Modifying Role of Sustainable Diets on the Association Between Particulate Matter and Biological Aging: The Guangzhou Biobank Cohort Study

ABSTRACT Air pollution accelerates biological aging via oxidative stress and inflammation, a process potentially mitigated by plant‐based diets. However, the role of dietary or genetic modulators in this relationship remains understudied. Our study aimed to examine whether adherence to Sustainable Diets modifies the associations of PM 2.5 and PM 10 exposure with biological aging, and to assess potential effect modification by genetic susceptibility to longevity. Data from 9527 participants in the Guangzhou Biobank Cohort Study were used to examine the association of one‐year average PM 2.5 and PM 10 exposure with biological aging, measured by phenotypic age, accelerated age, and relative telomere length (RTL). Sustainable diet adherence was assessed using Plant‐Based Diet Index (PDI) and Planetary Health Diet (PHD) scores, with higher scores indicating greater adherence. The mean age of participants was 64.6 years (SD = 6.0). Higher exposure to PM 2.5 ( β = 0.039) and PM 10 ( β = 0.028) was associated with increased phenotypic age and higher odds of accelerated aging (OR = 1.008 for PM 2.5 , OR = 1.005 for PM 10 ). These associations weakened with greater adherence to a sustainable diet (higher PDI/PHD scores). Stronger associations were found in those with lower polygenic risk scores for longevity. A suggestive association between higher PM exposure and shorter RTL was observed, particularly in participants ≥ 65 years and those with cardiovascular diseases. Sustainable dietary patterns rich in plant‐based foods may attenuate the associations between air pollution and biological aging in older adults. These findings highlight the modifying role of dietary patterns as a potential strategy to mitigate the pollution‐related aging burden.