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At least 127 records · Page 7Linked to original sources

Implications of the analysis of epidemiological data using a two-mutation carcinogenesis model for radiation risks.

A two-mutation carcinogenesis (TMC) model is used as a bridge between cellular radiation biological effects and the incidence of cancer. This model has been applied to several sets of experimental animal and epidemiological data. In this paper the advantage of the model and the implications for radiation risks at low doses are discussed with respect to the age and dose dependence of cancer incidence and the effect of age at exposure on radiation risk; the link between the radiation effect and background cancer incidence and the transfer of radiation risk across different population groups; the implications of acute and protracted radiation exposures for risks at low doses and the dose-effect relationship for radium induced bone cancer.

Age Factors↗

Some epidemiological data on leprosy collected in a mass survey in Burma.

In the WHO Leprosy BCG Trial in Burma a mass survey was undertaken to determine whether children had been exposed to patients with leprosy and, if so, the form of the index case. This paper presents the most important epidemiological data collected in this survey. The prevalence rate was 31.6 per 1 000. It seems that even if the prevalence rate is very high the L rate does not increase accordingly. The high T rates in areas of high endemicity seem to be related mainly to the degree of spreading of leprosy, even to persons who react to lepromin. Comparison of the results with data available for the area before the survey was made shows that 87% of the L cases had already been detected and that 54% of the T cases had not. There was a tendency for high L rates to be associated with high prevalence rates. The results do not suggest that any particular age group has greater susceptibility or resistance; the prevalence rates seemed to be related mainly to the age when exposure occurred. A higher prevalence of leprosy in males started to appear in the 10-14-year age group, and after the age of 15 the difference became impressive. Biological, socio-economic, and environmental factors seem to be responsible for the level of endemicity, which does not seem to be essentially or primarily related to ethnic origin.

Adolescent↗

The use of epidemiological data to direct resources in food safety control.

In the United States, food-borne disease results in financial losses estimated at $2.9 to $6.7 billion annually as a result of illness that is due to six specific food-borne pathogens. A model is proposed that analyzes epidemiological data and highlights areas in food safety control that have the greatest impact on food-borne disease. The model identifies Critical Control Points for use by the food industry, prioritizes criteria for inspection of food processes by regulatory authorities, and provides a focus for food hygiene training programs and campaigns. The model also provides a cost-benefit analysis that can be used to direct resources that are used in food safety control in a cost-effective manner.

Cost-Benefit Analysis↗

A review of the recent epidemiological data on the worldwide incidence of type 1 (insulin-dependent) diabetes mellitus. World Health Organization DIAMOND Project Group.

Nearly 70 registries from more than 40 countries have collected and published incidence data of childhood Type 1 (insulin-dependent) diabetes mellitus up to the end of the 1980s. The majority of incidence data comes from regions of high incidence i.e. from Europe and North America. All these published data facilitate the descriptive comparison of incidence and variation of the occurrence of Type 1 diabetes roughly throughout the northern hemisphere. The aim of this paper is to review and compare the most recent epidemiology data on the incidence of Type 1 diabetes among children under the age of 15 years. A clear difference in incidence appeared between northern and southern hemisphere with no countries below the equator having an incidence greater than 15.0 per 100,000. In contrast above the equator the disease is common. Between continents the variation in incidence showed that the lowest incidences were found in Asia, followed by Oceania (Australia and New Zealand), South and North America, and the highest rates were in Europe. The incidence varied from 0.6 per 100,000 in Korea and Mexico to 35.3 per 100,000 in Finland showing prominent worldwide variation in incidence of Type 1 diabetes. The largest intracontinental variation in incidence appeared in Europe, varying from the highest in Finland to the lowest (4.6 per 100,000) in northern Greece. The highest incidence in the world was in northern Europe, but within the continent scale there were some striking exceptions from the overall level of incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Lyme borreliosis in South Germany. Epidemiologic data on the incidence of cases and on the epidemiology of ticks (Ixodes ricinus) carrying Borrelia burgdorferi].

