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Perspective on the carcinogenic potential of phenytoin based on rodent tumor bioassays and human epidemiological data.

Phenytoin is a hydantoin-type anticonvulsive agent used extensively for nearly sixty years in the prophylactic treatment of grand mal and psychomotor seizures. 2. Based upon somewhat contentious evidence of phenytoin-induced lymphoma in mice and upon epidemiologic evidence of an association between anticonvulsive therapy and lymphoma in epilepsy patients, the International Agency for Research on Cancer (IARC) has collectively regarded these data as limited evidence of carcinogenicity. 3. Two year carcinogenicity studies of standard bioassay design conducted in mice and rats yielded statistically significant increased incidence of hepatocellular adenomas in mice at phenytoin plasma concentrations approximating the therapeutic anticonvulsive range. Tumor incidence in rats was not affected. Previous carcinogenicity studies have found similar increases in hepatic tumor incidence in mice. 4. Phenytoin is a known enzyme inducer and shows tumor promoting activity in chemically initiated mouse liver. Evidence for genotoxicity is weak or equivocal, consequently phenytoin-induced liver tumors appear to occur through nongenotoxic mechanisms. 5. Finally, despite six decades of extensive therapeutic use and thorough epidemiologic evaluation, there is no evidence for an association between liver cancer and phenytoin therapy in epilepsy patients. Thus, hepatocellular neoplasia in phenytoin-treated rodents appears to be of little significance to man.

Animals↗

Relative risk regression analysis of epidemiologic data.

Relative risk regression methods are described. These methods provide a unified approach to a range of data analysis problems in environmental risk assessment and in the study of disease risk factors more generally. Relative risk regression methods are most readily viewed as an outgrowth of Cox's regression and life model. They can also be viewed as a regression generalization of more classical epidemiologic procedures, such as that due to Mantel and Haenszel. In the context of an epidemiologic cohort study, relative risk regression methods extend conventional survival data methods and binary response (e.g., logistic) regression models by taking explicit account of the time to disease occurrence while allowing arbitrary baseline disease rates, general censorship, and time-varying risk factors. This latter feature is particularly relevant to many environmental risk assessment problems wherein one wishes to relate disease rates at a particular point in time to aspects of a preceding risk factor history. Relative risk regression methods also adapt readily to time-matched case-control studies and to certain less standard designs. The uses of relative risk regression methods are illustrated and the state of development of these procedures is discussed. It is argued that asymptotic partial likelihood estimation techniques are now well developed in the important special case in which the disease rates of interest have interpretations as counting process intensity functions. Estimation of relative risks processes corresponding to disease rates falling outside this class has, however, received limited attention. The general area of relative risk regression model criticism has, as yet, not been thoroughly studied, though a number of statistical groups are studying such features as tests of fit, residuals, diagnostics and graphical procedures. Most such studies have been restricted to exponential form relative risks as have simulation studies of relative risk estimation procedures with moderate numbers of disease events.

Age Factors↗

Two years' prospective collection of molecular and epidemiological data shows limited spread of hepatitis A virus outside risk groups in Amsterdam, 2000-2002.

We performed a viral sequencing study on samples representing all reported primary cases of acute hepatitis A virus (HAV) infection reported for 2 years in Amsterdam. Two regions of HAV RNA were amplified, sequenced, and used for phylogenetic analysis. Of 156 cases, strains of 104 isolates (66.6%) clustered into 3 genotypes: 1A, 1B, and 3. Two separate transmission circles occurred, without mutual interrelation. In genotype 1A, 4 clusters occurred in men having sex with men (MSM), and the fifth cluster was related to a virus from Morocco. In genotype 1B, 6 small clusters were directly related to the Moroccan virus. In genotype 3, strains were related to a virus from Pakistan. Our analysis indicates that, to stop transmission of HAV in Amsterdam, the entire MSM population and travelers to countries where HAV is endemic, especially children, should be vaccinated. Prevention strategies need not include the vaccination of all children living in Amsterdam.

Adolescent↗

Methodologic research needs in environmental epidemiology: data analysis.

A brief review is given of data analysis methods for the identification and quantification of associations between environmental exposures and health events of interest. Data analysis methods are outlined for each of the study designs mentioned, with an emphasis on topics in need of further research. Particularly noted are the need for improved methods for accommodating exposure assessment measurement errors in analytic epidemiologic studies and for improved methods for the conduct and analysis of aggregate data (ecologic) studies.

