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Biomedical subjects

J M Samet

Publications and source records attributed to J M Samet.

At least 181 records · Page 10Linked to original sources
PubMed1991

Environmental factors and atmospheric pollutants.

Respiratory infections result from complex interactions between the infectious organism and the host, and exposure to environmental pollutants may alter host resistance. The atmospheric pollutants implicated in respiratory infections include acidic aerosols, particles, nitrogen dioxide, ozone, sulfur dioxide, and household allergens. An extensive epidemiological literature has been established linking environmental tobacco smoke to increased occurrence of lower respiratory tract infections in children; exposure to smoke from cooking and heating fires may also increase the risk of serious infections. Experimental evidence suggests that exposure to nitrogen dioxide and acidic aerosols may impair specific host defense mechanisms. Individuals with underlying lung or heart disease, as well as infants and the elderly, are among those most susceptible to the effects of environmental pollutants. Efforts should be directed toward reducing the exposure of children to environmental tobacco smoke and products of unvented combustion while investigations continue.

Air Pollutants↗
PubMed1991

A population-based study of functional status and social support networks of elderly patients newly diagnosed with cancer.

We assessed the functional status and social support networks of 799 men and women aged 65 years or older newly diagnosed with cancer and living in six New Mexico counties. Functional limitations included depending on others for transportation (33%) and mental incompetence or poor recent memory (42%). The percentage of patients with functional limitation increased sharply with increasing age. In a substantial number of patients there was also evidence for poor social support networks; 26.5% of subjects lived alone and 38.9% had no children living in the vicinity. In a multiple logistic regression analysis, the predictors of having a poor social support network included non-Hispanic white ethnicity, advanced age, low income, and being a recent migrant to the area. Subjects with functional limitations were more likely to have poor social support networks than subjects without such limitations. The deleterious combination of impaired functional status and a limited social support network may explain why elderly cancer patients are at increased risk for not receiving appropriate therapy. Given the potential complexities involving the evaluation and appropriate treatment of cancer, care must be taken to adequately assess functional status and support mechanisms of older patients, and to provide adequate support to ensure compliance with treatment.

Activities of Daily Living↗
PubMed1990

Determinants of cancer stage. A population-based study of elderly New Mexicans.

To assess the role of delay and other factors in determining stage of cancer at diagnosis, the authors interviewed a population-based sample of 800 elderly persons with newly diagnosed cancer at selected sites. Lengthening delay interval was associated with a declining proportion of local stage cases for breast cancer but not other sites. Of the other determinants of stage examined, older age, having a family physician, receiving medical checkups, having greater knowledge of cancer, and having no functional loss were most strongly predictive of local stage. For breast cancer, performance of breast self-examination also predicted local stage.

Activities of Daily Living↗
PubMed1990

Snoring in a Hispanic-American population. Risk factors and association with hypertension and other morbidity.

Snoring was investigated in a survey of respiratory disease in Hispanic-Americans of a New Mexico community. A population-based sample of 1222 adults was studied with questionnaires and measurements of height, weight, and blood pressure. The age-adjusted prevalence of regular loud snoring was 27.8% in men and 15.3% in women. Snoring prevalence increased with age and obesity in both men and women. Cigarette smoking was also associated with snoring, but chronic obstructive lung disease and alcohol consumption were not. Snorers more frequently had hypertension, ischemic heart disease, and excessive daytime sleepiness. In contrast to other studies, after adjustment for confounding factors, there was no effect of snoring on hypertension (odds ratio, 1.0; 95% confidence interval, 0.7 to 1.5), but an effect on myocardial infarction was still demonstrable (odds ratio, 1.8; 95% confidence interval, 0.9 to 3.6). The association of snoring with sleepiness suggests that respiratory disturbance of sleep related to upper airway obstruction, such as sleep apnea, occurs more frequently in snorers in this population.

Adult↗
PubMed1990

Injury mortality in American Indian, Hispanic, and non-Hispanic white children in New Mexico, 1958-1982.

