Sleep disturbances associated with cigarette smoking.

Sleep disturbances resulting in insufficient sleep have been linked to negative physical, cognitive, and public health outcomes. Despite this, there has yet a study that examines the impact of smoking on sleep in a US based national sample. The current study sought to observe sleep disturbances associated with smoking status. Sleep disturbances in adults aged 20 years and above, from the 2005-2006 National Health and Nutrition Examination Survey, were measured among current, former, and never smokers (NS). Current smokers (CS) reported significantly less total sleep time, longer sleep onset latency, increased difficulty falling asleep, maintaining sleep, and waking up earlier than desired when compared to NS. Former smokers reported disturbances similar to NS and CS experienced poorer sleep than nonsmokers. Our study is the first to observe sleep difficulty by smoking status in a large, population-based, nationally representative sample. Recommendations for smoking cessation programs are discussed.

Comparison of digital with film radiographs for the classification of pneumoconiotic pleural abnormalities.

RATIONALE AND OBJECTIVES: Analog film radiographs are typically used to classify pneumoconiosis to allow comparison with standard film radiographs. The aim of this study was to determine if digital radiography is comparable to film for the purpose of classifying pneumoconiotic pleural abnormalities. MATERIALS AND METHODS: Subjects were 200 asbestos-exposed patients, from whom digital and film chest radiographs were obtained along with chest high-resolution computed tomographic scans. Using a crossover design, radiographs were independently read on two occasions by seven readers, using conventional International Labour Organization standards for film and digitized standards for digital. High-resolution computed tomographic scans were read independently by three readers. Areas under the receiver-operating characteristic curves were calculated using high-resolution computed tomographic ratings as the gold standard for disease status. Mixed linear models were fit to estimate the effects of order of presentation, occasion, and modality, treating the seven readers as a random effect. Comparing digital and film radiography for each reader and occasion, crude agreement and agreement beyond chance (κ) were also calculated. RESULTS: The linear models showed no statistically significant sequence effect for order of presentation (P = .73) or occasion (P = .28). Most important, the difference between modalities was not statistically significant (digital vs film, P = .54). The mean area under the curve for film was 0.736 and increased slightly to 0.741 for digital. Mean crude agreement for the presence of pleural abnormalities consistent with pneumoconiosis across all readers and occasions was 78.3%, while the mean κ value was 0.49. CONCLUSIONS: These results indicate that digital radiography is not statistically different from analog film for the purpose of classifying pneumoconiotic pleural abnormalities, when appropriate standards are used.

Comparison of serum cotinine concentration within and across smokers of menthol and nonmenthol cigarette brands among non-Hispanic black and non-Hispanic white U.S. adult smokers, 2001-2006.

BACKGROUND: The Food and Drug Administration (FDA) is examining options for regulating menthol content in cigarettes. There are many pharmacologic properties of menthol that may facilitate exposure to tobacco smoke, and it has been suggested that the preference for menthol cigarettes in black smokers accounts for their higher cotinine levels. OBJECTIVE: To assess cigarettes smoked per day-adjusted cotinine levels in relation to smoking a menthol or nonmenthol cigarette brand among non-Hispanic black and white U.S. adult smokers under natural smoking conditions. METHOD: Serum cotinine concentrations were measured in 1,943 smokers participating in the 2001 to 2006 National Health and Nutrition Examination Surveys (NHANES). The effect of smoking a menthol brand on cigarettes smoked per day-adjusted serum cotinine levels in these two populations was modeled by adjusting for sex, age, number of smokers living in the home, body weight, time since last smoked, and FTC (Federal Trade Commission)-measured nicotine levels. The 8- or 12-digit Universal Product Code (UPC) on the cigarette label was used to determine the cigarette brand and whether it was menthol. RESULTS: Smoking a menthol cigarette brand versus smoking a nonmenthol cigarette brand was not associated (P ≥ 0.05) with mean serum cotinine concentration in either black or white smokers. CONCLUSIONS: The higher levels of cotinine observed in black smokers compared with white smokers are not explained by their higher preference for menthol cigarette brands. IMPACT: Further studies like ours are needed to improve our ability to understand health consequences of future changes in tobacco product design.

Bone health in immigrant Hispanic women living in Texas.

