Air pollution and risk of sarcopenia: A two-sample Mendelian randomized study

Exposure to air pollution, genetic susceptibility, and prevalence of sarcopenia in the UK

BACKGROUND

The role of environmental factors, particularly air pollutants, in the prevalence of sarcopenia remains unclear.

OBJECTIVES

This study explored the relationship between the prevalence of sarcopenia and prolonged exposure to air pollutants, and investigated potential interactions with genetic susceptibility and inflammation.

METHODS

Data from 408,117 people at baseline and 35,060 participants in the longitudinal analysis in the UK Biobank were used in this prospective cohort study. Utilizing land use regression models, air pollutants (nitrogen dioxide (NO2), nitric oxides (NOx), and particulate matter with aerodynamic diameters of ≤2.5 μm (PM2.5) and ≤10 μm (PM10) were estimated and classified into quartiles. Alterations in body composition were among the secondary results.

RESULTS

Lastly, 3353 people (0.8 %) developed sarcopenia. Higher levels of air pollutants were linked to an increased prevalence of sarcopenia after controlling for confounding variables (highest vs lowest quartile: NOx, OR, 1.21 [95 % CI, 1.16-1.26]; NO2, OR, 1.22 [95 % CI, 1.16-1.27]; PM2.5, OR, 1.17 [95 % CI, 1.12-1.22]; PM10, OR, 1.15 [95 % CI, 1.10-1.20]; all P<.001). Longitudinal analysis revealed that air pollutants had adverse changes in body composition, including increased muscle fat infiltration and decreased muscle mass. At baseline, the probability of sarcopenia was strongly correlated with NOx, NO2, PM2.5, and PM10, and increased with elevated PRSBMI or CRP levels in subgroup analyses.

CONCLUSION

Air pollutants may contribute to accelerated muscle aging and highlight the importance of environmental factors in sarcopenia development.

Causal relationship and shared genes between air pollutants and amyotrophic lateral sclerosis: A large-scale genetic analysis

OBJECTIVE

Air pollutants have been reported to have a potential relationship with amyotrophic lateral sclerosis (ALS). The causality and underlying mechanism remained unknown despite several existing observational studies. We aimed to investigate the potential causality between air pollutants (PM2.5, NOX, and NO2) and the risk of ALS and elucidate the underlying mechanisms associated with this relationship.

METHODS

The data utilized in our study were obtained from publicly available genome-wide association study data sets, in which single nucleotide polymorphisms (SNPs) were employed as the instrumental variantswith three principles. Two-sample Mendelian randomization and transcriptome-wide association (TWAS) analyses were conducted to evaluate the effects of air pollutants on ALS and identify genes associated with both pollutants and ALS, followed by regulatory network prediction.

RESULTS

We observed that exposure to a high level of PM2.5 (OR: 2.40 [95% CI: 1.26-4.57], p = 7.46E-3) and NOx (OR: 2.35 [95% CI: 1.32-4.17], p = 3.65E-3) genetically increased the incidence of ALS in MR analysis, while the effects of NO2 showed a similar trend but without sufficient significance. In the TWAS analysis, TMEM175 and USP35 turned out to be the genes shared between PM2.5 and ALS in the same direction.

CONCLUSION

Higher exposure to PM2.5 and NOX might causally increase the risk of ALS. Avoiding exposure to air pollutants and air cleaning might be necessary for ALS prevention.

The causal effect of exposure to air pollution on risk of adverse pregnancy outcomes: A two-sample Mendelian randomisation study

BACKGROUND

Epidemiological studies have examined the relation between air pollution (NOx, NO2, PM2.5, PM2.5-10, and PM10) and adverse pregnancy outcomes (APOs). There's increasing evidence that air pollution increases the risk of APOs. However, the results of these studies are controversial, and the causal relation remains uncertain. We aimed to assess whether a genetic causal link exists between air pollution and APOs and the potential effects of this relation.

METHODS

A novel two-sample Mendelian randomisation (MR) study used pooled data from a large-scale complete genome correlation study. The primary analysis method was inverse variance weighting (IVW), which explored the expose-outcome relationship for assessing single nucleotide polymorphisms (SNPs) associated with air pollution. Further sensitivity analysis, including MR-PRESSO, MR-Egger regression, and leave-one analysis, was used to test the consistency of the results.

RESULTS

There was a significant correlation between air pollution-related SNPs and APOs. A robust causal link was found between genetic susceptibility to air pollution and APOs.

CONCLUSIONS

Our MR analysis reveals a genetic causal relation between air pollution and APOs, which may help provide new insights into further mechanisms and clinical studies in air pollution-mediated APOs.