Biomedical subjects

M D Lebowitz

Publications and source records attributed to M D Lebowitz.

At least 37 records · Page 2Linked to original sources

PubMed1991

Methods to assess respiratory effects of complex mixtures.

This paper evaluates the influence of exposures on acute and chronic airway obstruction. Clinical, physiological, and immunological aspects are important in evaluating the effects of the pollutant exposures. Aspects of the exposure-response relationships important enough to record are those factors interactive with the pollutants (e.g., smoking and other personal/behavioral factors) and precursor conditions. To determine baseline status and study chronic effects, one uses standardized and modified health questionnaires and standardized pulmonary function. Confirmatory studies of responsive airways, potentially assessed first by diurnal peak flow, can be done using post-bronchodilator maximum expiratory flow volume curves and methacholine challenges. Immunoglobulin determinations for immunological status (a predisposing/susceptibility factor), allergy skin tests (for immediate hypersensitivity status), and blood counts (mostly for eosinophils) are also important. Other tests that could be performed include expired carbon monoxide and/or carboxyhemoglobin and methemoglobin (for smoking and combustion exposures). Measures of acute effects are symptomatic responses (by questionnaires and diaries), responses of the airways (as measured by spirometry and peak flows), and changes in medication usage or associated medical care (in diaries). Methodologies should also include discussions of protocols and analysis.

Air Pollutants↗

PubMed1991

Prevalence rates of respiratory symptoms in Italian general population samples exposed to different levels of air pollution.

We surveyed two general population samples aged 8 to 64 living in the unpolluted, rural area of the Po Delta (northern Italy) (n = 3289) and in the urban area of Pisa (central Italy) (n = 2917). Each subject filled out a standardized interviewer-administered questionnaire. The Pisa sample was divided into three groups according to their residence in the urban-suburban areas and to outdoor air pollution exposure (automobile exhaust only or industrial fumes as well). Significantly higher prevalence rates of all the respiratory symptoms and diseases were found in Pisa compared with the Po Delta. In particular, rhinitis and wheezing symptoms were higher in all the three urban zones; chronic cough and phlegm were higher in the zone with the automobile exhaust and the additional industrial exposure. Current smoking was more frequent in the rural area, but the urban smokers had a higher lifetime cigarette consumption. Childhood respiratory trouble and recurrent respiratory illnesses were evenly distributed. Exposure to parental smoking in childhood and lower educational level were more frequent in Po Delta, whereas familial history of respiratory/allergic disorders and work and indoor exposures were more often reported in the city. Multiple logistic regression models estimating independently the role of the various risk factors showed significant odds ratios associated with residence in Pisa for all the symptoms but chronic phlegm. For example, those living in the urban-industrial zone had an odds ratio of 4.0 (4.3-3.7) for rhinitis and 2.8 (3.0-2.6) for wheeze with respect to those living in the Po Delta.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Characteristics of asthma among elderly adults in a sample of the general population.

This article describes the characteristics and course of asthma among subjects who were older than 65 years at the time of enrollment in a longitudinal study of a general population sample. It was present in 3.8 percent of men and 7.1 percent of women. An additional 4.1 percent of men reported having "asthma," but they also had seen a physician for "emphysema" and had smoked significantly; their "asthma" diagnosis is regarded as highly questionable. They did not show the elevated rate of allergy skin test reactivity of high serum IgE levels that were characteristic of other asthmatics. Many of the elderly asthmatics (mean age, 72 years) had severe disease with marked ventilatory impairment. There was a close relationship between the severity of wheezing complaints and impairment of the FEV1. Of the 46 patients, 48 percent reported an onset before age 40 years. There was no relationship between severity and age of onset or duration of disease. A second diagnosis of "chronic bronchitis" was reported by 46 percent of the asthmatics, but this did not delineate a distinctive group with late-onset, smoking-related disease. Death rates in the asthmatics tended to be higher than in nonasthmatics (odds ratio, 1.9; CI, 0.998 to 3.70, after stratifying by sex). Over a mean follow-up of 7.44 years, most symptoms as well as the FEV1 remained relatively stable. Chronic productive cough did tend to remit (p less than 0.01), but this was noted in the nonasthmatics as well. We estimate that no more than 19 percent of the asthmatics went into complete remission during follow-up. Most of these had mild initial symptoms; there were no remissions in subjects with severe disease at the time of entry. We concluded that asthma in the elderly is not a rare disease and may be associated with severe symptoms and chronic airways obstruction. If severe, it rarely goes into complete remission but tends to remain a severe, disabling disorder.