Among 2403 ticks (Ixodes ricinus) tested in 1985 for Borrelia 328 (13.6%) were carriers (adults about 20%, nymphs about 10%, larvae about 1%). The highest prevalence of infected ticks was among adult ticks in the Isar region north of Munich (33.8%). Among 9383 persons whose serum had been examined by fluorescence serology in 1985 and 1986, 1035 (11%) had raised Borrelia-specific IgG and/or IgM antibodies greater than or equal to 1:64. In 18.7% only IgM antibodies were demonstrated. Among 375 proven cases there were 78 with erythema migrans, 211 with neurological signs, 48 with Lyme arthritis and 36 with acrodermatitis. Seasonal incidence peaks were in June-August for erythema migrans, July-September for neurological signs, with no clear-cut seasonal peaks with Lyme arthritis and acrodermatitis. The incubation time for 80% of cases of each abnormality was 5-29 days for erythema migrans, 20-59 for neurological signs and 2-8 months for Lyme arthritis. Erythema migrans was most frequent among those aged 30-60 years, neurological signs among children and juveniles up to 20 years and those aged 40 to 70 years, Lyme arthritis among those aged 30-60 years, and acrodermatitis among those aged 40-80 years. Significantly more women than men developed acrodermatitis.

Acrodermatitis↗

[Epidemiological data on lower leg amputations. A study of 1487 amputations].

The examination is based on the operative amputee statistics at the university hospital Göttingen between 1983 and 1992 as well as the prosthetic treatment statistics at the university hospital for Technological Orthopedics and Rehabilitation (TO Münster) between January 1991 and March 1993. The comparison of epidemiologic data from both hospitals allow to give statements concerning etiology, level of amputation and age distribution. With a percentage of 78.6 dysvascular diseases were the principal cause for amputations at the Göttingen hospital, which is 10% less than described in modern literature. The respective percentage was 43% in Münster, followed by a 35.9% share for amputations caused by trauma. Our results demonstrate the relevance of amputations which are not due to dysvascular diseases in prosthetic treatment.

Adolescent↗

Early rescreen/recall in the UK National Health Service breast screening programme: epidemiological data.

OBJECTIVE: In the United Kingdom in 1994-95 about 16,500 women aged 50 to 64 were asked to come back earlier than the usual three yearly screening interval for further mammography (early rescreen (ES)) or for a range of further investigations at an assessment centre (early recall (ER)). This study aimed at providing epidemiological data on ES/ER, in particular, how often and why it is used, and what the outcome is of using it. SETTING: National Health Service breast screening programme in the United Kingdom. METHODS: All breast screening units were invited to complete a postal questionnaire. Two reminders were sent. The units were asked retrospectively to provide breast screening data about women aged 50 to 64 from their local computer systems. Women placed on ES/ER were followed up for at least one year. RESULTS: The response rate was 71% (69/97), of which 14% (10/69) were unable to provide the required data, leaving 59 completed questionnaires (61%). The rate of placing women on ES/ER was above 1.0% for 26/54 (48%) responding breast screening units and above 2.0% for 13/54 (24%) units. Women were placed on ES/ER because of (a) previous breast cancer (21% of cases; cancer detection rate 2.4%), (b) diagnostic uncertainty (51%; cancer detection rate 3.0%), or (c) family history (27%; cancer detection rate 0.6%). Breast screening units with a high rate of placing women on ER were significantly more likely to have a high recall rate (rs = 0.63; n = 53; p < 0.0005) or a high benign surgical biopsy rate (rs = 0.33; n = 49; p < 0.05), or both. The cancer detection rate of ES/ER tended to decrease with increasing ES/ER rates (rs = -0.37; n = 51; p < 0.01). CONCLUSIONS: A relatively large number of women were placed on ES or ER for a range of reasons. If the recommendations given are followed, the number of women placed on ER may be reduced while maintaining the cancer detection rate at the required level. The option of ES should not be used.

