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Biomedical subjects

M D Lebowitz

Publications and source records attributed to M D Lebowitz.

At least 109 records · Page 6Linked to original sources
PubMed1987

Respiratory effects of non-tobacco cigarettes.

Data from the Tucson epidemiological study of airways obstructive disease on smoking of non-tobacco cigarettes such as marijuana were analysed to determine the effect of such smoking on respiratory symptoms and pulmonary function. Among adults aged under 40, 14% had smoked non-tobacco cigarettes at some time and 9% were current users. The prevalence of respiratory symptoms was increased in smokers of non-tobacco cigarettes. After tobacco smoking had been controlled for men who smoked non-tobacco cigarettes showed significant decreases in expiratory flow rates at low lung volumes and in the ratio of the forced expiratory volume in one second to the vital capacity. This effect on pulmonary function in male non-tobacco cigarette smokers was greater than the effect of tobacco cigarette smoking. These data suggest that non-tobacco cigarette smoking may be an important risk factor in young adults with respiratory symptoms or evidence of airways obstruction.

Adolescent↗
PubMed1987

The epidemiological importance of intraindividual changes in objective pulmonary responses.

Debate continues about what constitutes significant and meaningful change in health status of individuals and populations. More importantly, the basic biological and medical criteria that are used for clinical and environmental judgments require further discussion and clarification. What proportion of loss of cardio-pulmonary function, overt disability, or mortality is sufficient to determine an "adverse health effect"? Health-oriented individuals, including researchers and clinicians, may choose to adhere to different criteria than other professional groups (e.g., legal, social). It is proposed in this paper that criteria for defining adverse health effects should represent clinically meaningful, as distinct from only statistically significant, responses. These include pulmonary function test results that indicate obstructive or restrictive diseases, and electrocardiogram results indicating coronary artery disease. Intraindividual changes that predict a meaningful medical change would be included; these changes should meet specific requirements in terms of what constitute normal vs. abnormal ranges of variation. Further, the proportion of the population defined to be impaired should be considered. These issues are the focus of this paper.

Adult↗
PubMed1987

Physiological changes in pulmonary development related to passive smoking and its interaction with active smoking.

The growth of pulmonary function between ages 5.5 and 25 years was determined in 1502 observations on 362 subjects from a representative population study of non-Mexican American whites in Tucson. There was an average of 8.8 years of follow-up, with a maximum of 12. The model developed was robust for follow-up of 3-7 observations (3 + years). Respiratory illnesses and smoking had the biggest negative impact on growth of forced expiratory volume in 1 s (FEV1), Vmax 50%/forced vital capacity (FVC) parental smoking and airway obstructive disease (AOD) were important also. Flow measures showed present and more persistent effects of disease and smoking than did FEV1.

Adolescent↗
PubMed1987

Time series analyses of respiratory responses to indoor and outdoor environmental phenomena.

A time series analysis was utilized to evaluate respiratory responses to outdoor and indoor air pollutant and aeroallergen exposures in potentially sensitive adults in a dry arid environment. Daily symptoms and peak flows were recorded in populations of asthmatics, allergic individuals, those with chronic lung disease symptoms, and asymptomatic individuals (total sample size of 204) over a period of a few years. Meteorology and ambient pollutant concentrations were measured in the basin. Indoor pollutant measurements were made for particulates and CO, indicating that gas stoves and tobacco smoking were the predominant indoor sources. Time series analysis helped determine appropriate lags between environmental stimuli and health responses. Asthmatics showed that most respiratory responses while asymptomatics showed no significant responses. Outdoor ozone, nitrogen dioxide, aeroallergens and meteorology, and indoor gas stoves were significantly related, independently and interactively, with symptoms and peak flow.

Air Pollutants↗
PubMed1987

Longitudinal changes in allergen skin test reactivity in a community population sample.

