New allergen sensitization might be associated with increased body mass index in children.

BACKGROUND: Results of previous studies have shown a relationship between obesity and allergic diseases. However, concrete evidence about the association between obesity and allergies has been lacking. OBJECTIVE: The present study aimed to evaluate the potential association between body mass index (BMI) and the change in sensitization on skin-prick tests in children over a 2-year follow-up period. METHODS: Children in first and second grade from six elementary schools were recruited in 2010. The same participants, now in third and fourth grade, were recruited again in 2012. The enrolled children underwent skin-prick tests and physical examinations in 2010 and again in 2012. RESULTS: Four hundred fourteen children (boys to girls, 208 to 206) were included. Among 414 participants, 73 children showed new sensitization and 24 children showed negative conversion of allergic sensitization after 2 years. One hundred sixty-one children showed positive results on both tests, and 156 children showed negative results on both tests. The mean (standard deviation) change in BMI (1.09 ± 1.81 kg/m(2)) over a 2-year follow-up in newly sensitized children was significantly greater than that of other groups (p = 0.008). CONCLUSION: Children who became newly sensitized to allergens tended to exhibit significant increases in BMI. Therefore, further evaluation of the relationship between obesity and allergy is needed.