Abstract
Background/Aim: The aim of this study was to explore the potential association between ovarian cancer and cataracts using the Longitudinal Health Insurance Research Database (LHIRD) of Taiwan.
Patients and Methods: A retrospective cohort study was conducted, and patients with ovarian cancer were age-matched with non-ovarian cancer patients in a 1:4 ratio. A total of 4,980 and 19,920 participants were classified into the ovarian cancer and non-ovarian cancer groups, respectively. The primary outcome was the presence of cataracts and cataract surgery. Cox proportional hazard regression was used to calculate the adjusted hazard ratio (aHR) and the 95% confidence intervals (CIs) of the primary outcomes between the groups.
Results: A total of 484 and cataract events were recorded in the ovarian cancer group, while 2,383 cataract events were recorded in the non-ovarian cancer group. The ovarian cancer group had a non-significantly higher incidence of cataracts compared to the non-ovarian cancer group (aHR=1.07, 95%CI=0.97-1.19, p=0.074), and the incidences of individuals with advanced cataracts receiving surgery were statistically equal between the ovarian cancer group and the non-ovarian cancer group (aHR=0.93, 95%CI=0.79-1.10, p=0.397). In subgroup analyses, differences in cataract incidences were not significant between ovarian cancer and non-ovarian cancer subgroups with different ages or durations of ovarian cancer (all p>0.05).
Conclusion: Ovarian cancer is associated with a marginally higher incidence of cataracts and cataract surgery.
Introduction
Ovarian cancer is a gynecological cancer with a high prevalence and the fifth leading cause of cancer-associated deaths in the female population (1, 2). Certain predisposing factors, including the utilization of oral contraceptives, delayed childbearing, family history of ovarian cancer, hormone replacement therapy, obesity, early menarche, and preceding endometriosis, can contribute to the development of ovarian cancer (1, 3, 4). The current treatment interventions for ovarian cancer include surgical removal, conventional chemotherapy, and new types of chemotherapy, such as bevacizumab (5, 6). Even with prompt treatment, ovarian cancer has a poor prognosis, and its five-year survival rate is low (7).
Certain diseases are often associated with or develop alongside ovarian cancer (8, 9). For example, the prognosis of ovarian cancer in individuals with type-2 diabetes mellitus (T2DM), a disease caused by insulin resistance, is worse (10). In addition to T2DM, a significant correlation has been reported between ovarian cancer and higher body mass index status (4). Patients with hyperlipidemia, a metabolic syndrome like T2DM, have a higher chance of developing ovarian cancer (11). Apart from metabolic syndrome-related morbidities, dementia is a neurodegenerative condition that is associated with higher oxidative stress and pre-existing ovarian cancer (12, 13).
A cataract is an ophthalmic morbidity that results from the opacification of crystalline lens fibers and presents with blurry vision and a change in refraction status (14). Previous studies have proposed that T2DM and chronic kidney disease are significantly associated with cataract development (15). However, studies on the relationship between ovarian cancer and subsequent cataract development are scarce. Because both ovarian cancer and cataracts are associated with high oxidative stress (16, 17), there may be an association between these two diseases.
This study examined the potential relationship between ovarian cancer and subsequent cataract development using the Longitudinal Health Insurance Research Database (LHIRD) of Taiwan. The incidences of severe cataracts that warranted surgery were also analyzed.
Patients and Methods
Ethics declaration. This study complied with the Declaration of Helsinki of 1964 and its amendments. The study was also approved by the Taiwan National Health Insurance Administration and the Institutional Review Board of Chung Shan Medical University (Project code CS1-20108). The requirement for written informed consent was suspended by these institutions because of the retrospective design of the present study.
Data origin. The Taiwan LHIRD is derived from the Taiwan National Health Insurance Research Database (NHIRD), which contains the medical files of the 23 million Taiwanese people who settled in Taiwan from 1/1/2000 to 12/31/2020. The LHIRD contains the medical files of approximately two million people randomly extracted from the NHIRD using automated software provided by the Taiwan National Health Insurance Bureau. The information contained in the LHIRD and the NHIRD is similar and includes the International Classification of Diseases-Ninth Revision (ICD-9) diagnostic code, International Classification of Diseases-Tenth Revision (ICD-10) diagnostic code, age, sex, job, insurance amount, site of residence, level of education, interval of admission (if available), image claimed codes, laboratory claimed codes, medical division codes, procedure/surgical claimed codes, and the international ATC codes. Only information on image exams, laboratory exams, procedures/surgeries, and medication covered by the Taiwan National Health Insurance Service can be obtained from the LHIRD.