Breast Neoplasms↗

Exploitation of statistical tables: conceptual interaction with epidemiologic data.

Health-care applications need flexible data and interaction models capable of dealing with data of different natures coming from different sources. These applications are usually devoted to diverse user groups, often casual or novice. The user interface must help the user to understand the database information content in his or her querying process. The authors synthetically describe FLN, a system featuring an integrated interaction with epidemiologic data. In an integrated model the statistical aspects of data (macro data) are represented, together with the intensional and extensional views of the variables involved in statistical tables.

Database Management Systems↗

Use of quantitative epidemiologic data in regulatory approaches to air pollution.

Ambient air is a complex mixture containing a variety of substances, some of which are known to be carcinogenic. To develop a homogeneous approach for regulating the emission of these compounds, their individual carcinogenic potential needs to be placed on a comparable scale. The unit risk may be considered as an appropriate measure that condensates dose-response analyses of epidemiologic data into a single, easily interpretable estimate. Given the information on the carcinogenic potency of single compounds, more information on the occurrence of the components and the relation of emissions to specific emittents needs to be considered. In Germany, an approach has been developed that combines different assumptions on complex mixtures for the regulation of the overall risk. This paper outlines some of the principal aspects of the underlying concepts.

Air Pollution↗

Epidemiologic data on the relationships of caloric intake, energy balance, and weight gain over the life span with longevity and morbidity.

Animal experiments have shown that calorically restricted (CR) animals weigh less and live longer than their ad libitum-fed peers. Are these observations applicable to human beings? This is an important question because the prevalence of obesity in America has increased markedly over recent years. We examine whether there are physiologic effects that occur with CR in humans that could plausibly explain the observed longevity of laboratory animals associated with CR. We also review epidemiologic data from observational and interventional studies on the relationships of caloric intake, energy balance, and weight gain with age-related diseases and longevity. Additionally, data on whether long-term, sustained maintenance of weight loss is feasible, as well as the degree of CR achieved in clinical trials, are summarized. Finally, we provide recommendations regarding further epidemiologic research that will help clarify unanswered questions in these areas.

Energy Intake↗

Spatial-temporal and phylogenetic analyses of epidemiologic data to help understand the modes of transmission of endemic typhoid fever in Samoa.

Salmonella enterica serovar Typhi (S. Typhi) is either widely distributed or proximally transmitted via fecally-contaminated food or water to cause typhoid fever. In Samoa, where endemic typhoid fever has persisted over decades despite water quality and sanitation improvements, the local patterns of S. Typhi circulation remain unclear. From April 2018-June 2020, epidemiologic data and GPS coordinates were collected during household investigations of 260 acute cases of typhoid fever, and 27 asymptomatic shedders of S. Typhi were detected among household contacts. Spatial and temporal distributions of cases were examined using Average Nearest Neighbor and space-time hotspot analyses. In rural regions, infections occurred in sporadic, focal clusters contrasting with persistent, less clustered cases in the Apia Urban Area. Restrictions to population movement during nationwide lockdowns in 2019-2020 were associated with marked reductions of cases. Phylogenetic analyses of isolates with whole genome sequences (n = 186) revealed one dominant genotype 3.5.4 (n = 181/186) that contains three Samoa-exclusive sub-lineages: 3.5.4.1, 3.5.4.2, and 3.5.4.3. Variables of patient sex, age, and geographic region were examined by phylogenetic groupings, and significant differences (p<0.05) associated genetically-similar isolates in urban areas with working ages (20-49 year olds), and in rural areas with age groups typically at home (<5, 50+). Isolates from asymptomatic shedders were among all three sub-lineages. Whole genome sequencing provided evidence of bacterial genetic similarity, which corroborated 10/12 putative epidemiologic linkages among cases and asymptomatic shedders, as well as 3/3 repeat positives (presumed relapses), with a median of one single nucleotide polymorphism difference. These findings highlight various patterns of typhoid transmission in Samoa that differ between urban and rural regions as well as genomic subtypes. Asymptomatic shedders, detectable only through household investigations, are likely an important reservoir and mobile agent of infection. This study advances a "Samoan S. Typhi framework" that supports current and future typhoid surveillance and control efforts in Samoa.

