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THREE DEFINITIONS: The metabolic or X syndrome is defined by an association of metabolic anomalies leading to an increased risk of cardiovascular complications. Today, there are at least 3 definitions of X syndrome: those of WHO, EGIR and NCEP. To varying degrees they associate increased abdominal fat, hypertension, glucose tolerance abnormality (ranging from hyperinsulinism to diabetes), and hypertriglyceridemia with low HDL cholesterol. FROM AN EPIDEMIOLOGICAL POINT OF VIEW: The prevalence of metabolic syndrome depends on the definition used and varies with the country or ethnic group considered. About 25% of the US and 10% of the French adult populations are concerned. THE RISK OF COMPLICATIONS: According to clinical trials, people with metabolic syndrome have a 2 to 4-fold increase in risk for coronary heart disease. Some of them have a particularly high risk (association of most features of the syndrome, association of an increased waist circumference and hypertriglyceridemia, presence of biological markers such as elevated C-reactive protein or microalbuminuria). Metabolic syndrome is also associated with a 4-fold increase in risk for developing diabetes.
A portable data recording system that works on the basis of a microcomputer has been developed. The main advantage of this system consists in the carrying out of checks for illogical and contradictory entries during the process of recording. False entries can immediately be corrected. The data are temporarily stored on disks. Subsequent to the completion of the investigation they are automatically transmitted by a transfer program to the computer-system in the computer center. This excludes any human errors occurring in the course of the transfer of the data. During a pilot study, the advantages of the microcomputer system were shown by comparing frequency of examination and recording errors using conventional recording methods and the microcomputer system.
A national registry for cystic fibrosis was established in France in 1993. A questionnaire is sent once a year to different health care units. The first questionnaire was analyzed in 1992: 1,893 patients (53% males) were identified. 28% were over 15 years of age, 13% more than 20, and 1% over 35. Usually, diagnosis had been suggested by respiratory signs, followed by digestive tract signs and growth impairment and meconial ileus. 13% were diagnosed in screening programmes. Diagnosis was made before 1 year in 66% of the subjects (mean = 7 months). All the data collected and the functional and bacteriologic data were compared with those observed in the United States and Canada. It should also be noted that 38 patients were grafted during this study year and that it is too early to analyze the general outcome for all subjects. The creation of this registry is an important step towards a better understanding of the epidemiology of cystic fibrosis in the French population.
During the 1988 outbreak of 15 cases of Type 1 poliomyelitis mainly among previously vaccinated young adults in Israel, there were conflicting views on the need for and timing of mass vaccination. Since there was a possibility that the initially localized outbreak may spread more widely, it was felt that an early decision on vaccination policy should be made. Public health officials were faced with varied interpretations of the existing data on the extent of the immune status of the population; some indicating that as many as 15% of young adults lacked immunity to the Type 1 virus. Two major questions posed were whether or not the outbreak was a purely localized event in a single subdistrict, and whether the seasonality of the disease would limit its spread. Based on historical data, probability analysis of three cases occurring outside the subdistrict at the time of the outbreak suggested more widespread dispersion of the virus. Further analysis indicated very limited seasonality of the disease in this region, suggesting that the onset of colder weather would have little impact on the spread of the virus. Careful analysis of the local epidemiology of the disease is an important tool for guiding urgent decisions on mass intervention policy in outbreak situations.
The word "asbestos" is used to designate the main commercial types of asbestos (chrysotile, crocidolite, amosite) but there exist numerous asbestiform fibrous minerals, which are commercially valueless but widespread at the surface of the earth. Among them zeolite has already created health hazards in Turkey. Measurement of fibres in air and in tissues can contribute to a better knowledge of lung and body fibre burden associated with diseases. Among fibre-related diseases, studies have recently focused on clinical, epidemiological and pathogenic aspects of pleural fibrosis and lung or pleural cancer. At present the roles of the different types of fibres in the genesis of these diseases remain controverted. However, tobacco smoke associated with inhaled asbestos fibres provokes a multiplied risk of lung cancer. Regarding asbestos there exist regulations in most industrial countries designed to protect workers and diminish environmental pollution.
Incidence rates of colorectal cancer are relatively low in Asian populations, in which soy foods are commonly consumed. Soybeans and soy foods are an almost exclusive source of isoflavone intake. In in vitro studies, isoflavones have been shown to have various anticarcinogenic properties such as inhibition of protein tyrosine phosphorylation, induction of apoptosis, antiangiogenesis, and inhibition of DNA topoisomerase. Thus the protective role of soy foods and isoflavones in the etiology of colorectal cancer is a matter of interest. We therefore reviewed animal and epidemiological studies of colorectal cancer in relation to soybeans, soy foods, and isoflavones. Animal studies fairly consistently showed that soyfoods or isoflavones inhibited the formation of aberrant crypt foci, but did not clearly demonstrate an inhibitory effect of soy foods and isoflavones on the development of chemically-induced colorectal cancer. Several case-control studies have suggested that soy food consumption may confer a reduced risk of colorectal cancer although the findings are rather inconsistent. Most of the previous studies, especially in Japan, ascertained only the frequency of consuming selected soy foods, and thus were defective as regards the measurement of the total consumption of soy foods. Further epidemiological studies are needed to clarify the role for soy foods in colorectal carcinogenesis.
