Incidence of retinal vein occlusion with long-term exposure to ambient air pollution.

Han-Wei Zhang,Yuan-Pei Lin,Fung-Chang Sung,Chung Y Hsu,Victor C Kok,Tsai-Chung Li,Chi Pang Wen,Chao-Wen Lin,Chun-Hung Tseng,Chao A Hsiung,Wisit Cheungpasitporn

doi:10.1371/journal.pone.0222895

Abstract

This study aimed to investigate whether long-term exposure to airborne hydrocarbons, including volatile organic compounds, increases the risk of developing retinal vein occlusion (RVO) among the population of Taiwan. A retrospective cohort study involving 855,297 people was conducted. Cox proportional hazards regression analysis fitted the multiple pollutant models for two targeted pollutants, including total hydrocarbons (THC), nonmethane hydrocarbons (NMHC) were used, and the risk of RVO was estimated. The chi-squared test and one-way analysis of variance were used to test differences in demographics and comorbidity distribution among tertiles of the targeted pollutants. Before controlling for multiple pollutants, hazard ratios for the overall population were 19.88 (95% CI: 17.56–22.50) at 0.51-ppm increases in THC and 4.33 (95% CI: 3.97–4.73) at 0.27-ppm increases in NMHC. The highest adjusted hazard ratios for different multiple pollutant models of each targeted pollutant were statistically significant (all p values were ≤0.05) for all patients at 29.67 (95% CI: 25.57–34.42) for THC and 16.24 (95% CI: 14.14–18.65) for NMHC. Our findings suggest that long-term exposure to THC and NMHC contribute to RVO development.

Highlights

Retinal vein occlusion (RVO), the second most common retinal vascular disease, is characterized by painless vision loss [1]
Note: hazard ratios (HRs), hazard ratio; 95% confidence intervals (CIs), 95% confidence interval; NMHC, nonmethane hydrocarbons; SO2, sulfur dioxide; O3, ozone; NO2, nitrogen dioxide; PM2.5, fine particulate matter < 2.5 μm in size. aAdditional pollutants were added into NMHC models for the multiple analysis only when the Pearson’s correlation coefficient was < 0.3. bCox regression models were adjusted for age, gender, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, asthma, arrhythmia, cerebrovascular diseases, hypertension, diabetes mellitus, hyperlipidemia, smoking-related diagnose, morbid obesity, glaucoma, hypercoagulable state, retinal arteriolar disorder, and ambient temperature, controlled pollutants. ‡p < 0.001
Note: RVO, retinal vein occlusion; PY, person-years; HR, hazard ratio; 95% CI, 95% confidence interval; THC, total hydrocarbons; NMHC, nonmethane hydrocarbons. 5:21 PMaTertile values in ppm (THC, NMHC) were as follows: THC (T1 level: < 2.28, T2 level: 2.28 and < 2.40, T3 level: 2.40); NMHC (T1 level: < 0.29, T2 level: 0.29 and < 0.36, T3 level: 0.36). bCox regression models were adjusted for age, gender, comorbidities, and ambient temperature. p < 0.05, ‡p < 0.001

Summary

Introduction

Retinal vein occlusion (RVO), the second most common retinal vascular disease, is characterized by painless vision loss [1]. If the retinal vein is blocked, it cannot drain blood from the retina, leading to retinal hemorrhage, vascular tortuosity, cotton wool spots, and optic disc edema. Increased vascular pressure leads to fluid leakage and cystoid macular edema, a vision-threatening complication. Eyes with capillary nonperfusion may develop ocular neovascularization, which carries a risk of vision loss. RVO can be classified into branch retinal vein occlusion (BRVO), hemiretinal vein occlusion, and central retinal vein occlusion (CRVO) depending on the obstruction site

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