Aged↗

PubMed1991

Respiratory symptoms and risk factors in an Arizona population sample of Anglo and Mexican-American whites.

Prevalence rates of respiratory symptoms and diseases in a large group of Anglos and Mexican-Americans were analyzed. Each subject completed a questionnaire. Among current smokers, chronic productive cough and dyspnea were significantly higher in both ethnic groups; wheezy symptoms were higher in Anglos. There were no significant differences in the symptom prevalence rates between the two groups, after stratifying by current cigarette consumption and CRT. The spirometric values were not significantly different. In both ethnic groups, the prevalence rates of wheeze, SOBWHZ and asthma were significantly higher in those who had CRT. Among Anglos, less educated smokers had significantly higher prevalence rates of SOBWHZ and dyspnea; nonsmokers with less education had higher prevalence rates of cough, chronic cough and dyspnea. Our results confirm the importance of CRT and lower educational level as risk factors for respiratory symptoms. Ethnicity is not associated with symptomatology or lung function impairment.

Adult↗

PubMed1991

Exposure assessment approaches to evaluate respiratory health effects of particulate matter and nitrogen dioxide.

Several approaches can be taken to estimate or classify total personal exposures to air pollutants. While personal exposure monitoring (PEM) provides the most direct measurements, it is usually not practical for extended time periods or large populations. This paper describes the use of indirect approaches to estimate total personal exposure for NO2 and particulate matter (PM), summarizes the distributions of these estimates, and compares the effectiveness of these estimates with microenvironmental concentrations for evaluating effects on respiratory function and symptoms. Pollutant concentrations were measured at several indoor and outdoor locations for over 400 households participating in an epidemiological study in Tucson, Arizona. Central site monitoring data were significantly correlated with samples collected directly outside homes, but the former usually had higher pollutant concentrations. Integrated indices of daily total personal exposure were calculated using micro-environmental (ME) measurements or estimates and time-budget diary information. Peak expiratory flow rates (PEFR) were measured for up to four times a day during two-week study periods. In thirty children (ages 6-15 years) with current diagnosed asthma, a significant reduction in PEFR was associated with NO2 levels measured outside of their homes. Additional decrements of morning PEFR were found in those children sleeping in bedrooms with higher measured NO2 levels. Morning and noon PEFR decrements were also linked to higher morning NO2 levels that were measured at central monitoring stations. Effects of PM were also found, but were limited to morning PEFR. No effects were found in non-asthmatic children. The relationship of PEFR to the calculated indices of daily average total exposure were weaker than to the microenvironment concentrations. This suggests that diary and ME monitoring data need to yield better time resolution in order to incorporate short-term average exposures to higher concentrations into the exposure indices and into the analysis of within day health responses.

Adolescent↗

PubMed1991

Effects of home environment on respiratory symptoms and lung function in a general population sample in north Italy.

Effects of indoor pollution exposure were evaluated in a general population sample (n = 3,289) living in the Po River Delta area. Prevalence rates of chronic cough in men and dyspnoea in women were significantly higher in association with the use of bottled gas (propane) for cooking instead of natural gas (methane). Chronic cough and phlegm in men and dyspnoea in women were significantly associated with the use of a stove for heating. When combining type of heating and fuel used, in men a trend toward higher prevalence rates of chronic cough and phlegm was shown in those with stove or fan heating (regardless of the fuel); in women the trend reached statistical significance for dyspnoea. The relationship between stove (regardless of fuel) and decrease in forced expirograms was statistically significant only in women. In multiple logistic models, accounting for independent effects of age, smoking, pack-years, parents' smoking, socio-economic status, body mass index, significantly increased odds ratios were found in males for the associations of: bottled gas for cooking with cough (1.66) and dyspnoea (1.81); stove for heating with cough (1.44) and phlegm (1.39); stove fuelled by natural gas and fan or stove fuelled other than by natural gas with cough (1.54 and 1.66). In females, significantly increased odds ratios were found only for dyspnoea when associated with bottled gas for cooking (1.45), stove for heating (1.46), stove fuelled by natural gas (1.58), stove or fan fuelled other than by natural gas (1.73).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Differential rates of lung growth as measured longitudinally by pulmonary function in children and adolescents.

