Search PubMed⌕ Search

Biomedical subjects

J M Samet

Publications and source records attributed to J M Samet.

At least 199 records · Page 11Linked to original sources
PubMed1990

The risk of nitrogen dioxide: what have we learned from epidemiological and clinical studies?

Nitrogen dioxide (NO2) is an oxidant gas which contaminates ambient air in many urban and industrial locations, and indoor air in homes with combustion appliances. The Environmental Protection Agency presently regulates NO2 in ambient air as a "criteria" pollutant. In spite of decades of laboratory, clinical, and epidemiological research, the health effects of NO2 exposure on humans are not well understood. The toxicological evidence suggests that increased susceptibility to infection, functional deficits from effects on airways, and deterioration of the status of persons with chronic respiratory conditions, including asthmatics, are of potential concern. This paper provides a perspective on the present evidence related to human health effects of NO2. It addresses methodological barriers that limit the available data; assesses the adequacy of the data for risk assessment; and proposes a research agenda to obtain needed information on the health effects of NO2.

Air Pollutants↗
PubMed1989

Radon and lung cancer.

Radon, an inert gas released during the decay of uranium-238, is ubiquitous in indoor and outdoor air and contaminates many underground mines. Extensive epidemiologic evidence from studies of underground miners and complementary animal data have documented that radon causes lung cancer in smokers and nonsmokers. Radon must also be considered a potentially important cause of lung cancer for the general population, which is exposed through contamination of indoor air by radon from soil, water, and building materials. This review describes radon's sources, levels in U.S. homes, dosimetry, the epidemiologic evidence from studies of miners and the general population, and the principal, recent risk assessments.

Humans↗
PubMed1989

Stomach cancer among New Mexico's American Indians, Hispanic whites, and non-Hispanic whites.

Stomach cancer incidence rates vary by ethnic group in New Mexico, with American Indians and Hispanic Whites at higher risk than the state's non-Hispanic White population. To further characterize the descriptive epidemiology of this disease in New Mexico, we investigated temporal trends in stomach cancer mortality and incidence rates. Stomach cancer mortality rates declined over a 25-year period (1958-1982) among New Mexico's Hispanic and non-Hispanic Whites. Birth cohort analysis suggests that much of the decline was achieved prior to 1968. Stomach cancer mortality rates did not drop among American Indians during the same period. Stomach cancer incidence rates remained constant for Hispanic Whites, non-Hispanic Whites, and American Indian males over a 13-year period (1969-1982), but more than doubled among American Indian females. Although environmental factors have been implicated in the etiology of stomach cancer, little is currently known about the distribution of such risk factors among the ethnic groups described in this report. The environmental and biological correlates of sex, ethnicity, and socioeconomic status that determine stomach cancer risk merit further investigation in New Mexico.

Adult↗
PubMed1989

High-performance liquid chromatography separation of phospholipid classes and arachidonic acid on cyanopropyl columns.

An HPLC method for the separation and analysis of arachidonic acid and eight phospholipid classes is described: phosphatidylglycerol, phosphatidylinositol, cardiolipin, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin, and 2-lysophosphatidylcholine. The separation is carried out at 60 degrees C on 2 cyanopropyl columns using a gradient of acetonitrile and 5 mM sodium acetate (pH 5.0). Cyanopropyl columns require a lower proportion of water in the mobile phase to elute the more polar phospholipids than other types of columns and are thus less prone to equilibration problems. The method is highly reproducible (average coefficient of variation for each retention time less than or equal to 3.5%) and permits analysis of peaks by phosphorus content. Data obtained by analyzing lipid extracts from rat alveolar macrophages prelabeled with [G-3H]-arachidonic acid were analyzed by this HPLC method and compared to standard analysis by TLC. There was a significant correlation between the radioactivity profiles obtained with the two chromatographic methods (HPLC versus TLC) by linear regression analysis [HPLC = 0.83 (TLC) + 3.58, n = 25, r = 0.95, P less than 0.001].

Animals↗
PubMed1989

Surrogate measures of dietary intake.

