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Learn more: PMC Disclaimer | PMC Copyright Notice BMJ Open . 2025 Dec 31;15(12):e110999. doi: 10.1136/bmjopen-2025-110999 Search in PMC Search in PubMed View in NLM Catalog Add to search Association between pneumoconiosis and cataract risk: a nationwide retrospective cohort study in Taiwan Jen-Suo Cheng Jen-Suo Cheng 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, An Nan Hospital, China Medical University, Tainan, Taiwan Find articles by Jen-Suo Cheng 1 , Yen-Sung Lin Yen-Sung Lin 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, An Nan Hospital, China Medical University, Tainan, Taiwan Find articles by Yen-Sung Lin 1 , Cheng-Li Lin Cheng-Li Lin 2 Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan Find articles by Cheng-Li Lin 2 , Ning-Yi Hsia Ning-Yi Hsia 3 Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan Find articles by Ning-Yi Hsia 3 , Te-Chun Shen Te-Chun Shen 4 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan 5 School of Medicine, China Medical University, Taichung, Taiwan 6 Department of Critical Care Medicine, Chu Shang Show Chwan Hospital, Nantou, Taiwan Find articles by Te-Chun Shen 4, 5, 6, ✉ , Der-Yang Cho Der-Yang Cho 7 Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan Find articles by Der-Yang Cho 7 Author information Article notes Copyright and License information 1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, An Nan Hospital, China Medical University, Tainan, Taiwan 2 Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan 3 Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan 4 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan 5 School of Medicine, China Medical University, Taichung, Taiwan 6 Department of Critical Care Medicine, Chu Shang Show Chwan Hospital, Nantou, Taiwan 7 Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise. None declared. ✉ Dr Te-Chun Shen; [email protected] Received 2025 Sep 17; Accepted 2025 Dec 15; Collection date 2025. Copyright © Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: https://creativecommons.org/licenses/by-nc/4.0/ . PMC Copyright notice PMCID: PMC13059939 PMID: 41475828 Abstract Abstract Objectives To investigate whether pneumoconiosis increases the risk of cataract. Design Nationwide population-based retrospective cohort study. Setting Taiwan’s National Health Insurance database, which covers >99% of the population. Participants The study included 19 841 adults newly diagnosed with pneumoconiosis between 2001 and 2020 and 79 364 age-matched and sex-matched individuals without pneumoconiosis. Participants with a prior history of cataract were excluded. Outcome measures The primary outcome was incident cataract identified through International Classification of Diseases diagnostic codes. Subgroup analyses were performed to evaluate cataract risk across different strata of age, sex and comorbidity. In addition, among patients with pneumoconiosis, we conducted a secondary analysis evaluating the association between systemic corticosteroid use and cataract development. Results During follow-up, the incidence of cataract was significantly higher in the pneumoconiosis cohort (38.9 vs 35.3 per 1000 person-years). Patients with pneumoconiosis had an increased risk of cataract after adjustment for age, sex and comorbidities (adjusted HR (aHR)=1.22, 95% CI 1.18 to 1.26). Elevated risks were observed in both men (aHR=1.22, 95% CI 1.18 to 1.26) and women (aHR=1.20, 95% CI 1.13 to 1.29). All age groups showed increased risks, with the highest estimate observed among patients aged ≥75 years (aHR=1.24, 95% CI 1.19 to 1.30). Subgroup analyses showed an increased risk in patients with pneumoconiosis who had no comorbidities (aHR=1.12, 95% CI 1.07 to 1.18). In a secondary analysis, systemic corticosteroid exposure was not significantly associated with cataract development (adjusted OR=0.65, 95% CI 0.39 to 1.09). Conclusions Pneumoconiosis is associated with an increased risk of cataract. Routine ophthalmologic surveillance should be considered in pneumoconiosis management. Keywords: RESPIRATORY MEDICINE (see Thoracic Medicine), OPHTHALMOLOGY, EPIDEMIOLOGY STRENGTHS AND LIMITATIONS OF THIS STUDY. Uses a large, nationwide population-based cohort from Taiwan’s National Health Insurance database, covering more than 99% of the population, minimising selection bias. Employs a rigorous 1:4 age-matched and sex-matched design with extensive adjustment for comorbidities and medication use, strengthening causal inference. Demonstrates consistent associations across multiple subgroups, including age, sex and comorbidity strata, highlighting the robustness of the findings. Lacks information on lifestyle and occupational factors (eg, smoking, alcohol use, ultraviolet exposure, protective equipment use) and cataract subtypes, which may lead to residual confounding. Introduction Pneumoconiosis is a group of occupational lung diseases caused by the inhalation and accumulation of dust particles in the lungs, leading to chronic airway inflammation, pulmonary fibrosis and impaired respiratory function. 