analysis limited to the pneumoconiosis cohort, systemic corticosteroid use exceeding 28 cumulative days was not significantly associated with cataract development. Competing risk analyses yielded results consistent with the primary findings.
Several limitations should be acknowledged. Case identification was based on administrative diagnostic codes, which introduces the possibility of misclassification, although prior validation and routine expert review of Taiwan's National Health Insurance database support overall diagnostic reliability. In addition, the database lacked information on lifestyle and occupational exposures, such as smoking, alcohol use, ultraviolet radiation, protective eyewear use, and workplace safety practices, which may contribute to residual confounding. The absence of these variables may affect estimates of cataract risk. Finally, data on laboratory measures, imaging findings, and specific cataract subtypes were not available, limiting evaluation of potential biological pathways.
The study was funded by An Nan Hospital, and the researchers reported no competing interests, wrote Te-Chun Shen, MD, of China Medical University Hospital, and colleagues.
Source: BMJ Open
