Determinants of serum tryptase in a general population: The relationship of serum tryptase to obesity and asthma

摘要

Background: Recent studies indicate that mast cells are more abundant in the obese state. Total serum tryptase (ST) is a marker of mast cell numbers or activity. Since obesity and asthma have been consistently linked in epidemiological studies, a possible higher mast cell activity in obesity could be a factor between the two conditions. The aim of this study was to investigate determinants of ST and whether a potential association between obesity and allergic respiratory disease would be influenced by levels of ST in obese persons. Methods: Measurements of ST (ImmunoCAP Tryptase assay), atopy (skin prick test reactivity), methacholine bronchial hyperresponsiveness (BHR), body mass index (BMI) and serum lipids were performed in a general population of 1,216 persons aged 15-69 years. Results: ST increased significantly with increasing BMI. The median ST level increased from 3.3 μg/l in persons with BMI <25 to 4.4 μg/l in persons with BMI >30, p < 0.0001. Age (p < 0.0001), male sex (p = 0.0009) and smoking (p = 0.022) were positively associated with ST, whereas alcohol consumption (p = 0.005) was inversely associated with ST. ST was not associated with atopy, symptoms of allergic respiratory disease or BHR. A positive association between symptoms of allergic respiratory disease and obesity (OR = 1.98, 95% CI = 1.25-3.14) was not influenced by obesity-related differences in ST. Conclusions: Increasing BMI was significantly associated with increasing ST and the prevalence of symptoms of allergic respiratory disease. However, mast cell activity/burden (assessed by ST levels) did not influence the association between BMI and asthma/rhinitis symptoms.