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Biomedical subjects

S Preston-Martin

Publications and source records attributed to S Preston-Martin.

At least 91 records · Page 5Linked to original sources
PubMed1993

Primary tumors of the brain, cranial nerves and cranial meninges in Victoria, Australia, 1982-1990: patterns of incidence and survival.

This report presents for the first time a detailed analysis of the distribution of primary brain tumors in a population in Australia. Data on 3,575 cases of benign and malignant tumors of the brain, cranial nerves and cranial meninges diagnosed among residents of the state of Victoria from 1982 to 1990 are used to calculate incidence rates and survival by histologic type, age and sex and to compare incidence of birthplace, socioeconomic status and year of diagnosis. No sharp decline in incidence rates is seen among those over age 60 and only small increases in incidence over the 9-year period have been observed. The overall incidence rates, distributions by histologic type, and patterns of excess incidence among those born in Southern and Eastern Europe and the Middle East are similar to observations in other geographic areas. No clear trend relating incidence and socioeconomic status is observed. Survival after brain tumor diagnosis is better among women then men (52 vs. 37% survive 5 years); this difference is attributable to the greater frequency among men of the more aggressive tumor types. The most striking male over female excess is for medulloblastoma, a type that occurs predominantly in the pediatric age group. This excess coupled with the fact that this tumor occurs at a much younger age in males may suggest the presence of a genetic predisposition in some patients with this disease.

Adolescent↗
PubMed1992

Oral and pharyngeal cancer and occupation: a case-control study.

We studied the relation between occupation and oral and pharyngeal cancer with a population-based case-control study conducted in four areas of the United States. The study group included 1,114 incident male and female cases and 1,268 frequency-matched controls. After adjustment for age, race, smoking, alcohol, and study location, an analysis of lifetime occupational histories revealed a small number of noteworthy associations. Risk was increased among male carpet installers (23 cases, 4 controls), with an adjusted odds ratio of 7.7 [95% confidence interval (CI) = 2.4-24.9], and tended to rise with longer duration of employment. A decreased risk was found among male and female textile mill workers (odds ratio 0.48, 95% CI = 0.27-0.88). Previously reported increases in oral cancer risks among printing workers, electrical and electronics workers, and workers other than carpet installers who were possibly exposed to formaldehyde were not found in this study. For several employment groups, including male machinists, primary metal industry workers, petroleum industry workers, painters, furniture and fixture industry workers, woodworking machine operators, and workers with inferred exposure to fossil fuel combustion, odds ratios were approximately 2.0 for cancers of pharyngeal sites.

Adolescent↗
PubMed1992

Risk of leukemia caused by diagnostic x-rays.

Using BEIR V risk estimates and age-specific population dose estimates, we estimate that approximately 12% of leukemias may be attributable to diagnostic x-rays. Earlier estimates were markedly lower (< or = 1%) because of their use of earlier risk coefficients, different dose rate effectiveness factors, and, in one case, a methodological error.

Age Factors↗
PubMed1991

Mouthwash use and oral conditions in the risk of oral and pharyngeal cancer.

Interviews with 866 patients with cancer of the oral cavity and pharynx and 1249 controls of similar age and sex from the general population in four areas of the United States revealed increased risks associated with the regular use of mouthwash. Risks of oral cancer were elevated by 40% among male and 60% among female mouthwash users, after adjusting for tobacco and alcohol consumption. Risks among both sexes generally increased in proportion to duration and frequency of mouthwash use. The increased risks were confined to users of mouthwash high in alcohol content, consistent with the elevated risks associated with drinking alcoholic beverages. Except for a higher prevalence of leukoplakia among cases, little relationship was found with oral or dental conditions, although denture wearing was reported more often by patients with cancer of the gums. These findings, together with other studies, provide further incentive for clarifying the association between mouthwash use and oral cancer.

Adult↗
PubMed1991

Astrocytoma risk related to job exposure to electric and magnetic fields.