Childhood fatalities from injuries are a serious public health problem in New Mexico, a state which ranks second in the nation in injury-related mortality rates. To determine the extent of injury mortality in children in this state, and to examine time trends and differences in mortality rates in New Mexico's American Indian, Hispanic, and non-Hispanic white children aged 0-14 years, we analyzed vital records collected from 1958 to 1982. American Indian children experienced the highest mortality rates from all external causes combined. Among all three major ethnic groups, children aged 0-4 years were at the highest risk for injury fatalities. Unintentional injuries accounted for 85% of all injury-related deaths. Motor vehicle crashes and drowning were the first and second leading causes of death in all three groups, while other important causes of death included fire, choking on food or other objects, poisoning, and homicide. Although the fatality rates on most types of injuries decreased over the 25-year period, childhood fatality rates for motor vehicle crashes and homicide increased in each ethnic group. Despite the overall decrease in injury mortality rates in New Mexican children, the rates are excessively high compared to other states, especially in American Indian children.

Adolescent↗
PubMed1990

Changes in surgical treatments: the example of hysterectomy versus conization for cervical carcinoma in situ.

From 1969 through 1985, 4584 women in the state of New Mexico were diagnosed with carcinoma in situ of the cervix. Of these women, 65.5% underwent hysterectomy while 31.1% had a conservative therapy (primarily conization). Over the 17-year period, there was a steady increase in the percentage of women receiving conservative therapies, from 11.8% in 1969 to 50.3% in 1985. Younger women, unmarried women and American Indian women were more likely to receive conservative therapy. This marked shift in therapeutic approach occurred during a time of apparent controversy as to the optimal treatment for cervical carcinoma in situ, and illustrates a rapid change in surgical practice in the absence of any controlled trials comparing the two major treatment modalities.

Adolescent↗
PubMed1990

Environmentally mediated disorders of the respiratory tract.

Although much of the evidence in environmental lung disease remains equivocal, some environmental exposures are known to be clinically relevant. Ambient air pollution remains of concern as a source of morbidity, particularly for susceptible populations such as persons with asthma, chronic obstructive pulmonary disease, or cardiac disease and the elderly. The adverse effects of several components of indoor air pollution have been established. Environmental tobacco smoke contributes to lower-respiratory illness in infants; office workers exposed to thermophilic actinomycetes contaminating ventilation systems have developed hypersensitivity pneumonitis; and in the home, components of house dust and fungus spores may provoke asthma via immediate hypersensitivity. The evidence is less compelling for a link between other exposures and disorders of the respiratory tract. For example, formaldehyde may be responsible for provoking vague respiratory symptoms and even nasal cancers; however, the associations are unproved. Likewise, the relation between low-level exposure to asbestos and the development of lung cancer, although a concern, is not conclusively established. The clinician should be aware of practical measures for patients who inquire about air cleaning. Often, relatively simple solutions are effective. A knowledge of sources and exposures as well as an understanding of the principles of inhalation lung injury should prove useful in directing patient care.

Air Pollutants↗
PubMed1990

Symptoms, signs, and ill-defined conditions: a leading cause of death among minorities.

The Manual of the International Classification of Diseases, Injuries, and Causes of Death includes the category, "symptoms, signs, and ill-defined conditions" for nonspecific causes of death. To determine whether this categorization of cause of death is commonly applied to New Mexico's minority populations, the authors examined state vital records data for 1958-1982. Age-specific and age-adjusted death rates were calculated by 5-year intervals for Hispanics, American Indians, and non-Hispanic whites. Death rates attributed to symptoms, signs, and ill-defined conditions in all three major ethnic groups in New Mexico far exceeded the national rate for whites. For males in the period 1978-1982, American Indians had the highest rates (115.6 per 100,000 males), followed by Hispanics (58.3 per 100,000 males), and non-Hispanic whites (49.2 per 100,000 males); the national rates were 41.3 and 13.1 per 100,000 males for blacks and whites, respectively. Comparable differences were observed among females. The authors suggest that the death rate for deaths attributed to symptoms, signs, and ill-defined conditions may be a potential indicator of access to and use of health services and that the categorization may strongly affect cause-specific death rates in minority populations.

Adult↗
PubMed1990

Comparison of self- and spouse reports of snoring and other symptoms associated with sleep apnea syndrome.

