Abstract
OBJECTIVE: To investigate the potential effect of modification of antihypertensive medications on the association of nitrogen dioxide (NO(2)) long-term exposure and chronic kidney disease (CKD). METHODS: Data of the national representative sample of adult population from the China National Survey of Chronic Kidney Disease (2007-2010) were included in the analyses, and exposure data of NO(2) were collected and matched. Generalized mixed-effects models were used to analyze the associations between NO(2) and CKD, stratified by the presence of hypertension and taking antihypertensive medications. The stratified exposure-response curves of NO(2) and CKD were fitted using the natural spine smoothing function. The modifying effects of antihypertensive medications on the association and the exposure-response curve of NO(2) and CKD were analyzed. RESULTS: Data of 45 136 participants were included, with an average age of (49.5±15.3) years. The annual average exposure concentration of NO(2) was (7.2±6.4) μg/m(3). Altogether 6 517 (14.4%) participants were taking antihypertensive medications, and 4 833 (10.7%) participants were identified as having CKD. After adjustment for potential confounders, in the hypertension population not using antihypertensive medications, long-term exposure to NO(2) was associated with a significant increase risk of CKD (OR: 1.38, 95%CI: 1.24-1.54, P < 0.001); while in the hypertension population using antihypertensive medications, no significant association between long-term exposure to NO(2) and CKD (OR: 0.96, 95%CI: 0.86-1.07, P=0.431) was observed. The exposure-response curve of NO(2) and CKD suggested that there was a non-linear trend in the association between NO(2) and CKD. The antihypertension medications showed significant modifying effects both on the association and the exposure-response curve of NO(2) and CKD (interaction P < 0.001). CONCLUSION: The association between long-term exposure to NO(2) and CKD was modified by antihypertensive medications. Taking antihypertensive medications may mitigate the effect of long-term exposure to NO(2) on CKD.