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Biomedical subjects

M D Lebowitz

Publications and source records attributed to M D Lebowitz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Early childhood respiratory symptoms and the subsequent diagnosis of asthma.

BACKGROUND: Respiratory symptoms are frequent in very young children, and the relation of these symptoms to later asthma in some of these children is unknown. OBJECTIVE: The aim of the study was to describe the natural history of respiratory symptoms in a community-based sample of young children who were prospectively observed for as long as 11 years. METHODS: Subjects were participants in the Tucson Epidemiologic Study of Airways Obstructive Disease. They were under 5 years of age at enrollment and were studied by means of a parent-administered mail survey instrument every 1 to 2 years for 3 to 11 years. RESULTS: Among subjects younger than 1 year of age, no single respiratory symptom, such as cough or wheeze only with colds, significantly increased the risk of a subsequent diagnosis of asthma. Among 1- and 2-year-olds, however, those with wheeze only with colds and those with attacks of shortness of breath with wheeze were more likely to be diagnosed with asthma later when compared with children without those symptoms (odds ration = 2.1; p < 0.05 for wheeze only with colds). At ages 3 to 4 years, symptoms were even more strongly associated with subsequent asthma (odds ratio = 7.2; p < 0.0001 for attacks of shortness of breath with wheeze). CONCLUSION: Although respiratory symptoms reported by parents very early in life are not significantly associated with future asthma, those symptoms that begin at or persist through ages 3 to 4 years are.

Adolescent↗
PubMed1996

Epidemiological studies of the respiratory effects of air pollution.

Environmental epidemiological studies of the health effects of air pollution have been major contributors to the understanding of such effects. The chronic effects of atmospheric pollutants have been studied, but, except for the known respiratory effects of particulate matter (PM), they have not been studied conclusively. There are ongoing studies of the chronic effects of certain pollutant classes, such as ozone, acid rain, airborne toxics, and the chemical form of PM (including diesel exhaust). Acute effects on humans due to outdoor and indoor exposures to several gases/fumes and PM have been demonstrated in epidemiological studies. However, the effects of these environmental factors on susceptible individuals are not known conclusively. These acute effects are especially important because they increase the human burden of minor illnesses, increase disability, and are thought to decrease productivity. They may be related to the increased likelihood of chronic disease as well. Further research is needed in this latter area, to determine the contributions of the time-related activities of individuals in different microenvironments (outdoors, in homes, in transit). Key elements of further studies are the assessment of total exposure to the different pollutants (occurring from indoor and outdoor source) and the interactive effects of pollutants. Major research areas include determination of the contributions of indoor sources and of vehicle emissions to total exposure, how to measure such exposures, and how to measure human susceptibility and responses (including those at the cellular and molecular level). Biomarkers of exposures, doses and responses, including immunochemicals, biochemicals and deoxyribonucleic acid (DNA) adducts, are beginning to promote some basic knowledge of exposure-response, especially the mechanisms. These will be extremely useful additions to standard physiological, immunological, and clinical instruments, and the understanding of biological plausibility. The outcomes of all this work will be the management of risks and the prevention of respiratory diseases related to air pollution.

Air Pollutants↗
PubMed1996

Rates of decline in lung function among subjects who restart cigarette smoking.

Several studies have demonstrated that smokers who are able to break the habit generally experience reductions in respiratory symptoms and improvement in pulmonary function; however, far less attention has been given to smokers who are unsuccessful in their attempts at quitting. Recent reports have suggested that these subjects (restarters) may have steeper rates of decline in pulmonary function than subjects never attempting to quit smoking. In this study, we compared rates of decline in FEV1 between restarters and subjects who remained current, ex-smokers, or never-smokers throughout the observation period. The results showed that, in both sexes, subjects who attempt to quit the habit and then restart have significantly steeper rates of decline in their FEV1 than subjects who continue smoking uninterrupted. Female restarters also have significantly steeper rates of decline in FEV1 than ex-smokers. These effects were independent of the amount smoked and respiratory diseases.

Adult↗
PubMed1995

Persistence and new onset of asthma and chronic bronchitis evaluated longitudinally in a community population sample of adults.