A sample population of 67 males and 71 females with longitudinal lung function and other anthropometric measurements from all non-Hispanic white children in the Tucson Epidemiological Study of Airway Obstructive Diseases (AOD) was studied to evaluate biological determinants of the rate of lung growth. Groups within gender were defined by the following factors: 1) maximum height, 2) age at maximum forced expiratory volume at 1 second (FEV1), 3) % predicted initial FEV1 or FEV1/FVC ratio. Only groups defined by low initial function (FEV1 or FEV1/FVC less than or equal to 85% predicted versus greater than 85% predicted) showed statistically significant differences from those with more "normal" function by comparing their maximum % of predicted FEV1s and FEV1/FVC ratios. The longitudinal FEV1 data by age for the latter groups were characterized by a mathematical model (polynomial smoothing spline) yielding optimal fitted curves and an estimate of each group's growth velocity curve. The statistical comparisons between these fitted curves indicate that subjects with low initial pulmonary function continued to have significantly lower FEV1 values for males older than 13.12 years and for females between 8.23 and 15.3 years. At post-hoc analysis persistent wheezing was more likely in the initially more impaired group. Disease at the end of follow-up was not related to initial functional status.

Adolescent↗

PubMed1990

The Po River Delta epidemiological study of obstructive lung disease: sampling methods, environmental and population characteristics.

A longitudinal study on chronic obstructive lung disease (AOD) has been started in the Po River Delta in northern Italy. The first cross-sectional study was conducted in this previously unpolluted rural area before the start of operation of a large thermoelectric power plant (2,649 megawatt). A significant output of air pollutants is expected. This will permit us to carry out a "natural experiment" to study the effects of air pollutants (SO2 and suspended particulates). A multistage stratified cluster design was chosen. Stratification was based on age and socio-economic characteristics (SES) of households, and was performed in two steps, using the different indices computed from the census data. Geographic zones represented four areas of different predicted pollution exposure, once the plant started operating. There were 3,289 subjects in the selected age group (8-64) who agreed to participate (78%); only 11% refused to participate. The participants were representative of the clusters and SES. Participants had slightly fewer employed males, who did not participate due to work. The stratification and staging method allowed us to keep an acceptable level of precision and efficiency in the sample. In fact age-related differences were not found among the SES strata and geographic zones; various socio-economic characteristics, verified from the questionnaire information, were consistent with the SES stratification. Differences between geographic zones were related to the number of households of different SES within clusters; however this reflects the characteristics of the general population in the area.

Air Pollutants↗

PubMed1990

A longitudinal study of risk factors in asthma and chronic bronchitis in childhood.

The prevalence, persistence, incidence and remission rates of reported diagnosed asthma and chronic bronchitis has been studied longitudinally over ten years in a representative community sample of children and adolescents. The objectives are to evaluate the rates of change over time, the role of family history of disease, and the social risk factors in the longitudinal course of disease. The relationship between the two reported diagnoses is very high, about half of each group having the other diagnosis. Each diagnosis has specific symptoms with which it is associated. Remission of clinical disease is associated with continuing symptoms in about half of such cases. The incidence rates and remissions of cases as they have occurred over time were associated with different symptoms and risk factors. A family history of lung disease and family social characteristics are significant risk factors affecting the presence of these diseases, and how they change. Discussion suggests these factors may affect possible precursors, such as lower respiratory tract illnesses, as well as personal habits (such as smoking), which are related to both diagnoses. Further, the interactions of these risk factors appear to significantly influence impairments of lung function at the beginning of adult life, and potential subsequent disease.

Adolescent↗

PubMed1990

An association of human congenital cardiac malformations and drinking water contaminants.

During an informal study in 1973 it was noted that approximately one third of patients with congenital heart disease lived in a small area in the Tucson Valley. In 1981 groundwater for a nearly identical area was found to be contaminated with trichloroethylene and to a lesser extent with dichloroethylene and chromium. Contamination probably began during the 1950s. Affected wells were closed after discovery of contamination. This sequence of events allowed investigation of the prevalence of congenital heart disease in children whose parents were exposed to the contaminated water area as compared with children whose parents were never exposed to the contaminated water area. The contaminated water area contained 8.8% of the Tucson Valley population and 4.5% of the labor force. Using their case registry, the authors interviewed parents of 707 children with congenital heart disease who, between 1969 and 1987, 1) conceived their child in the Tucson Valley, and 2) spent the month before the first trimester and the first trimester of the case pregnancy in the Tucson Valley. Two random dialing surveys showed that only 10.5% of the Tucson Valley population had ever had work or residence contact, or both, with the contaminated water area, whereas 35% of parents of children with congenital heart disease had had such contact (p less than 0.005). The prevalence of congenital cardiac disease (excluding syndromes, children with atrial tachycardia or premature infants with patent ductus arteriosus) in the Tucson Valley was 0.7% of live births and with syndromes was calculated to be 0.82%. The odds ratio for congenital heart disease for children of parents with contaminated water area contact during the period of active contamination was three times that for those without contact (p less than 0.005) and decreased to near unity for new arrivals in the contaminated water area after well closure. The proportion of infants with congenital heart disease as compared with the number of live births was significantly higher for resident mothers in the contaminated water area than for mothers with no exposure. No other environmental agent could be identified that was localized to the contaminated water area, but one could have been missed. The data show a significant association but not a cause and effect relation between parental exposure to the contaminated water area and an increased proportion of congenital heart disease among live births as compared with the proportion of congenital heart disease among live births for parents without contaminated water area contact.

