Objective: Air pollution is associated with a number of health outcomes in childhood. In this study, we investigated whether air pollution is related to children's height.
Methods: The 1946 British birth cohort study recruited 5,362 children born in 1 week in March 1946. Height was measured when the children were aged 2, 4, 6, 7, 11 and 15 years. Data on socio-economic conditions and other characteristics were obtained in interviews. Areas of children's residence were categorised into four groups of air pollution on the basis of published coal-consumption data.
Results: After controlling for socio-economic factors, we found that air pollution was associated with children's height at several ages. The association, adjusted for socio-economic factors, was strongest at the age of 7 years, when children in the most polluted areas were 1.2 (95% confidence interval 0.5-1.8) cm shorter than those in the least polluted areas. After the age of 7 years the effect of air pollution diminished and disappeared by the age of 15 years. Further adjustment for birth weight and respiratory illness in childhood did not change this pattern.
Conclusions: Children's height was inversely associated with air pollution, but the magnitude of the effect depended on age. However, the biological mechanisms linking children's growth with air pollution are not evident, and it remains to be confirmed whether the relationship is genuine and causal.