Publications

Respiratory exposure to zinc oxide results in metal fume fever, a flu-like illness characterized by dose-dependent increases in pulmonary tumor necrosis factor-alpha (TNF) and interleukin-8 (IL-8). To examine whether mononuclear cells are a source of these proinflammatory cytokines, we exposed U937 cells to zinc oxide in vitro. Cell culture supernatant TNF and IL-8 was measured after 3, 8, and 24 hours of exposure to zinc oxide in varying concentrations. Zinc oxide exposure in vitro led to TNF release in a dose-dependent manner at 3, 8, and 24 hours (analysis of variance [ANOVA] P = 0.0001). IL-8 demonstrated a statistically significant zinc exposure response at 8 hours (ANOVA P = 0.005) and 24 hours (ANOVA P = 0.02). IL-8 at 8 hours correlated with 3-hour TNF levels (r = 0.52, P = 0.04). These data demonstrate that in vitro zinc oxide exposure stimulates U937 mononuclear cells to release TNF and IL-8 consistent with in vivo observations in metal fume fever.

The effect of environmental tobacco smoke (ETS) exposure on adults with asthma has not been well characterized. In a prospective cohort study of 451 nonsmoking adults with asthma, we evaluated the impact of ETS exposure on asthma severity, health status, and health care utilization over 18 mo. There were 129 subjects (29%; 95% CI, 25-33%) who reported regular ETS exposure, falling into three categories: exposure at baseline but none at follow-up (n = 43, 10%), no baseline exposure and new exposure at follow-up (n = 56, 12%), and exposure at both baseline and follow-up (n = 30, 7%). In cross-sectional analyses, subjects with baseline ETS exposure had greater severity-of-asthma scores (score difference, 1.7; 95% CI, 0. 2-3.1), worse asthma-specific quality of life scores (score difference, 3.5; 95% CI, 0.03-7.0), and worse scores on the Medical Outcomes Study SF-36 physical component summary (score difference, 3. 0; 95% CI, 0-6.0) than unexposed subjects. They also had greater odds of emergency department visits (odds ratio [OR] = 2.1; 95% CI, 1.2-3.5), urgent physician visits (OR = 1.9; 95% CI, 1.1-3.3), and hospitalizations (OR = 1.9; 95% CI, 1.02-3.6). In longitudinal follow-up, subjects reporting ETS cessation showed improvement in severity-of-asthma scores (score reduction, -3.2; 95% CI, -4.4 to -2. 0) and physical component summary scores (score increase, 5.3; 95% CI, 2.6-8.1). Environmental tobacco smoke cessation decreased the odds of emergency department visits (OR = 0.4; 95% CI, 0.2-0.97) and hospitalizations (OR = 0.2; 95% CI, 0.04-0.97) after adjustment for covariates. Environmental tobacco smoke initiation was associated with greater asthma severity only in subjects with high-level (>= 3 h/wk) exposure (score increase, 1.4; 95% CI, 0.03-2.7). In conclusion, self-reported ETS exposure is associated with greater asthma severity, worse health status, and increased health care utilization in adults with asthma.

OBJECTIVE

To evaluate the impact of patient demographics, clinical features, and job-related factors on the time until return to work after carpal tunnel release surgery.

METHODS

We employed a cross-sectional community-based study of 59 patients who had undergone carpal tunnel release surgery. Sociodemographic, clinical, and job-related characteristics and time to return to work were obtained by interview and from medical records. Exposure to ergonomic risk was derived from an independently validated job matrix. Time to return to work after surgery was analyzed by survival techniques.

RESULTS

Median time to return to work was 5 weeks. After adjustment, the relative rate (RR) of return to work per week after surgery was most strongly decreased by the receipt of workers' compensation, RR 0.2 (95% confidence interval [CI] 0.1-0.5), and by the exposure to bending and twisting of the hand prior to surgery, RR 0.7 (95% CI 0.5-0.9) per hour. Female gender was another predictor of decreased return to work, RR 0.5 (95% CI 0.3-0.8).

CONCLUSIONS

Patients receiving workers' compensation, those exposed to higher levels of bending and twisting of their hands and wrists, and women were slower to return to work after carpal tunnel release surgery.

