Childhood allergies and obesity relationship: Identification of novel non-invasive biomarkers

Asthma and obesity are among the most common chronic childhood disorders, both having had a parallel dramatic increase in prevalence worldwide in recent decades. The parallel epidemics of asthma and obesity over the past few decades have spurred research into obesity as a risk factor for asthma. However, little is known regarding the impact of asthma on obesity incidence. In a large-scale prospective study, we assess effects of allergies on BMI at age 7 (n=5,158) in Japan. Parents completed the International Study of Asthma and Allergies in Childhood questionnaires about symptoms of allergic diseases (wheeze, rhinoconjunctivitis, and eczema) at age 1, 2, 4, and 7 years. BMI (kg/m²) was measured at age 7. We also examined three inflammatory urine biomarkers at age 7 including 8-hydroxy-2 deoxyguanosine (8-OHdG), hexanoyl-lysin (HEL), and 4-Hydroxynonenal (HNE). We differentiated obesity risk in children according to asthma phenotype and try to find underlying mechanism in asthma-obesity relationship (n = 568). Wheeze at age 1, 2, and 4 years of age was significantly associated with higher BMI at age 7. In contrast, rhinoconjunctivitis and eczema did not show significant association with BMI at age 7. HEL, as one of omega 6 fatty acid oxidation biomarkers, had higher urinary levels among children with wheeze at age 7. However, other urinary biomarkers did not show significant association with BMI and risk of allergic diseases at age 7. As conclusion, we showed that early life wheeze, but not rhinoconjunctivitis and eczema, is associated with higher childhood BMI. More studies are warranted to explore mechanistic relationship of asthma with obesity in children.