Osteoporosis is a serious national public health problem, and is expected to increase significantly over the next few decades, especially in women. A limitation of bone health research exists since few studies have involved Hispanic women, and even fewer, Hispanic immigrant women. For this study we examined the effects of anthropometric, behavioral, and health history variables on bone mineral density (BMD) in 84 immigrant Hispanic women, age 40 and above. BMD was assessed at the spine, femur, and forearm using dual energy x-ray absorptiometry (DXA). Demographic information, health histories, and behavioral risk factors were obtained from a questionnaire. In the younger group (mean age = 44.1 years) 61% had spinal osteopenia, and in the postmenopausal group (mean age = 53.0 years) 59% had osteopenia and 13% had osteoporosis. Femur sites were free of osteoporosis. Mean body mass index (BMI) was 31.8 ± 6.1 and mean waist girth was 95.6 ± 12.5 cm, indicating overall and abdominal obesity. Partial correlations indicated a significant positive relationship between body fat variables and total femur BMD values. ANOVAs revealed no differences in BMD values at any bone site across tertile levels for calcium intake or for physical activity. However, supplemental and dietary calcium intakes were very low and few participants engaged in regular physical activity outside of work and activities of daily living (ADL). In light of the expected increase in osteoporosis in this population and the prevalence of spinal osteopenia in the younger participants, education about the health risks of osteoporosis should be made available to this group.

Interlaboratory comparability of serum cotinine measurements at smoker and nonsmoker concentration levels: a round-robin study.

INTRODUCTION: Cotinine, the primary proximate metabolite of nicotine, is commonly measured as an index of exposure to tobacco in both active users of tobacco and nonsmokers with possible exposure to secondhand smoke (SHS). A number of laboratories have implemented analyses for measuring serum cotinine in recent years, but there have been few interlaboratory comparisons of the results. Among nonsmokers exposed to SHS, the concentration of cotinine in blood can be quite low, and extensive variability in these measurements has been reported in the past. METHODS: In this study, a group of seven laboratories, all experienced in serum cotinine analysis, measured eight coded serum pools with concentrations ranging from background levels of about 0.05 ng/ml to relatively high concentrations in the active smokers range. All laboratories used either gas-liquid chromatography with nitrogen-phosphorus detection or liquid chromatography with mass spectrometric detection. RESULTS: All seven laboratories reliably measured the cotinine concentrations in samples that were within the range of their methods. In each case, the results for the pools were correctly ranked in order, and no significant interlaboratory bias was observed at the 5% level of significance for results from any of the pools. DISCUSSION: We conclude that present methods of chromatographic analysis of serum cotinine, as used by these experienced laboratories, are capable of providing accurate and precise results in both the smoker and the nonsmoker concentration range.

Optimal serum cotinine levels for distinguishing cigarette smokers and nonsmokers within different racial/ethnic groups in the United States between 1999 and 2004.

Cotinine, a metabolite of nicotine, is widely used to distinguish smokers from nonsmokers in epidemiologic studies and smoking-cessation clinical trials. As the magnitude of secondhand smoke exposure declines because of proportionally fewer smokers and more clean-indoor-air regulations, the optimal cotinine cutpoint with which to distinguish smokers from nonsmokers is expected to change. The authors analyzed data on 3,078 smokers and 13,078 nonsmokers from the National Health and Nutrition Examination Survey for 1999-2004. Optimal serum cotinine concentrations for discriminating smokers from nonsmokers were determined using receiver operator characteristic curve analysis. Optimal cotinine cutpoints were 3.08 ng/mL (sensitivity = 96.3%, specificity = 97.4%) and 2.99 ng/mL (sensitivity = 86.5%, specificity = 93.1%) for adults and adolescents, respectively. Among adults, optimal cutpoints differed by race/ethnicity: They were 5.92 ng/mL, 4.85 ng/mL, and 0.84 ng/mL for non-Hispanic blacks, non-Hispanic whites, and Mexican Americans, respectively. Among adolescents, cutpoints were 2.77 ng/mL, 2.95 ng/mL, and 1.18 ng/mL for non-Hispanic blacks, non-Hispanic whites, and Mexican Americans, respectively. Use of the currently accepted cutpoint of 14 ng/mL overestimates the number of nonsmokers in comparison with the proposed new overall cutpoint of 3 ng/mL or the race/ethnicity-specific cutpoints of 1-6 ng/mL.

Co-occurring conditions associated with FMR1 gene variations: findings from a national parent survey.