Participant selection. A retrospective cohort study was conducted, and participants in the LHIRD were assigned to the ovarian cancer group if they met the following criteria: 1) diagnosed with ovarian cancer in accordance with ICD-9/ICD-10 diagnostic codes; 2) pelvic ultrasound exam, cancer antigen 125 test, or computed tomography conducted before ovarian cancer diagnosis in accordance with surgical claimed codes; 3) pelvic exam conducted before ovarian cancer diagnosis in accordance with the procedure claimed codes; and 4) ovarian cancer diagnosis provided by a gynecologist in accordance with medical division codes. The index date in the present study was six months after ovarian cancer diagnosis. Several exclusion criteria were adopted: 1) legal blindness diagnosed before the index date in accordance with ICD-9/ICD-10 diagnostic codes, 2) ocular neoplasms diagnosed before the index date in accordance with ICD-9/ICD-10 diagnostic codes, 3) eye removal surgery performed before the index date in accordance with surgical claimed codes, 4) severe ocular trauma diagnosed before the index date in accordance with ICD-9/ICD-10 diagnostic codes, 5) ovarian cancer diagnosed before 2001 or after 2018 to prevent prolonged or inadequate ovarian cancer exposure, and 6) primary outcomes identified before the index date. For comparison, one ovarian cancer participant was age-matched to four non-ovarian cancer patients who constituted the non-ovarian cancer group. A total of 4,980 and 19,920 participants were classified into the ovarian and non-ovarian cancer groups, respectively. The participant selection flowchart is presented in Figure 1.
The flowchart of participant selection. N: Number; LHIRD: Longitudinal Health Insurance Research Database.
Primary outcome. The primary outcome of the present study was the presence of cataracts and prominent cataracts receiving surgery. Cataract in the current study was identified based on these conditions: 1) cataract diagnosis in accordance with ICD-9/ICD-10 diagnostic codes, 2) slit-lamp examination in accordance with procedure claimed codes, and 3) cataract diagnosis in the ophthalmic division. The criterion for prominent cataract surgery included cataract plus cataract surgery in accordance with the surgical claimed code. To evaluate the time between ovarian cancer diagnosis and cataract events more precisely, only cataract events occurring after the index date were classified as the primary outcome. The participants in the present study were monitored until either the primary outcome developed, they left the Taiwan National Health Insurance service, or the last date in the LHIRD (12/31/2020).
Outcome covariates. To more accurately investigate cataract events between the groups, several factors were adjusted for in the analysis: age, days of hospitalization (if available), T2DM, hypertension, dyslipidemia, ischemic heart diseases, peripheral vascular occlusion, corticosteroid usage, end-stage renal disease, and pterygium. The presence of these factors was deduced in accordance with demographic codes, the ICD-9/ICD-10 diagnostic codes, procedure claimed codes, and the ATC codes in the LHIRD. In addition, only confounding factors recorded up to 180 days before the index date in the LHIRD were considered as covariates to standardize the intervals of these factors and their effects on primary outcomes.
Statistical analysis. SAS version 9.4 (SAS Institute Inc, Cary, NC, USA) was used to conduct statistical analyses in the present study. Descriptive analyses were used to determine the demographic status, morbidities, and medications used in the ovarian and non-ovarian cancer groups, and the normality of the study group data was validated using the Shapiro-Wilk test, which showed a normal distribution (p>0.05). The Chi-square test was used to compare the distribution of each factor between the ovarian cancer and non-ovarian cancer groups. Cox proportional hazard regression was used to calculate the adjusted hazard ratio (aHR) and linked 95% confidence interval (CI) of cataract events between the ovarian cancer and non-ovarian cancer groups. The effects of age, length of hospitalization, systemic comorbidities, medications, and ocular disorders were adjusted for in the Cox proportional hazards regression analysis. Regarding subgroup analyses, ovarian cancer patients were categorized by age (50 years) and ovarian cancer duration (<2 years, 2-4 years, and >4 years). After that, Cox proportional hazard regression was conducted again after adjusting for all the factors mentioned above. Statistical significance was represented by p<0.05, and a p-value less than 0.001 was reported as p<0.001.
