Lung function, bronchial hyperresponsiveness (BHR) and metabolic risk factors in adults: Preliminary results from the gene environment interaction in respiratory disease (GEIRD) survey

Impaired lung function is a risk factor for cardiovascular events and mortality, and is associated with insulin resistance and type 2 diabetes mellitus. It is well known that a common mechanism, such as insulin resistance and obesity, underlies metabolic syndrome (MS). Our aim was to assess the association between lung function and MS in the GEIRD study, a nested multi-case control survey, in Verona, Italy. The study population included 1117 subjects (aged 20-66 years) who underwent spirometry (n=1113) and methacholine challenge (n=472). MS was defined according to the presence of 3 or more of the following factors: blood pressure of 130/85 mmHg or higher, abdominal obesity (waist girth: men>=102,women>=88cm), self reported dyslipidemia, self reported diabetes. We studied the association of FEV1, FVC (% predicted), FEV1/FVC (%) and BHR (defined as a PD20<1mg) with MS and each of its components (using multiple linear or logistic regression adjusted for sex, age, height, smoking habits and case-control status). MS was associated with reduced FEV1% predicted (b=-3.4,95%CI: -6.5,-0.2), but not with FEV1/FVC (%) (b=-0.2,95%CI: -1.6,1.2). A negative but not statistically significant association between MS and FVC% predicted (b=-4.3, 95%CI:-8.8,0.2) was found. A positive association emerged between MS and BHR (OR=8.79, 95%CI: 2.3-33.8). Among MS components, only abdominal obesity was related with a reduced FVC% predicted (b=-3.5, 95%CI: -6.0,-0.9). Our data indicate that low FEV1% predicted and BHR are associated with MS. The results of the present analysis deserves further investigation.