We compared self- and spouse reports of snoring and other symptoms of sleep apnea syndrome ascertained from married couples in a community-based survey. Agreement between the two types of report varied between 70-98%, but was modest (kappa = -0.01-0.52) when adjusted for chance. For men, spouse reports yielded higher prevalence rates for snoring and for four other symptoms. For women, estimates of symptom prevalence were consistently lower by spouse report than by self-report. In multivariate analyses, the effect on snoring of gender and obesity increased and of age decreased when spouse reports were compared to self-reports. Snoring, according to spouse reports, was a significant risk factor for ischemic heart disease, but snoring according to self-reports showed a smaller effect and was not statistically significant. Snoring was not associated with hypertension when defined by either self- or spouse report. These observations suggest that questionnaire data of snoring and other symptoms of sleep apnea syndrome may be misclassified in part, and that such misclassification can affect estimates of prevalence and effects.

Adult↗
PubMed1990

Comparability of information provided by elderly cancer patients and surrogates regarding health and functional status, social network, and life events.

Stressful life events may adversely affect health, but these effects may be mitigated by a strong social support network. The elderly should be a focus for investigation in this area, but epidemiologic studies in the elderly are often complicated by the need to rely upon information collected from surrogates. We assessed the degree to which 622 elderly cancer patients and surrogates agreed in their answers to questions about life events, social network, and health and functional status. We compared spouses, friends, and children as surrogates by evaluating (1) their agreement with index subjects and (2) the proportion of surrogates of each type who could not answer one or more questions. Agreement for most items on health and functional status was at least moderately good, but agreement was more inconsistent for questions about social network and major life events. Agreement was higher when factual information was solicited than when the question regarded more personal information or attitudes. For questions about health status, social network, and life events, spouses agreed more closely with index subjects than did children or friends. For questions about functional status, however, agreement did not vary consistently by respondent type. We found no consistent effects of the index subject's age or cognitive status on levels of agreement, nor did we find evidence of bias in the surrogates' responses.

Activities of Daily Living↗
PubMed1990

Design issues in epidemiologic studies of indoor exposure to Rn and risk of lung cancer.

Recent data on indoor air quality have indicated that Rn (222Rn) and its decay products are frequently present in domestic environments. Since studies of Rn-exposed miners have established that Rn decay products are a lung carcinogen, their presence in indoor air raises concerns about an increase in lung cancer risk for the general population. To directly evaluate lung cancer risk from domestic exposure to Rn and its decay products, as well as to evaluate risk assessments derived from studies of Rn-exposed underground miners, several epidemiologic studies of indoor Rn exposure have been initiated or are planned. This paper calculates sample sizes required for a hypothetical case-control study to address several important hypotheses and shows the impact of several difficult problems associated with estimating a subject's Rn exposure. We consider the effects of subject mobility, choice of the exposure response trend which is used to characterize an alternative hypothesis, and errors in the estimation of exposure. Imprecise estimation of Rn exposure arises from errors in the measurement device, exposure to Rn decay products from sources outside the home, inability to measure exposures over time in current as well as previous residences, and the unknown relationship between measured concentration and lung dose of alpha energy from the decay of Rn and its progeny. These methodological problems can result in large discrepancies between computed and actual study power. Failure to anticipate these problems in the design of a study can result in inaccurate estimates of power. We conclude that case-control studies of indoor Rn and lung cancer may require substantial numbers of subjects in order to address the many questions of importance that burden current risk assessments with uncertainty. We suggest pooling data from studies with the largest numbers of cases and with the most precise estimates of Rn exposure as the best approach for meeting present research needs.

Air Pollutants, Radioactive↗
PubMed1990

Environmental tobacco smoke: exposure-response relationships in epidemiologic studies.

Demonstration of a dose-response relationship for environmental tobacco smoke (ETS) is an important indication of causality. Central to the analysis and interpretation of dose-response relations as described in epidemiological studies is the relationship between dose and exposure. It must be recognized that in studies of ETS we have only surrogate measures of dose, and these surrogate measures (based on exposure) are imperfect. The question-based measures of ETS exposure generally have not been standardized, may have limited validity and reliability, and cannot comprehensively describe total ETS exposure, exposure to individual ETS components, nor doses of biologically relevant agents at target sites. Nevertheless, useful data have been yielded in epidemiologic studies linking ETS exposure to increased respiratory infection and symptoms, reduced lung growth in children, and increased lung cancer in nonsmoking adults. The more consistent exposure-response data for studies on acute health in children may reflect the greater difficulty in measuring exposure in studies of chronic health in adults.