1 It primarily affects workers in mining, construction and manufacturing industries, where exposure to silica, coal and other respirable particulates is common. 2 Although occupational safety has improved over recent decades, pneumoconiosis remains a major public health concern, particularly in developing countries where regulations and their enforcement are insufficient. 3 Beyond its well-recognised respiratory complications, increasing evidence suggests that pneumoconiosis may exert systemic effects, 4 , 6 including potential impacts on ocular health. 7 , 11 Cataract, defined as clouding of the natural lens, is one of the leading causes of visual impairment and blindness worldwide. 12 13 Ageing is the most established risk factor; however, environmental and occupational exposures also play substantial roles in cataractogenesis. 14 15 Prolonged ultraviolet radiation, oxidative stress and metabolic disorders have been associated with cataract formation. 12 13 16 17 Occupational hazards—such as toxic chemicals, dust and physical irritants—have likewise been linked to elevated cataract risk, 7 , 11 underscoring the need for further investigation into workplace-related ocular conditions. The relationship between pneumoconiosis and cataract remains insufficiently understood. Prior studies have primarily focused on siderosis-related cataracts, 7 , 9 with additional evidence linking welding fumes, 10 desert dust exposure, 11 ambient air pollution 18 19 and indoor pollution 20 to cataract risk. These findings suggest that potential mechanisms may involve both direct ocular exposure to particulate matter and systemic inflammatory responses induced by respiratory dust deposition. A large occupational disease registry study in China reported that both pneumoconiosis and cataract were among the more frequently observed conditions, 21 suggesting a possible association between them. Given the limited existing literature, further research is warranted to clarify the relationship between pneumoconiosis and cataract. Therefore, this study aimed to evaluate whether patients with pneumoconiosis have a higher incidence of cataract than the general population using a nationwide retrospective cohort. The findings may inform occupational health policy and potential preventive strategies. Materials and methods Data source Taiwan’s National Health Insurance (NHI) system was established in 1995 and has since covered >99% of the population and included >97% of healthcare institutions. To facilitate academic research, the Ministry of Health and Welfare in Taiwan has established the Health and Welfare Data Science Centre to manage the NHI database. This comprehensive database stores detailed medical records of all insured individuals since 1995. The Health and Welfare Data Science Centre encrypted all personal and identifiable information before data release. The research team obtained legal access to NHI data from 2001 to 2020, covering 23 977 904 individuals. Protocol refinement The original approved research protocol (CMUH113-REC1-145) was designed to investigate the risk of ocular disorders in patients with occupational lung disease using the Taiwan NHI database. The present analysis represents a refinement of that protocol. Specifically, among the spectrum of occupational lung diseases, we focused on pneumoconiosis, which is the most prevalent and clinically important condition in Taiwan and globally. Likewise, within the broad category of ocular disorders, we restricted the analysis to cataract, the most common and representative outcome with substantial biological plausibility and epidemiological evidence of association ( online supplemental table ). Such narrowing of scope from a broader protocol is consistent with the principle of focusing on the most relevant exposures and outcomes and remains within the range of the approved study aims. No analyses outside the original protocol