Data Interpretation, Statistical↗

["Are rich people healthier?"--Representative epidemiological data on socioeconomic group-specific disease prevalences among adults in Germany].

BACKGROUND AND OBJECTIVE: The aim of this study was to determine representative nationwide data on differences in the prevalence of specific diseases between socioeconomic groups. METHODS: The "First National Health Survey for the Federal Republic of Germany" was conducted from October 1997 to March 1999 in the form of a standardized cross-sectional questionnaire study. The data were elicited about the 35 most common diseases and socioeconomic status. The net sample was made up of a total of 7125 persons aged 18 to 79. RESULTS: A significantly higher prevalence in subjects of lower socioeconomic status was identified for typical orthopaedic diseases as well as for hypertension, chronic bronchitis, gastric and vascular disease. The most apparent socioeconomic difference to the detriment of socially deprived subjects was identified for addiction disease and diabetes. In contrast, numerous allergic diseases such as food allergies, urticaria, and allergic diseases of the respiratory tract and eyes were approximately twice as common among members of higher socioeconomic groups. Various gastrointestinal and renal diseases (hepatitis, gastritis, pyelonephritis) were also more common in higher socioeconomic groups. These socioeconomic differences were still apparent after adjustment for age and gender. CONCLUSION: This study provides representative socioeconomic group-specific prevalence data on a total of 35 clinical entities for the Federal Republic of Germany. Although the self-reporting involved in large epidemiological studies of this kind is associated with a certain amount of bias, it is nonetheless clear that the frequently cited "socioeconomic gradient", i. e., a higher disease prevalence among lower socioeconomic groups, seems not to apply for numerous disease entities; for which the association seems to be in the opposite direction. This phenomenon requires explanation.

Adult↗

[Obesity and mortality. Italian epidemiologic data].

The relationship of indicators of obesity, such as the body mass index (BMI) and the skinfold thickness in some areas (SKIN) to all causes mortality have been analyzed in three italian epidemiological studies. They are the Seven Countries Study--italian areas conducted on 2480 men at entry and followed-up for 25 years; the Brisighella study conducted on 1123 men and 1100 women aged 30-69 and followed-up for 15 years; and the NFR study in Rome conducted on 3395 men aged 46-66 and followed-up of 6.5 years. The univariate analysis concerning the BMI for various age groups, the two sexes, and variable periods of follow-up has almost systematically showed a parabolic inverted J shaped relationship with minimal levels of risk for BMI values of 27-29 units. However this was not the case for the women group and for the oldest men where no clear relationship was found. The analysis concerning the SKIN provided similar but less clear-cut results. The multivariate analysis has confirmed the parabolic relationship of BMI to all causes mortality even in the presence of other 4-5 covariates. The left branch of risk is higher than the right one and its slope could be reduced, although not completely, by the exclusion of heavy smokers, of those who died within the first 5 years of follow-up, of those who were carriers of severe diseases at entry examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Neoplastic and borderline lesions of the prostate: autopsy study and epidemiological data.

Early detection and management of prostatic cancer (PC) is an important public health problem in all industrialized countries, where the relative rate of the elderly population is rapidly increasing. We examined the epidemiology of PC in the province of Trieste, Italy and studied the relationship between prostatic intraepithelial neoplasia (PIN) and PC. The average annual incidence of PC was 99.3 per 100,000 (1,739 new prostatic cancer cases were histologically diagnosed at autopsy or in surgical specimens between 1980 and 1993). In patients over 85 years of age, the incidence rate was 1,209 per 100,000 compared with 64 per 100,000 in the 55-64 age group. Trends in PC incidence rates showed a significant increase among men under 64 years of age and those between 65-74 years. Survival analysis showed that 94% of the patients with well differentiated PC were alive at 5 years, compared with 80% and 40% of those with moderately differentiated and poorly differentiated cancer, respectively. We studied 130 whole autopsy prostates, 70 radical prostatectomies with carcinoma, 63 transurethral resections or adenomectomies without cancer from patients who later developed PC and 94 transurethral resections or adenomectomies from patients who did not develop PC. The 102 prostatic cases with cancer had a high rate of PIN, and the relative frequency of PIN 3 was high (almost 70%, versus almost 0% in benign prostates). In addition, the frequency of PIN was higher in benign prostates of patients who later developed PC (almost 50% of the cases) than in benign autopsy and surgical prostates. PIN was spatially associated with cancer in 75% of the cases. This study confirms the strong relationship between PIN and PC.

