Obesity and Pulmonary Function in African Americans.
BACKGROUND
Obesity prevalence in United States (US) adults exceeds 30% with highest prevalence being among blacks. Obesity is known to have significant effects on respiratory function and obese patients commonly report respiratory complaints requiring pulmonary function tests (PFTs). However, there is no large study showing the relationship between body mass index (BMI) and PFTs in healthy African Americans (AA).


OBJECTIVE
To determine the effect of BMI on PFTs in AA patients who did not have evidence of underlying diseases of the respiratory system.


METHODS
We reviewed PFTs of 339 individuals sent for lung function testing who had normal spirometry and lung diffusion capacity for carbon monoxide (DLCO) with wide range of BMI.


RESULTS
Functional residual capacity (FRC) and expiratory reserve volume (ERV) decreased exponentially with increasing BMI, such that morbid obesity resulted in patients breathing near their residual volume (RV). However, the effects on the extremes of lung volumes, at total lung capacity (TLC) and residual volume (RV) were modest. There was a significant linear inverse relationship between BMI and DLCO, but the group means values remained within the normal ranges even for morbidly obese patients.


CONCLUSIONS
We showed that BMI has significant effects on lung function in AA adults and the greatest effects were on FRC and ERV, which occurred at BMI values < 30 kg/m2. These physiological effects of weight gain should be considered when interpreting PFTs and their effects on respiratory symptoms even in the absence of disease and may also exaggerate existing lung diseases.
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Alem
A
Mehari
Howard University, Department of Internal Medicine, Washington, District of Columbia, United States of America.
Samina
S
Afreen
Howard University, Department of Internal Medicine, Washington, District of Columbia, United States of America.
Julius
J
Ngwa
Howard University, Department of Internal Medicine, Washington, District of Columbia, United States of America.
Rosanna
R
Setse
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Alicia N
AN
Thomas
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Vishal
V
Poddar
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Wayne
W
Davis
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Octavius D
OD
Polk
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Sheik
S
Hassan
Howard University, Division of Pulmonary Diseases, Washington, District of Columbia, United States of America.
Alvin V
AV
Thomas
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005105:Expiratory Reserve Volume / Q000502:physiology*; D005260:Female; D005652:Functional Residual Capacity / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000473:pathology*; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012115:Residual Volume / Q000502:physiology; D012129:Respiratory Function Tests; D014109:Total Lung Capacity / Q000502:physiology; D014481:United States; D055815:Young Adult