were conducted. Patient and public involvement None. Case and control cohorts All newly diagnosed pneumoconiosis cases between 2001 and 2020 were included in this study. Pneumoconiosis was defined based on International Classification of Diseases (ICD) codes 500–505 and J60–J65. A patient was identified as having pneumoconiosis if the ICD code appeared in one hospitalisation record or two outpatient records. Individuals diagnosed with cataract before the diagnostic date were excluded. A 1:4 matched control cohort was established using the previously identified pneumoconiosis cohort. Controls were selected based on age, sex and diagnostic date, ensuring comparability. Individuals diagnosed with cataract before the diagnostic date were also excluded. After establishing the disease and control cohorts, each patient with pneumoconiosis was matched with four non-pneumoconiosis controls of the same age and sex, with neither group being previously diagnosed with cataract. Many studies have reported similar methodologies. 5 6 22 23 The use of ICD codes for disease classification in Taiwan’s NHI system has been extensively validated, with positive predictive values ranging from 80% to 99% in most studies. 24 The study followed both the pneumoconiosis and control cohorts from the diagnostic date until the cataract occurrence, NHI system withdrawal, death or 31 December 2021, whichever came first ( figure 1 ). Figure 1. The protocol of study participants’ enrolment. Open in a new tab Study objectives and covariates The primary outcome of this study was the cataract incidence identified using ICD codes 366, H25, H26 and H28. The study considered age, sex and comorbidities as covariates. Relevant comorbidities, including hypertension (ICD codes 401–405, I10–I16), diabetes mellitus (ICD codes 250, E08–E13), hyperlipidaemia (ICD codes 272 and E78), and asthma and chronic obstructive pulmonary disease (COPD) (ICD codes 491–493, 496, J41–J45), were identified before the index date for statistical adjustments. Cataract and comorbidity definitions followed the same criteria as pneumoconiosis, requiring one hospitalisation or two outpatient diagnoses for classification. Statistical analysis Baseline characteristics were compared using χ 2 tests for categorical variables and t-tests for continuous variables. Kaplan–Meier survival analysis was used to estimate the cumulative incidence of cataract in the pneumoconiosis and control cohorts, with log-rank tests applied to assess statistical significance. Cox proportional hazards regression models (both univariate and multivariate) were used to estimate crude and adjusted HRs with 95% CIs. To evaluate the potential impact of corticosteroid exposure, we additionally assessed systemic corticosteroid use after pneumoconiosis diagnosis, defined as more than 28 cumulative days of systemic corticosteroid use, and compared cataract risk between users and non-users using multivariable logistic regression. Because patients with pneumoconiosis experience higher mortality rates, we further applied the Fine–Grey competing risk model, treating death as a competing event, to estimate subdistribution HRs (sHRs) while accounting for the competing risk of death. All statistical analyses were performed using SAS software V.9.4 (SAS Institute, Cary, North Carolina, USA). Results The present study enrolled a total of 19 841 patients with pneumoconiosis and 79 364 individuals without pneumoconiosis. The baseline characteristics of the study population are listed in table 1 . The age and sex distributions were similar between the pneumoconiosis and control groups. However, the prevalence of comorbidities differed significantly between the pneumoconiosis and non-pneumoconiosis groups, including hypertension (38.5% vs 41.0%, p<0.001), diabetes mellitus (15.3% vs 18.5%, p<0.001), hyperlipidaemia (21.0% vs 22.2%, p<0.001) and asthma/COPD (34.3% vs 14.7%, p<0.001). The mean follow-up times were 7.47±6.18 years for the pneumoconiosis group and 7.55±6.09 years for the control group. Table 1. Characteristics for individuals with and without pneumoconiosis. Pneumoconiosis P value * No Yes N=79 364 N=19 841 n % n % Age 0.99 20–64 13 024 16.4 3256 16.4 65–74 29 092 36.7 7273 36.7 ≥75 37 248 46.9 9312 46.9 Mean±SD 62.0 ±13.6 62.1 ±13.5 0.35 Gender 0.99 Men 65 308 82.3 16 327 82.3 Women 14 056 17.7 3514 17.7 Comorbidity Hypertension 32 506 41.0 7640 38.5 <0.001 Diabetes mellitus 14 680 18.5 3028 15.3 <0.001 Hyperlipidaemia 17 593 22.2 4168 21.0 <0.001 