# Oxidative balance score and all-cause mortality among hypertensive individuals

## TL;DR

A higher oxidative balance score is linked to lower mortality risk in people with hypertension, suggesting that antioxidant-rich diets and healthy lifestyles may help reduce deaths.

## Contribution

This study introduces the oxidative balance score (OBS) as a novel predictor of mortality risk in hypertensive individuals.

## Key findings

- Higher oxidative balance scores were associated with a 34% reduced mortality risk in the highest quartile compared to the lowest.
- Each unit increase in OBS reduced mortality risk by 2%, with a nearly linear dose-response relationship confirmed.
- Kaplan-Meier survival curves showed better survival outcomes for individuals with higher OBS.

## Abstract

Oxidative stress contributes to hypertension and its complications. The oxidative balance score (OBS) could therefore provide insight into the relationship with mortality in hypertensive individuals. We aimed to investigate the association between OBS and all-cause mortality using data from National Health and Nutrition Examination Survey 2007–18.

Our sample comprised 11 196 hypertensive participants. We calculated OBS based on dietary and lifestyle factors and categorised participants accordingly into quartiles. We used Cox proportional hazards model to assess associations between OBS and mortality, and restricted cubic spline (RCS) analyses to determine dose-response relationships. Lastly, we conducted Kaplan-Meier survival curves and stratified/sensitivity analyses.

1764 deaths occurred during a median follow-up time of 73.4 months. Higher OBS was significantly associated with lower mortality risk, whereby participants in the highest OBS quartile had a 34% reduced mortality risk compared to those in the lowest quartile (hazard ratio (HR) = 0.66; 95% confidence interval (CI) = 0.51–0.84, P = 0.001). Each unit increase in OBS reduced mortality risk by 2% (HR = 0.98; 95% CI = 0.96–0.99, P < 0.001). We observed similar results for dietary and lifestyle OBS. RCS analyses indicated a nearly linear dose-response relationship between OBS and the risk of all-cause mortality (P-value for nonlinearity >0.05). Kaplan-Meier curves confirmed better survival in those with higher OBS (log-rank P-value <0.001). Stratified analyses showed stronger protective effects in individuals with middle incomes and those without a history of cancer (P-value for interaction <0.05). Sensitivity analyses confirmed the robustness of these findings.

Higher OBS levels, along with its dietary and lifestyle subscale scores, are significantly associated with a reduced risk of all-cause mortality among hypertensive individuals. These findings highlight the importance of oxidative balance and the potential benefits of antioxidant-rich diets and healthy lifestyles in reducing mortality risk for this population.