A 7-year population study of primary angle closure glaucoma admissions and climate in Taiwan

Purpose: Using data from seven years of hospital admissions in Taiwan, this study sets out to investigate meteorological factors associated with primary angle closure glaucoma (PACG). We investigated the relationship between PACG admissions and five different climate indices. Method: Hospital admissions data from the Taiwan National Health Insurance Research Database (1997 to 2003) provided monthly PACG admission rates (per 100,000 population). We categorized the 4,722 PACG cases by gender and age (including four subgroups: 40-49, 50-59, 60-69, and ≥ 70 years). After adjusting for the time-trend effect, the Auto-Regressive Integrated Moving Average regression method was performed to evaluate the effects of climatic and monthly factors on PACG admission rates. Results: The mean annual rate of PACG admissions across the entire study period was 9.48/100,000 and higher in females than males (11.28 vs. 7.80/100,000). The PACG admissions were significantly higher in March for male patients, and for the 60 to 69-year-old and > 69-year-old age groups (p < 0.05). After adjustment for seasonality, month, and time-trend, a significant association between relative humidity and monthly PACG admission rates was observed for the total data set, for males, and for the 60- to 69-year-old (p < 0.05) populations. No such relationship existed with temperature, rainfall, barometric pressure or hours of sunshine. Conclusion: This is the largest, nationwide, population-based study to investigate the dependence of PACG admission rates on meteorological conditions. PACG admission rates were significantly higher in March and with increased relative humidity. We recommend data be collected from other regions and from other ethnic groups to determine the general pattern worldwide.