Children entering primary school have to undergo a medical examination performed by the doctors and nurses of France's Education Ministry. According to a survey carried out in 1999-2000 among a sample of 30,000 pupils who'd just undergone their medical examination, 14% of 6 year old children were overweight, including 4% who were obese and 10% who were moderately overweight. Children living in big cities and priority education areas (zones d'éducation prioritaires ­ ZEP) are more likely to be overweight than those living in rural communities. Asthma affects between 6 and 12% of children with various degrees of severity, and is more common among boys than girls.