Background: A positive association between body mass index (BMI) and allergic diseases has recently been suggested; however the sex-dependence of this association remains controversial. The aim of the present study was to explore the relationship between BMI and asthma and eczema, as well as its sex-dependence in young adolescents.
Methods: Self-reported data obtained through the standardized International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three written questionnaires of 2926 young adolescents aged 13-14 years old from randomly selected schools in Skopje (Republic of Macedonia) were used. The BMI for each individual was calculated and used-both unadjusted and adjusted for confounding factors-as a variable for analysis. The international cut-off points for BMI for overweight and obesity by sex and age were used. Because of the very low prevalence of obesity (1.5 %), obese respondents were included in the overweight group. The data were statistically analyzed by the chi-square test, the t-test for independent samples and odds ratios (OR, 95 % CI) in binary logistic regression.
Results: Being overweight was significantly associated with an increased risk of having a dry night cough without a cold or chest infection (adjusted OR: 1.54; 95 % CI: 1.09-2.16; p = 0.01) and with having had self-reported asthma at some time (adjusted OR: 2.36; 95 % CI: 1.02-5.44; p = 0.04) in boys only. A significant association between overweight and other symptoms of asthma or atopic eczema was not established.
Conclusion: These findings suggest a male-specific positive association between overweight and a current dry night cough and having received a diagnosis of asthma at some time. No association was found with other asthma symptoms or atopic eczema in young adolescents.