Long-term exposure to particulate air pollution associated with the progression of type 2 diabetes mellitus in China: effect size and urban-rural disparities

BMC Public Health. 2025 Apr 26;25(1):1565. doi: 10.1186/s12889-025-22394-z.

ABSTRACT

BACKGROUND: Recent Western studies link long-term particulate matter (PM) exposure to type 2 diabetes mellitus (T2DM) progression, but little is known for low- and middle-income countries. This study aimed to estimate the relationship between PM exposure and T2DM progression in China, and also assess urban-rural disparities.

METHODS: Using 7-year cohort data of 1.3 million Chinese over 40, a multistate model estimated the associations of PM exposure with T2DM progression. Covariates included demographics, socioeconomic status, health behaviors, medication, and meteorological factors. Sub-sample analyses were done for rural and urban areas.

RESULTS: For participants exposed to high levels of ${\text{PM}}_{2.5}$ , the 5-year absolute risks of developing T2DM and its complications were 4.31% (95% CI: 4.22-4.40) and 31.04% (95% CI: 29.97-32.08), respectively. In the low- ${\text{PM}}_{2.5}$ -exposure group, these risks were 3.82% (95% CI: 3.74-3.91) and 30.55% (95% CI: 29.43-31.65). For each 10 µg/m³ increase in ${\text{PM}}_{2.5}$ exposure, the HRs (95% CI) for the progression from no T2DM diagnosis to a T2DM diagnosis were 1.13 (1.13-1.14), and for the progression from T2DM to the development of T2DM complications were 1.04 (1.03-1.06). Moreover, the HRs (95% CI) for mortality risk were 1.09 (1.08-1.09) for participants without T2DM, 1.06 (1.00-1.14) for those with T2DM, and 1.10 (1.05-1.16) for those with T2DM complications. Similar associations were observed for other PM-related metrics. In rural areas, PM exposure was more strongly associated with the progression from T2DM and its complications to death. Conversely, in urban areas, PM exposure had a stronger association with the progression from a non-T2DM state to a formal T2DM diagnosis. Urban residents are exposed to higher levels of toxic components like heavy metals, potentially increasing T2DM risk, yet urban healthcare infrastructure offers protection against T2DM-related mortality.

CONCLUSIONS: PM exposure is significantly associated with T2DM progression. Urban areas should focus on primary prevention, while rural areas need to improve secondary and tertiary prevention like healthcare services.

PMID:40287677 | DOI:10.1186/s12889-025-22394-z