Der-Chong Tsai

Epidemiology of Idiopathic Central Serous Chorioretinopathy in Taiwan, 2001–2006: A Population-based Study

Objectives The epidemiology of idiopathic central serous chorioretinopathy (CSCR) is not well understood in an Asian population. The present study aimed to investigate the incidence and risk factors for corticosteroid-unrelated CSCR using Taiwan’s National Health Insurance Research Database. Methods and Results From 2001 to 2006, a total of 786 patients (500 [63.6%] males) who were newly diagnosed with CSCR, aged from 20 to 64 years and had no history of corticosteroid prescription were identified as incident cases of idiopathic CSCR. 3606 age-, gender-, and enrollment time-matched subjects were randomly selected as the control group. The mean annual incidence was 0.21‰ (0.27‰ for males, and 0.15‰ for females; P<0.001), with a male/female ratio of 1.74. The peak incidence was in the 35- to 39-year-old age group (0.30‰), followed by the 40- to 44-year-old age group (0.26‰). Males had a significantly higher mean annual incidence than female only in the middle age groups. Conditional logistic regression was used to estimate the odds ratios (ORs) for potential risk factors of idiopathic CSCR. Only exposure to anti-anxiety drugs (OR, 1.63; 95% confidence interval, 1.09–2.44) was found to be independently associated with idiopathic CSCR among males. No risk factors of idiopathic CSCR were found for females. Conclusions This study provides the nationwide, population-based data on the incidence of idiopathic CSCR in adult Asians, and suggests that exposure to anti-anxiety drugs is an independent risk factor for idiopathic CSCR among males.

The Risk of Cataract Associated With Repeated Head and Neck CT Studies: A Nationwide Population-Based Study

OBJECTIVE Medical radiation-induced cataracts, especially those resulting from head and neck CT studies, are an issue of concern. The current study aimed to determine the risk of cataract associated with repeated radiation exposure from head and neck CT. MATERIALS AND METHODS This study used information from a random sample of 2 million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. Exposed cases consisted of patients with head and neck tumor 10-50 years old who underwent at least one CT between 2000 and 2009. The nonexposed control group was composed of subjects who were never exposed to CT studies but who were matched by time of enrollment, age, sex, history of coronary artery disease, hypertension, and diabetes. RESULTS There were 2776 patients in the exposed group and 27,761 matched subjects in the nonexposed group. The exposed group had higher overall incidence of cataracts (0.97% vs 0.72%; adjusted hazard ratio [HR], 1.76; 95% CI, 1.18-2.63). Further stratifying the number of CT studies in the exposed group into one or two, three or four, and five or more revealed that cataract incidence increased gradually with increasing frequency of CT studies (0.79%, 0.93%, and 1.45%, respectively) (p=0.001, adjusted for trend). Radiation exposure due to repeated head and neck CT studies was independently associated with an increased risk of developing cataracts when the cumulative CT exposure frequency involved more than four studies (adjusted HR, 2.12; 95% CI, 1.09-4.14). CONCLUSION Repeated exposure to head and neck CT is significantly associated with increased risk of cataract.

Sleep Apnea and Risk of Retinal Vein Occlusion: A Nationwide Population-Based Study of Taiwanese

PURPOSE To explore the relationship of sleep apnea and the subsequent development of retinal vein occlusion (RVO). DESIGN A retrospective nonrandomized, matched-control cohort study using the Taiwan National Health Insurance Research Database. METHODS From 1997 through 2007, we identified newly diagnosed sleep apnea cases in the database. A control group without sleep apnea, matched for age, gender, and comorbidities, was selected for comparison. The 2 cohorts were followed up, and the occurrence of RVO was observed. RESULTS Of the 35 634 sampled patients (5965 sleep apnea patients vs 29 669 controls), 52 (0.15%) experienced RVO during a mean follow-up period of 3.72 years, including 13 (0.22%, all branch RVO) from the sleep apnea cohort and 39 (0.13%, 39 branch RVO and 10 central RVO) from the control group. Kaplan-Meier analysis revealed the tendency of sleep apnea patients toward RVO development (P = .048, log-rank test). Patients with sleep apnea experienced a 1.94-fold increase (95% confidence interval, 1.03 to 3.65; P = .041) in incident RVO, which was independent of age, gender, and comorbidities. CONCLUSIONS Sleep apnea may be an independent risk factor for RVO.

Risk of central serous chorioretinopathy in adults prescribed oral corticosteroids: a population-based study in Taiwan.