To investigate the association between occupational exposure to low-frequency electric and magnetic (EM) fields and risk of brain tumors, a study was performed in Los Angeles County on 272 male adults with primary intracranial gliomas or meningiomas and 272 neighborhood controls. Complete occupational histories were collected. Risk associated with employment for more than 10 years in jobs that are presumed to entail exposure to EM fields was computed for various histological groupings. A nonsignificantly elevated risk of 1.7 was found for gliomas (all types pooled: 95% confidence interval 0.7-4.4), and a nonsignificantly reduced risk of 0.3 (95% confidence interval 0.03-3.2) was found for meningiomas. For astrocytomas, which form a subtype of the gliomas, a significantly elevated risk of 10.3 (95% confidence interval 1.3-80.8) was found; a significant upward trend (P = .01) of tumor incidence with increasing length of employment was observed. Most astrocytoma patients who worked in occupations involving exposure to EM fields were electricians or electrical engineers.

Adult↗
PubMed1991

The relation of socioeconomic status to oral and pharyngeal cancer.

We assessed the relation between socioeconomic status and risk of oropharyngeal cancer in a population-based interview study of 762 male cases and 837 male controls in four areas of the United States. Three primary indicators of socioeconomic status were evaluated: education, occupational status, and percentage of potential working life spent in employment. With adjustment for the effects of established risk factors, such as use of tobacco products, alcohol consumption, and poor dentition, a relatively low percentage of years worked was also a risk factor. Educational attainment and occupational status were not independently related to risk of oropharyngeal cancer. These results are consistent with the hypothesis that behaviors that lead to social instability, and/or social instability itself, are linked to an increased risk of oral and pharyngeal cancers.

Adult↗
PubMed1991

Evaluation of the evidence that tobacco-specific nitrosamines (TSNA) cause cancer in humans.

Considerable evidence exists that TSNA may cause cancer in humans. Strong evidence suggests that the NNN and NNK in snuff are at least partially responsible for the excess of oral cancer among snuff dippers. Tobacco smoke, because it is a combustion product, is a far more complex matrix than is smokeless tobacco. Nonetheless, NNK is well established as a lung carcinogen in laboratory animals at levels similar to those experienced by heavy smokers. Although the epidemiology of the smoking/lung cancer association has been studied extensively and is well established as a causal relationship, few attempts have been made to determine the effective constituents in tobacco smoke, much less to quantify them and to reduce their levels in consumer products. More work is needed to determine TSNA uptake in smokers and users of smokeless tobacco and to determine the factors involved in the possible endogenous formation of TSNA and in their metabolic activation or inhibition of their formation. Exploratory work is in progress with various biological markers that may prove useful in quantifying the levels of TSNA exposure in humans. Epidemiologic evidence indicates that in addition to tobacco use other factors are causally related to the development of cancers of the oral cavity, lung and esophagus and that these factors (e.g., radon exposure in uranium miners who smoke) can act synergistically. Experimental investigation of some of these synergistic effects may prove to be a step in the direction of determining the proportion of various cancers that are likely to be attributable to various causes and ultimately to the various constituents of tobacco exposure.

Humans↗
PubMed1991

Gliomas and meningiomas in men in Los Angeles County: investigation of exposures to N-nitroso compounds.

We conducted a case-control study of primary tumours of the brain and cranial meninges in Los Angeles County to investigate the hypothesis that these tumours are related to occupational exposures. We also collected limited data on diet and personal habits that are likely to involve exposure to N-nitroso compounds (NOC), NOC precursors and modulators of NOC metabolism. Interviews were conducted with 272 men with a brain tumour diagnosed in 1980-84 and with 272 individually matched neighbourhood controls. The study was of sufficient size to allow for separate analyses of the 202 pairs of glioma patients and of the 70 patients of meningioma. Six glioma cases and one control had worked in the rubber industry, in which excesses of brain tumour have been shown in previous studies and where there are high levels of volatile NOC at various work sites. Ten meningioma patients and five controls had used cooling, cutting or lubricating oils, and most had used these daily (eight cases; four controls). Cases and controls were not different, however, with respect to other occupations known to involve exposures to NOC. Cases and controls also did not differ in their consumption of alcoholic beverages or cigarettes or in their passive exposure to cigarette smoke. The most striking dietary finding was a significant protective effect among glioma pairs of use of vitamin supplements, which increased with increasing frequency of use (p for trend = 0.04; odds ratio for use at least twice a day = 0.4 (95% confidence interval = 0.24-0.77)).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Increased cell division as a cause of human cancer.

