Association between the oxidative balance score and all-cause and cardiovascular mortality in populations with cardiovascular-kidney-metabolic syndrome stages 0–3: a prospective cohort study

Abstract Background This study aims to investigate the association between the Oxidative Balance Score (OBS) and mortality outcomes in individuals with cardiovascular-kidney-metabolic (CKM) syndrome stages 0–3. Methods Using data from ten National Health and Nutrition Examination Survey cycles (1999–2018), we analyzed 17677 participants with CKM syndrome stages 0–3. OBS was calculated using 20 components (16 nutritional elements and 4 lifestyle factors). Cox proportional hazards models evaluated associations between OBS and mortality outcomes, adjusting for relevant covariates. Results During the follow-up period (mean 122.4 months), there were 1983 deaths (8.16% of participants), of which 439 (1.71%) were due to cardiovascular disease. Multifactorial Cox regression showed that each standard deviation increment in the OBS corresponded to a significant 13% decrease in all-cause mortality risk (HR 0.87, 95% CI 0.82–0.92, P < 0.001) and an 18% reduction in cardiovascular mortality risk (HR 0.82, 95% CI 0.72–0.92, P < 0.001). When examining quartiles, individuals in the highest OBS quartile exhibited a 33% reduced risk of all-cause mortality (HR 0.67, 95% CI 0.57–0.79, P for trend < 0.001) and a 34% lower cardiovascular mortality risk (HR 0.66, 95% CI 0.46–0.94, P for trend < 0.001) compared to those in the lowest quartile. Subgroup analyses indicated that this protective relationship was most evident in CKM syndrome stages 1 and 2, with a significant interaction detected between OBS and CKM stage for all-cause mortality ( P for interaction < 0.05). Conclusions The study demonstrated that elevated OBS was significantly associated with reduced risks of both all-cause and cardiovascular mortality among populations with CKM syndrome stages 0–3.