Purpose: To investigate the incidence and risk factors for central serous chorioretinopathy (CSCR) in adults who use oral corticosteroids in Taiwan. Methods: This is a population-based nested case–control study between 2000 and 2008. From the Taiwan National Health Insurance Research Database, adults who were repetitively prescribed oral corticosteroids were included as the study cohort. Of those, newly diagnosed CSCR cases were identified and the CSCR incidence was calculated. Subjects matched for age, gender, and the enrollment time were randomly selected as the controls. Corticosteroids use was compared between the cases and controls. Poisson and conditional logistic regressions were used to analyze the potential risk factors for CSCR. Results: Among 142,035 oral corticosteroids users, 320 cases of CSCR were identified, and 1,554 matched controls were randomly selected. The incidence rate of CSCR was 44.4 (95% confidence interval, 39.5–49.3) cases per 100,000 person-years. Multivariate Poisson regression showed that male patients and those aged 35 years to 44 years had significantly higher incidence rates of CSCR. There were no differences in either median dosage or mean duration of systemic corticosteroid treatment between the cases and controls. After adjusting for other confounders, current use of oral corticosteroids was found to be significantly associated with the risk of CSCR (odds ratio, 2.40; 95% confidence interval, 1.49–3.89). Conclusion: Male gender, middle age, and current use of oral corticosteroids were found to be the risk factors for CSCR. However, oral corticosteroids dosage and treatment duration were not associated with the CSCR risk.

Central serous chorioretinopathy and risk of ischaemic stroke: a population-based cohort study

Background Central serous chorioretinopathy (CSCR) is a common maculopathy that features choroidal circulatory disturbance. This population-based cohort study aimed to explore the relationship between CSCR and the future development of ischaemic stroke. Methods Data were obtained from Taiwans national health insurance research database. From 2000 to 2007, 1814 patients with newly diagnosed CSCR were eligible for inclusion in the study cohort. Using stratified random sampling, 9648 enrollees matched with the study subjects in terms of sex, age, monthly income, geographical location and time of enrolment were selected as the control group. Stroke-free survival analysis was assessed using a Kaplan–Meier method. Cox proportional hazard regressions were performed to calculate the HR of ischaemic stroke for the two groups after adjusting for possible confounding variables. Results Of the sampled patients, 45 (2.5%) from the CSCR cohort and 157 (1.6%) from the control group developed ischaemic stroke during a mean follow-up period of 3.9±2.2 years. CSCR patients had a significantly higher incidence of ischaemic stroke than those without a diagnosis of CSCR (p=0.003). After adjusting for age, sex and chronic comorbidities at baseline, CSCR patients were found to have a 1.56-fold (95% CI 1.11 to 2.18, p=0.010) greater risk of a subsequent ischaemic stroke than the matched controls. Conclusions CSCR is an independent indicator for the increased risk of subsequent ischaemic stroke development.

Increased risk of erectile dysfunction among males with central serous chorioretinopathy – a retrospective cohort study

Purpose:  Central serous chorioretinopathy (CSCR) mostly affects middle‐aged men and has been associated with stress and hypercortisolism. We hypothesized that some factors prone to inducing CSCR could also have a harmful effect on erectile function. This study aimed to investigate the risk of subsequent erectile dysfunction after CSCR using Taiwan National Health Insurance Research Database.

Study design, rationale and methods for a population‐based study of myopia in schoolchildren: the Myopia Investigation study in Taipei

To describe the study design, rationale and methodology of the Myopia Investigation Study in Taipei (MIT).

Prevalence and risk factors for myopia in second-grade primary school children in Taipei: A population-based study

Background High myopia is associated with multiple ocular morbidities that may lead to irreversible blindness. Because high myopia in an adult is thought to be related to onset of myopia in very early childhood, detecting myopia early and working to improve modifiable risk factors may help reduce the development of high myopia. In this study, we tried to evaluate the prevalence of myopia and associated risk factors in second‐grade primary school children in Taipei, Taiwan. Methods A questionnaire was distributed to the participants’ parents, and their written informed consent was obtained before performing eye examinations that included visual acuity testing and cycloplegic autorefraction. Multiple logistic regression models were applied to assess possible risk factors associated with myopia. Myopia was defined as spherical equivalent of −0.50 D or less in either eye. Results The prevalence of myopia in the second graders was 36.4%. After adjustment for other characteristics, the following variables were significantly associated with a higher risk of myopia: male sex [odds ratio (OR) = 1.24, p < 0.001]; suburban residence (vs. urban; OR = 1.10, p = 0.02); lower maternal education level (OR = 1.25, p < 0.001); the presence of myopia in one parent (OR = 1.66, p < 0.001) or both parents (OR = 2.82, p < 0.001); time spent on near‐work activity every day (OR = 1.21, p < 0.001); shorter visual distance when doing near‐work activity (OR = 1.17, p < 0.001); and participation in an after‐school tutorial program (OR = 1.20, p < 0.001). By contrast, resting after 30 minutes of near‐work activity (OR = 0.84, p < 0.001) and spending more time participating in outdoor activities on weekends (OR = 0.91, p = 0.03) were significantly associated with a lower risk of myopia. Conclusion Our findings indicate that lifestyle and reading habits impact the development of myopia during early childhood. Behavior modification, such as more time spent outside during the day and limited near‐work activity, may be a feasible strategy for curbing the increasingly high prevalence of myopia in Taipei.