Adult↗

[Biomechanical overload diseases: epidemiologic data].

Work-related musculoskeletal disorders are a major problem for industrialised societies, particularly in view of the elevated prevalence of low back pain (LBP) and carpal tunnel syndrome (CTS) among manual workers. Epidemiological studies show that work-related risk factors, such as lifting, twisting, bending, exposure to whole body vibration, and prolonged postures are prominent risk factors for LBP. For CTS, repetitive movements, hand-arm vibrations and use of forceful hand movements appear to be the major work-related risk factors. Psychological and psychosocial factors can also affect the onset of both disorders. This review provides an overview of the main evidence in the scientific literature on these issues.

Biomechanical Phenomena↗

[Tuberculin survey and its meaning for a correct prevention in a high risk population. Epidemiological data relative to students of the faculty of medicine and soldiers residing in Ferrara (author's transl)].

The Authors list the results obtained from a tuberculin survey carried out on students of the Faculty of Medicine of the University of Ferrara (school year 1977/1978) and on enlisting soldiers. A different skin positivity is here confirmed: a higher percentage in males (27.41%) than in females (17.91%). A higher frequency of positive responses is noted in students originating from the centre-south of Italy. Such tendency is principally due to the greater differences in skin positivity found in females. Students over 26 years of age show a skin positivity of more than 40%, whilst for 17 to 20 years old skin positivity ranges between 22% to 25%. The frequency of skin positivity in soldiers confirms the data found in male students of the same age group. Post vaccine control, although limited to a smaller group of students, shows a definite turn towards positivity with an average figure in both sexes of 63%. The Authors, although admit having carried out their survey on a small population, believe to have contributed with useful information on the epidemiological situation of tuberculosis in age groups with scarce statistical data.

Adolescent↗

The role of "negative" epidemiology data in the evaluation of risk.

The identification and quantification of risk is a complex process that depends upon a variety of different disciplines. All contribute, but none provides a complete and comprehensive perspective. In the past, emphasis has been placed upon the limitations of each individually. Toxicology, for example, is plagued by low predictive value positive; epidemiology, by qualitative measures of exposure. Focusing instead upon the contributions of each to the whole, and the contributions of all of the data--both "positive" and "nonpositive"--a better understanding of potential hazards can be achieved. Examples are provided for styrene and phenoxy herbicides.

Animals↗

[Epidemiological data on snake bite cases reported in Benin from 1994 to 2000].

Snake bites constitute a frequent occupational injury, mainly occuRring during agricultural activities in Benin as in the majority of tropical countries. The present study was performed within the scope of a periodic epidemiological analysis of occupational injuries over the past 15 years. It is a retrospective study based on the snake bites reported by the Ministry of Public Health from 1994 to 2000. The data collected through the medical centre registers showed that, with a total of 30,273 cases declared during these 7 years, snakebites represent less than 1% of the whole causes of admission. Although the prevalence was weak, the lethality was very high (15%). Envenomations involved more deaths than malaria and acute respiratory infections together. One third of cases occurred in adults and teenagers. Lethality in infants was not negligible. The two departments of northern Benin accounted for 314 of the envenomations. Lethality does not appear to be decreasing. The routine management of cases should be improved by appropriate training for health care workers and the introduction of a therapeutic strategy at every level of the medical system.

Adolescent↗

[Estrogens and cardiovascular risk in postmenopausal women. I. Epidemiologic data].

The possible role of oestrogens in modifying the occurrence of ischaemic heart disease and cardiovascular disease (CVD) in general in postmenopausal women has long been controversial. Analysis of the literature indicates a difference between the epidemiological studies published before 1980 and those published recently. In the former, the risk in women using oestrogen replacement therapy (ERT) was either unchanged or increased when compared with those women who did not use ERT. In the latter the trend has changed and a clear protective effect of ERT has been shown. These contradictory results might be explained by a change in prescribing habits, using lower oestrogen doses and selecting women with no risk factor for CVD as candidates for long-term ERT.

Adult↗