Adult↗

PubMed1990

Chronic respiratory effects of indoor formaldehyde exposure.

The relation of chronic respiratory symptoms and pulmonary function to formaldehyde (HCHO) in homes was studied in a sample of 298 children (6-15 years of age) and 613 adults. HCHO measurements were made with passive samplers during two 1-week periods. Data on chronic cough and phlegm, wheeze, attacks of breathlessness, and doctor diagnoses of chronic bronchitis and asthma were collected with self-completed questionnaires. Peak expiratory flow rates (PEFR) were obtained during the evenings and mornings for up to 14 consecutive days for each individual. Significantly greater prevalence rates of asthma and chronic bronchitis were found in children from houses with HCHO levels 60-120 ppb than in those less exposed, especially in children also exposed to environmental tobacco smoke. In children, levels of PEFR decreased linearly with HCHO exposure, with the estimated decrease due to 60 ppb of HCHO equivalent to 22% of PEFR level in nonexposed children. The effects in asthmatic children exposed to HCHO below 50 ppb were greater than in healthy ones. The effects in adults were less evident: decrements in PEFR due to HCHO over 40 ppb were seen only in the morning, and mainly in smokers.

Adolescent↗

PubMed1990

Environmental contaminants and low-level cancer risks: perceptions and scientific strategies.

Scientific and public perceptions concerning low-level lung cancer risks may vary. Recently the public has been more convinced of causal links between low-level risk agents and cancer, and more interested in prevention of environmental exposures, especially those induced by others. Thus, scientific strategy is partly driven by the public need to resolve issues concerning the importance of low-level exposures and risks. Further, investigators have been challenged intellectually to create methodologies in order to study some of these relationships further, and scientific curiosity has been stimulated by the difficulties of pursuing such investigations. The importance of host characteristics, including the genetic bases of susceptibility, has become a major theme. Likewise, host behaviour has become a potential positive factor (e.g. diet) as well as a negative factor in the risk model for low-level agents. This paper discusses some of the information available on low-level agents and some of the methodological issues involved in studying them. The importance of measuring exposure as well as response is stressed, especially multi-pollutant exposures and interactions with host behaviour.

Asbestos↗

PubMed1990

Methodological issues in the epidemiological investigations of lung cancer related to low-level risks.

There are several major issues that create great difficulties in the study of low-level risks for lung cancer. Further attention needs to be addressed to the difficulties in design, ascertainment, classification, confounding and analysis found in the environmental epidemiological aspects of the investigation. Host predisposition is an important factor that requires further characterization in the process of conducting these environmental epidemiological investigations. Within the exposure assessment aspects of these investigations, major difficulties arise from the need to obtain total exposure estimates, dose estimates and in evaluating the interactions of the several pollutants of concern in exposure settings of interest. Low-level risks for lung cancer imply difficulties in the assessment of exposure-dose pattern. Further, bio-markers are needed to focus more on dose. Further, low-level risk ratios produce difficulties in distinguishing the effects of confounders. In order to facilitate further studies of lung cancer related to low-level risks, we will have to create new, more specific, and more efficient study designs. These studies will require much better exposure assessment and case ascertainment than typical of previous studies, and more complete measurement of confounders.

Environmental Exposure↗

PubMed1990

Longitudinal analysis of the effects of acute lower respiratory illnesses on pulmonary function in an adult population.