A cohort of 1333 subjects, aged 3 years and older, was followed for a mean of 8.1 years to assess changes in allergen skin test reactivity. The overall prevalence of reactivity to the five antigen mixtures was 39.1% during the initial survey and 50.7% after the follow-up period. The greatest increase in prevalence occurred among children and teenagers (22.2% and 19.5%) with only minimal increases after the age of 65 years (6.0%). No difference in prevalence between male and female subjects was apparent, either initially or at the end of the follow-up period. In-migration to the Tucson area was a major factor in determining changes in reaction prevalence. Among subjects more than 35 years of age, recent in-migrants accounted for most of the increased prevalence. Comparisons of atopy among consistent smoking groups confirmed the previous observation that smokers are less atopic than either nonsmokers or exsmokers, probably because of a self-selection process. In contrast, exsmokers were generally the most atopic, both initially and at the end of the longitudinal observation period. The high overall prevalence of allergen reactivity in this population is believed to be due in large measure to high year-round concentrations of multiple aeroallergens in the Tucson environment.

Adult↗
PubMed1987

Multivariate analysis of ambient environmental factors and respiratory effects.

Relationships between respiratory health and environmental conditions (pollen, pollution and meteorology) are investigated in 204 subjects in four symptom groups in four geographical clusters in Tucson. Techniques used are principal components, factor and path analysis. Daily respiratory symptoms and peak expiratory flows were recorded during a three-year period. Ambient pollutants, meteorological conditions and pollen types were monitored in or near the clusters. Factor-based scales, which are climate and season specific, are developed for the environmental variables. Three pollutant/meteorological scales represent 'Summer', 'Winter', and 'Humidity'. Four pollen scales represent early and late spring, summer and fall pollen types. Relationships between environmental variables, respiratory symptoms and peak expiratory flow are analyzed with path diagrams, after accounting for age, sex, smoking habits and stove type. The different effects of the environment on asthmatics, allergics and airways obstructive disease subjects have been demonstrated. Many relationships were found between environmental factors and respiratory responses. The pollutant and meteorological variables are related to respiratory symptoms and peak flow directly as well as through interactions with pollen types. Some of the largest positive coefficients are seen in association with seasonal pollen types, specifically, rhinitis and dyspnoea.

Adult↗
PubMed1987

Longitudinal study of pulmonary function development in childhood, adolescence, and early adulthood. Development of pulmonary function.

The growth of pulmonary function between 5.5 and 25 yr of age was determined using 1,511 observations over time on 353 subjects from a representative population sample of white non-Mexican-Americans in Tucson. There was an average of 8.8 yr of follow-up, with a maximum of 12. The method used was shown to be robust for span of follow-up from 3 to 12 yr (3 to 7 observations), and the results were verified by standard statistical methods. The standard error of the estimate decreased linearly with follow-up, indicating the need for longitudinal evaluation. Respiratory symptoms and diagnoses had the biggest negative impact on growth of lung function, using FVC, FEV1, Vmax50, and size-compensated flows (Vmax50/FVC). Smoking had the next biggest negative impact. Smoking cessation was shown to have a positive impact on growth of pulmonary function. Using a second linear model to adjust for individual variability and the random variability over surveys, individual growth showed similar trends. Further negative impacts were due to parental smoking, especially as it interacts with active smoking and respiratory disease. Flows at end of follow-up (Vmax50, Vmax50/FVC) were more sensitive than FEV1 to the effects of concurrent disease and smoking, and more persistent effects of these factors in early adulthood.

Adolescent↗
PubMed1987

The "horse-racing effect" and predicting decline in forced expiratory volume in one second from screening spirometry.

Longitudinal spirometric data on adults in a general population sample confirmed an overall relationship between rate of change in FEV1 (delta FEV1) and mean FEV1/Ht3. This relationship between FEV1 "slope" and "level" has been called a "horse-racing effect" and is the basis for the widely accepted concept that detecting a low FEV1 will predict a rapid decline in FEV1 and the development of clinically significant COPD. However, when both age and smoking habits were taken into account, the effect persisted only in male smokers. Even in them, it was dependent on the inclusion of part of the delta FEV1 in calculation of the mean FEV1 value. While neither a low initial FEV1/Ht3 nor percent predicted FEV1 significantly predicted a subsequent rapid fall in FEV1, presumably because of regression toward the mean, other initial spirometric variables proved better predictors, at least among male smokers. In them, a low FEV1/FVC ratio on entry was almost uniformly associated with a high rate of decline in FEV1. This was not seen in ex-smokers with similar initial spirometric findings. Also, delta FEV1 could not be predicted with any precision in women regardless of their smoking status. The findings strongly support the concept that detection of early airway disease by spirometric screening will identify those male smokers who are likely to develop clinically significant illness if they continue to smoke and that smoking cessation, even at this point, can markedly improve the prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Longitudinal changes in forced expiratory volume in one second in adults. Effects of smoking and smoking cessation.

