IgE is associated with body mass index: the United States national health and nutrition examination survey (NHANES) 2005–2006

Abstract

BACKGROUND: In both obesity and allergy, inflammation occurs. Therefore, we examined the association between body mass index (BMI), a measure of general obesity, and serum IgE level, a measure of allergy. METHODS: We analyzed data on 1933 men and 1802 women in NHANES 2005–2006. We included participants aged above 20 years who had valid data on BMI and IgE level. Pregnant women were excluded from this study. Using the complex sampling function of SPSS, the unstandardized regression coefficient, b, for the relationship between BMI and the natural logarithm of IgE level was calculated. RESULTS: There was a sex difference in IgE level (P < 0.001). Before adjustment, IgE was associated with BMI in women (b = 0.451, P = 0.006) and in the overall population (b = 0.338, P = 0.001). After adjusting for race/ethnicity, age and sex except in sex-specific analysis, the association in women (b = 0.382, P = 0.018) and the overall population (b = 0.309, P = 0.006) remained significant. After further adjustments for physical activity, alcohol consumption and smoking, the association was still significant in women (b = 0.373, P = 0.010) and the overall population (b = 0.323, P = 0.003). The association was attenuated but remained significant in women (b = 0.233, P = 0.036) and the overall population (b = 0.179, P = 0.042) after further adjustment for levels of liver enzymes and C-reactive protein. CONCLUSIONS: In this nationally representative population-based survey, IgE level is associated with BMI. The attenuation in the association after controlling for liver enzymes and C-reactive protein suggests that hepatic inflammation accounts for some of the association.