OBJECTIVES

Accurate measurement of asthma severity is critical for research evaluating asthma health outcomes. There are, however, no widely accepted asthma severity measures. A severity-of-asthma score, which is based on self-reported information, was previously developed and validated in subjects recruited from pulmonary and allergy subspecialty practices. The purpose of this study was to validate the severity-of-asthma score in subjects treated by family practice physicians and to compare asthma severity in subjects treated by family practitioners (n = 150) with those seen by allergists (n = 217) and pulmonologists (n = 384).

METHODS

The study was an ongoing panel study of adults with asthma. Subjects were a random sample of board-certified family practice, allergy, and pulmonary physicians. Each physician registered patients with asthma aged 18 to 50 years. Of 869 subjects registered, 751 (86%) completed structured telephone interviews. The family practice panel was recruited approximately 3 years after the subspecialty panel.

RESULTS

In the family practice subjects, the severity-of-asthma score demonstrated internal consistency (Cronbach's alpha 0.76) and concurrent validity, correlating strongly with asthma-specific quality of life, SF-36 General Health and Physical Functioning scales, and subject-perceived asthma severity. After controlling for demographic characteristics, a 5-point score increment was associated with increased emergency department visits, urgent physician visits, and restricted activity days. The mean severity score was highest in the pulmonary group (11.8 +/- 6.3), followed by the allergy (10.3 +/- 5.3) and family practice (9.3 +/- 5.5) groups.

CONCLUSIONS

The severity-of-asthma score was a valid measure in generalist-treated subjects. Asthma severity varied significantly by physician specialty.

CONTEXT

The association between environmental tobacco smoke (ETS) exposure and respiratory symptoms has not been well established in adults.

OBJECTIVE

To study the respiratory health of bartenders before and after legislative prohibition of smoking in all bars and taverns by the state of California.

DESIGN

Cohort of bartenders interviewed before and after smoking prohibition.

SETTING AND PARTICIPANTS

Bartenders at a random sample of bars and taverns in San Francisco.

MAIN OUTCOME MEASURES

Interviews assessed respiratory symptoms, sensory irritation symptoms, ETS exposure, personal smoking, and recent upper respiratory tract infections. Spirometric assessment included forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) measurements.

RESULTS

Fifty-three of 67 eligible bartenders were interviewed. At baseline, all 53 bartenders reported workplace ETS exposure. After the smoking ban, self-reported ETS exposure at work declined from a median of 28 to 2 hours per week (P<.001). Thirty-nine bartenders (74%) initially reported respiratory symptoms. Of those symptomatic at baseline, 23 (59%) no longer had symptoms at follow-up (P<.001). Forty-one bartenders (77%) initially reported sensory irritation symptoms. At follow-up, 32 (78%) of these subjects had resolution of symptoms (P<.001). After prohibition of workplace smoking, we observed improvement in mean FVC (0.189 L; 95% confidence interval [CI], 0.082-0.296 L; 4.2% change) and, to a lesser extent, mean FEV1 (0.039 L; 95% CI, -0.030 to 0.107 L; 1.2% change). Complete cessation of workplace ETS exposure (compared with continued exposure) was associated with improved mean FVC (0.287 L; 95% CI, 0.088-0.486; 6.8% change) and mean FEV1 (0.142 L; 95% CI, 0.020-0.264 L; 4.5% change), after controlling for personal smoking and recent upper respiratory tract infections.

CONCLUSION

Establishment of smoke-free bars and taverns was associated with a rapid improvement of respiratory health.

STUDY OBJECTIVES

To evaluate whether findings from surveillance bronchoscopy predict survival following lung transplantation.

DESIGN

Retrospective review and analysis of 498 bronchoscopies with transbronchial biopsy (TBB) and BAL performed in 34 patients after lung transplantation.

SETTING

University-based, tertiary referral medical center.

PATIENTS

Thirty-four patients after lung transplantation. The mean age at transplantation was 49+/-9 years; 20 (59%) were female. Twenty-four (71%) underwent single and 10 (29%) underwent bilateral lung transplantation. The most common pretransplantation diagnostic groups were emphysema/COPD without concomitant alpha1-antiprotease deficiency (n = 13) and other obstructive disease processes (n = 10).

INTERVENTIONS

Over follow-up, subjects underwent multiple bronchoscopies with TBB and BAL. The median number per subject was 15 (25 to 75% range 13 to 17).