BACKGROUND: Some patients with chronic obstructive pulmonary disease may share the clinical characteristics of those with asthma; their disease is sometimes called "asthmatic bronchitis." Whether there is a difference between asthmatics who do and do not develop chronic bronchitis is not yet clear. We investigated whether asthma and chronic bronchitis may share some "allergic" phenotypes and whether asthmatic individuals who develop chronic bronchitis subsequently have steeper declines in lung function. METHODS: Known risk factors for decline in lung function were analyzed in a representative community population of adults followed up longitudinally since 1972 in Tucson, Ariz, in groups with persistent, newly developed, and past diagnoses of asthma and chronic bronchitis. We evaluated contributions of initial level of forced expiratory volume in 1 second (FEV1), reversibility with isoproterenol hydrochloride nebulized aerosol bronchodilator treatment, percentage of blood eosinophils to determine eosinophilia, and IgE level. RESULTS: The concurrence of chronic bronchitis and asthma is associated with a steeper decline in FEV1 than is asthma as the sole diagnosis. Asthmatics (those with persistent asthma with and without chronic bronchitis) had the greatest prevalence of increased reversibility with isoproterenol therapy and with eosinophilia. The prevalence of eosinophilia was also high in those with newly diagnosed chronic bronchitis without asthma; however, this was not the case in those with persistent chronic bronchitis without asthma. Larger bronchodilator responses were related to steeper declines in FEV1, both in persistent asthma and in chronic bronchitis. CONCLUSIONS: Bronchodilator response and eosinophilia are generally believed to be hallmarks of asthma. We show that these characteristics may be present in chronic bronchitis as well. The presence of a large (> 25%) bronchodilator response is associated with a steeper decline in FEV1.

Adult↗
PubMed1995

Exposure assessment needs in studies of acute health effects.

It is known that pollutants in the outdoor and indoor environments are associated with acute adverse effects on health. The acute health effects produced include a wide range, from minor biological changes to causes of illness and exacerbation of disease, to death. Valid assessment of total exposures in various microenvironments are much more meaningful in terms of the various health responses. Short and long exposure times are both important, especially as related to the locations of such exposure and activities engaged in at the time. The quantitative character of exposure-response relationships will require more extensive research on obtaining appropriate exposure information, including monitoring and validating exposures and time activities, and on further modelling. More knowledge is also needed regarding the quantitative nature of the acute health effects, combined effects of different pollutants, and on the effects of various co-variates, effect-modifiers, and confounders. Efforts should also consist of promoting acute health effects studies that have appropriate monitoring and exposure assessment.

Air Pollutants↗
PubMed1995

Asthmatic risk factors and bronchial reactivity in non-diagnosed asthmatic adults.

Specific respiratory signs and symptoms are thought to occur prior to diagnoses of asthma as part of the natural history. These signs and symptoms include: high IgE, a history of wheezing symptoms, and/or excessive declines in lung function. The first two are thought to distinguish asthma from other airway obstructive diseases (AOD). To predict subsequent AOD, twelve years of follow-up (1972-84) data from the Tucson longitudinal epidemiological study of AOD in a community population were evaluated on 687 subjects aged 19-70 years on entry. To determine the likelihood that non-asthmatics that have these specific risk factors would have marked or intermediate bronchial reactivity to methacholine, an experimental study was performed. This was done in 1984-85 in a robust, efficient post-hoc stratified sample of male subjects ages 30-55 from the population followed from 1972. They were subsequently followed through 1991. Persistent symptoms best predicted final pulmonary function and new diagnosed AOD in subjects in the population. Previously diagnosed AOD also predicted lower pulmonary function. The experimental results indicate that predisposition to reactivity appears likely without the presence of diagnosed asthma. Further, the experimental subjects with high risk had increased symptomatology and decreased lung function when tested at follow-up; not all of the reactivity was explained by these factors. An attempt to predict reactivity by physician evaluation and special questionnaire was not fruitful. In addition, wheeze per se often disappeared without later evidence of asthma (or AOD) diagnosis, questioning some international tendencies to label all wheeze as asthma. Thus, high IgE significantly predicted bronchial responsiveness, but high IgE and symptoms are neither necessary nor sufficient. Also, both preclinical and clinical asthma predict eventual low lung function.

Adult↗
PubMed1995

Longitudinal evaluation of the association between pulmonary function and total serum IgE.

The role of immunoglobulin E (IgE) in the development and course of impaired ventilatory function and chronic obstructive pulmonary disease (COPD) required further study. This role has been examined in the longitudinal Tucson Epidemiological Study of Airways Obstructive Disease, which started in 1972. The association between IgE and longitudinal changes in pulmonary function measures was examined in subjects in the community population sample in Tucson who had an initial age of 35 or more. There were a total of 1,533 such subjects with lung function tests over the 20 yr period who also had IgE determinations. A significant inverse association was found between total serum IgE and FEV1/FVC that was independent of smoking and asthma status. The finding was statistically separate from the relation with age in all but elderly current smokers (age > 55). The magnitude of this effect in nonasthmatic subjects was relatively small. For asthmatic subjects, however, the inverse association was larger in both current and never smokers. Subjects excluded from the current analysis either did not have an IgE measurement and/or had no pulmonary function values after 35 yr of age. These findings suggest that higher IgE levels may indicate the presence of a disease process that may involve inflammation and/or other mechanisms related to IgE production, which impair lung function over time. However, in this study we were not able to account for possible parental or inheritance contributions to increases in total IgE, which have been shown to be important.