Asthma/COPD 11 677 14.7 6800 34.3 <0.001 Open in a new tab * χ2 test and t-test. COPD, chronic obstructive pulmonary disease. The findings revealed a significantly higher incidence of cataract in the pneumoconiosis cohort compared with the control cohort, with incidence rates of 38.9 and 35.3 per 1000 person-years, respectively ( table 2 ). This translates to a crude 1.10-fold increased risk of developing cataract among patients with pneumoconiosis compared with individuals without the disease. After adjusting for age, sex, comorbidities and medication use, the adjusted HR (aHR) for cataract development in patients with pneumoconiosis was 1.22 (95% CI 1.18 to 1.26), showing a significantly elevated risk. Table 2. Risk factor analyses for cataract among all study individuals. Event PY Rate * Crude HR (95% CI) Adjusted HR † (95% CI) Pneumoconiosis No 21 171 599 151 35.3 1 (Reference) 1 (Reference) Yes 5761 148 254 38.9 1.10 (1.07 to 1.13) ‡ 1.22 (1.18 to 1.26) ‡ Age 20–64 1652 220 051 7.51 1 (Reference) 1 (Reference) 65–74 11 757 287 727 40.9 5.55 (5.27 to 5.85) ‡ 5.46 (5.18 to 5.76) ‡ ≥75 13 523 239 627 56.4 7.78 (7.38 to 8.19) ‡ 7.48 (7.09 to 7.90) ‡ Gender Men 5046 169 720 29.7 1 (Reference) 1 (Reference) Women 21 886 577 684 37.9 1.23 (1.19 to 1.27) ‡ 0.91 (0.88 to 0.94) ‡ Comorbidity Hypertension 11 796 224 873 52.5 1.77 (1.72 to 1.81) ‡ 1.10 (1.07 to 1.13) ‡ Diabetes mellitus 5664 88 068 64.3 1.93 (1.88 to 1.99) ‡ 1.39 (1.35 to 1.44) ‡ Hyperlipidaemia 6966 129 717 53.7 1.61 (1.57 to 1.66) ‡ 1.23 (1.19 to 1.26) ‡ Asthma/COPD 5035 96 511 52.2 1.50 (1.46 to 1.55) ‡ 1.21 (1.17 to 1.25) ‡ Open in a new tab * Incidence rate per 1000 person-years. † Multivariable analysis including age, gender and comorbidity. ‡ p<0.001. COPD, chronic obstructive pulmonary disease; PY, person-years. Subgroup analyses consistently revealed that a higher risk of cataract development across age groups, sex and comorbidity status ( table 3 ). Specifically, the risk was most pronounced in individuals aged ≥75 years (aHR=1.24, 95% CI 1.19 to 1.30). Similarly, both men (aHR=1.22, 95% CI 1.18 to 1.26) and women (aHR=1.20, 95% CI 1.13 to 1.29) with pneumoconiosis exhibited a significantly higher risk than their non-pneumoconiosis counterparts. Among patients with pneumoconiosis without comorbidities, the risk of cataract remained higher than in the control cohort (aHR=1.12, 95% CI 1.07 to 1.18). Table 3. Incidence and HRs of cataract for individuals with and without pneumoconiosis by age, gender and comorbidity. Pneumoconiosis Crude HR (95% CI) Adjusted HR * (95% CI) No Yes Event PY Rate † Event PY Rate † Age 20–64 1260 176 934 7.12 392 43 116 9.09 1.28 (1.14 to 1.43) ‡ 1.22 (1.08 to 1.36) ‡ 65–74 9264 230 866 40.1 2493 56 861 43.8 1.09 (1.04 to 1.14) ‡ 1.15 (1.10 to 1.21) ‡ ≥75 10 647 191 351 55.6 2876 48 276 59.6 1.08 (1.03 to 1.12) ‡ 1.24 (1.19 to 1.30) ‡ Gender Men 17 275 463 202 37.3 4611 114 482 40.3 1.08 (1.05 to 1.12) ‡ 1.22 (1.18 to 1.26) ‡ Women 3896 135 949 28.7 1150 33 772 34.1 1.19 (1.11 to 1.27) ‡ 1.20 (1.13 to 1.29) ‡ Comorbidity § No 8377 349 260 24.0 2051 75 595 27.1 1.13 (1.08 to 1.19) ‡ 1.12 (1.07 to 1.18) ‡ Yes 12 794 249 891 51.2 3710 72 659 51.1 1.00 (0.96 to 1.04) 1.02 (0.99 to 1.06) Open in a new tab * Multivariable analysis including age, gender and comorbidity. † Incidence rate per 1000 person-years. ‡ p<0.001. § Individuals with any comorbidity of hypertension, diabetes, hyperlipidaemia and asthma/chronic obstructive pulmonary disease were classified into the comorbidity group. PY, person-years. To further evaluate whether corticosteroid exposure contributed to cataract development, we examined systemic corticosteroid use after pneumoconiosis diagnosis. As shown in table 4 , patients who received systemic corticosteroids more than 28 cumulative treatment days did not have a significantly increased risk of cataract compared with non-users (adjusted OR (aOR)=0.65, 95% CI 0.39 to 1.09). Because patients with pneumoconiosis experience higher mortality, we additionally performed a Fine–Grey competing risk analysis, treating death as a competing event. The results ( table 5 ) remained consistent with our primary Cox regression results. Pneumoconiosis remained significantly associated with cataract (adjusted sHR=1.21, 95% CI 1.11 to 1.29). Table 4. Events and ORs of cataract-associated corticosteroid use and dose for patients with pneumoconiosis. Non-cataract Cataract Adjusted OR * (95% CI) Non-corticosteroid user 8148 57.9% 3960 68.7% 1.00 (Reference) Corticosteroid