Parents enrolling in a national survey of families of children with fragile X (FX) reported whether each of their children had been diagnosed or treated for developmental delay or eight conditions frequently associated with FX: attention problems, hyperactivity, aggressiveness, self-injury, autism, seizures, anxiety, or depression. This article reports results for 976 full mutation males, 259 full mutation females, 57 premutation males, and 199 premutation females. Co-occurring conditions were frequently reported for all FMR1 gene variations. The number of co-occurring conditions experienced was strongly associated with parent reports of their child's ability to learn, adaptability, and quality of life. Most individuals with the full mutation experienced multiple co-occurring conditions, with a modal number of 4 for males and 2 for females. Most (>80%) full mutation males and females had been diagnosed or treated for attention problems. Premutation males, when compared with a matched group of non-FX males, were more likely to have been diagnosed or treated for developmental delay, attention problems, aggression, seizures, autism, and anxiety. Premutation females were more likely to have been diagnosed or treated for attention problems, anxiety, depression, and developmental delay. Clusters of conditions were identified, seeming to occur in an additive fashion. Self-injury, autism, and seizures rarely occurred in isolation, but were more likely in individuals who also had problems with attention, anxiety, and hyperactivity. The findings provide a reference point for future studies on the prevalence and nature of co-occurring conditions in FX; suggest the possibility that certain conditions cluster together; provide evidence that male and female carriers experience elevated rates of co-occurring conditions compared with matched groups of non-carrier children; and emphasize the importance of including an assessment of co-occurring conditions in any clinical evaluation of individuals with abnormal variation in the FMR1 gene.

Brief report: screening items to identify patients with limited health literacy skills.

BACKGROUND: Patients with limited literacy skills are routinely encountered in clinical practice, but they are not always identified by clinicians. OBJECTIVE: To evaluate 3 candidate questions to determine their accuracy in identifying patients with limited or marginal health literacy skills. METHODS: We studied 305 English-speaking adults attending a university-based primary care clinic. Demographic items, health literacy screening questions, and the Rapid Estimate of Adult Literacy in Medicine (REALM) were administered to patients. To determine the accuracy of the candidate questions for identifying limited or marginal health literacy skills, we plotted area under the receiver operating characteristic (AUROC) curves for each item, using REALM scores as a reference standard. RESULTS: The mean age of subjects was 49.5; 67.5% were female, 85.2% Caucasian, and 81.3% insured by TennCare and/or Medicare. Fifty-four (17.7%) had limited and 52 (17.0%) had marginal health literacy skills. One screening question, "How confident are you filling out medical forms by yourself?" was accurate in detecting limited (AUROC of 0.82; 95% confidence interval [CI]=0.77 to 0.86) and limited/marginal (AUROC of 0.79; 95% CI=0.74 to 0.83) health literacy skills. This question had significantly greater AUROC than either of the other questions (P<.01) and also a greater AUROC than questions based on demographic characteristics. CONCLUSIONS: One screening question may be sufficient for detecting limited and marginal health literacy skills in clinic populations.

Comparison between 60 matched pairs of postmenopausal black and white women: analysis of risk factors related to bone mineral density.

PURPOSE: Osteoporosis is a systemic disease in which bone density is reduced, leading to weakness of the skeleton and increased vulnerability to fractures. The purpose of this study was to compare known or suspected risk factors (medical, gynecological, and lifestyle characteristics) related to bone loss between 60 matched pairs of black and white postmenopausal women. METHODS: The two racial groups were matched one for one on selective anthropometric variables [age (years), standing height (cm), and body weight (kg)] in order to equate age and body size between groups. Information on risk factors was obtained from an orally administered questionnaire and body composition variables (in addition to those used for matching) assessed by anthropometry and total body dual energy X-ray absorptiometry (DXA). Four skinfold sites (chest, triceps, mid-axillary, and abdomen) were measured with Harpendon calipers and four body circumferences (chest, forearm contracted, waist, and gluteal) were assessed with a Gulick tape. DXA radius, spine, femur, and whole body measurements were obtained on a Hologic QDR-2000 with software version 7.20. RESULTS: White women reported significantly higher proportions of alcohol use, family history of broken bones, and a greater utilization of hormones, calcium and vitamins than did black women. Black women reported a greater numbers who had other diseases (i.e., overactive thyroid, diabetes, rheumatoid arthritis, or kidney stones). Although age and body weight were similar in both groups, black women had greater lean tissue and less body fat than white women. Blacks had significantly higher bone mineral density across all body sites with the exception of the mid- and ultra-distal radius. CONCLUSION: On the basis of these data, it was concluded that part of the difference often observed in bone density between black and white postmenopausal women might be due to lifestyle factors.