Adult↗
PubMed1995

The relationship between parental and children's serum IgE and asthma.

This paper examines the familial aggregation of physician-diagnosed asthma in relation to the age- and sex-standardized total serum IgE levels of children and their parents in a sample of the general population in Tucson, Arizona, that has been followed in a longitudinal study for over 20 yr. There were 591 nuclear families containing 1,177 children who provided information about the presence or absence of a physician diagnosis of asthma. The serum IgE data were less complete: both parents and one or more of their children in 251 of the nuclear families, containing 468 children, had serum IgE levels measured. There was a very strong tendency for asthmatic patients to have asthmatic children, but only a small part of this appeared to be related to the familial aggregation of total serum IgE. In the absence of an asthmatic parent, there was a slight but significantly higher prevalence of asthma in children of whom both parents had IgE levels in the highest tertile. Very high rates of children's asthma depended on there being an asthmatic parent who also had at least moderate levels of serum IgE. It was also shown that asthmatic children have considerably higher total IgE levels than would be expected on the basis of their parents' IgE levels alone. The data appear compatible with several familial-aggregation hypotheses and a strong environmental influence determining which children are likely to develop asthma. We speculate that the inflammation in the airways of asthmatic patients itself tends to increase the serum IgE level, possibly secondary to mediators that it generates.

Adolescent↗
PubMed1995

Ambulatory monitoring of peak expiratory flow. Reproducibility and quality control.

Eighty-five children and 230 adults from a population study performed ambulatory peak flow readings three times a day for 1 to 2 weeks following a home visit. Three peak expiratory flow (PEF) readings were reported for each of 5,809 test sessions. Within each test session, the third maneuver most frequently (40% of the time) gave the highest PEF reading. This did not vary throughout the day. In subgroups of children and women with a history of asthma or asthma symptoms (hereinafter referred to as "asthma"), the first maneuver during the evening test sessions more frequently gave the highest readings. However, maneuver-induced bronchospasm occurred during less than 5% of the test sessions in both subjects with asthma and in other subjects. The within test session PEF reproducibility was good: overall, the highest and second highest reading matched within one division (10 L/min) 73% of the time and within 30 L/min (9% of the reading) 95% of the time. The best reproducibility was noted after the first two days of testing, during evening and bedtime test sessions (vs morning), and in girls and men. In the group with at least 2 weeks of testing, the coefficient of repeatability (CR) for the week-to-week PEF lability index was 10% for healthy adults and 17% for healthy children. As expected, repeatability was not as good for adults with asthma (CR = 17%) and children with asthma (CR = 28%).

Adult↗
PubMed1995

Adverse effects of eosinophilia and smoking on the natural history of newly diagnosed chronic bronchitis.

BACKGROUND: Little is known about risk factors for the progression of disease in individuals with newly developed chronic bronchitis (CB). In addition to the effects of smoking, there was specific clinical and epidemiologic interest in the importance of traits such as eosinophilia and wheezing, more commonly associated with asthma, in the progression of this disease. METHODS: We evaluated adult individuals with and without diagnosed CB longitudinally in a representative community population in Tucson, Ariz. These subjects were followed up for 13 years since 1972. Because we were interested in CB specifically, those with diagnoses of emphysema and asthma were removed from the data set. Initial level of FEV1 (%FEV1) and slopes in FEV1 were corrected for covariates and other important variables. RESULTS: As expected, persistent and newly diagnosed CB was significantly more common in current and ex-smokers. Furthermore, initial lung function was lower, and decline in FEV1 was steeper in smokers with persistent and newly diagnosed CB. Newly diagnosed cases had steeper declines in FEV1 (-6.84 mL/yr below grand mean of -11.18 mL/yr) than normal subjects (+0.95 mL/yr). The incidence rate of newly diagnosed CB was significantly higher in those with eosinophilia (13.7%) than without eosinophilia (6.7%). Finally, new cases with eosinophilia had similar initial %FEV1 (95.4 +/- 1%) but much larger declines in function than new cases without eosinophilia: -24.5 versus -16.6 mL/yr. Adverse effects of wheeze were largely explained by smoking and eosinophilia. CONCLUSION: Eosinophilia is an important aspect of CB in addition to smoking, and it should be considered in its evaluation. The presence of eosinophilia in newly diagnosed CB, with or without wheeze, may warn the clinician of the possibility of a rapid decline in FEV1.

Adult↗
PubMed1995

Air pollution and upper respiratory symptoms in children from East Germany.