In studying health and disease in elderly subjects, information may be needed concerning current or past dietary intake. Regardless of whether emphasis is placed on current or past intake, the validity of self-reported dietary information probably diminishes with increasing respondent age. In studying diet in elderly subjects, obtaining information from surrogate sources may improve data quality and provide information otherwise unavailable for decreased or incompetent subjects. This review addresses availability of data from surrogates, validity of surrogate responses, and methodological issues in analysis of surrogate data. This literature review documents that surrogate respondents can provide dietary information, but the data on elderly persons are extremely limited. The literature also indicates that surrogate dietary data may introduce misclassification in analytical investigations, but that surrogate data may be useful in descriptive studies. Methodological studies on surrogate reporting should facilitate research on diet and disease in elderly subjects.

Aged↗
PubMed1989

Questionnaire assessment of lifetime and recent exposure to environmental tobacco smoke.

In a sample of 149 adult nonsmokers recruited in New Mexico in 1986, the authors assessed the reliability of questionnaire responses on lifetime exposure to tobacco smoke in the home. They also compared urinary cotinine levels with questionnaire reports of environmental tobacco smoke exposure during the previous 24 hours. The agreement of responses obtained on two occasions within six months was high for parental smoking during childhood: 94% for the mother and 93% for the father. For the amounts smoked by the mother and the father during the subject's childhood, the agreement between the two interviews was moderate: 52% and 39%, respectively. For the number of hours per day that each parent smoked in the home during the subject's childhood, the Spearman correlation coefficients also indicated only moderate reliability (r = 0.18 for maternal smoking and r = 0.54 for paternal smoking). For each set of interviews, responses concerning recent tobacco smoke exposure and urinary cotinine levels were correlated to only a modest degree. The authors conclude that adults can reliably report whether household members smoked during their childhood, but information on quantitative aspects of smoking is reported less reliably.

Adult↗
PubMed1989

Health implications of radionuclide levels in cattle raised near U mining and milling facilities in Ambrosia Lake, New Mexico.

This study was conducted to determine radionuclide tissue levels in cattle raised near U mining and milling facilities. Ambrosia Lake, New Mexico, has been the site of extensive U mining for 30 y and contains several underground U mines, a processing mill, and two large U tailings piles. Ten cows were purchased from two grazing areas in Ambrosia Lake and ten control animals were purchased from Crownpoint, New Mexico. Muscle, liver, kidney, and bone tissue taken from these animals, and environmental samples, including water, grasses and soil collected from the animals' grazing areas, were analyzed for 238U, 234U, 230Th, 226Ra, 210Pb, and 210Po. Mean radionuclide levels in cattle tissue and environmental samples from Ambrosia Lake were higher in almost every comparison than those found in respective controls. Liver and kidney tissues were particularly elevated in 226Ra and 210Po. Radiation dose commitments from eating cattle tissue with these radionuclide concentrations were calculated. We concluded that the health risk to the public from eating exposed cattle is minimal, unless large amounts of this tissue, especially liver and kidney, are ingested.

Animals↗
PubMed1989

Radon progeny exposure and lung cancer risk in New Mexico U miners: a case-control study.

A case-control study was conducted to describe lung cancer risk in a cohort of New Mexico underground U miners. The subjects included 65 cases and 230 age-matched controls, most with exposures below 3.50 J h m-3 (1000 WLM). The risk for lung cancer was increased for all cumulative exposures to Rn progeny of 0.35 J h m-3 (100 WLM) or greater. The odds ratios were unchanged with control for cigarette smoking. With exclusion of subjects with exposures above 3.50 J h m-3 (1000 WLM), the estimated excess relative risk was 0.3% per mJ h m-3 (1.1% per WLM). The risk was greater for younger subjects and the data were consistent with a multiplicative interaction between cigarette smoking and exposure to Rn progeny.

Adult↗
PubMed1989

Survival after cancer surgery of elderly patients in New Mexico, 1969-1982.

To examine the effects of advancing age, sex, and ethnicity on estimated 30-day survival after surgery for cancer, we reviewed population-based data on 16,130 cancer cases collected by the New Mexico Tumor Registry from 1969-1982. For surgery at most sites, mortality increased with increasing age. The highest mortality was observed for sites requiring laparotomy or thoracotomy. Sex and ethnicity (Hispanic versus non-Hispanic white) had little effect on short-term survival. Comparison of short-term survival for two time periods, 1969-1975 and 1976-1982, showed a strong trend of improving survival for many sites.

