Long-term Exposure to Air Pollution Associated With CKD

A study published in Ecotoxicology and Environmental Safety found that ambient air pollution, specifically carbon monoxide (CO) and sulfate dioxide (SO₂), were associated with chronic kidney disease (CKD) in Southwest China, where air pollution is more concentrated.

The researchers used the China Multi-Ethnic Cohort (CMEC) study for participants of this study. There were 80,225 participants for this study aged 30 to 79 years and were collected from 5 provinces from May 2018 to September 2019. Face-to-face interviews were conducted to collect baseline data based on an electronic questionnaire.

Participants were excluded if they didn’t have a recorded residential address, were at their residential address for less than 3 years, didn’t have serum creatinine data, or had missing information on covariates. Fasting blood was collected from all participants and air pollution data was collected from the ChinaHighAirPollutants Data set.

The 80,225 participants of the study had a mean age of 51.8 years, 39.6% were male, and 15.4% of the participants were aged 65 years or older; 1980 (2.47%) had CKD. The 3-year average of particulate matter, nitrogen dioxide, CO, ozone, and SO₂ concentrations were 40.7 μg/m³, 21.4 μg/m3, 0.87 mg/m³, 79.2 μg/m³, and 14.4 μg/m³ at the participants’ addresses respectively.

The researchers found that an increase of 0.1 mg/m3 on the 3-year average CO concentration (odds ratio [OR], 1.20; 95% CI, 1.05-1.37) and 1 μg/m³ 3-year average SO₂ concentration (OR, 1.07; 95% CI, 1.00-1.14) were associated with CKD. Particulate matter, nitrogen dioxide, and ozone were not associated with CKD.

The effects of particulate matter, CO, ozone, and SO₂ were found to be more prevalent in men whereas the effects of nitrogen dioxide were more prevalent in women. The effects of particulate matter, nitrogen dioxide, CO, ozone, and SO₂ were also more prevalent in participants aged younger than 65 years. The effects of particulate matter, nitrogen dioxide, and CO were higher in participants who did not drink alcohol whereas those who drank alcohol were more affected by the effects of ozone and SO₂.

Particulate matter, nitrogen dioxide, SO₂, ozone, and CO had greater effects on participants who smoked whereas the effects of particulate matter, nitrogen dioxide, and SO₂ were higher in participants exposed to second-hand smoking. The results demonstrated that age, smoking, and body mass index are effect modifiers for associations between the 5 pollutants and CKD.

There were some limitations to this study. The data for this study was cross-sectional, which means the strength of the evidence was relatively weak. The exposure data is based on resident addresses of the participants, which means that indoor and outdoor exposure and travel patterns were not taken into account. The study used an estimated glomerular filtration rate to make renal function inferences, which means the gold standard of glomerular filtration rate measurement was not used.

The researchers concluded that long-term exposure to ambient CO and SO₂ was associated with CKD in individuals aged 30 to 79 years in Southwest China.

Reference

Li S, Meng Q, Laba C, et al. Associations between long-term exposure to ambient air pollution and renal function in southwest China: the China multi-ethnic cohort (CMEC) study. Ecotoxicol Environ Saf. Published online July 8, 2022. doi:10.1016/j.ecoenv.2022.113851