The effect of 15 weeks of exercise on balance, leg strength, and reduction in falls in 40 women aged 65 to 89 years.

OBJECTIVE: Risk of falling increases as people age, and decreased leg strength and poor balance have been implicated as contributors. Our aims were to:1) assess the efficacy of a fall-prevention exercise program on balance and leg strength in women aged 65 to 89 years and 2) conduct a 1-year follow-up to determine the effect of exercise on fall rates. METHODS: Forty women were classified by falling history and fear of falling and assigned to exercise and control groups using stratified randomization. We used the Berg Balance Scale, Get-up and Go, Functional Reach, and Wall-Sit Tests to evaluate changes in balance and leg strength before and after a supervised 15-week exercise program (31-hr sessions/week). We conducted 1-year follow-up telephone interviews and compared the number of falls reported by exercise and control groups.The study used a 2 x 2 (exercise/control by pretest/post-test) factorial design with the testing times being a repeated factor, so we used analysis of variance (ANOVA) to evaluate differences between the 2 groups across testing times. Power analysis computed a priori with STPLAN software (Version 4.2) showed that a sample size of 40 was necessary to determine statistical differences in balance and leg strength. RESULTS: Exercise subjects showed significant improvement on 5 of 14 items (5.2%, p < or = 05 to 34.4%, p < or = .01) in the Berg Balance Scale and on the total score (6.8%, p < or = .05). Leg strength increased significantly (p < or = .05) on post-test as measured by the Wall-Sit Test. Control subjects reported 6 falls and exercise subjects no falls during the follow-up year, but this difference was not significant using Fischer's exact test (p=.106). CONCLUSION: The exercise program resulted in increased balance and leg strength, but did not result in a significant difference in falls during the follow-up period. Further research with a larger and possibly older sample is needed to more adequately investigate this question. Health care providers who work with older women should provide exercise programs in which balance and leg strength are emphasized.

Peak physiologic responses to arm and leg ergometry in male and female patients with airflow obstruction.

STUDY OBJECTIVE: To investigate differences in work capacity for the arms and legs in patients with moderate-to-severe COPD. DESIGN: Cross-sectional investigation. PATIENTS: One hundred twenty-four patients (90 men and 34 women) aged 45 to 81 years with moderate-to-very severe COPD. FEV(1) ranged from 0.70 to 2.79 L/min (FVC, 1.73 to 5.77 L; FEV(1)/FVC, 24 to 69%). All patients were in stable condition at the time of testing and receiving a stable drug regime. MEASUREMENTS: Each patient completed a demographic and medical history questionnaire, pulmonary function studies (spirometry, lung volumes, and diffusion capacity), peak exercise ergometry with gas exchange for the arms and legs; they also rated their subjective assessment of perceived dyspnea and extremity fatigue using Borg scores during exercise. RESULTS: Patients were of comparable age, with men taller and heavier than women. Smoking history was significantly less for women (47.9 pack-years vs 66.6 pack-years for men) even though each group presented with equivalent age (p > 0.05). Women were less obstructed than men, with FEV(1)/FVC (mean +/- SD) of 46.5 +/- 10.9% vs 40.2 +/- 9.3%, respectively. Ventilatory limitation during exercise was noted for all patients studied. Peak work capacity was greater for men, and leg peak responses were greater than arm values for each gender. As airway obstruction increased, work capacity became more limited. Peak arm work achieved was 38.9 +/- 19.6 W, oxygen uptake (VO(2)) was 903.9 +/- 263.5 mL/min, and minute ventilation (VE) was 33.7 +/- 9.5 L. Peak leg work value was 62.9 +/- 24.8 W, VO(2) was 1,091.4 +/- 321.5 mL/min, and VE was 39.3 +/- 12.0 L. Hence, arm values were 62%, 83%, and 85% of the measured leg values, respectively. Dyspnea and extremity effort scores were similar for men and women, and for arms and legs. Regression analysis was used to derive prediction equations for arm work from measured leg ergometry testing. For watts of work, a three-variable model emerged explaining 66% of the variance; VO(2) yielded a four-variable model with 80% of the variance explained; and VE yielded a three-variable model explaining 72% of the variance. CONCLUSION: Arm work is reduced by 38% that of the legs, while more modest reductions are noted for VO(2) and VE, suggesting greater mechanical efficiency for leg work as compared to arm work. These data also suggest greater metabolic demand for respiratory muscles and arm ergometry. Dyspnea and extremity Borg scores were equivalent for each modality and level of airway obstruction studied, suggesting that perception plays an important role in limiting exercise, and that a threshold for termination of exercise may exist. Further, peak leg ergometry results can be used with pulmonary function indexes to predict peak arm workload in watts, VO(2), and VE. These data may be used to assist the clinician in prescribing rehabilitation or estimating arm exercise ability when arm testing is unavailable.

