Long-term exposure to NO2 and PM2.5 and the occurrence of chronic kidney disease among patients with type 2 diabetes in Taiwan

Abstract

Background: Individuals diagnosed with type 2 diabetes (T2D) frequently exhibit chronic kidney disease (CKD) which may be caused by environmental hazards such as exposure to air pollutants. However, limited research has explored the effects of prolonged exposure to air pollutants on CKD development in this population. This study examines the relationship between long-term exposure to air pollutants and CKD incidence in a longitudinal cohort of individuals with type 2 diabetes in Taiwan METHODS: Between 2003 and 2005, we recruited 1316 T2D patients (693 females [52.66 %]; mean age 56.16 ± 8.97 years). Patients were followed until December 31, 2012, with at least two clinical visits. Baseline demographics, medical history, and biomarker levels were collected. The development of CKD was determined by eGFR level < 60 mL/min/1.73 m². Monthly averages of nitrogen dioxide (NO₂) and fine particulate matter [PM ≤ 2.5 μm in aerodynamic diameter (PM_2.5)] were acquired from 72 ambient air monitoring stations. The kriging method was employed to estimate the exposure levels to PM_2.5, NO_2, temperature, and relative humidity in the participants' residential areas. Cox regression with time-dependent covariates regression was applied to assess the impact of long-term exposure to air pollutants and CKD risk.

Results: Of 992 patients with normal renal function at baseline, 411 (41.43 %) experienced CKD occurrence over a median follow-up period of 5.45 years. The incidence of CKD was 93.96 cases per 1000 person-years. In multivariable adjusted models, patients exposed to PM_2.5 levels above the third quartile of (>33.44 μg/m³) and NO₂ levels above the fourth quartile (>22.55 ppb) were found to have an increased risk of CKD occurrence compared to lower exposure levels.

Conclusions: This longitudinal study highlights the increased risk of CKD in individuals with type 2 diabetes due to prolonged exposure to NO₂ and PM_2.5, emphasizing the need for tailored air quality management strategies for this high-risk population.

Keywords: Air pollution; Chronic kidney disease; EGFR; NO(2); Particulate matter; Renal function; Type 2 diabetes.