The effect of anthropometric and socioeconomic factors on the racial difference in lung function.

African-Americans have lower lung function than whites. However, the relative contributions of body habitus and socioeconomic factors are unknown. To address this question, we analyzed data from 1242 white (806 women, 436 men) and 1084 African-American (696 women, 388 men) asymptomatic, nonsmoking adult participants of the third National Health and Nutrition Examination Survey (NHANES III). African-Americans were poorer, had larger FEV(1)/FVC and body mass index (BMI), but lower sitting height, FEV(1) and FVC than whites. Cross-sectional regression analyses using spirometric, anthropometric, and socioeconomic data were performed separately by sex to investigate racial differences in lung function. Sitting height accounted for 35-39% of the race difference in both sexes. Poverty index accounted for about 7.5% and 2.5% of the racial difference in women and men, respectively, whereas the effect of education accounted for about 2% in women and 4.7% in men. With further adjustment for BMI, we could account for only about half of the racial difference in FEV(1) and FVC. We conclude that the racial difference in lung function is only partially explained by a shorter upper body segment in African-Americans. Although low socioeconomic indicators are related to lower lung function, they explain only a small proportion of this racial difference.

The effect of gender on the relationship between body fat distribution and lung function.

Although abdominal obesity, as measured by waist-to-hip ratio (WHR), has long been recognized as a risk factor for metabolic and cardiovascular diseases, little is known about the effect of WHR on pulmonary function, especially in women. In this study of 1094 men and 540 women (18-102 years) from the Baltimore Longitudinal Study of Aging (BLSA), we examined the effect of WHR on forced expiratory volume in 1 s (FEV(1)). Cross-sectional analyses, after accounting for body mass index (BMI) and other variables, showed a strong inverse association of WHR with FEV(1) in men (beta = -1.338, P=.0001) but not in women. Furthermore, larger values of WHR were associated with greater reductions of forced vital capacity (FVC) in men (beta = -1.383, P =.0005) compared to women (beta = -0.679, P =.02). Thus, body fat distribution has independent effects on lung function that are more prominent in men than women.

Determinants of maximal inspiratory pressure. The Baltimore Longitudinal Study of Aging.

A variety of methods for subject selection and test procedures have been used for the determination of normal values and reference equations for maximal inspiratory pressure (MIP). In the cross-sectional study described here, we made MIP measurements on 668 men and women in the Baltimore Longitudinal Study of Aging (BLSA), using a standardized electronic procedure. Results were combined with spirometric and anthropometric measurements. After subjecting them to rigorous health screening, we analyzed a well-defined, healthy subgroup of 139 men and 128 women with a wide age range (20 to 90 yr), using multiple linear regression, for the purpose of determining the effect of age, other correlates, normal values, and gender-specific reference equations for MIP. The gender effect was strong, with the average MIP values of the men being about 30% higher than those of the women (101 cm H2O and 72 cm H2O, respectively). The reference equation for men is: MIP +/- standard error of the estimate (SEE) = 126 - 1.028 x age + 0.343 x weight (kg) +/- (22.4); and for women: MIP +/- SEE = 171 - 0.694 x age + 0. 861 x weight (kg) - 0.743 x height (cm) +/- (18.5). These equations may be used for the assessment of inspiratory muscle strength.