London air pollution 'linked to higher teenage blood pressure'

Tiny pollutants were associated with higher blood pressure, particularly among girls

An information sign at Tower Hill in central London for the Ultra Low Emission Zone. PA
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Higher blood pressure among teenagers living in London has been linked to long-term exposure to tiny air pollution particles, with stronger links in girls, according to research.

Data was analysed from more than 3,000 adolescents by scientists from King's College London, who found that exposure to high levels of nitrogen dioxide — a pollutant from diesel traffic in London — is associated with lower blood pressure in this group.

More research is urgently needed to assess how air pollution may be affecting the cardiovascular health of children and adolescents, said the team who published their findings in the journal Plos One.

Senior author Seeromanie Harding, a professor of social epidemiology from Kings College London, said the study “provides a unique opportunity to track exposures of adolescents living in deprived neighbourhoods”.

“Given that more than one million under-18s live in neighbourhoods where air pollution is higher than the recommended health standards, there is an urgent need for more of these studies to gain an in-depth understanding of the threats to, and opportunities for, young people’s development," Prof Harding said.

Pollution particles are small enough to be inhaled into the body.

They can make their way into the bloodstream, causing damage to blood vessels and airways.

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For the study, the researchers examined the effects of air pollution on children at 51 schools across London.

They analysed data from 3,284 adolescents, following up from ages 11-13 and 14-16.

The results show Particulate Matter (PM2.5) — tiny pollutants that come from car exhaust fumes, building, and industry materials — was associated with higher blood pressure across all ages, particularly among girls.

Meanwhile, nitrogen dioxide was associated with lower blood pressure.

“The effect of NO2 on blood pressure is similar to what we and other researchers have observed previously after ingesting green leafy vegetables or beetroot juice," said co-author Dr Andrew Webb, also from King’s College.

“These are rich in dietary nitrate, which increases circulating nitrite concentration in the blood and lowers blood pressure, an effect that may also be sustained over weeks or months with continued ingestion of nitrate-rich vegetables.”

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Researchers also found teenagers from ethnic minority groups were exposed to higher annual average concentrations of pollution at home than their white peers.

But they said the effect of pollutants on blood pressure did not vary according to ethnicity, weight, or economic status.

“The findings highlight the potential detrimental role of exposure to higher concentrations of particulate matter on adolescents’ blood pressure levels," said corresponding author Dr Alexis Karamanos, from the same university.

“Further studies following the same adolescents over time in different socio-economic contexts are needed to understand whether and how exposure to higher pollutant concentrations may affect differently the cardiovascular health of children and adolescents.”

Updated: February 08, 2023, 8:58 PM