Humans↗

Epidemiological data sources in Estonia: a survey of registries and databases.

BACKGROUND: Central and Eastern European countries offer opportunities for studying the health effects of historical and present exposures, as well as the transition to a market economy. A prerequisite for research is the availability of good-quality information. This study was undertaken to describe sources of individual data that are available for epidemiological research in Estonia. Particular attention was paid to the methods of operation of health registries. METHODS: Information was collected during site visits, interviews with registry personnel and from published reports. For health registries, information was specifically requested on data collection, scope of recorded data, quality control, electronic linkage capability and use of data in research. RESULTS: The authors describe 35 data sources containing individual information on vital status, mortality, morbidity, natality and women's health, health and health care, and occupation. The most important health registries are the cancer registry, with data from 1968, and the medical birth registry, with data from 1992. Computerised cause-of-death information is available from 1983. Electronic linkage can be done with most of the data sources, the main matching variable being the eleven-digit personal identification number. Factors potentially affecting data-quality in health registries are undefined legal basis, scarcity of funding and staff, poor acknowledgement of problems, and rare scientific use of registry DISCUSSION: Various data sources are available for epidemiological research in Estonia. Thus far, collected data have largely been an under-used scientific resource. In health registries, more attention should be paid to quality control and continuous involvement of researchers.

Birth Certificates↗

A standardized benchmark approach to the use of cancer epidemiology data for risk assessment.

Clarity and scientific validity are two criteria for assessing the quality of communications between scientists and risk managers. Regulating permissible exposures on the basis of very-low-dose risk extrapolation uses scientific information that may not meet either criterion. With regard to clarity, it is difficult for an individual to conceive of the meaning of risks on the order of 1 in 1,000,000 lifetime excess. With regard to scientific validity, the uncertainties of extrapolating risks at very low doses are evident in the wide variation in results produced depending on the statistical and pharmacokinetic assumptions made. An alternative approach is to fix benchmarks from which safety factors are chosen (Gaylor, 1983). For epidemiological data, we propose a benchmark of that exposure which would cause 1% cancer excess with 10 yr of exposure followed by 30 yr of further followup. These values have been chosen at this stage of development since they are close to observable values in many cancer epidemiology studies. In the first stage, excess cancer risk versus duration of exposure is plotted and the excess risk is estimated for a exposure duration of 10 yr. The next step involves a short linear extrapolation from the exposure levels linked with this excess risk to the exposure levels that would cause a 1% excess risk over a duration of 10 yr. We have established preliminary benchmarks from published data for benzene and radon daughter exposure. Permissable exposure levels might then be set by deciding on safety factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogens, Environmental↗

Ordinal regression models for epidemiologic data.

Health status is often measured in epidemiologic studies on an ordinal scale, but data of this type are generally reduced for analysis to a single dichotomy. Several statistical models have been developed to make full use of information in ordinal response data, but have not been much used in analyzing epidemiologic studies. The authors discuss two of these statistical models--the cumulative odds model and the continuation ratio model. They may be interpreted in terms of odds ratios, can account for confounding variables, have clear and testable assumptions, and have parameters that may be estimated and hypotheses that may be tested using available statistical packages. However, calculations of asymptotic relative efficiency and results of simulations showed that simple logistic regression applied to dichotomized responses can in some realistic situations have more than 75% of the efficiency of ordinal regression models, but only if the ordinal scale is collapsed into a dichotomy close to the optimal point. The application of the proposed models to data from a study of chest x-rays of workers exposed to mineral fibers confirmed that they are easy to use and interpret, but gave results quite similar to those obtained using simple logistic regression after dichotomizing outcome in the conventional way.

Asbestos, Amphibole↗