Obesity and pulmonary function in Navajo and Hopi children

Background: Although several reports have shown an adverse cardiovascular and metabolic risk profile associated with childhood obesity, few reports have examined the effects of childhood obesity on pulmonary function. Objective: The purpose of this study was to examine the influence of obesity on pulmonary function in Navajo and Hopi children. Methods: Subjects included 256 (110 males, 146 females) Hopi children 6-12 years of age and 557 (274 males, 283 females) Navajo children 6-12 years of age (N=813). The body mass index was used to classify subjects as normal weight, overweight, or obese on the basis of international reference values. Forced vital capacity (FVC), forced expired volume in one second (FEV1), FEV1% (FEV1 to FVC ratio; FEV1/FVC), and forced expiratory flow between 25%-75% of vital capacity (FEF25-75) were determined according to the American Thoracic Society recommendations. Results: Approximately 26% of Navajo and Hopi children were defined as overweight (26.0% of boys and 25.6% of girls) and an additional 16% (14.6% of boys and 17.7% of girls) were defined as obese. In general, the patterns showed an increase in pulmonary function between normal weight and overweight children and a decrease in pulmonary function of obese children. Significant differences among groups existed for FEV1% and FEF25-75 in boys and FVC and FEV1 in girls. Conclusions: The results indicate the pulmonary consequences of obesity in children and provide further evidence of the adverse consequences of pediatric obesity among Native Americans.