Prevalence of respiratory-related ailment among residents of gas flaring states in Nigeria: a systematic review and meta-analysis

Gas flaring, the chief source of toxic pollutants and air pollution in Nigeria, has continued to raise global public health interest. This study attempts to provide comprehensive information on the respiratory disease burden associated with gas flaring in Nigeria, which is not readily available. Studies reporting the incidence and prevalence of respiratory diseases among residents of gas flaring states in Nigeria were systematically reviewed using standardized approved guidelines. Thirteen studies were identified from the data search. The mean pooled prevalence of respiratory diseases among the residents of the gas flaring states was determined using random-effect meta-analyses. The pooled mean prevalence of respiratory disease was 43% (95% CI: 32–54%). Rivers State had the highest prevalence of 53% (95% CI: 34–71%, I = 100%, P < 0.00001), 43% (95% CI: 23–63%, I = 98%, P < 0.00001) in Delta State, and Akwa-Ibom State had the lowest prevalence of 22% (95% CI: − 11–54%, P = 0.19; I = 99%, P < 0.00001). The respiratory illness prevalence of the mixed state study which sampled three Niger Delta states (Rivers, Delta, and Bayelsa) was 75% (95% CI: 70–80%, P < 0.00001), while the study sampling both Bayelsa and Rivers States was 15% (95% CI: 15–16%, P < 0.00001). The test for subgroup difference stratified by region was statistically significant (X = 558.29, P < 0.00001, I = 99.3%). The prevalence of gas flaring–induced respiratory ailment in gas flaring zones is very high and understudied in Nigeria. This study establishes the ground for assessing the effect of long-term exposure to gas flaring as a risk factor for respiratory illness in Nigeria. It is hoped that information from this study will drive discussion and proactive actions, towards achieving zero carbon emission and reducing gas flaring–induced respiratory illness in Nigeria.