The data from a longitudinal population study in Tucson, Arizona, were used to evaluate the effects of acute lower respiratory illnesses on pulmonary function in subjects over 25 years of age. In five of nine surveys performed during the first 13 years of follow-up (1972-1985), similar questions were asked concerning chest colds occurring in the past few years. There were 1,151 men and 1,473 women who had questionnaire and spirometric data collected in at least one of these surveys. The random effects longitudinal model with first-order autoregressive error structure was used in the analysis of changes in pulmonary function after the acute illness episode, adjusted for the effects of age, height, cigarette smoking, and chronic respiratory diseases. The analyses indicated that pulmonary function is reduced for several years after a single chest cold in men and after multiple chest colds in women. After an episode of pneumonia, pulmonary flow indices were reduced, with lower values sometimes persisting for several years.

Adult↗

PubMed1990

Carbon monoxide diffusing capacity, other indices of lung function, and respiratory symptoms in a general population sample.

To assess the relationships among single-breath diffusing capacity for CO (DLCOsb) (13), respiratory symptoms, and cigarette smoking in a general population sample, the data of 718 men and 894 women 20 yr of age or older were analyzed, and comparisons were performed with flow-volume curve (MEFV) variables and the slope of the alveolar plateau (DN2%/L) as well. Percent predicted DLCOsb and its correction for alveolar volume (DL/VA) were significantly lower in smokers than in nonsmokers. The relationship of presence/absence of respiratory symptoms and cigarette smoking with DLCOsb and DL/VA was significant. DLCO indices were almost always selected as discriminant variables in multivariate analysis between asymptomatic and symptomatic subjects. Poor concordance among lung function tests was evident: in men, 30% with abnormal (i.e., lower than 97.5% percentile) and 21% with normal DLCO indices also had abnormal MEFV parameters and/or DN2%/L. In women, the corresponding figures were 24 and 10%, respectively. In men, when considering only DLCO indices, the percentage of symptomatic subjects with abnormal lung function tests ranged from 33% in those with at least one symptom to 45% in those complaining of dyspnea. When the proportion of symptomatic subjects with DN2%/L and MEFV abnormalities were added, it increased to 56 and 66%, respectively. However, in women the proportion of symptomatic subjects with abnormal lung function indices was very small. These results indicate the usefulness of including CO diffusing capacity in epidemiologic surveys in the detection of abnormalities.

Adolescent↗

PubMed1990

Comparisons of spirometric reference values and the proportions of abnormal subjects among male smokers and those symptomatic in a community population.

A comparison was performed of various population reference equations for several spirometric measurements. The objective was to determine if the different equations yielded similar distributions of the percent predicted values, similar reference values for asymptomatic nonsmokers (i.e., normal subjects), criteria (or cutoff points) for who might be defined statistically as normal, and similar proportions of smokers and symptomatic subjects who would fall below the criteria values and thus be considered statistically abnormal. The cross-sectional study population of adults in Tucson, subjects of an ongoing study, was used. Most of the equations yielded reasonably similar distributions of percent predicted values. Older and/or more unusual equations did not yield similar results. Using the lower 95th percentile criteria yielded similar cutoff points as reference values for statistical normality, and similar proportions of statistically abnormal among various smoking and symptomatic groups; some of the equations used did not. When the criteria used were the lower 1.645 SEE, or the published criteria, the proportions considered statistically abnormal were very low or very high; again, some equations gave very disparate results. The first conclusion was that the use of the lower 95th percentile criteria was more sensitive and specific. It was concluded also that most equations yield sufficiently similar results such that the choice of reference equation from those available would depend on other criteria.

Adult↗

PubMed1990

Relationships between pulmonary function and changes in chronic respiratory symptoms. Comparison of Tucson and Cracow longitudinal studies.

Parallel analyses of data from two longitudinal studies, one in Poland and one in the United States, were performed to assess the relationships between pulmonary function and respiratory symptoms. Similar relationships were seen in the both cities using the same methods of analysis. The rate of FEV1 decline and its final level were related to the prior presence of attacks of breathlessness or to a syndrome that also included wheezing and diagnosed asthma. Initial FEV1 level was lower in subjects with dyspnea appearing during the follow-up than in the never-symptom group. These relationships were independent of smoking habits. The consistencies in the parallel analyses strengthen the relationships observed. In Tucson, Ariz, the FEV1 decline in smokers with persistent chronic cough was greater than that due to separate effects of the symptom and smoking. This suggests that chronic cough may be an indicator of an increased effect of tobacco smoke on pulmonary function.

Adult↗

PubMed1990

Epidemiology of chronic obstructive pulmonary disease.

Morbidity and mortality rates for chronic obstructive pulmonary disease (COPD) have been increasing over time. Epidemiologic investigators of COPD have been exploring the reasons for these increases through prevalence surveys and longitudinal studies. This article examines some of the recent findings.

Air Pollution↗