Association of Pulmonary Function with Adiposity and Metabolic Abnormalities in Urban Minority Adolescents

Abstract

Rationale: Childhood obesity is a known risk factor for pulmonary diseases, likely due to obesity-mediated alteration of pulmonary function. Inflammation and mechanical fat load are two proposed causative mechanisms for altered pulmonary function among obese children; however, the association of metabolic abnormalities with pulmonary function among children is poorly understood.Objectives: We investigated the independent association of truncal and general adiposity and metabolic abnormalities with pulmonary function in a sample of urban minority adolescents.Methods: Spirometry and lung volume indices were compared between adolescents with general (body mass index [BMI] . 95th percentile) or truncal adiposity (waist circumference . 90th percentile) and normal-weight (BMI , 85th percentile or waist circumference < 90th percentile) and between those with metabolic abnormalities (homeostatic model assessment of insulin resistance [HOMA-IR] in the top quartile or high-density lipoprotein [HDL] , 40 mg/dl) and those with a normal metabolic profile.Measurements and Main Results: Obese adolescents had lower lung volumes, including residual volume (RV), RV/TLC ratio, expiratory reserve volume (ERV), and FRC, and higher inspiratory capacity (IC) than normal-weight adolescents, but did not differ in measures of lower airway obstruction, FEV 1 /FVC ratio, and mid-expiratory flow rate. Adolescents with high HOMA-IR had lower FEV 1 /FVC ratio, RV, RV/TLC ratio, ERV, and FRC and higher IC, whereas those with low HDL had lower FEV 1 /FVC and RV/TLC ratios. After adjusting for adiposity, HOMA-IR remained a predictor of ERV (b = 21.4; P = 0.02) and FEV 1 /FVC ratio (b = 20.5; P = 0.03), and HDL remained a predictor of FEV 1 /FVC ratio (b = 0.1; P = 0.01). General adiposity was a predictor of FRC (b = 20.5; P , 0.001), IC (b = 0.3; P , 0.001), RV (b = 20.8; P , 0.0001), and RV/TLC ratio (b = 20.2; P , 0.0001), and truncal adiposity was a predictor of RV (b = 220.3; P = 0.03) and FRC (b = 213.8; P = 0.004). Thus, adiposity and metabolic abnormalities were independent predictors of ERV, but only metabolic abnormalities independently predicted FEV 1 /FVC ratio. Although general adiposity predicted RV and RV/TLC ratio, truncal adiposity was predictive of RV and FRC, conferring additional risk above general adiposity. Conclusions:These results suggest that metabolic abnormalities and adiposity are independently associated with pulmonary function deficits among urban adolescents. Metabolic assessment of obese adolescents may identify those at risk of developing obesity-associated pulmonary morbidity.

Inflammation, Metabolic Dysregulation, and Pulmonary Function among Obese Urban Adolescents with Asthma

“…Although Th-cell responses were associated with insulin resistance, which mediated their association with pulmonary function, monocyte activation was inversely associated with serum HDL but its association with pulmonary function was partly mediated by BMI. These results suggest that systemic nonatopic inflammation among obese urban adolescents with asthma is associated with metabolic abnormalities, and may underlie pulmonary function deficits found in childhood obesity-related asthma (7).…”

“…13-18 years, were recruited from clinics at Children's Hospital at Montefiore, as previously described (7). The study cohort was comprised of 42 obese subjects with asthma, 42 normal-weight subjects with asthma, 40 obese subjects without asthma, and 44 healthy control subjects.…”

“…Recent studies have found an association between obesitymediated metabolic abnormalities, including insulin resistance and low highdensity lipoprotein (HDL), and asthma (6). Insulin resistance and low HDL are also independent predictors of pulmonary function, particularly FEV 1 /FVC ratio and expiratory reserve volume (7), indices known to be reduced among obese subjects with asthma. Whether obesity-mediated systemic inflammation underlies the association of metabolic abnormalities and pulmonary function deficits among obese children with asthma is not known.…”

Adipokines, asymmetrical dimethylarginine, and pulmonary function in adolescents with asthma and obesity

“…There is an emerging evidence that metabolic abnormalities may also affect pulmonary function [20][21]. Obesity is associated with dyslipidemia, which has been associated with wheeze [22].…”

Obesity and Bronchodilator Response in Black and Hispanic Children and Adolescents With Asthma

“…Consistent with prior studies, all comparisons were made between the nonobese (BMI , 95th percentile) and obese (BMI Ն 95th percentile) groups. [17][18][19][20][21] Bronchodilator Response Spirometry was performed according to the American Th oracic Society guidelines to measure pulmonary function before albuterol administration and then repeated 15 min aft er administration of four puff s of albuterol (90 m g per puff ). 22 Spirometry was repeated a third time aft er a second dosage of albuterol (two puff s if , 16 years old or four puff s if Ն 16 years old).…”