MEASUREMENTS AND RESULTS

We calculated the overall median BAL WBCs and median percent neutrophils (polymorphonuclear leukocytes [PMNs]) among all of the BALs performed for each subject. We then calculated the mean +/- SD of those median values. We used Cox proportionate hazards to assess mortality risk. The median overall follow-up observation period for the cohort was 560 days. There were 11 deaths during this period. Twenty-four subjects (71%) had acute rejection (AR) grades 2 to 4 (mild to severe), and nine (27%) had obliterative bronchiolitis (OB) diagnosed by TBB at any point. The mean value for BAL WBCs was 366+/-145 x 10(3) per milliliter; for percentage PMNs, the mean was 7+/-10%. Adjusting for age, gender, single vs bilateral lung transplantation, pretransplantation diagnostic group, presence of AR, presence of OB, BAL WBC concentration, and lymphocyte CD4/CD8 ratio, PMN percent was a significant predictor of mortality (p = 0.02).

CONCLUSIONS

Ongoing inflammation manifested by an increased percentage PMNs over repeated bronchoscopies predicts mortality following lung transplantation. Biopsy data alone may be insufficient to identify posttransplantation patients at risk of poor outcome.

BACKGROUND

Asthma has been found to be among the most common conditions in the working age population and is among the most common causes of work limitation, but we could find no longitudinal studies of employment among persons with this condition.

METHODS

A panel of 601 persons with a diagnosis of asthma from random samples of northern California pulmonologists and allergy-immunologists were interviewed as many as three times at 18-month intervals by a trained survey worker to report on the severity of disease, demographic characteristics, and the extent of their employment. Their employment was then compared to that of a matched sample from the U.S. Bureau of the Census Current Population Survey.

RESULTS

Ninety-two percent of the persons with asthma had worked at some point prior to study enrollment. Among persons with onset during adulthood, only 29% of those who were not employed at disease onset were working at study enrollment, compared to 68% among those who were employed. Among the 420 persons interviewed three times, 75, 81, and 75%, respectively, were employed as of the three interviews. Among these 420, 66% were continuously employed and 15% were continuously not employed. The principal determinants of continuity of employment were demographic and employment characteristics, not medical ones. The employment rate and hours of work per week and per year of the persons with asthma were similar to the matched sample.

CONCLUSIONS

Asthma has not substantially impeded the employment of the persons with asthma we studied, with the exception that those who were not employed at disease onset continued to have low employment rates.

BACKGROUND

In general practice settings, the proportion of adult asthma attributable to occupational factors is not known.

OBJECTIVE

The goal of this study was to estimate the proportion of adult asthma cases that can be attributed to occupational factors initiating new disease onset and exacerbating preexisting disease.

METHODS

We performed a cross-sectional analysis of interview data for 150 adults with asthma recruited from a random sample of family practice specialists. We ascertained the asthma and work histories of the subjects and estimated the proportion with likely work-initiated asthma and work-related asthma recrudescence.

RESULTS

Seventy-four subjects (49%) reported adult-onset asthma while employed; an additional 25 (17%) reported recrudescence of previously quiescent childhood-onset asthma during employment. Of those with new-onset asthma while employed, 15 (10% of the study group; 95% confidence interval, 5 to 15%) were employed in occupations at increased risk of occupational asthma initiation on the basis of an independent job scoring matrix. Of those with asthma recrudescence in adulthood, seven (5% of the study group; 95% confidence interval, 2 to 8%) were employed in occupations at increased risk of exposures aggravating asthma.

CONCLUSIONS

Among adults with asthma treated in general practice settings, > 1 in 10 patients has a work history strongly suggestive of a potential relationship between exposure and disease.

We performed analyses to examine the structure, validity, and responsiveness to change of the Marks Asthma Quality of Life Questionnaire (AQLQ), originally validated in Australia in a self-administered format, among 539 U.S. subjects with asthma. Subjects were interviewed twice by telephone over an 18-month period. Based on factor analyses, the subscale structure of the AQLQ was modified slightly to eliminate item overlap among subscale scores. Cross-sectionally, total AQLQ scores were significantly correlated in expected directions with baseline asthma severity scores (r = 0.58), SF-36 physical (r = -0.66) and mental (r = -0.40) health status scores, and pulmonary function (FEV1% predicted, r = -0.14). Longitudinally, changes in AQLQ total and subscale scores were significantly (P<0.01) associated with changes in asthma severity and both physical and mental status. The AQLQ, administered by telephone, appears to be useful for assessing changes in the impact of adult asthma.