The interaction between genetic predicted gut microbiome abundance and particulate matter on the risk of incident asthma in adults

Air pollution and gut microbial abundance (GMA) are both closely related with asthma incidence. This study aims to explore significant interact on the risk of incident asthma in adult exist between GMA and PM_2.5 exposure based on a prospective cohort of UK Biobank. Polygenic score of GMA was calculated using 19 distinct single nucleotide polymorphisms. PM_2.5 exposure was predicted using a validated Land Use Regression model. Incident asthma was identified by linking with medical encounters or first occurrence source. Cox proportional hazards regression models were used to evaluate the associations. Hazard ratios (HRs) and 95 % confidence intervals (CIs) were calculated. During an average follow-up of 11.4 years within 390,054 participants, a total of 11,312 asthma cases occurred with an incidence density of 2.54 per 1000 person years. Participants with the highest PM_2.5 and GMA exposure were associated with a 13 % (HR = 1.13, 95 % CI: 1.05, 1.22; P_{for trend} < 0.001) higher and 16 % (HR = 0.84, 95 %CI: 0.74, 0.94; P_{for trend} < 0.01) lower risk of incident asthma, respectively. A significant negative additive interaction between GMA and PM_2.5 exposure with the risk of incident asthma in adult was found (Relative Excess Risk due to Interaction = -0.08, 95 % CI, -0.16, -0.002). Participants with very high GMA and lowest PM2.5 exposure level were associated with a 26 % (HR = 0.74, 95 % CI: 0.57, 0.96) lower risk of incident asthma. A higher level of GMA has the potential to alleviate the detrimental effect of PM_2.5 exposure on the risk of asthma in adults. Strategies targeting GMA, such as modifying diet and using probiotics supplement may be helpful for preventing asthma derived from PM_2.5 exposure.