[Association between ambient air pollution and biological aging among the middle-aged and older adults: a systematic review].

Objective: To summarize and elucidate the impact of ambient air pollution on biological aging among middle-aged and older adults. Methods: "Air pollution""Biological age""Epigenetic age""Biological aging"and"Epigenetic aging", as well as specific names of air pollutants and biological age were used as search keywords. This study searched the databases of PubMed and Web of Science for eligible English articles and CNKI, CQVIP, Wanfang, CBM, CSTP and other Chinese databases for eligible Chinese articles from inception until June 30, 2023. The language was limited to Chinese and English. Results: Among the 14 included articles, five studies investigated the impact of air pollution on DNA methylation age using different algorithms, while six studies explored the relationship between air pollutants and telomere length. Six studies focused on frailty as an outcome, and an additional study revealed the relationship between fine particulate matter (PM_2.5) and its components with composite indicator age (KDM age). The results indicated that, although different forms of biological ages were susceptible to different ambient air pollutants at different degrees, previous studies had consistently found that the increased levels of PM_2.5 and one of its major components, black carbon (BC), could significantly accelerate the biological aging of middle-aged and older adults. Similar trends were observed with nitrogen oxides (NO_x) and ozone (O₃) but with relatively limited evidence. Conclusion: Major air pollutants could accelerate the biological aging of middle-aged and older adults.