Age Factors↗
PubMed1989

Nitrogen dioxide and respiratory infection: pilot investigations.

Laboratory and human studies have raised concern that exposure to nitrogen dioxide may increase the frequency and severity of respiratory infections in children and adults. Cooking with a natural-gas-fueled stove exposes a home's residents to short-term peaks of nitrogen oxides and to higher average levels of nitrogen oxides than are measured in homes with electric stoves. We have designed a longitudinal study of infants to determine if nitrogen dioxide exposure from cooking stoves increases the incidence or severity of respiratory infections during the first 18 months of life. Pilot investigations for the longitudinal study were conducted from 1984 through 1986. This report provides the results of the pilot investigations. The first study, conducted in 1984 and 1985, was designed to document (1) that appropriate subjects could be recruited; (2) that nitrogen dioxide concentrations in Albuquerque homes were in the range of interest; (3) that an infant's personal exposure to nitrogen dioxide could be estimated; and (4) that a valid, feasible approach for surveillance could be implemented. To accomplish these goals, the families of infants were recruited at two Albuquerque hospitals, and their homes were monitored for nitrogen dioxide using a passive sampling tube. With this approach, we successfully recruited 147 households; monitoring for nitrogen dioxide showed substantially higher levels in homes with gas stoves than in homes with electric stoves, as previously found in other U.S. cities. More detailed investigations in a sample of the homes showed that personal exposures of the infants, who did not attend day care, could be satisfactorily estimated by room concentrations. We also demonstrated that mothers would complete a daily calendar-diary on respiratory symptoms and provide information every two weeks on illnesses occurring since the previous surveillance call. The second pilot study, conducted in 1986, was designed to refine the system for illness surveillance. Additional goals were to test further the methods for exposure assessment and to evaluate recruitment of subjects through pediatric practices. We recruited 75 infants and followed them over a four-month period. Information from the surveillance system was compared with the clinical assessments of the project's nurse practitioner and the subjects' physicians, and with the results of viral cultures. We also evaluated biweekly versus weekly surveillance calls. Overall, the results of the second pilot study documented that a surveillance system for respiratory illness that incorporates calendar-diaries and biweekly telephone calls is a feasible, relatively unbiased, and sensitive method for studying respiratory illness in a large population of infants. We also found that subjects could be successfully recruited through a pediatric practice.(ABSTRACT TRUNCATED AT 400 WORDS)

Cohort Studies↗
PubMed1989

Ethnic differences in mortality from acute rheumatic fever and chronic rheumatic heart disease in New Mexico, 1958-1982.

To examine time trends and differences in mortality rates from acute rheumatic fever and chronic rheumatic heart disease in New Mexico's Hispanic, American Indian, and non-Hispanic white populations, we analyzed vital records data for 1958 through 1982. Age-adjusted mortality rates for acute rheumatic fever were low and showed no consistent temporal trends among the three ethnic groups over the study period. Age-adjusted and age-specific mortality rates for chronic rheumatic heart disease in Hispanic and non-Hispanic whites decreased over the 25-year period, although rates were higher among Hispanics than among non-Hispanics during most of the time period. In American Indians, age-adjusted mortality rates for chronic rheumatic heart disease increased between 1968 and 1977 to twice the non-Indian mortality rates during the same period. Despite this increase in mortality from chronic rheumatic heart disease among New Mexico's American Indians from 1968 to 1977, the New Mexico data generally reflect national trends of decreasing mortality from chronic rheumatic heart disease.

Acute Disease↗
PubMed1989

Injury mortality in New Mexico's American Indians, Hispanics, and non-Hispanic whites, 1958 to 1982.

