Restrictive lung function and asbestos-induced pleural fibrosis. A quantitative approach.

To assess further the clinical significance of asbestos-induced pleural fibrosis, we used a computer algorithm to reconstruct images three dimensionally from the high-resolution computerized tomography (HRCT) scan of the chest in 60 asbestos-exposed subjects. Pulmonary function tests, chest radiographs, and HRCT scans were performed on all study subjects. The volume of asbestos-induced pleural fibrosis was computed from the three-dimensional reconstruction of the HRCT scan. Among those with pleural fibrosis identified on the HRCT scan (n = 29), the volume of the pleural lesion varied from 0.01% (0.5 ml) and 7.11% (260.4 ml) of the total chest cavity. To investigate the relationship between asbestos-induced pleural fibrosis and restrictive lung function, we compared the computer-derived estimate of pleural fibrosis to the total lung capacity and found that these measures were inversely related (r = -0.40; P = 0.002). After controlling for age, height, pack-years of cigarette smoking, and the presence of interstitial fibrosis on the chest radiograph, the volume of pleural fibrosis identified on the three-dimensional reconstructed image from the HRCT scan was inversely associated with the total lung capacity (P = 0.03) and independently accounted for 9.5% of the variance of this measure of lung volume. These findings further extend the scientific data supporting an independent association between pleural fibrosis and restrictive lung function.

High-resolution CT-derived measures of lung density are valid indexes of interstitial lung disease.

To assess the validity of computer-assisted methods in analyzing the lung parenchyma imaged with high-resolution computed tomography (HRCT), we compared computer-derived estimates of lung density to other, more traditional, measures of parenchymal injury in 24 subjects with idiopathic pulmonary fibrosis (IPF) and 60 subjects with extensive occupational exposure to asbestos. Gray scale density histograms were constructed from the HRCT images. The gray scale histogram of both study groups was of a skewed unimodal distribution. However, compared with the asbestos-exposed subjects, the patients with IPF had a gray scale distribution that was significantly shifted to the right (greater density) and flatter. In a multivariate analysis, after controlling for age and cigarette smoking, we found that the mean and median gray scale densities were independently associated with the presence of moderate-to-severe dyspnea, a higher International Labour Office chest X-ray category, a lower forced vital capacity, and a higher concentration of macrophages and eosinophils in the bronchoalveolar lavage fluid. These factors accounted for > 70% of the variance of the mean and median gray scale densities. Interestingly, no differences in gray scale density measures were noted between patients with IPF and patients with asbestosis when these other factors were taken into account. Our results suggest that computer-derived density analysis of the lung parenchyma on the HRCT scan is a valid, clinically meaningful, and objective measure of interstitial lung disease.

Physician recognition of hypochondriacal patients.

To examine primary care physician recognition of hypochondriacal patients, we identified a series of such patients in a general medicine clinic using the Whiteley Index. Clinic physicians made blind global ratings of severity of physical disease and unreasonable fear of illness (hypochondriasis) and completed a checklist of somatizing characteristics. Patient records were audited for diagnoses, laboratory tests, consultations, and medications prescribed. Twenty-nine (14%) of 210 patients scored above an established cutoff on the Whiteley Index. These hypochondriacal patients were rated by clinic physicians as more hypochondriacal and were more often given psychiatric diagnoses. Also, clinic physicians identified more somatizing features among hypochondriacal patients including their own reaction to them. This recognition of hypochondriac characteristics may have contributed to better management but may need to be raised to the diagnostic level for maximum benefit.

Correlates of hypochondriasis in a nonclinical population.

Because few community surveys of hypochondriasis have been completed, little is known about the epidemiology of this disorder outside of clinical populations. To address this deficiency, the authors obtained information about hypochondriasis and pertinent characteristics from a group of first-degree relatives of hypochondriacal and nonhypochondriacal probands who participated in a family study. In addition to psychiatric diagnoses, the authors elicited information on demographic variables, medical history, impairment in functioning, psychiatric comorbidity, psychiatric symptoms, personality traits, and childhood experiences. The authors identified hypochondriasis in 7.7% of the relatives. These relatives had a high rate of comorbid anxiety, depressive, and somatoform disorders. They also reported substantial physical and psychological impairment, including diminished work performance and disability. In addition, these relatives reported greater utilization of health care but less satisfaction with that care. These relatives showed most of the same characteristics found in earlier studies of hypochondriacal patients.

