Air Pollution Control Mitigates Frailty Progression: Evidence from Two Cohorts of Older Adults and DNA Methylation Insights

Frailty is an underappreciated but modifiable clinical
syndrome,
but little about how air quality improvements could influence frailty
progression is known. Here, we utilized two Chinese cohorts with repeated
follow-up visits to address this knowledge gap and explored the underlying
DNA methylation mechanisms. We first conducted a multistate modeling
analysis in the Chinese Longitudinal Healthy Longevity Study (CLHLS),
a nationwide cohort with 21,654 older adults who had participated
in at least two survey waves. An interquartile range reduction in
PM2.5 exposure increased the likelihood of improvement
for frail/prefrail individuals by more than 50% while lowering their
risks of worsening frailty or mortality. A quasi-experimental study
within a CLHLS subcohort of 1816 adults, leveraging the implementation
of China’s Clean Air Act, further validated these findings.
Additionally, in the Guangxi Eco-Environmental Health and Aging Studya
regional prospective cohort based in Guilin, Chinawe included
235 older adults with follow-up data and identified three frailty-related
CpG sites that were associated with PM2.5 exposure. The
CpG site cg25453797 mapped to the PRKCE gene was
robustly associated with the change in frailty. These findings demonstrate
that air quality improvement benefits older adults by alleviating
the frailty burden. DNA methylation may serve as a potential biomarker
to capture the health benefits of environmental policy interventions.