Pollution exposure can cause multimorbidity risk

Exposure to the air pollution known as fine particulate matter (PM2.5) is associated with an increased risk of having a cluster of multiple chronic diseases, according to a new study published this week in the open-access journal PLOS Global Public Health.

In the new study, the researchers used data on 19,098 respondents of the China Health and Retirement Longitudinal Study (CHARLS) surveys from 2011 to 2015, as well as historical satellite data on PM2.5 exposure over 15 years. Participants were people aged 45 to 85 from 125 cities across China.

The team modeled the associations between self-reported chronic disease diagnosis and PM2.5 exposure, the data revealed four distinct groups of multimorbidity, with patients sorting into respiratory, musculoskeletal, cardio-metabolic, or healthy clusters. The analysis showed that a 1µg/m3

increase in cumulative exposure to PM2.5 over 15 years was associated with a 2.4 percent increased chance of belonging to the respiratory cluster, a 1.5 percent increased chance of belonging to the musculoskeletal cluster, and a 3.3 percent increased chance of belonging to the cardio-metabolic cluster. However, the models also showed a U-shaped association, with both lower and higher PM2.5 exposure associated with increased multimorbidity. The increased multimorbidity at the low end of the may be due to differences in rural-urban living and economic development, the authors hypothesized.

The authors concluded that current PM2.5 levels are harmful to human health among the majority of Chinese adults, and that for most low and middle income countries, efforts to reduce PM2.5 would likely be associated with a substantial reduction in the burden of multiple diseases.

Reference: Hu K, Keenan K, Hale JM, Liu Y, Kulu H (2022) A longitudinal analysis of PM2.5 exposure and multimorbidity clusters and accumulation among adults aged 45-85 in China. PLOS Glob Public Health 2(6): e0000520. https://doi.org/10.1371/journal.pgph.000052.