user 5932 42.1% 1801 31.3% 0.65 (0.39 to 1.09) Open in a new tab * The model was adjusted for age, sex and comorbidities. Table 5. Subhazard ratios of cataract for individuals with and without pneumoconiosis by age, gender and comorbidity. Crude SHR (95% CI) Adjusted SHR * (95% CI) Pneumoconiosis 1.10 (1.07 to 1.13) † 1.21 (1.11 to 1.29) † Age 20–64 1.28 (1.14 to 1.43) † 1.28 (1.13 to 1.44) † 65–74 1.09 (1.05 to 1.14) † 1.12 (1.07 to 1.18) † ≥75 1.08 (1.04 to 1.12) † 1.22 (1.17 to 1.27) † Gender Men 1.08 (1.05 to 1.12) † 1.22 (1.18 to 1.27) † Women 1.19 (1.12 to 1.27) ‡ 1.20 (1.12 to 1.29) † Comorbidity § No 1.13 (1.08 to 1.19) † 1.24 (1.18 to 1.31) † Yes 1.00 (0.96 to 1.04) 1.17 (1.12 to 1.21) † Open in a new tab * Multivariable analysis including age, gender and comorbidity. † p<0.01. ‡ p<0.001. § Individuals with any comorbidity of hypertension, diabetes, hyperlipidemia, and asthma/chronic obstructive pulmonary disease were classified into the comorbidity group. PY, person-years; SHR, subhazard ratio. Kaplan–Meier survival analysis demonstrated a significantly higher cumulative incidence of cataract in the pneumoconiosis group than the control group (p<0.001) ( figure 2 ). The survival curves diverged early during the follow-up period and continued to separate over time. Figure 2. Cumulative incidence of cataract for individuals with and without pneumoconiosis. Open in a new tab Discussion This study provides compelling evidence that pneumoconiosis is significantly associated with an increased risk of cataract. Using a large, nationwide cohort, a higher incidence of cataract was observed in patients with pneumoconiosis than those in the control cohort, with the association remaining robust even after adjusting for age, sex and comorbidities. Our findings underscore the need to consider ocular health as part of the broader spectrum of systemic complications associated with pneumoconiosis. The possible explanation for the observed association between pneumoconiosis and cataract lies in two distinct but plausible mechanistic pathways. First, systemic inflammatory responses triggered by chronic pulmonary dust deposition may contribute to cataractogenesis. Persistent lung inflammation in pneumoconiosis can lead to the release of circulating cytokines and increased oxidative stress, both of which are known to disrupt lens protein stability, promoting denaturation and aggregation. 25 , 28 This systemic effect parallels mechanisms observed in pneumoconiosis-related cardiovascular diseases, where inflammation originating in the lungs exerts distant effects on other organ systems. 29 30 Second, direct exposure of the ocular surface to dust particles, particularly in occupational environments lacking adequate eye protection, may result in localised lens damage. Airborne particulate matter can physically irritate or penetrate the anterior segment of the eye, potentially accelerating cataract formation. 1011 18 , 20 This pathway is especially relevant in labour-intensive settings where ocular safety measures may be insufficient. In addition to the potential mechanisms described above, corticosteroid exposure warrants consideration given its known association with posterior subcapsular cataracts. However, in our study, systemic corticosteroid use after pneumoconiosis diagnosis did not demonstrate a significant increase in cataract risk. In stratified and dose-related analyses, corticosteroid users showed no elevated odds of cataract compared with non-users, and the inverse point estimates likely reflect treatment indication bias, survival bias or unmeasured confounding rather than any true protective effect (data not shown). Therefore, corticosteroid exposure does not appear to account for the increased cataract risk observed in patients with pneumoconiosis in this cohort. Age-stratified analysis revealed that the risk of cataract was highest in individuals aged 75 and older, a finding consistent with the well-established role of ageing in cataract development. 