New Mexico has extraordinarily high injury mortality rates. To better characterize the injury problem in New Mexico, we calculated proportionate injury mortality and age-adjusted and age-specific injury mortality rates for the state's 3 major ethnic groups--American Indians, Hispanics, and non-Hispanic whites. According to death certificate data collected from 1958 to 1982 and US population census figures, age-adjusted mortality rates for total external causes varied widely between the sexes and among the ethnic groups. Males in each ethnic group consistently had higher average annual age-adjusted external mortality rates than females. Injury mortality rates for American Indians of both sexes were 2 to 3 times higher than those for the other New Mexico ethnic groups. Motor vehicle crashes were the leading cause of death from injury for all 3 groups. Homicide accounted for twice the proportion of injury death in Hispanic compared with non-Hispanic white males (12.5% and 6.1%, respectively), while the proportion of males dying of suicide was highest in non-Hispanic whites. Deaths from excessive cold and exposure were leading causes of injury mortality for American Indians, but these causes were not among the leading causes of injury mortality for Hispanics or non-Hispanic whites. We conclude that the minority populations in New Mexico are at high risk for injury-related death and that the major causes of injury mortality vary substantially in the state's predominant ethnic populations.

Adolescent↗
PubMed1988

Changing treatment of breast cancer in New Mexico from 1969 through 1985.

A review of information from the New Mexico Tumor Registry on women diagnosed as having primary breast cancer from 1969 through 1985 revealed temporal changes in the surgical treatment of this disease. After 1980 the percentage of women receiving breast-conserving surgery for local-stage disease increased from 6% to 25%. Most surgeons performing operations for breast cancer had not performed a breast-conserving operation before 1981 but had used this procedure at least once in the period from 1981 through 1985. Women younger than 50 years or older than 80 years were most likely to undergo this procedure. In that period, radiotherapy after breast-conserving surgery could not be documented for 26% of the women 65 years old or younger or for 56% of the women aged 65 years or older. Thus, there has been a marked shift in New Mexico in the surgical approach to local-stage breast cancer in the 1980s. This shift involved most surgeons treating the disease and included women of all age groups. The apparent lack of adjuvant radiotherapy in some women receiving conservative surgeries may prove to be a deleterious consequence of this change in surgical management.

Age Factors↗
PubMed1988

Delay in seeking care for cancer symptoms: a population-based study of elderly New Mexicans.

To characterize the delay by the elderly in seeking care for cancer symptoms, we interviewed 800 New Mexicans, greater than or equal to 65 years of age, with newly diagnosed cancer. Overall, 29.4% of the subjects were asymptomatic when cancer was detected, and 48.0% presented within 2 months of symptom onset. However, 19.2% of the subjects delayed seeking care for at least 12 weeks and 7.4% delayed at least 1 year. Site of cancer was the strongest determinant of delay. Hispanics tended to report longer delay than non-Hispanics, and age was not associated with delay. Of the numerous other factors considered, only having a regular checkup was significantly associated with delay interval.

Aged↗
PubMed1988

Diabetes, gallbladder disease, obesity, and hypertension among Hispanics in New Mexico.

Because Hispanics in the Southwest are genetically admixed with American Indians, the hypothesis has been advanced that the excess occurrence of diabetes mellitus, obesity, and gallbladder disease in this ethnic group may be genetic in origin and results from genes derived from American Indians. This report describes the prevalence of these diseases in 1,175 adult Hispanic participants in a survey of a New Mexico community conducted in 1984-1985. At nearly all ages, the majority of subjects had a body mass index of 25 kg/m2 or greater, and a substantial proportion exceeded 30 kg/m2. The prevalence of obesity was much greater in these Hispanics than is shown in nationwide data for US whites. Diabetes mellitus was also reported more often by Hispanic subjects in this survey than by US whites nationwide. A report of gallbladder trouble or of gallbladder removal was common in both males and females; the prevalence of gallbladder removal was as high in this population as in Mexican Americans previously studied in Starr County, Texas. In spite of the high prevalence of obesity, hypertension was less frequent among the New Mexico Hispanics than is shown in nationwide data for US whites. These findings complement those of previous surveys in Texas, which have shown a notably high proportion of adults to be obese, to have non-insulin-dependent diabetes mellitus, and to have gallbladder disease. The similar epidemiology of these diseases in the Hispanics of New Mexico and the Mexican Americans of Texas supports the hypothesis that American Indian admixture underlies the development of these conditions in Hispanics throughout the Southwest.

Adolescent↗