Association between oxidative balance score and kidney function among Chinese adults: impact of gender, diabetes and hypertension

Background Oxidative stress, as quantified by the Oxidative Balance Score (OBS) reflecting the balance between antioxidant and pro-oxidant exposures, plays a pivotal role in kidney function. This study aims to investigate the association between OBS and kidney function, examining gender, diabetes, and hypertension as potential effect modifiers. Methods Cross-sectional data from 9,343 participants in Fujian Province (2020–2021) were analyzed. OBS was calculated using 10 dietary and lifestyle components. Logistic regression assessed associations between OBS and kidney function, stratified by gender, diabetes, and hypertension, with interaction terms. Mediation analysis evaluated the role of neutrophil-to-high-density lipoprotein ratio (NHR) and platelet-to-high-density lipoprotein ratio (PHR). Results OBS was inversely associated with low estimated glomerular filtration rate (eGFR) in hypertensive women without diabetes (odds ratio (OR) = 0.58, 95% confidence interval (CI) 0.39–0.86). A similar inverse association was observed in normotensive (OR = 0.47, 95% CI 0.25–0.86) men and prehypertensive men (OR = 0.52, 95% CI 0.33–0.81), independent of diabetes status. Additionally, a significant interaction between OBS and hypertension in men suggested a hypertension-dependent effect. Mediation analysis further indicated that the NHR and PHR accounted for 19.37% and 13.04% of the OBS effects on albuminuria, respectively. NHR also accounted for 9.41% of the association between OBS and low eGFR among normotensive and prehypertensive men. Conclusion Our findings highlight the importance of considering gender and hypertension status when evaluating the association between OBS and kidney function, particularly in normotensive and prehypertensive men.