Longitudinal changes in FEV1 (delta FEV1) in relationship to smoking habits were examined in 1,705 adults enrolled in a prospective study of a general population sample. In both men and women, there were excessive rates of decline in FEV1 in smokers, at least in those smoking more than 10 cigarettes per day. The excess decline of smokers was age dependent, particularly in men, with much of the excess loss of function occurring between 50 and 70 yr of age. Effects of smoking on delta FEV1, observed minus expected delta FEV1 and observed minus expected percent delta FEV1, were greater in men than in women even when controlled for current cigarette dose. Ex-smokers show delta FEV1 values similar to those of nonsmokers. In subjects younger than 35 yr of age, quitting smoking during follow-up was associated with an actual increase in FEV1. In men 50 to 70 yr of age, smoking cessation early in the study appeared to lead to a relatively prompt return to normal rates of functional decline. Thus, the findings suggest relatively prompt beneficial effect of smoking cessation even in late middle age.

Age Factors↗
PubMed1986

An eight-year study of the viral agents of acute gastroenteritis in humans: ultrastructural observations and seasonal distribution with a major emphasis on coronavirus-like particles.

During an 8-yr period, 862 stool specimens from patients with gastroenteritis were examined by electron microscopy after negative staining with 2% phosphotungstic acid (pH 6.5). Forty-one percent of the specimens submitted over an 8-yr period were determined to be positive for virus or viruslike particles belonging to one or more of seven morphologically distinct viral groups. Coronavirus-like particles (CVLPs) were present in 69.8% of the positive stool specimens. Membranous profiles containing "complement-type" holes (10 nm in diameter) were identified in some preparations containing CVLPs. The second most prevalent viral agent found in stool specimens was the rotavirus (17% of all positive stools). The incidence of other viruses identified in the survey were as follows: adenovirus 4.5%, picorna/parvovirus agents 2.9%, Norwalk-like agent 2.9%, astrovirus 1.9%, and calicivirus 0.5%. Unclassified small round viruses (approximately 25-30 nm in diameter) represented 0.5%. It was also determined that there was a seasonal distribution in excretion of all viruses except for CVLPs. A greater number of viruses were identified in the cooler, drier months of the year.

Adenoviruses, Human↗
PubMed1986

Longitudinal changes in forced expiratory volume in one second in adults. Methodologic considerations and findings in healthy nonsmokers.

Longitudinal changes in FEV1 (delta FEV1) have been examined in a sample of the general population of Tucson, Arizona. Adults with satisfactory spirometric tests in all 7 surveys performed over a period of 11 yr showed some between-survey differences in mean FEV1. Although small in absolute magnitude, such survey biases (which would be impossible to detect unless multiple spirometric tests were carried out on a relatively large group of subjects) could have a marked effect on calculated changes in FEV1 and may explain the widely divergent delta FEV1 values reported in the literature. After adjusting for survey biases, the relationships of delta FEV1 to age, sex, and body size were examined in "healthy" nonsmokers in the population who were followed for an average of 9.6 yr. The FEV1 showed an accelerating decline with age, and delta FEV1 was best explained by a model of proportional change in which it is a function of Age X Height3. Longitudinally determined delta FEV1 showed much less decline in function and a later apparent age of onset of decline than suggested by cross-sectional analyses. While small "learning effects" in longitudinal calculations cannot be excluded, most of the cross-sectional versus longitudinal differences are probably ascribable to past events that have adversely affected the FEV1 in older adults, thereby increasing cross-sectional age effects. Present findings also suggest that generally applicable "prediction equations" for delta FEV1 probably cannot be developed and that delta FEV1 values should only be compared between groups studied in an identical manner within a given study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Vectorcardiographic and blood pressure correlates of obstructive pulmonary diseases in a community population.

