Visceral adiposity is associated with cytokines and decrease in lung function in women with persistent asthma

Abdominal obesity is associated with a risk of cardiovascular diseases, metabolic syndrome and decreased lung function. However, it is not known whether asthma control is influenced by the accumulation of adipose tissue in the various abdominal compartments.

OBJECTIVE

To determine associations among abdominal adiposity distribution, asthma control, lung function and cytokines in women.

METHODS AND DESIGN

In this cross-sectional study of asthmatic women, data on demographic variables, comorbid conditions, disease history, anthropometric and spirometric measurements were collected. Subcutaneous (SAT) and visceral (VAT) adipose tissues were measured by ultrasound, and the steatosis level was obtained. Asthma control was assessed according to Global Initiative for Asthma (GINA) criteria. Atopy was defined on the basis of allergen-specific Immunoglobulin E and/or skin prick testing. Cytokine levels were determined using enzyme-linked immunosorbant assays (ELISAs).

RESULTS

Eighty-three asthmatic women were included, 37% of whom had uncontrolled asthma. After controlling for variables, a negative association between asthma control and VAT and the VAT/SAT ratio was observed. VAT was negatively associated with respiratory parameters after controlling for explanatory variables. In an adjusted model, body mass index (BMI) and SAT were inversely associated with the adiponectin serum level and VAT was associated with the interleukin 6 level. In conclusion, visceral obesity was negatively associated with asthma control and lung function; and positively associated with increased levels of interleukin 6 in women. We hypothesize that women should be studied as a separate group, and we suggest further studies with a control group to know if the uncontrolled asthmatic group is directly affected by visceral adipose inflammatory markers.

Central obesity and other factors associated with uncontrolled asthma in women

Background

Asthma remains an uncontrolled disease. The Comorbidities, particularly obesity, and several other factors have been identified as being individually associated with asthma control, and these factors vary among different countries and between sexes. Studies have suggested that the harmful effects of these factors are greatest among women. The aim of the present study was to identify associated factors with uncontrolled asthma in women at the outpatient clinic of a Federal University Hospital in Rio de Janeiro, Brazil.

Methods

Cross-sectional study with asthmatic women, older than 18 years old. All subjects were included according to stringent criteria. The study used a structured questionnaire with data about demographic variables, education level, comorbid conditions, and disease history. Anthropometric and spirometric measurements were obtained. Asthma control was assessed by three different tools: the Asthma Control Test (ACT), the Asthma Control Questionnaire (ACQ) and the Global Initiative for Asthma (GINA) criteria.

Results

A total of 124 women were included, and 57%, 38% and 21% were totally controlled according to ACT, ACQ and GINA criteria, respectively. A total of 31.5% were obese. According to the CI (Conicity Index) and WC (waist circumference) respectively, 84% and 68% were centrally obese. There was no association between asthma control and age, education, duration of the disease or BMI (Body Mass Index) in the three models, but there was a significant association between central obesity and asthma control with the ACQ and GINA assessment tools, controlling for explanatory variables such as GERD (gastroesophageal reflux disease). Pre-bronchodilator percent predicted forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC) were significantly associated with age and FVC was also associated with central obesity.

Conclusions

Asthma remains uncontrolled in women despite treatment, and central obesity seems to have a negative influence on the control of the disease. We believe that women should be studied as a separate group and suggest prospective studies with assessment of fat distribution and biomarkers, controlling for possible comorbidities associated with asthma control.