RATIONALE & OBJECTIVE: Increasing evidence has linked ambient fine particulate matter (ie, particulate matter no larger than 2.5 μm [PM]) to chronic kidney disease (CKD), but their association has not been fully elucidated, especially in regions with high levels of PMpollution. This study aimed to investigate the long-term association of high PMexposure with incident CKD in mainland China. 2.5 2.5 2.5
STUDY DESIGN: Prospective cohort study.
SETTING & PARTICIPANTS: 72,425 participants (age ≥18 years) without CKD were recruited from 121 counties in Hunan Province, China.
EXPOSURE: Annual mean PMconcentration at the residence of each participant derived from a long-term, full-coverage, high-resolution (1 × 1 km), high-quality dataset of ground-level air pollutants in China. 2.5 2
OUTCOMES: Incident CKD during the interval between the baseline examination of each participant (2005-2017) and the end of follow-up through 2018.
ANALYTICAL APPROACH: Cox proportional hazards models were used to estimate the independent association of PMwith incident CKD and the joint association of PMwith temperature or humidity on the development of PM-related CKD. Restricted cubic splines were used to model exposure-response relationships. 2.5 2.5 2.5
RESULTS: Over a median follow-up of 3.79 (IQR, 2.03-5.48) years, a total of 2,188 participants with incident CKD were identified. PMexposure was associated with incident CKD with an adjusted hazard ratio of 1.71 (95% CI, 1.58-1.85) per 10-μg/mgreater long-term exposure. Multiplicative interactions between PMand humidity or temperature on incident CKD were detected (all P < 0.001 for interaction), whereas an additive interaction was detected only for humidity (relative risk due to interaction, 3.59 [95% CI, 0.97-6.21]). 2.5 2.5 3
LIMITATIONS: Lack of information on participants' activity patterns such as time spent outdoors.
CONCLUSIONS: Greater long-term ambient PMpollution is associated with incident CKD in environments with high PMexposure. Ambient humidity has a potentially synergetic effect on the association of PMwith the development of CKD. 2.5 2.5 2.5
PLAIN-LANGUAGE SUMMARY: Exposure to a form of air pollution known as fine particulate matter (ie, particulate matter ≤2.5 μm [PM]) has been linked to an increased risk of chronic kidney disease (CKD), but little is known about how PMaffects CKD in regions with extremely high levels of PMpollution. This longitudinal cohort study in China investigates the effect of PMon the incidence of CKD and whether temperature or humidity interact with PM. Our findings suggest that long-term exposure to high levels of ambient PMsignificantly increased the risk of CKD in mainland China, especially in terms of cumulative average PM. The associations of PMand incident CKD were greater in high-humidity environments. These findings support the recommendation that reducing PMpollution should be a priority to decrease the burden of associated health risks, including CKD. 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
