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.

Racial differences in smoking abstinence rates in a multicenter, randomized, open-label trial in the United States.

BACKGROUND: This study evaluates differences in smoking abstinence between white and minority smokers using pharmaceutical aids. METHODS: This is an analysis of data from a multi-center, randomized, clinical trial conducted in the United States. Of the 1,684 subjects randomized to one of three medications (nicotine inhaler, bupropion, or a combination of both), 60% were women and 10% were minority races. RESULTS: Factors associated with a decreased likelihood of smoking at 12 weeks were older age (OR = 0.971, p < 0.0001), being married (OR = 0.678, p = 0.0029), using bupropion SR (OR = 0.480, p < 0.0001), and using combination therapy (OR = 0.328, p < 0.0001). Factors associated with an increased likelihood of smoking were higher tobacco dependence scores (OR = 1.244, p < 0.0001), prior quit attempts (OR = 1.812, p = 0.004), and being a minority (OR = 1.849, p = 0.0083). Compared to white smokers, minority smokers were significantly older at time of study entry (46 vs. 42 years, p < 0.0001), less likely to be married (35% vs. 59%, p < 0.0001), older at smoking initiation (21 vs. 19 years of age, p < 0.0001), and had a lower abstinence rate (16% vs. 26%, p = 0.0065). CONCLUSION: Regardless of the treatment used, minority smokers in the US have lower smoking abstinence after treatment for tobacco dependence. Future research should focus on the improvement in treatment strategies for minority smokers.

Enrollment of African Americans onto clinical treatment trials: study design barriers.

PURPOSE: African Americans have the highest cancer mortality rates and poorest survival and are more often uninsured and underinsured compared with other ethnic groups. Minority participation in clinical trials has traditionally been low, with reports ranging from 3% to 20%. The present study systematically assesses 235 consecutively diagnosed African American cancer patients regarding recruitment onto cancer treatment clinical trials at Howard University Cancer Center between January 1, 2001, and December 31, 2002. Our intent is to determine the rate-limiting factors associated with enrolling African Americans onto clinical trials at a historically black medical institution. PATIENTS AND METHODS: Two hundred thirty-five consecutively diagnosed African American cancer patients were assessed for participation in clinical trials at Howard University Hospital and Cancer Center. The study population comprised 165 women and 70 men. RESULTS: The overall eligibility rate was 8.5% (20 of 235 patients); however, among those eligible, the enrollment rate (ie, enrollment among the eligible population) was 60.0% (12 of 20 patients). Comorbidities rendered 17.1% of the patient population ineligible for the trials. Advanced disease stage, associated with poor performance status, premature death, and short life expectancy, made an additional 10% of the patient population ineligible. Respiratory failure, HIV positivity, and anemia accounted for 37.8% of the comorbidities in this population. Cardiovascular diseases and renal insufficiency represented 16.2% of the comorbidities. CONCLUSION: It was evident that study design exclusion and inclusion criteria rendered the majority of the study population ineligible. Among African Americans, comorbidity is a major issue that warrants considerable attention.