Predicting oxygen uptake for men and women with moderate to severe chronic obstructive pulmonary disease.

OBJECTIVE: To develop regression equations for estimating peak oxygen consumption (Vo(2)) for men and women with moderate to severe chronic obstructive pulmonary disease (COPD) from the 6-minute walk test (6MWT). DESIGN: Multivariate analysis of patient pulmonary function and exercise gas exchange indices to 2 outcomes for the 6MWT (distance ambulated, calculated work [6M(WORK)]). SETTING: A university hospital and clinics. PARTICIPANTS: A total of 124 patients (90 men 34 women; age range, 45\N81y), from the community, with moderate to very severe COPD. Forced expiratory volume in 1 second (FEV(1)) ranged from.70 to 2.79L/min, forced vital capacity (FVC) ranged from 1.73 to 5.77L, and FEV(1)/FVC ranged from 24% to 69%. All patients were in stable condition at the time of testing and were on a stable drug regimen. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pulmonary function testing was completed according to American Thoracic Society criteria. Cycle ergometry with gas exchange, by using a ramp protocol, was completed. The 6MWT was done in the hospital corridor, with distances recorded after each minute. Work capacity by each method was reduced from the normal predicted. RESULTS: Peak oxygen uptake (Vo(2)) averaged 1184+/-302mL/min for men and 860+/-256mL/min for women (58%, 68% of predicted, respectively). Ventilatory reserve was limited at an achieved peak ventilation (Ve) of 79.9%+/-19.1% of predicted. Borg scores for dyspnea and leg fatigue were equivalent for each test modality, with leg fatigue being slightly higher for each gender. 6M(WORK) for the 6MWT was the strongest independent predictor of peak Vo(2) (r=.81, P<.0001), whereas that for distance ambulated was correlated at r equal to.54 (P<.0001). This is a 36% improvement in the variance accounted for by the application of 6M(WORK) as the outcome for the 6MWT. Generalized regression modeling was then used to develop equations for the estimation of peak Vo(2) for the 6MWT. Additional variables included in the model were diffusing capacity of lung for carbon dioxide, FVC, maximal inspiratory pressure, weight (in kilograms), and age, with their appropriate interactions. This derived regression model accounted for 79% on the variance for estimation of peak Vo(2) in the patients studied. CONCLUSION: Peak Vo(2) can be estimated for men and for women by using the generalized equations presented. The calculation of 6M(WORK) is an improvement over distance ambulated as the 6MWT outcome. These data build on the existing body of knowledge for the 6MWT and extend its application for patients with COPD. Knowledge of the peak Vo(2) can be used for patient assessment, serial monitoring, evaluating disability, and as a common index of function across modalities. The calculation of 6M(WORK) outperformed distance ambulated and is easily converted to other indices of caloric expenditure that are commonly used in the laboratory and clinical settings.

6-minute walk work for assessment of functional capacity in patients with COPD.