Results
The initial features of the ovarian cancer and non-ovarian cancer groups are presented in Table I. The age distributions were similar between the two groups (p=0.849), while the length of hospital stay was significantly longer in the ovarian cancer group (p=0.002). Analysis of diseases and medications showed that the ratios of hypertension, T2DM, and ischemic heart diseases were significantly higher in the ovarian cancer group (all p<0.05), while the other indexes did not show significant differences between the ovarian cancer group and the non-ovarian cancer group (all p>0.05) (Table I).
Baseline indexes in the two study cohorts.
During the study interval, 484 and 2,383 events of cataracts were recorded in the ovarian cancer group and the non-ovarian cancer group, respectively. Based on the results of Cox proportional hazard regression, the ovarian cancer group had a non-significantly higher incidence of cataracts compared to the non-ovarian cancer group (aHR=1.07, 95%CI=0.97-1.19, p=0.074) (Table II). Similarly, the incidences of prominent cataracts that received surgery were statistically identical between the ovarian cancer group and the non-ovarian cancer group (aHR=0.93, 95%CI=0.79-1.10, p=0.397) (Table II). In the subgroup analysis, no significant differences in cataract incidence were found between the ovarian cancer and non-ovarian cancer subgroups across different age intervals (both p>0.05) (Table III). Additionally, the possibility of cataract development in the ovarian cancer population compared to the non-ovarian cancer population was not affected by the duration of ovarian cancer (all p>0.05) (Table III).
Risk of main outcome between the two cohorts.
Subgroup analysis for cataract development stratified by age and ovarian cancer duration.
Discussion
In the present study, cataract events in the ovarian cancer group had a non-significantly higher incidence compared to the non-ovarian cancer group. In addition, the incidences of prominent cataracts that received surgery were similar between the two groups. Furthermore, the correlation between ovarian cancer and cataracts was not affected by the difference in age or ovarian cancer duration.
Ovarian cancer has been shown to develop via several pathways (18-20). Genetic mutations are a risk factor for ovarian cancer, with variations in BRCA1 and BRCA2 genes increasing the probability of high-grade serous ovarian carcinoma (21). In addition to gene mutations, steroid hormones such as progesterone and estrogen contribute to the modification of the ovarian environment and a higher risk of ovarian cancer (22). Oxidative stress can also lead to the development of ovarian cancer (23, 24), with the antioxidant-associated gene NRF2 predicting ovarian cancer prognosis (25). A reactive oxygen species, the antioxidant enzyme NAD(P)H:quinone oxidoreductase 1 can influence the effectiveness of ovarian cancer chemotherapy (26), while increasing levels of inducible nitric oxide synthase and superoxide dismutase were observed in women with ovarian cancer (17). Concerning the pathophysiology of cataracts, exposure to ultraviolet light is a known risk factor for cataract development in the general population (15). Additionally, hyperglycemic status impairs crystalline lens fibers, resulting in cataracts (27). Oxidative stress is also positively correlated with the development of cataracts (16). Increasing concentrations of reactive oxygen species and lipid peroxidation were observed in the formed cataracts (28), and total antioxidant capacity and ascorbic acid levels were negatively correlated with the severity of cataracts (29). Because higher oxidative stress was observed in both cases of ovarian cancer and cataracts (16, 17), we speculated that ovarian cancer may be associated with cataract development. This hypothesis was partially supported by the results of the present study.
The ovarian cancer population had a non-significantly higher risk of developing cataracts compared to the individuals without ovarian cancer. Previous population-based research studies showed that ovarian cancer can cause distal diseases such as ischemic stroke (30). However, current evidence of the relationship between ovarian cancer and eye disease is relatively limited. This may be due to the insignificant correlation between ovarian cancer and cataract episodes. We discarded cataract events that developed before the index date; thus, the order of occurrence of ovarian cancer and cataracts may be credible. Moreover, we controlled for several covariates, including age, hypertension, T2DM, and corticosteroid application, which are known risk factors for cataract development, in the Cox proportional hazard regression analysis (15, 31). Although there is no strong correlation between pterygium and cataract development, the development of pterygium correlates with high ultraviolet light exposure, which is also a risk factor for cataract occurrence (15, 32). Thus, the insignificantly higher incidence of cataracts in the ovarian cancer group may be credible. The percentage of cataract events and total person-years were lower in the ovarian cancer group than in the non-ovarian cancer group, potentially due to the higher mortality rate of patients with ovarian cancer compared with the general population (7). However, the aHR of cataracts in the ovarian cancer group was marginally higher than the aHR of the non-ovarian cancer group; this difference may become significant if more patients are enrolled. On the other hand, the incidences of cataract surgeries in the two groups were similar. Because the rates of cataract occurrence were similar between the two groups, it is conceivable that the ratio of prominent cataracts that required surgery did not show any difference between groups.