Vectorcardiography was performed on 2,449 subjects, aged six years and older, in the Tucson (Ariz) Epidemiological Study of Airway Obstructive Diseases (AOD), 95 percent of the white non-Mexican Americans in the stratified cluster population sample. The objectives were to confirm previous relationships and to determine if hypothesized changes in the vectorcardiogram (VCG) could predict AOD. Trained nurse technicians performed the VCGs, which were read and interpreted by a cardiologist. Vectorcardiographic results were broadly interpreted for abnormalities. Also, calculated vector means and angles were compared to standard questionnaire responses for medical history, to maximum expiratory flow-volume variables, and to values for blood pressure; these were all corrected for sex, age, height, weight, and the ponderal index. Values were expressed as percentages of predicted. Over 80 percent of the VCGs were found to be normal. Measured hypertrophy was related to disease; there were significantly more abnormalities in those with histories of heart disease, hypertension, arteriosclerosis, and AOD, when examined by types of ventricular hypertrophy and VCG-identified heart disease or hypertension; findings of AOD and heart disease were also correlated significantly. Of all the ventricular hypertrophy, right ventricular hypertrophy (RVH), type C, was confirmed to be the predominant type associated with decreased pulmonary function in all smoking groups. Systolic blood pressure was related to RVH, type A, and diastolic 4 and 5 blood pressure with RVH, types A and B. The vectors' magnitude and angles were related to abnormality of pulmonary function in those with and without heart disease and AOD.

Adolescent↗
PubMed1985

Methodological considerations of epidemiological diagnoses in respiratory diseases.

Since epidemiological research depends extensively on questionnaire responses, a comparison of such responses with a standardized medical evaluation was conducted. It was found that standardized questionnaires do well in comparison for certain kinds of information on chronic conditions. However, clinical evaluations will elicit more information, specifically of a milder nature. It was concluded that standardized epidemiological questionnaires are satisfactory for survey of chronic conditions.

Adolescent↗
PubMed1985

Respiratory effects in relation to estimated tar exposure from current and cumulative cigarette consumption.

Relationships between estimated "tar" exposure from current and past cigarette consumption, were related to respiratory symptoms and function during the seventh survey (1981-1983) of the Tucson epidemiologic study of airways obstructive diseases. Smokers (n = 582; 280 males and 302 females) and exsmokers (n = 621; 345 males and 276 females), answered detailed questions on current and past smoking, and performed flow-volume maneuvers. Cough and phlegm were significantly associated with estimated "tar" exposure from current cigarette consumption. Cough, phlegm, and dyspnea were associated with reported deep inhalation in both sexes, while wheeze was so associated in females. In young smokers (less than 35 years), symptoms were more prevalent in those who had predominantly smoked cigarettes with estimated high "tar." Total exposure was more important in older smokers. Generally, exsmokers showed a lower prevalence of symptoms than smokers. Cross-sectional lung function measurements were significantly related to total estimated "tar" exposure and age. Multiple logistic regressions provided models which helped predict symptoms and lung function impairment in smokers and exsmokers on the basis of estimated "tar" exposure and pack-years of smoking.

Adolescent↗
PubMed1985

Estimates of C. immitis infection by skin test reactivity in an endemic community.

This report is a comparison of two delayed hypersensitivity skin test reagents, coccidioidin and Spherulin, available for detection of prior infection by Coccidioides immitis. Coccidioidin proved to be a somewhat more sensitive reagent (33.4 per cent positive, vs 29.6 per cent for Spherulin). This difference persisted in the subjects when grouped by age, sex, exposure history, or history of coccidioidomycosis. Skin test reactivity to both reagents declined with age. Independent of exposure history coccidioidin detected 7.3 per cent of the subjects who were not detected by Spherulin; Spherulin detected prior infection in only 3.5 per cent of the subjects not detected by coccidioidin. These results differ from those of previously reported studies.

Adolescent↗
PubMed1984

Analysis of relationships between symptoms and environmental factors over time.

Weekly respiratory symptom information was obtained on a random population of 3800 whites in Tucson. We asked weekly about 14 symptoms representing acute respiratory illnesses (ARI), rhinitis (Rh), and other conditions. The denominator for each week was about 80 randomly chosen subjects from the study population. Interactions of the air pollutants total suspended particulate, oxidants, carbon monoxide, nitrogen oxides for the basin, meteorological information, and aero-allergens were examined. The temporal and spatial interactions between the weekly symptoms and the environmental factors were tested utilizing multivariate methods such as Fourier analyses, multiple regression, and the stimulus-response method, adjusting for lags and controlling for season. Multiple regressions with a smoothing function (using fourier or other methods) yield significant correlations between symptoms and the environmental factors, and separate the ARI's from the Rh's and the miscellaneous symptoms.

Air Pollution↗