Fat Distribution and End-Expiratory Lung Volume in Lean and Obese Men and Women

doi:10.1378/chest.07-1728

Chest

Volume 134, Issue 4, October 2008, Pages 704-711

https://doi.org/10.1378/chest.07-1728 Get rights and content

Background

Although obesity significantly reduces end-expiratory lung volume (EELV), the relationship between EELV and detailed measures of fat distribution has not been studied in obese men and women. To investigate, EELV and chest wall fat distribution (ie, rib cage, anterior subcutaneous abdominal fat, posterior subcutaneous fat, and visceral fat) were measured in lean men and women (ie, < 25% body fat) and obese men and women (ie, > 30% body fat).

Methods

All subjects underwent pulmonary function testing, hydrostatic weighing, and MRI scans. Data were analyzed for the men and women separately by independent t test, and the relationships between variables were determined by regression analysis.

Results

All body composition measurements were significantly different among the lean and obese men and women (p < 0.001). However, with only a few exceptions, fat distribution was similar among the lean and obese men and women (p > 0.05). The mean EELV was significantly lower in the obese men (39 ± 6% vs 46 ± 4% total lung capacity [TLC], respectively; p < 0.0005) and women (40 ± 4% vs 53 ± 4% TLC, respectively; p < 0.0001) compared with lean control subjects. Many estimates of body fat were significantly correlated with EELV for both men and women.

Conclusions

In both men and women, the decrease in EELV with obesity appears to be related to the cumulative effect of increased chest wall fat rather than to any specific regional chest wall fat distribution. Also, with only a few exceptions, relative fat distribution is markedly similar between lean and obese subjects.

Section snippets

Subjects

Nine lean men (< 25% body fat) and 10 obese men (> 30% body fat), and 11 lean women and 10 obese women were recruited through local advertisements (ie, BMI ranges were used for recruitment purposes, and the percentage of body fat was confirmed after written consent was obtained). The lean and obese men also participated in another study,¹⁸ which focused on the effects of obesity on respiratory mechanics during exercise. The lean and obese women exclusively participated in this prospective study

Subjects

Subject characteristics are shown in Table 1. All body circumferences, ratios and BMIs were significantly different between the lean and obese subjects for both men and women (p < 0.001). Both total body fat and lean body mass were significantly greater (p < 0.001) in the obese men compared with the lean men (Fig 1, top, A). The same was true for the lean and obese women (Fig 1, bottom, B). Among the men, all subjects were currently nonsmokers, while two of the lean men were ex-smokers (smoking

Discussion

We have reported for the first time the associations between direct measures of chest wall fat distribution and measures of lung function in lean and obese men and women. We also have reported that the chest wall fat distribution was closely similar between lean and obese men and women, which means that the increase in chest wall fat distribution was proportional to the overall increase in obesity. Therefore, almost all measurements of overall obesity (eg, BMI and percentage of body fat) and

Acknowledgment

The authors wish to express their appreciation to P.T. Weatherall, MD, Tommy Tillery, RT (R) (MR)(CT), Brian Fox, RT (R)(MR), and Jerri Payne, PA-C, of the Rogers NMR Center at University of Texas Southwestern Medical Center; and Judy L. Barron and R. Michael Collins of the Institute for Exercise and Environmental Medicine for their assistance with this project. The authors also acknowledge the editorial contributions of Helen E. Wood, PhD.

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This research was supported by an American Lung Association Career Investigator Award, AHA, TX Affiliate Grant, and the King Charitable Foundation Trust.

The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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Chest

Original ResearchPulmonary Function TestingFat Distribution and End-Expiratory Lung Volume in Lean and Obese Men and Women

Background

Methods

Results

Conclusions

Section snippets

Subjects

Subjects

Discussion

Acknowledgment

Respir Med

Chest

J Clin Epidemiol

Am J Clin Nutr

Chest

Chest

Chest

Chest

Chest

Chest

Clin Chest Med

Am J Clin Nutr

J Lipid Res

Chest

Mild obesity does not limit change in end-expiratory lung volume during cycling in young women

J Appl Physiol

Effects of obesity on respiratory function

Am Rev Respir Dis

Body composition and the expiratory reserve volume in lean and obese men and women

Int J Obes

Exercise end-expiratory lung volumes in lean and moderately obese women

Int J Obes

Longitudinal changes of body mass index, spirometry and diffusion in a general population

Eur Respir J

Usefulness of anthropmetry and DXA in predicting intra-abdominal fat in obese men and women

Obes Res

Quantification of adipose tissue by MRI: relationship with anthropometric variables

J Appl Physiol

Relationships of generalized and regional adiposity to insulin sensitivity in men

J Clin Invest

Original Research
Pulmonary Function Testing
Fat Distribution and End-Expiratory Lung Volume in Lean and Obese Men and Women