31 However, even among younger patients with pneumoconiosis (aged 20–64 years), the increased risk remained statistically significant, suggesting that occupational exposure may contribute to premature cataract formation, emphasising the importance of early screening and intervention in high-risk workers. Kaplan–Meier survival analysis demonstrated that the cumulative incidence of cataract in patients with pneumoconiosis significantly increased over time compared with the control group, further supporting the long-term effects of occupational dust exposure on ocular health. Given the chronic and progressive nature of pneumoconiosis, this finding emphasises the need for continuous ophthalmologic monitoring in affected individuals. Moreover, the potential impact of competing mortality warrants further consideration, given that patients with pneumoconiosis have substantially higher all-cause mortality than the general population. In conventional Cox models, deaths occurring before cataract diagnosis are treated as non-informative censoring events, potentially leading to an overestimation of cataract incidence if death is related to both pneumoconiosis and the censoring mechanism. To address this methodological concern, we applied a Fine–Grey competing risk model using death as a competing event. The competing-risk–adjusted subdistribution HR remained significant and was highly consistent with the primary Cox regression estimate, indicating that the elevated cataract risk among pneumoconiosis patients persists even when accounting for differential mortality. These findings suggest that informative censoring due to death did not materially bias our results and reinforce the robustness of the observed association. Nonetheless, competing mortality may still attenuate the absolute incidence of cataract in real-world clinical settings, implying that early ophthalmologic assessment may be particularly important for high-risk workers who may not survive long enough to develop clinically apparent cataracts. The use of a large, well-characterised nationwide database with extensive follow-up data is a major strength of this study. The high coverage rate of Taiwan’s NHI system (>99.9%) minimises selection bias and ensures a representative sample of the general population. 32 33 Furthermore, the rigorous cohort matching process helped control for potential confounding variables, increasing the reliability of our findings. However, several limitations should be acknowledged. First, disease classification relied on ICD codes, which may introduce misclassification bias. Nevertheless, Taiwan’s NHI database undergoes routine expert review and validation, reducing the likelihood of diagnostic errors. Second, the database does not contain information on important lifestyle and occupational factors, including smoking, alcohol consumption, ultraviolet exposure, use of protective eyewear and workplace protective practices. These unmeasured confounders may influence cataract risk and potentially bias our findings. For example, smoking and UV exposure are known to increase cataract formation, and insufficient protective eyewear in high-dust environments may further elevate ocular risk; these factors could bias the association away from the null. In contrast, alcohol consumption may exert mixed effects depending on drinking patterns. Third, laboratory parameters, imaging data and precise cataract subtype classifications were unavailable, limiting our ability to explore underlying biological mechanisms more comprehensively. Conclusion This nationwide cohort study provides evidence that patients with pneumoconiosis have an increased risk of cataract after adjustment for age, sex and major comorbidities. Given the chronic nature of pneumoconiosis and its systemic health implications, routine ophthalmologic surveillance may warrant incorporation into clinical management. Integrating regular eye examinations into occupational health surveillance programmes may facilitate earlier detection and intervention for cataract in this high-risk population. Supplementary material online supplemental file 1 bmjopen-15-12-s001.docx (27.9KB, docx) DOI: 10.1136/bmjopen-2025-110999 Acknowledgements We are grateful to the MOHW Health and Welfare Data Science Centre at China Medical University for providing administrative and technical support. Footnotes Funding: The study was supported by An Nan Hospital (ANHRF113-01). The funding source had no involvement in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication. Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online ( https://doi.org/10.1136/bmjopen-2025-110999 ). Provenance and peer review: Not commissioned; externally peer reviewed. Patient consent for publication: Not applicable. Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research. Ethics approval: The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of China Medical University Hospital (CMUH-113-REC1-145). 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