Myopia Development Among Young Schoolchildren: The Myopia Investigation Study in Taipei

Purpose To investigate the annual incidence of myopia and associated factors among young schoolchildren in Taipei City. Methods The Myopia Investigation Study in Taipei was a citywide, population-based cohort study. During the fall 2013 semester (baseline), a total of 11,590 grade 2 schoolchildren completed ocular examination and were included for further analysis. A parent-completed questionnaire was administered to collect data on risk factors for myopia development. Follow-up visits were arranged biannually over 3 years. The first-year results are reported here. Schoolchildren who were emmetropic/hyperopic at baseline and had myopia (spherical equivalent ≤ -0.5 diopters) in either eye at follow-up were identified as having incident myopia. Results Among 7376 baseline nonmyopic participants, 6794 (92.1%) were examined during the first-year follow-up, and 1856 (25.2%) with incident myopia were identified. The incidence density of myopia was 31.7 (95% confidence interval [CI]: 30.6-32.8) per 100 person-years. Cox hazard proportional regression analysis revealed that participants who were emmetropic at baseline (hazards ratio [HR]: 19.37; 95% CI: 4.84-77.57), who had two myopic parents (HR: 1.21; 95% CI: 1.04-1.42), and who spent ≥5 hours every week on after-school tutoring programs (HR: 1.12; 95% CI: 1.02-1.22) had greater risk for incident myopia. By contrast, protective factors included suburban area of residence (HR: 0.91; 95% CI: 0.83-1.00) and spending ≥30 minutes outdoors after school every weekday (HR: 0.90; 95% CI: 0.82-0.99). Conclusions This study provides population-based data on the annual incidence of myopia among Taiwanese schoolchildren, and found that baseline refractive status, parental myopia, area of residence, time outdoors after school on weekdays, and time spent on after-school tutoring programs are associated with risk of new-onset myopia.

Age-Related Macular Degeneration and Risk of Degenerative Dementia among the Elderly in Taiwan: A Population-Based Cohort Study.

PURPOSE To investigate the relationship between age-related macular degeneration (AMD) and future development of Alzheimers disease (AD) or senile dementia. DESIGN A longitudinal case-control study using the Taiwan National Health Insurance Research Database. PARTICIPANTS From 2001 to 2009, the newly diagnosed AMD cases aged ≥65 years in the database were recruited as the AMD cohort (n=4993). Of those, there were 540 with and 4453 without exudative AMD diagnoses. Subjects without any AMD, matched for age, gender, and time of enrollment, were randomly sampled as the control cohort (n=24,965) for comparison. METHODS Alzheimers disease/senile dementia-free survival analysis was assessed using a Kaplan-Meier method. Cox proportional hazard regressions were performed to calculate the hazard ratios (HR) of AD or senile dementia for the 2 cohorts after adjusting for preexisting comorbidities and number of clinical visits. MAIN OUTCOME MEASURES The first-ever diagnosis of AD or senile dementia during the observation period. RESULTS Of the 29 958 sampled subjects, 1589 (5.3%) were diagnosed with AD or senile dementia during a mean follow-up period of 4.4 years, including 294 (5.9%) from the AMD cohort and 1295 (5.2%) from the control cohort. The incidence of AD or senile dementia was higher in patients with AMD than in the controls (P=0.044), with an HR of 1.44 (95% confidence interval [CI], 1.26-1.64) after adjusting for covariates. The stratified analysis showed that the adjusted HR for AD or senile dementia was 1.35 (95% CI, 0.89-2.06) for exudative AMD versus the controls and 1.44 (95% CI, 1.26-1.65) for nonexudative AMD versus the controls. CONCLUSIONS This study provides large-scale, population-based evidence that AMD, especially nonexudative AMD, is independently associated with an increased risk of subsequent AD or senile dementia development.