Carcinogenesis research is increasingly focused on chemicals that are not genotoxic and yet, at high doses, can induce cancer, apparently by increasing cell proliferation. We hypothesize that increased cell division per se stimulated by external or internal factors is also associated with the development of many human cancers. Although this hypothesis is well substantiated in the experimental literature, it has not been generalized as an important mechanism for carcinogenesis in human populations. Under this increased cell division model, the pathogenesis of cancer may result from molecular genetic errors induced during the process of cell division and from altered growth control of malignant or premalignant cells. Molecular genetic analysis of human cancers has shown that tumor cells contain multiple genetic defects including mutations, translocations, and amplifications of oncogenes and are reduced to homozygosity for putative tumor suppressor genes; these phenomena all require cell division for their occurrence and fixation. Increased cell division increases the risk of such events occurring. An accumulation of a combination of such genetic errors leads to a neoplastic phenotype. Examples are discussed of human cancers in which increased cell division, which drives the accumulation of genetic errors and can lead to neoplastic transformation, is caused by hormones, drugs, infectious agents, chemicals, physical or mechanical trauma, and other chronic irritation.

Animals↗
PubMed1990

Leukemia in Utah and radioactive fallout from the Nevada test site. A case-control study.

Previous studies reported an association between leukemia rates and amounts of fallout in southwestern Utah from nuclear tests (1952 to 1958), but individual radiation exposures were unavailable. Therefore, a case-control study with 1177 individuals who died of leukemia and 5330 other deaths (controls) was conducted using estimates of dose to bone marrow computed from fallout deposition rates and subjects' residence locations. A weak association between bone marrow dose and all types of leukemia, all ages, and all time periods after exposure was found. This overall trend was not statistically significant, but significant trends in excess risk were found in subgroups defined by cell type, age, and time after exposure. The greatest excess risk was found in those individuals in the high-dose group with acute leukemia who were younger than 20 years at exposure and who died before 1964. These results are consistent with previous studies and with risk estimates for other populations exposed to radiation.

Acute Disease↗
PubMed1990

Exposure of nonsmoking women to environmental tobacco smoke: a 10-country collaborative study.

The interpretation and interpretability of epidemiologic studies of environmental tobacco smoke (ETS) depend largely on the validity of self-reported exposure. To investigate to what extent questionnaires can indicate exposure levels to ETS, an international study was conducted in 13 centers located in 10 countries, and 1,369 nonsmoking women were interviewed. The present paper describes the results of the analysis of self-reported recent exposure to ETS from any source in relation to urinary concentrations of cotinine. Of the total, 19.7 percent of the subjects had nondetectable cotinine levels, the median value was 6 ng/mg, and the cut-point of the highest decile was 24 ng/mg. The proportion of subjects misreporting their active smoking habit was estimated at between 1.9 and 3.4 percent, depending on whether cut-points of 50 or 100 ng/mg creatinine were used. Large and statistically significant differences were observed between centers, with the lowest values in Honolulu, Shanghai, and Chandigarh, and the highest in Trieste, Los Angeles, and Athens. Mean cotinine/creatinine levels showed a clear linear increase from the group of women not exposed either at home or at work, to the group of those exposed both at home and at work. Values were significantly higher for women exposed to ETS from the husband but not at work, than for those exposed at work but not from the husband. The results of linear regression analysis indicated that duration of exposure and number of cigarettes to which the subject reported being exposed were strongly related to urinary cotinine. ETS exposure from the husband was best measured by the number of cigarettes, while exposure at work was more strongly related to duration of exposure. After adjustment of number of cigarettes for volume of indoor places, a similar increase in cotinine (5 ng/mg) was predicted by the exposure to 7.2 cigarettes/8 h/40 m3 from the husband and 17.9 cigarettes/8 h/40 m3 at work. The results indicate that, when appropriately questioned, nonsmoking women can provide a reasonably accurate description of ETS exposure. Assessment of individual exposure to ETS should focus on daily duration and volume of indoor places where exposure occurred.

Adult↗
PubMed1990

Diet and oral and pharyngeal cancer among blacks.

Data from a population-based multicenter case-control study were examined to assess for the first time the relationship between diet and oral and pharyngeal cancer among blacks. An increased intake of fruits and vegetables was associated with a decreased risk for oral cancer among both men and women, although the protective effect was stronger among men. Risk also declined in both sexes with an increase in the consumption of vitamin C and fiber and in men only for carotene and vitamin E. In both sexes, no associations were found with an intake of smoked, pickled, or charcoal-grilled meats or of hot beverages. However, the consumption of nitrite-containing meats was linked to increased risk among men. The dietary patterns of risk for blacks were generally similar to those previously reported for whites; however, a lower consumption of fruits and vegetables among blacks in this study may contribute to their higher rates of oral and pharyngeal cancer.

