Research suggests first year ‘critical window’ in which toxic air can increase weight gain.
Early exposure to air pollution from vehicles increases the risk of children becoming obese, new research has found.
High levels of nitrogen dioxide, which is emitted by diesel engines, in the first year of life led to significantly faster weight gain later, the scientists found. Other pollutants produced by road traffic have also been linked to obesity in children by recent studies.
Nitrogen dioxide pollution is at illegal levels in most urban areas in the UK and the government has lost three times in the high court over the inadequacy of its plans. The pollutant also plagues many cities in Europe and around the world.
The World Health Organization (WHO) revealed last Monday that 90% of the world’s children are breathing unsafe air, a situation described as “inexcusable” by the WHO’s head. Concern over the impact of toxic air on children’s health is rising as research reveals serious long-term damage to both their physical and mental health.
A large recent study found toxic air significantly increases the risk of low birth weight, leading to lifelong damage to health. Others linked air pollution with birth defects, cot deaths and the first direct evidence of pollution particles in mothers’ placentas has also been revealed.
The new research, published in the journal Environmental Health, followed 2,318 children in southern California and built on earlier work which had identified traffic pollution as a major risk factor for the development of obesity in children.
The research investigated the impact of air pollution from busy main roads, where diesel trucks are common, in the crucial first year of life. They found that by age 10, children suffering high early exposure were almost 1kg heavier on average than those with low exposure. The scientists took a series of other factors into account, including gender, ethnicity and parental education, and think it is unlikely that variations in diet could explain the strong link found.
“Our study suggests that early life may represent a critical window of exposure where increased [air pollution] may result in increased risk for higher childhood [weight] trajectories, which in turn may lead to childhood obesity,” the researchers concluded.