Children who frequently eat fast food are far likelier to have severe asthma compared to counterparts who tuck into fruit, a large international study published on Monday said.
Researchers asked nearly half a million teenagers aged 13 to 14 years old and children aged six and seven about their eating habits and whether in the previous year they had experienced wheezing, eczema or an itchy, blocked nose when they did not have a cold or flu.
The questionnaires – completed by a parent or guardian for the younger children – were distributed in scores of countries.
The study marks the latest phase in a long-running collabourative programme, the International Study of Asthma and Allergies in Childhood (ISAAC), which was launched in 1991.
The investigators filtered out factors that could skew results, such as maternal smoking during pregnancy, sedentary lifestyle and body-mass index, in order to focus purely on diet.
They found that fast food was the only food type that could be clearly linked to asthma severity.