Whereas evidence of adverse effects of air pollution on lower respiratory tract illnesses in children is increasing, little is known about the effects of high and moderate levels of air pollution on the incidence of upper respiratory illnesses. 9 to 11 year old schoolchildren (n = 1,854) living in Leipzig, East Germany were studied. The presence of upper respiratory symptoms was documented by a physician. Daily mean and maximum concentrations of SO2, particulate matter (PM) and NOx, as well as temperature and humidity, were measured. Furthermore, a self-administered questionnaire was distributed to the parents to assess confounding factors. Parents of 1,500 (81%) children returned the questionnaire. When controlling for paternal education, passive smoke exposure, number of siblings, temperature and humidity, increased risks for the development of upper respiratory symptoms were found in the winter months for SO2 mean concentrations (odds ratio (OR) = 1.72; 95% confidence interval (95% CI) 1.19-2.49). NOx mean concentrations (OR = 1.53; 95% CI 1.01-2.31) and PM maximum values (OR = 1.62; 95% CI 1.08-2.45). In the summer months, only NOx mean concentrations were associated with a significantly increased risk (OR = 1.82; 95% CI 1.21-2.73). A combination of high mean levels of different pollutants resulted in the highest risk (OR = 2.10; 95% CI 1.30-3.37 in the winter, and OR = 2.16; 95% CI 1.23-3.81 in the summer). We conclude that high concentrations of SO2, and moderate levels of particulate matters and NOx are associated with an increased risk of developing upper respiratory symptoms in childhood.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1994

Familial resemblance for immunoglobulin levels.

The familial resemblance for immunoglobulin A, D, E, G, and M levels was investigated with family data collected in Canada and the U.S., entertaining both multifactorial and single gene hypotheses. Significant familial effects were found for each of the immunoglobulins, and there was significant support for a major gene hypothesis for IgA and IgD levels. Whereas there have been several reports suggesting a major gene determinant for IgE levels, including that from our own Canadian study, analysis of the U.S. sample suggested that a multifactorial component parsimoniously explained the observed familial resemblance.

Analysis of Variance↗
PubMed1994

Findings before the diagnosis of asthma in young adults.

BACKGROUND: Asthma is a poorly understood disease. Risk factors are not established, and the natural history of the disease is unknown. OBJECTIVE: Using subjects of a community-based study, we have prospectively compared young adults destined to develop asthma with control subjects to determine differences between them before diagnosis. METHODS: Subjects were participants of the Tucson Epidemiologic Study of Airways Obstructive Disease. They were studied between the ages of 15 and 19 and subsequently every 1 to 2 years until they were at least 21 years old with questionnaire, spirometry, allergy skin testing, and serum IgE testing. RESULTS: Logistic regression showed that "wheeze" and "attacks of shortness of breath with wheeze" were independently predictive of asthma. Positive allergy skin test results occurred more frequently among subjects who later received a diagnosis of asthma, and initially these subjects had higher serum IgE levels than control subjects (geometric mean IgE = 173.8 IU/ml vs 52.5 IU/ml for control subjects; p < 0.005). Although initial spirometric testing did not distinguish between future asthmatic subjects and control subjects, repeat testing after diagnosis did show significant differences in flows at low lung volumes. CONCLUSIONS: These data suggest that symptoms and findings suggestive of asthma may be present for many years before diagnosis.

Adult↗
PubMed1994

Longitudinal analysis of the effects of smoking onset and cessation on pulmonary function.

We examined the effects of smoking onset and cessation on FEV1 in participants in the Tucson Epidemiological Study of Airways Obstructive Disease 18 yr of age or older who reported a change in smoking habits during 17 yr of follow-up. Subjects were classified as "new quitters" (n = 288) and "new starters" (n = 45) at each survey on the basis of questionnaire responses concerning current smoking habits. The pulmonary function data were analyzed using a mixed longitudinal or random effects model (REM). We compared FEV1 before and after changing smoking habits in the same subjects while adjusting for important covariables such as height, pack-years, and respiratory symptoms and diseases. The results for smoking cessation showed a beneficial effect related to quitting that was largest for younger subjects and decreased linearly with age. For women, quitting resulted in an improvement in FEV1 of 4.3% at 20 yr of age which decreased to 2.5% by 80 yr of age. Men had an improvement of only 1.2% at 20 yr of age and no improvement at 80 yr of age. After excluding subjects with low initial function (FEV1/FVC in the lowest quartile) and those with only a single observation after quitting, men (n = 70) showed a significantly higher FEV1 improvement of 4% at 20 yr of age that decreased linearly to zero by age 80 yr. In contrast, women in this subgroup (n = 89) had nearly the same degree of improvement at all ages. The onset results showed mean FEV1 values after starting smoking that were higher at the younger ages (< 23 yr) and that decreased more rapidly with age, compared with nonsmoking mean estimates, in both sexes.

Adult↗