UNLABELLED: The 6-min walk (6MW) test is commonly used to assess exercise capacity in patients with COPD and to track functional change resulting from disease progression or therapeutic intervention. Not surprisingly, distance covered has been the preferred outcome for this test. However, distance walked does not account for differences in body weight that are known to influence exercise capacity. OBJECTIVE: The aim of this study was to evaluate the 6-min distance x body weight product (6MWORK) as an improved outcome measure with a solid physiologic foundation. PATIENTS AND METHODS: One hundred twenty-four men and women with moderate-to-severe COPD volunteered and completed the testing sequence, which included pulmonary function, a peak effort ramp cardiopulmonary exercise study with gas exchange, and the 6MW. Means and SD were generated for the variables of interest. Differences were analyzed using analysis of variance techniques. Correlation coefficients and receiver operating characteristic (ROC) curves were calculated for the 6-min walk distance (6MWD) and 6MWORK with indexes of pulmonary function, work performance, and Borg scores for dyspnea and effort. RESULTS: Men and women presented with a significant smoking history that also differed by gender (48 vs 66 pack-years, respectively; p < 0.01). The mean (+/- SD) FEV(1) values were 45 +/- 12.6% and 48 +/- 12.1%, respectively (not significant), while the diffusing capacity of the lung for carbon monoxide (DLCO) was 14.7 +/- 6.1 vs 10.3 +/- 3.9 mL/min/mm Hg, respectively (p < 0.001), for men and women. The 6MWD averaged 416.8 +/- 79.0 m for men and 367.8 +/- 78.6 m for women, and these differences were significant (p < 0.002). When 6MWD was compared as the percent predicted of normal values, each gender presented with a similar reduction of 78.6 +/- 14.5% vs 79.9 +/- 17.5% (p > 0.05), respectively. 6MWORK averaged 35,370 +/- 9,482 kg/m and 25,643 +/- 9,080 kg/m (p < 0.0001) for men and women, respectively. 6MWORK yielded higher correlation coefficients than did 6MWD when correlated with DLCO, lung diffusion for alveolar ventilation, FEV(1), FEV(1)/FVC ratio, watts, peak oxygen uptake, peak minute ventilation, and peak tidal volume. The ROC curve demonstrated that 6MWORK had a significantly larger calculated area under the curve (p < 0.05) [plot of 100-sensitivity to specificity for each variable of interest for all subjects] than 6MWD when differentiating an objectively selected definition of low work capacity vs high work capacity (bike ergometry work, < 55 vs > 55 W, respectively). CONCLUSIONS: We conclude that work calculated as the product of distance x body weight is an improved outcome measure for the 6MW. 6MWORK can be used whenever the 6MW is required to estimate a patient's functional capacity. This measure is also a common measure, which can be converted to indexes of caloric expenditure for direct cross-modality comparisons.

Criterion validity of the Duke Activity Status Index for assessing functional capacity in patients with chronic obstructive pulmonary disease.

PURPOSE: This study evaluated the concurrent criterion validity of the Duke Activity Status Index (DASI) with respect to standard physiologic work capacity indices in patients with chronic obstructive pulmonary disease (COPD) and compared its performance with similar surrogates. METHODS: 119 patients with moderate to severe COPD (86 men, 33 women) completed medical and smoking histories, physical examination, pulmonary function testing (PFT), cycle ergometry (CE), arm ergometry (AE), and 6-minute walk distance (6MWD), DASI, the Sickness Impact Profile-68 (SIP-68) and the Chronic Respiratory Disease Questionnaire (CRDQ). Correlation methods were used to assess the validity of the potential surrogates DASI and the domain scores for SIP-68 and CRDQ, with the standards CE, AE, PFT, and 6MWD (as a standard). RESULTS: The mean DASI score was 33.4 +/- 13.0. Significant Pearson correlations (P <.01) were observed between the DASI and PFT outcomes maximum voluntary ventilation (r =.28); peak expiratory flow (r =.21); diffusion capacity of lung for carbon monoxide (r =.30). For CE, the correlations with DASI were oxygen consumption (VO(2))(r =.34); minute ventilation (r =.25); watts (r =.37). For AE, the correlations with DASI were VO(2) (r=.38); watts (r =.47). For 6MWD, the correlation was r =.53. Higher correlations were obtained for the distance completed during the first minute of the 6MWD and ergometric indices as well as DASI scores: watts(AE) (r =.39); VO(2AE) (r =.45); watts(CE) (r =.50); VO(2CE) (r =.44). Correlation coefficients for all SIP-68 and CRDQ domain and total scores were lower than corresponding correlations obtained for the DASI. Regression analysis demonstrated that the DASI and 6MWD were important (P <.05) for predicting VO(2) or work for CE while DASI and SIP range or CRDQ dyspnea entered for AE, when gender, age, BMI, and the FEV1 were forced into the model. In forward stepwise analyses, DASI entered first for AE, and 6MWD entered first for CE. The DASI was selected in 3 of 4 models with R(2) values ranging from.47 to.70. SIP-68 and CRDQ subscores were significant as additional predictors. CONCLUSIONS: DASI has high criterion validity for predicting CE and/or AE outcomes in the COPD population. It is warranted in addition to the 6MWD, and its predictive significance and simplicity recommends it over several other self-administered instruments for evaluating functional capacity.