Intragastric balloon for the treatment of obesity: evaluation of pulmonary function over a 3-month period

Impact of obesity on pulmonary function: current understanding and knowledge gaps

PURPOSE OF REVIEW

Obesity is an increasing world-wide public health concern. Obesity both causes respiratory symptoms and contributes to many cardiorespiratory diseases. The effects of obesity on commonly used lung function tests are reviewed.

RECENT FINDINGS

The effects of obesity on lung function are attributed both to mechanical factors and to complex metabolic effects that contribute to a pro-inflammatory state. The effects of obesity on lung function correlate with BMI and correlate even better when the distribution of excess adipose tissue is taken into account, with central obesity associated with more prominent abnormalities. Obesity is associated with marked decreases in expiratory reserve volume and functional residual capacity. Total lung capacity, residual volume, and spirometry are less affected by obesity and are generally within the normal range except with severe obesity. Obesity decreases total respiratory system compliance primarily because of decreased lung compliance, with only mild effects on chest wall compliance. Obesity is associated with impaired gas transfer with decreases in oxygenation and varied but usually mild effects on diffusing capacity for carbon monoxide, while the carbon monoxide transfer coefficient is often increased.

SUMMARY

Obesity has significant effects on lung function. The relative contribution of the mechanical effects of obesity and the production of inflammatory cytokines by adipose tissue on lung function needs further study.

The relationship between body fat and respiratory function in young adults

The relationship between adiposity and respiratory function is poorly understood. Most studies investigating this have used indirect measures of body fat and few have assessed how changes in adiposity influence lung function.Body fat measured by bio-electrical impedance analysis, body mass index, waist circumference, spirometry, body plethysmography and transfer factor were measured at ages 32 and 38 years in 361 non-smoking, non-asthmatic participants from a population-based birth cohort.Higher percentage body fat was associated with lower spirometric and plethysmographic lung volumes, but not with airflow obstruction, or transfer factor at 32 years. Changes in adiposity between ages 32 and 38 years were inversely associated with changes in lung volumes. These associations were generally stronger in men than women, but an association between increasing adiposity and lower airway function (forced expiratory volume in 1 s/forced vital capacity) was only found in women. Similar associations were found for body mass index and waist circumference.Higher percentage body fat is associated with lower lung volumes. Direct and indirect measures of adiposity had similar associations with lung function. Adiposity had a greater effect on lung volumes in men than women but was associated with airway function only in women. There was little evidence that adiposity influenced transfer factor.

Obesity: systemic and pulmonary complications, biochemical abnormalities, and impairment of lung function

Obesity is currently one of the major epidemics of this millennium and affects individuals throughout the world. It causes multiple systemic complications, some of which result in severe impairment of organs and tissues. These complications involve mechanical changes caused by the accumulation of adipose tissue and the numerous cytokines produced by adipocytes. Obesity also significantly interferes with respiratory function by decreasing lung volume, particularly the expiratory reserve volume and functional residual capacity. Because of the ineffectiveness of the respiratory muscles, strength and resistance may be reduced. All these factors lead to inspiratory overload, which increases respiratory effort, oxygen consumption, and respiratory energy expenditure. It is noteworthy that patterns of body fat distribution significantly influence the function of the respiratory system, likely via the direct mechanical effect of fat accumulation in the chest and abdominal regions. Weight loss caused by various types of treatment, including low-calorie diet, intragastric balloon, and bariatric surgery, significantly improves lung function and metabolic syndrome and reduces body mass index. Despite advances in the knowledge of pulmonary and systemic complications associated with obesity, longitudinal randomized studies are needed to assess the impact of weight loss on metabolic syndrome and lung function.

Six-month intragastric balloon treatment for obesity improves lung function, body composition, and metabolic syndrome

BACKGROUND

The purpose of this study is to establish whether the use of an intragastric balloon (IGB) for 6 months improves lung function, metabolic parameters, and body fat distribution in patients with overweight/obesity and metabolic syndrome (MS).

METHODS

This is a longitudinal and interventional study on 40 adults, whose anthropometric, laboratory, and lung function parameters were assessed and who underwent dual-energy X-ray absorptiometry (DXA) before implantation and after removal of IGB.

RESULTS

The total lung capacity (TLC) (p = 0.0001), functional residual capacity (FRC) (p = 0.0001), residual volume (p = 0.0005), and expiratory reserve volume (ERV) (p = 0.0001) were significantly reduced by IGB. The body mass index (BMI) significantly decreased from a median of 39.1 kg/m(2) at the beginning of the study to 34.5 kg/m(2) at the end of the 6-month period (p = 0.0001). At the end of the study, 31 participants (77.5%) no longer met the diagnostic criteria of MS. The percentage of truncal, android, gynoid, and total fat investigated by DXA exhibited significant reductions (p = 0.0001). Significant correlations were found between delta TLC and delta waist circumference (ρ = -0.34; p = 0.03), delta FRC and delta IMC (ρ = -0.39; p = 0.01), delta ERV and delta BMI (ρ = -0.44; p = 0.005), and delta ERV and delta high-density lipoprotein (HDL) (ρ = -0.37; p = 0.02). Significant correlations were also found between delta ERV and delta truncal (ρ = -0.51; p = 0.004), android (ρ = -0.46; p = 0.01), gynoid (ρ = -0.55; p = 0.001), and total fat (ρ = -0.59; p = 0.0005).

CONCLUSIONS

IGB efficiently induced weight loss and promoted the improvement of lung function parameters, with a reduction of the restrictive ventilatory defect. It also promoted improvements of MS and the pattern of body fat distribution.