Regarding subgroup analysis, the incidences of cataract development were not significantly different between the groups based on age differences. Age is a known risk factor for ovarian cancer, with the cancer being more prevalent in women aged 60 to 70 years (33). Additionally, 92.6% of patients aged over 80 years present with cataracts, higher than their younger counterparts (34). In the present study, the aHR of cataracts was higher in patients older than 60 years compared to those younger than 60 years. The lower limit of the 95%CI (0.99) for ovarian cancer patients older than 60 years indicates marginal significance. We speculate that the incidence of cataracts in the ovarian cancer population may be significant if more elderly participants are enrolled. Subgroup analysis stratified by disease interval demonstrated no difference in cataract incidence in ovarian cancer groups with different disease durations. The prolonged disease course associated with ovarian cancer could be correlated with persistent oxidative stress, which should theoretically increase the chances of related morbidity. The results of the present study further indicate that ovarian cancer does not extensively alter the probability of cataract development.
Ovarian cancer is a common cancer in the female population, second only to breast cancer (7). An estimated 230,000 women developed ovarian cancer in 2018 (7), and the annual number of deaths due to ovarian cancer is over 90,000 per year (1). Geographically, Europe, Oceania, and North America have the highest ovarian cancer-related mortality rates (35). Cataract is also a prominent disease and the leading cause of reversible visual impairment or blindness globally (14). Approximately 95 million people have cataracts worldwide (34), and more than one million people receive cataract surgery annually in the United States, causing a huge socioeconomic burden (14). Because both ovarian cancer and cataracts affect many people, any possible correlation between them can be investigated.
Study limitations. The LHIRD and NHIRD are claimed databases, which means that only claimed codes for diagnoses, examinations, and treatments are available. Consequently, multiple critical information, such as the size, location, and laterality of ovarian cancer, the results of ultrasound and computed tomography examinations of ovarian cancer patients, the levels of progesterone and estrogen in ovarian cancer patients, the levels of cancer antigen 125 in ovarian cancer patients, the therapeutic outcomes of ovarian cancer, the recurrence of ovarian cancer (if any), the type of cataracts, the grade of cataracts, the visual acuity of cataract patients, the refractive status of cataract patients, details of cataract surgeries, the outcome of cataract surgery, and details of co-morbidities cannot be evaluated or cannot be evaluated well. Additionally, the retrospective cohort design of the present study makes the homogeneity of the study population lower than that of prospective clinical trials and may result in some bias. Exposure to ultraviolet light and the level of reactive oxygen species are important risk factors for cataract formation; however, we could not consider their effects because the LHIRD did not contain records for these variables. Finally, most of the patients in the LHIRD are Han Taiwanese; thus, the external validity of the present study may be reduced.
Conclusion
In conclusion, ovarian cancer was correlated with marginally higher incidences of cataract development after adjusting for the effects of multiple factors. Furthermore, the incidence of cataracts in the ovarian cancer population was not affected by age or ovarian cancer duration. Consequently, routine ophthalmic examination in the ovarian cancer population is adequate for determining the risk of cataracts. Further large-scale prospective studies are required to evaluate the association between ovarian cancer and other ophthalmic disorders.
Footnotes
Authors’ Contributions
Conceptualization, C.-K.C.; methodology, S.-F.Y. and C.-K.C.; software, C.-K.C.; formal analysis, J.-Y.H.; data curation, Y.-L.C. and C.-K.C.; writing-original draft preparation, C.-Y.L.; writing-review and editing, C.-K.C.; visualization, C.-K.C.; validation, C.-K.C.; supervision, C.-K.C. All Authors have read and agreed to the submitted version of the manuscript.
Conflicts of Interest
The Authors have no proprietary or commercial interest in any materials mentioned in this article.
Funding
None.
- Received March 7, 2025.
- Revision received March 30, 2025.
- Accepted March 31, 2025.
- Copyright © 2025 The Author(s). Published by the International Institute of Anticancer Research.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).