Adult↗
PubMed1990

Review of radon and lung cancer risk.

Radon, a long-established cause of lung cancer in uranium and other underground miners, has recently emerged as a potentially important cause of lung cancer in the general population. The evidence for widespread exposure of the population to radon and the well-documented excess of lung cancer among underground miners exposed to radon decay products have raised concern that exposure to radon progeny might also be a cause of lung cancer in the general population. To date, epidemiological data on the lung cancer risk associated with environmental exposure to radon have been limited. Consequently, the lung cancer hazard posed by radon exposure in indoor air has been addressed primarily through risk estimation procedures. The quantitative risks of lung cancer have been estimated using exposure-response relations derived from the epidemiological investigations of uranium and other underground miners. We review five of the more informative studies of miners and recent risk projection models for excess lung cancer associated with radon. The principal models differ substantially in their underlying assumptions and consequently in the resulting risk projections. The resulting diversity illustrates the substantial uncertainty that remains concerning the most appropriate model of the temporal pattern of radon-related lung cancer. Animal experiments, further follow-up of the miner cohorts, and well-designed epidemiological studies of indoor exposure should reduce this uncertainty.

Air Pollutants, Radioactive↗
PubMed1990

Variability of measures of exposure to environmental tobacco smoke in the home.

We assessed the variability of four markers of environmental tobacco smoke exposure in 10 homes with 20 nonsmoking and 11 smoking household members. We obtained exposure questionnaires, saliva and urine for cotinine, and air particle samples for respirable particles and nicotine on 10 sampling days: every other day over 10 days, and then 1 day every other week over 10 wk. The mean concentrations of respirable particles in the 10 homes ranged from 32.4 to 76.9 micrograms/m3, and concentrations of nicotine ranged from 0.6 to 6.9 micrograms/m3. Linear regression models that included indicator variables for self-reported exposure explained 9 and 6% of the variability of the respirable particle and the nicotine concentrations, respectively. The individual mean urinary cotinine levels standardized to creatinine concentration ranged from 3.9 to 55.8 ng/mg Cr, and for salivary cotinine the mean levels ranged from 0.9 to 4.3 ng/ml. Indicator variables for self-reported exposure explained 8 and 23% of the variability of the urinary and salivary cotinine levels, respectively. We conclude that because of the marked variability of these measures, multiple measurements are needed to establish a stable profile of exposure to environmental tobacco smoke in the home.

Adolescent↗
PubMed1990

Mortality from infectious diseases among New Mexico's American Indians, Hispanic whites, and other whites, 1958-87.

To examine ethnic differences in infectious disease-related mortality in New Mexico's American Indian, Hispanic White and other White populations, we analyzed vital records data from 1958 to 1987. We found that for most infectious causes, American Indians had the highest mortality rates, followed by Hispanics. The state's minority populations remain at increased risk for infectious disease mortality.

Adolescent↗
PubMed1990

A personal monitoring study to assess workplace exposure to environmental tobacco smoke.

We enrolled 15 nonsmoking volunteers to evaluate the feasibility of measuring personal exposure to environmental tobacco smoke (ETS) at work and to characterize workplace exposures. During one workshift, we obtained questionnaires on exposure, saliva and urine for cotinine, and personal air samples for respirable particles and nicotine. The levels of cotinine, respirable particles, and nicotine varied widely with self-reports of exposure to ETS, but on average increased with increasing exposure.

Adult↗
PubMed1990

Violent death in the West: suicide and homicide in New Mexico, 1958-1987.

We examined New Mexico vital statistics data for suicides and homicides among the state's Hispanics, Native Americans, and non-Hispanic whites collected from 1958 to 1987. We found high age-adjusted rates for both suicides and homicides among Hispanic and Native American males, in comparison with rates for non-Hispanic white males. Suicide rates among Native American women were comparatively low, contrasting with their high homicide rates. Homicide rates for males in all three ethnic groups increased substantially over the 30-year study period. We conclude that death from violent causes, both suicide and homicide, is a major public health problem in New Mexico, and disproportionately affects minority males.

Adolescent↗