Adult↗
PubMed1990

Descriptive epidemiology of primary tumors of the spinal cord and spinal meninges in Los Angeles County, 1972-1985.

This report presents data on the distribution of 462 primary tumors of the spinal cord and spinal meninges (both benign and malignant) diagnosed among residents of Los Angeles County from 1972 to 1985. Incidence rates of gliomas, meningiomas, nerve sheath tumors, and all histologic types combined are presented for specific age, sex, and ethnic groups. The highest rates are seen for meningiomas in women (age-adjusted rate 3/million/year compared to 1/million/year for the other two histologic types in women and for each of the three types in men). Proportional incidence ratios for spinal tumors are elevated among men and women born in Eastern Europe and among Jewish residents of Los Angeles County. The incidence rates appear not to relate to the social class.

Adolescent↗
PubMed1990

Brain and salivary gland tumors related to prior dental radiography: implications for current practice.

Five epidemiological studies of brain, cranial meninge, and salivary gland tumor sites reviewed implicate prior dental radiography with increased risk of subtentorial intracranial meningiomas and tumors of the parotid gland. Diagnostic radiography (medical and dental) was the most important risk factor identified for parotid gland cancers; among Los Angeles County residents, about 85% of the cumulative parotid dose from diagnostic radiography came from dental examinations. Irradiation of patients during dental radiography declined substantially from 1920 to 1988; it is uncertain whether current low doses increase risk. Recommendations for exposure reduction are made.

Adolescent↗
PubMed1989

Risk factors for gliomas and meningiomas in males in Los Angeles County.

Detailed job histories and information about other suspected risk factors were obtained during interviews with 272 men aged 25-69 with a primary brain tumor first diagnosed during 1980-1984 and with 272 individually matched neighbor controls. Separate analyses were conducted for the 202 glioma pairs and the 70 meningioma pairs. Meningioma, but not glioma, was related to having a serious head injury 20 or more years before diagnosis [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-5.4], and a clear dose-response effect was observed relating meningioma risk to number of serious head injuries (P for trend = 0.01; OR for greater than or equal to 3 injuries = 6.2; CI = 1.2-31.7). Frequency of full-mouth dental X-ray examinations after age 25 related to both glioma (P for trend = 0.04) and meningioma risk (P for trend = 0.06). Glioma, but not meningioma risk, related to duration of prior employment in jobs likely to involve high exposure to electric and magnetic fields (P for trend = 0.05). This risk was greatest for astrocytoma (OR for employment in such jobs for greater than 5 years = 4.3; CI = 1.2-15.6). More glioma cases had worked in the rubber industry (discordant pairs 6/1) and more worked in hot processes using plastics (9/1). More meningioma cases had jobs that involved exposure to metal dusts and fumes (discordant pairs 13/5), and six of these cases and two controls worked as machinists. Finally, there was a protective effect among glioma pairs relating to frequency of use of vitamin C and other vitamin supplements (P for trend = 0.004); the OR for use at least twice a day was 0.4 (CI = 0.2-0.8).

Alcohol Drinking↗
PubMed1989

Case-control study of lung cancer in Los Angeles county welders.

A case-control study of lung cancer in white male welders was undertaken to investigate possible environmental and occupational causes of a 50% excess of lung cancer observed in this occupational group. The subjects were identified from a population-based cancer registry in Los Angeles County. A standardized questionnaire was administered to either subjects or proxy informants of 90 lung cancer cases and 116 non-lung-cancer controls. Significantly increased risks of lung cancer were associated with tobacco smoking (odds ratio 7.6, p less than .005) and shipyard welding with at least a 10-year latency since first exposure (odds ratio 1.7, p less than .05). Although there were elevated risks associated with some specific welding processes, none were statistically significant. Control subjects were more likely to have had exposure to confined-space welding (odds ratio 0.6, 95% CI = 0.3-1.2), and this association was greatest where there had been at least a 20-year latency since first exposure (0.5, 95% CI = 0.3-1.0). We conclude that the excess of lung cancer in this welding population is contributed to by a higher frequency of smoking and probable exposure to asbestos in shipyards. Other factors may be important, but probably because of limited power and reliance on proxy information, this study failed to detect other statistically significant risks.

Adult↗