In a new analysis involving adolescents living in London, exposure to higher levels of the pollutant nitrogen dioxide was associated with lower systolic blood pressure, while exposure to higher levels of particulate matter 2.5 (PM2.5) was associated with higher systolic blood pressure. Alexis Karamanos of King’s College London and colleagues present these findings in the open-access journal PLOS ONE on Feb. 8, finding that these associations are stronger for girls than for boys.
Exposure to air pollutants is associated with a greater risk of cardiovascular disease, hospital visits and death. The rapidly growing body of adolescents may be particularly susceptible to long-term effects of exposure to air pollutants, including effects on blood pressure. However, most previous studies on air pollution and blood pressure have focused on adults.
To better understand these associations in adolescents, Karamanos and colleagues analyzed data collected as part of the Determinants of Adolescent Social Well-Being and Health (DASH) study, which tracked the well-being of thousands of ethnically diverse London schoolchildren over time. follows. For this analysis, they used data from 3,284 adolescents in DASH to examine links between blood pressure and exposure to pollution in the form of nitrogen dioxide and PM2.5; exposures were estimated based on the annual mean levels of pollutants where each participant lived.
The researchers found that greater estimated exposure to nitrogen dioxide was associated with lower systolic blood pressure, and greater estimated exposure to PM2.5 was associated with higher systolic blood pressure. These associations were stronger in girls than in boys. No evidence was found for an association between nitrogen dioxide/PM2.5 and diastolic blood pressure.
For example, an increase in nitrogen dioxide of 1 µg/m3 was associated with a reduction in systolic blood pressure of 0.30 mmHg (95% CI 0.18 to 0.40) for girls and a reduction in systolic blood pressure of 0.19 mmHg (95% CI 0.07 to 0.31) for boys. Meanwhile, an increase in PM2.5 by 1 μg/m3 was associated with an increase of 1.34 mmHg (95% CI 0.85 to 1.82) in systolic blood pressure for girls and an increase of 0.57 mmHg (95 % CI 0.04 to 1.03) of systolic blood pressure for girls. guys. The associations between pollutants and blood pressure were consistent regardless of ethnicity, body size, or socioeconomic status
Eighty percent of the adolescents surveyed were from minority ethnic groups, and the residential estimates suggest that these adolescents were exposed to higher levels of pollutants than their white peers.
The researchers call for further studies to confirm and clarify these findings, particularly among young people from different socioeconomic backgrounds. They also note that levels of nitrogen dioxide and PM2.5 in London remain well above World Health Organization guidelines, suggesting opportunities to reduce pollution and improve the lifelong health of adolescents in the city.
Seeromanie Harding, from King’s College, London, adds: “This longitudinal study offers a unique opportunity to track the exposure of adolescents living in deprived areas. As more than 1 million young people under the age of 18 live in neighborhoods where air pollution exceeds recommended health standards, there is an urgent need for more of these studies to gain an in-depth understanding of threats and opportunities for youth development .”
- Karamanos A, Lu Y, Mudway IS, Ayis S, Kelly FJ, Beevers SD, et al. (2023) Associations between air pollutants and blood pressure in an ethnically diverse cohort of adolescents in London, England. PLoS ONE 18(2): e0279719. DOI: 10.1371/journal.pone.0279719