Combined oxidant capacity, redox-weighted oxidant capacity and elevated blood pressure: A panel study

Abstract

Background: Evidence is limited on the potential health effects of Ox (sum value) and Oxwt(weighted value), the two surrogates for ozone (O3) and nitrogen dioxides (NO2). Objectives: To investigate the impacts of Ox and redox-weighted oxidant capacity (Oxwt) on blood pressure (BP). Methods: A panel study was conducted with four repeated follow-up visits among 40 healthy college students in Hefei, Anhui Province, China from August to October, 2021. We measured BP by using an automated sphygmomanometer and obtained hourly data of air pollutants at a nearby site. The sum of O3 and NO2 (Ox) and their weighted average (Oxwt) were obtained as exposure variables. We applied linear mixed-effect models to evaluate the effects of Ox and Oxwton systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP) and pulse pressure (PP). Results: Totally, 160 pairs of valid BP values were obtained. The 24-h mean levels of Ox and Oxwt were 64.38 μg/m3 and 110.28 μg/m3, respectively. Overall, both Ox and Oxwt were significantly linked with SBP, DBP and MAP at most lag periods, whereas non-significant with PP. A 10-μg/m3 increase in Oxwt at lag 0–24 h was linked to increases of 2.43 mmHg (95% CI: 0.96, 3.91) in SBP, 2.31 mmHg (95% CI: 1.37, 3.26) in DBP and 2.35 mmHg (95% CI: 1.35, 3.36) in MAP, while the corresponding effect estimates for Ox were 1.51 mmHg (95%CI: 0.60, 2.43), 1.43 mmHg (95% CI: 0.85, 2.02) and 1.46 mmHg (95%CI: 0.83, 2.09). In two-pollutant models, our results were almost unchanged after controlling for simultaneous exposure to other pollutants. The effects were more pronounced among males and those with physical activity. Conclusions: The findings provide first-hand evidence that short-term exposure to Ox and Oxwt was associated with BP increases in young adults.

Keywords

• Air pollution
• Combined oxidative capacity
• Redox-weighted oxidant capacity
• BP
• Panel study