Determinants of Serum Tryptase in a General Population: The Relationship of Serum Tryptase to Obesity and Asthma

Abstract

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.

Histamine skin reactivity increases with body mass index in Korean children

“…Fenger etal. [21] also showed that serum tryptase, a marker of mast cell number and activity, increased with increasing BMI. It is plausible that the relationship between BMI and response to histamine is mediated by increased mast cell activity or count.…”

Insect Sting Reactions and Specific IgE to Venom and Major Allergens in a General Population

“…However, serum tryptase seems not to be associated with atopy and allergic respiratory disease [29], and patients with indolent mastocytosis without skin lesions have been found to have a high reaction rate to insect stings but a lower baseline serum tryptase than other groups of mastocytosis patients [30]. …”

Macrophage activation, age and sex effects of immunometabolism in obese asthma

“…However, tryptase was significantly increased only in obese children, compared to non-obese children and not across all age groups. This may be explained by the effect of age on tryptase, as tryptase levels increase in adults independent of BMI [22], which may have confounded our analysis. In another human study, WARD et al [23] also found no association between BMI and tryptase in obese and non-obese children with and without glucose intolerance and diabetes mellitus ( p=0.068).…”