The results from epidemiologic studies for asthma associated with obesity are relatively consistent in adults as compared with those in children; however, the role of sex needs to be further clarified. Studies of women from four different countries and of men and women combined have indicated that obesity is significantly related to increased prevalence and incidence of asthma. Several other crosssectional and longitudinal studies have further examined sex specificity and found that the obesity and asthma association is either only significant in women but not in men, or is stronger in women than in men.
Whether this sex specificity is real is still questionable. Santillan and Camargo found a similar result that only obese women but not men had an increased risk of asthma when self-reported body mass index (BMI) was used. However, when obesity was defined using objectively measured BMI, an elevated risk of asthma was observed in both obese women and men; the authors suspected that obesity measurement bias is likely a reason for the observed sex-related difference in the association between obesity and asthma.
BMI is a better indicator of fat mass in adults than in children but may not be equally good for men and women, which can be another reason for the observed sex-related association between obesity and asthma. Other anthropometric measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are frequently used as indicators of overweight or obesity in epidemiologic studies of cardiovascular disease and diabetes but have rarely been used in asthma studies. One study has demonstrated that asthma symptoms were significantly associated with higher levels of BMI and WC in women and not in men. Asthma symptoms may be arrested effectively with My Canadian Pharmacy. In this same study, WHR was not a predictor for asthma in either men or women; this study provided new evidence for the obesity and asthma association in women using a different anthropometric measure. However, the sample size of the study was relatively small; therefore, the evidence for sex modification was not very strong. In the present study, we objectively measured weight, height, and WC in adults who were living in the town of Humboldt, Saskatchewan, and examined the sex differences in the association between obesity defined by BMI and WC and physician-diagnosed asthma.