Biomass Fuel Use and Risk of Cataract: Systematic Review and Meta-Analysis

Aims: There is an increasing recognition of the putative association between the use of biomass fuels and the risk of cataracts. However, the exact strength of this association is currently unknown. Our aim was to synthetically quantify the association between biomass fuel use and cataract.
Study Design: Systematic review and meta-analysis.
Methodology: Using results from the MEDLINE®, Scopus®, Web of Science® and Google® searches, we conducted a random-effects meta-analysis of the published studies. We also conducted subgroup meta-analyses, meta-regressions and sensitivity analyses to determine the contribution of potential confounders to between-study heterogeneity which was measured by the tau-squared and I2 statistics. Summary effect sizes (SES) were estimated using the DerSimonian and Laird method and the 95% confidence intervals (CI) and 95% prediction intervals (PI) were also estimated. Publication bias was examined using funnel plots and Egger’s test.
Results: In spite of significant between-study heterogeneity (I2 70%, p=8.1x10-5), biomass fuel use was associated with a significantly increased risk of cataract (SES 2.12; 95% CI 1.61-2.80; 95% PI 0.88-5.09). Age-, gender- and other methodological differences did not significantly contribute to between-study heterogeneity but Indian studies showed a statistically significant association between biomass fuel use and cataract. Statistically homogeneous studies (n = 8) showed an SES of 2.01 (95% CI and PI 1.67-2.41).
Conclusion: Synthetic evidence from observational studies indicates that biomass fuel use may increase the risk of cataract. Public health initiatives aimed at avoidance of biomass fuel use may reduce the burden of cataracts especially in settings where biomass fuels are commonly used.