Scientists are now calling for youngsters to be routinely checked for problems and work to protect them from smog. The team looked at more than 350,000 five to 12-year-olds in Europe, the US and China. They dug further into 14 studies, looking at the effects of different sized particles found in the air on youngsters’ blood pressure.
Less than a month of exposure to bigger particulate was enough to significantly raise systolic blood pressure – the top-line figure showing the force blood is pumped around the body.
Finer particles and nitrogen dioxide from traffic had the same result on diastolic pressure – the lower figure showing the resistance to blood flow in vessels.
Study author Professor Yao Lu, of King’s College, London, said: “The findings provide evidence of a positive association between short and long-term exposure to certain environmental air pollutants and blood pressure in children and adolescents. Our study indicates that both short-term and long-term exposure to some ambient air pollutants may increase blood pressure values among children and adolescents.
“Previous studies have found that the lungs of children may be exposed to higher concentrations of ambient particles than adults, suggesting that children would be at greater risk from the adverse effects of air pollution.
“Exposure to high levels of air pollutants during childhood increases the likelihood of high blood pressure in children and adolescents, and their risk for high blood pressure as adults.”
Previous studies produced inconclusive findings on the link.
Prof Lu added: “Our analysis is the first to closely examine previous research to assess both the quality and magnitude of the associations between air pollution and blood pressure among children.” High blood pressure during childhood and adolescence is a risk factor for hypertension and heart disease in adulthood.
Prof Lu, who is also professor at Central South University in Changsha, China, added: “Lower exposure during childhood and adolescence might decrease the risk of hypertension and cardiovascular disease in adulthood.
“To reduce the impact of environmental pollution on blood pressure in children and adolescents, efforts should be made to reduce their exposure to environmental pollutants.
“Additionally, it is also very important to routinely measure blood pressure in children and adolescents, which can help us identify individuals with elevated blood pressure early.”
The study has been published in the Journal of the American Heart Association.