A family study of hypochondriasis.

To examine the diagnostic validity of hypochondriasis, we undertook a preliminary family study. Nineteen probands with and 24 without DSM-III-R hypochondriasis were identified among outpatients attending a general medicine clinic. Seventy-two first-degree relatives of hypochondriasis probands and 97 relatives of control probands were personally interviewed with the use of the Structured Clinical Interview for DSM-IV. These relatives also completed self-administered measures of hypochondriasis, psychological and somatic symptoms, and personality traits. No increase in the rate of hypochondriasis was found among the relatives of hypochondriasis probands compared with the relatives of control probands. With respect to other mental disorders, only somatization disorder was more frequent among the hypochondriacal relatives. These relatives also scored higher on measures of hostility, antagonism, and dissatisfaction with medical care. The findings of this study suggest that hypochondriasis may not be an independent disorder but a variable feature of other psychopathology, one that may include somatization disorder.

A 5-year follow-up study of generalized anxiety disorder and panic disorder.

To examine the course and outcome of subjects with generalized anxiety disorder (GAD) and panic disorder, we compared 64 patients with GAD and 68 patients with panic disorder who had participated in drug treatment studies and were interviewed an average of 5 years earlier. At baseline GAD subjects were significantly older, had an earlier onset, and longer duration of illness than panic subjects. GAD subjects also had less severe symptoms. At follow-up, diagnostic stability was observed for both GAD and panic disorder. Significantly fewer GAD subjects achieved full remission at follow-up (18% vs. 45%, p < .01). Subjects with GAD were significantly less anxious at baseline than the panic disorder comparison group, but at follow-up there were few significant differences between groups on most severity of illness variables. This change was due in great part to improvement in the panic disorder group with a concomitant lack of change in the GAD group.

The relationship between irritable bowel syndrome and psychiatric illness. A family study.

Although irritable bowel syndrome (IBS) is a common disorder among gastrointestinal clinic outpatients, it continues to be a diagnosis of exclusion. In treatment-seeking populations, IBS has been frequently associated with psychiatric illness, and this co-occurrence has added to controversy about the validity of the IBS diagnosis. This study is a preliminary effort to examine the nature of this relationship by using the family study design. The probands consisted of 20 patients with IBS and 20 patients who had undergone laproscopic cholecystectomy. Their first-degree relatives were interviewed to obtain lifetime diagnoses of functional gastrointestinal and psychiatric syndromes. Significantly more IBS probands had lifetime psychiatric illness than the cholecystectomy probands. The lifetime prevalence of IBS as well as other functional gastrointestinal syndromes was not significantly different between the groups of relatives. However, significantly more relatives of the IBS probands had lifetime psychiatric illness than the relatives of the cholecystectomy probands. Among the relatives with functional gastrointestinal disorders, significantly more had psychiatric illness. This preliminary study provides support for a relationship between IBS and psychiatric illness by the finding of an increased prevalence of psychiatric disorders among the relatives of patients who have IBS.

Illness fears in the general population.

OBJECTIVES: Because relatively little is known about illness fears, we sought to estimate the prevalence, risk factors, and morbidity associated with such fears in the community. METHODS: We conducted a brief telephone survey of persons aged 40 to 65 years from randomly selected households in the Johnson County, Iowa, area. Respondents were asked whether a series of illness and medical care items made them no more nervous, somewhat more nervous, or much more nervous than other people. Those who reported more discomfort were asked to what extent this interfered with medical care or caused impairment or distress. Information about demographic and health characteristics was also obtained. RESULTS: Five hundred persons, 62% of those contacted, responded to the survey. A factor analysis revealed four fear dimensions: illness/injury, medical care, blood/needle, and aging/death. Five percent of respondents reported much more nervousness in relation to at least four of six illness/injury items, 4% indicated that such fears interfered with their medical care, and 5% reported some negative effect on their life. Similarly, 5% of respondents reported much more nervousness in relation to at least two of four medical care items. Illness/injury fears were somewhat more common in persons with lower income and education and in those with medical conditions. CONCLUSIONS: This survey shows that fears of illness and medical care are common in the general population and indicates that lower socioeconomic status and experience with illness are associated with these fears. The findings also suggest that interference with care occurs among those with the strongest fears.

