Plant-based diets, genetic predisposition, and the risk of adult-onset asthma A prospective study

Emerging evidence has linked diets rich in plant-based foods with a lower risk of asthma, while the prospective evidence is limited. Therefore, we aimed to explore the association of plant-based diet quality with the risk of adult-onset asthma, and whether this association was modified by genetic predisposition.

A total of 163,689 asthma-free participants were enrolled in from the UK Biobank. Plant-based diet indices (including overall plant-based diet index [PDI], healthful plant-based diet index [hPDI], and unhealthful plant-based diet index [uPDI]) were calculated based on 17 major food groups from Oxford WebQ. Genetic predisposition for asthma was characterized using a weighted polygenic risk score (PRS). Cox proportional hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs).

During a median follow-up of 12.0 years, a total of 3015 new adult-onset asthma cases were documented. Compared to the lowest tertile, the multivariable-adjusted HRs (95% CIs) of adult-onset asthma in the highest tertile were 0.90 (0.83-0.99; P for trend = 0.029), 0.90 (0.82-0.99; P for trend = 0.025), and 1.23 (1.12-1.34; P for trend < 0.001), for the PDI, hPDI, and uPDI, respectively. In the analysis of joint associations of PDIs and PRS with the risk of adult-onset asthma, neither overall PDI nor hPDI showed a significant association in the high asthma-PRS group compared to the reference group, while uPDI did not show a significant association in the low asthma-PRS group.

For adult-onset asthma, both the overall PDI and hPDI were associated with a reduced risk of development, whereas uPDI was associated with an increased risk. Although no genetic effects were found to interact with the associations mentioned above, the associations showed slight variations across different genetic risk groups. Future studies are needed to explore these associations in more depth.