PURPOSE: While studies have examined the effects of mild to moderate obesity on pulmonary function, there have been no large studies that have specifically looked at the impact of morbid obesity. There have also been no studies that have looked at the way in which gender and age influence this impact on pulmonary function.
METHODS: Pulmonary function test (PFT) results were collected on 472 patients who were being evaluated for bariatric surgery between January 2001 and August 2006. The height and weight of each patient was recorded at the time of their PFT, from which their Body Mass Index (BMI) was calculated.
RESULTS: Records of a total of 472 patients who underwent PFTs as part of their evaluation for bariatric surgery were reviewed. Of these, 433 patients (325 Female and 108 Male) had a BMI > 40 kg/m2 and 244 were older than 40 years. Of the 39 subjects who had a BMI < 40 kg/m2, 24 were > 40 years. Among all patients, BMI had a significant impact on the Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), Expiratory Reserve Volume (ERV), Residual Volume (RV), Total Lung Capacity (TLC) and oxygenation (PaO2). In patients with a BMI < 40 kg/m2, gender and age had no impact, while in patients with a BMI > 40 kg/m2, there were significant differences in pulmonary function based on the gender and the age of the patient. FVC, FEV1, FEV1/FVC, ERV, TLC and PaO2 were all significantly reduced in males compared to females. Similarly, FVC was significantly reduced among subjects > 40 years when compared to those < 40 years.
CONCLUSION: Our study demonstrated the effects of morbid obesity on pulmonary function. It also established the greater impact of obesity in men, likely related to their central (upper body) pattern of fat distribution.
CLINICAL IMPLICATIONS: The results of our study along with the absence of an obstructive impairment in our patients suggests that asthma is being over-diagnosed in obese patients, especially women.
DISCLOSURE: Vishal Sekhri, None.