The role of endotoxin in grain dust-induced lung disease.

To identify the role of endotoxin in grain dust-induced lung disease, we conducted a population-based, cross-sectional investigation among grain handlers and postal workers. The study subjects were selected by randomly sampling all grain facilities and post offices within 100 miles of Iowa City. Our study population consisted of 410 grain workers and 201 postal workers. Grain workers were found to be exposed to higher concentrations of airborne dust (p = 0.0001) and endotoxin (p = 0.0001) when compared with postal workers. Grain workers had a significantly higher prevalence of work-related (cough, phlegm, wheezing, chest tightness, and dyspnea) and chronic (usual cough or phlegm production) respiratory symptoms than postal workers. Moreover, after controlling for age, gender, and cigarette smoking status, work-related respiratory symptoms were strongly associated with the concentration of endotoxin in the bioaerosol in the work setting. The concentration of total dust in the bioaerosol was marginally related to these respiratory problems. After controlling for age, gender, and cigarette smoking status, grain workers were found to have reduced spirometric measures of airflow (FEV1, FEV1/FVC, and FEF25-75) and enhanced airway reactivity to inhaled histamine when compared with postal workers. Although the total dust concentration in the work environment appeared to have little effect on these measures of airflow obstruction, higher concentrations of endotoxin in the bioaerosol were associated with diminished measures of airflow and enhanced bronchial reactivity. Our results indicate that the concentration of endotoxin in the bioaerosol may be particularly important in the development of grain dust-induced lung disease.

Low-dose methotrexate may cause air trapping in patients with rheumatoid arthritis.

Both rheumatoid arthritis (RA) and methotrexate (MTX) are reported to be associated with the development of pulmonary disease. To determine whether MTX enhanced the risk of developing abnormalities in pulmonary function in patients with RA, we prospectively studied 31 subjects (12 male, 19 female) with the diagnosis of classic RA for an average period of 4.4 yr (range, 1 to 5 yr). Each subject was placed on low-dose weekly MTX (mean 17 mg, range 2.5 to 40) for control of RA symptoms. Other medications included non-steroidal anti-inflammatory agents and prednisone if required for control of arthritis symptoms. No other immunosuppressive therapy was used. Each subject was evaluated by pulmonary function tests (PFT) and chest X-ray initially, and at 1, 2, 3.5, and 5 yr. Chest X-rays obtained initially and at the end of the study period were found to be normal. The percent predicted values for initial PFTs in the study group were within the normal range. From the beginning to the end of the observation period, the following mean changes in lung function were observed: 1.9% increase in TLC, 5.1% increase in residual volume (RV), 1.8% increase in FVC, 0.71% decrease in FEV1, 14.7% improvement in alveolar-arterial oxygen (A-aO2) difference, and a 12.7% increase in single-breath diffusing capacity (DLCO). To determine whether MTX (average dose, weekly dose, or cumulative dose) was significantly related to changes in pulmonary function, we used multivariate techniques to control for the initial measure of lung function while assessing the relationship between MTX and the subsequent measures of lung function.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of atopy in grain dust-induced airway disease.

To determine whether atopy influences the physiologic or inflammatory response to grain dust, we compared spirometric measures of airflow and bronchoalveolar lavage (BAL) measures of lower respiratory tract inflammation between demographically similar nonatopic (n = 10) and atopic (n = 10) study subjects after each of two inhalation exposures: Hanks' balanced salt solution (HBSS) and corn dust extract (CDE; 0.4 microgram of endotoxin/kg body weight). Subjects were healthy nonsmokers with similar baseline pulmonary function, without bronchial hyperreactivity, and had not participated in agriculture. Atopic subjects had two or more positive skin responses to 10 common environmental allergens. Both groups developed significant airflow obstruction and lower airway inflammation after CDE inhalation. Importantly, the magnitude of the post-CDE exposure airflow decrements, BAL cellularity, and BAL concentration of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-6, and IL-8 did not significantly differ between atopics and nonatopics. The concentrations of histamine and eosinophils in the BAL fluid were unaffected by CDE inhalation and did not significantly differ between atopics and nonatopics. Atopic status does not appear to be a significant determinant of airflow obstruction or lower airway inflammation following CDE inhalation. Our findings suggest that atopy may play, at most, a minor role in the development of grain dust-induced airway disease.