The concept of model validation is evolving in the scientific community. This paper addresses the comparison of observed and predicted estimates as one component of model validation as applied to the integrated exposure uptake biokinetic (IEUBK) model for lead in children. The IEUBK model is an exposure (dose)-response model that uses children's environmental lead exposures to estimate risk of elevated blood lead (typically > 10 micrograms/dl) through estimation of lead body burdens in a mass balance framework. We used residence-specific environmental lead measurements from three epidemiologic datasets as inputs for the IEUBK model to predict blood lead levels, and compared these predictions with blood lead levels of children living at these residences. When the IEUBK modeling focused on children with representative exposure measurements, that is, children who spent the bulk of their time near the locations sampled, there was reasonably close agreement between observed and predicted blood lead distributions in the three studies considered. Geometric mean observed and predicted blood lead levels were within 0.7 microgram/dl, and proportions of study populations expected to be above 10 micrograms/dl were within 4% of those observed.
Misclassification is a common source of bias and reduced efficiency in the analysis of discrete data. Several methods have been proposed to adjust for misclassification using information on error rates (i) gathered by resampling the study population, (ii) gathered by sampling a separate population, or (iii) assumed a priori. We present unified methods for incorporating these types of information into analyses based on log-linear models and maximum likelihood estimation. General variance expressions are developed. Examples from epidemiologic studies are used to demonstrate the proposed methodology.
According to population projections there will shortly be an increase in the number of aged people. Since these population groups show a high risk to develop old age dementia and because this sickness goes along with the need of care, it is necessary for planning future needs of buildings and funds to know about the extent of expected dementia and the number of people needing care. Based on population projections up to the year 2040 for the (West) German Länder of the Federal Republic of Germany and based on four epidemiological studies, we developed a model to project empirically the number of dementia cases for the next 50 years. This model is based on an exponential growth of prevalence with increasing age. According to our estimates the number of patients with severe and moderate dementia will rise by about 50% from 1990 until 2040. The expected number of people needing care is estimated to facilitate prospective planning as well as timely provision of adequate financial and personnel resources.
Results of this study show an increasing incidence of adenocarcinoma in the esophagus and cardia. The reasons of this rise are speculative. Adequate diagnostic and therapeutic strategies must be evaluated; these can only be performed in specialist centers.
DNA hybridisation of 309 consecutive Staphylococcus aureus clinical isolates with oligonucleotide probes specific for genes encoding Panton-Valentine leucocidin (luk-PV) and gamma-haemolysin (hlg) revealed that 99% of randomly selected strains carried the hlg locus whereas only 2% harboured the luk-PV as well as the hlg loci. Only 1% of the strains did not possess either gene. In a clinical prospective study of independent S. aureus strains, 58 Panton-Valentine leucocidin (PVL)-producing isolates were shown to be responsible for primary skin infections, mainly furuncles (86%). Phage susceptibility patterns and pulsed field gel electrophoresis (PFGE) profiles of DNA were shown to be polymorphic epidemiological markers of PVL-producing strains. In eight patients with recurrent furuncles, the PVL-producing strains isolated either from furuncles or from the anterior nares were considered to be identical in each based upon phage sensitivity profiles or PFGE patterns.
MOTIVATION: The wealth of single nucleotide polymorphism (SNP) data within candidate genes and anticipated across the genome poses enormous analytical problems for studies of genotype-to-phenotype relationships, and modern data mining methods may be particularly well suited to meet the swelling challenges. In this paper, we introduce the method of Belief (Bayesian) networks to the domain of genotype-to-phenotype analyses and provide an example application. RESULTS: A Belief network is a graphical model of a probabilistic nature that represents a joint multivariate probability distribution and reflects conditional independences between variables. Given the data, optimal network topology can be estimated with the assistance of heuristic search algorithms and scoring criteria. Statistical significance of edge strengths can be evaluated using Bayesian methods and bootstrapping. As an example application, the method of Belief networks was applied to 20 SNPs in the apolipoprotein (apo) E gene and plasma apoE levels in a sample of 702 individuals from Jackson, MS. Plasma apoE level was the primary target variable. These analyses indicate that the edge between SNP 4075, coding for the well-known epsilon2 allele, and plasma apoE level was strong. Belief networks can effectively describe complex uncertain processes and can both learn from data and incorporate prior knowledge. AVAILABILITY: Various alternative and supplemental networks (not given in the text) as well as source code extensions, are available from the authors. SUPPLEMENTARY INFORMATION: http://bioinformatics.oxfordjournals.org.
International variations and national time trends in disease rates suggest major associations between dietary fat and several important cancers. In contrast, case-control and cohort studies of dietary fat in relation to the same cancers generally report weak associations, or have failed to detect any association with fat intake. This study was undertaken in an attempt to understand the apparent discrepancy between these observations. The results provide an insight into the magnitude of cancer risk reduction that may follow from a practical reduction in dietary fat. Regression analyses of international variations in cancer incidence rates were used to estimate relative risks (RR) as a function of fat intakes for both males and females. These analyses focused on cancers of the breast, colon, rectum, ovary, and endometrium in females, and colon, rectum, and prostate cancers in males. Ages 55-69 and 30-44 were considered in order to compare RR estimates between an older and younger age group, and between post- and pre-menopausal women. Corresponding RR estimates were also calculated, based on the regression of changes in disease rates from the mid-1960s to 1980 on changes in dietary fat, using data from several countries. A strong degree of consistency with the RR estimates from international comparisons was observed. The international regression analyses were also used to project changes in cancer rates among Japanese migrants to the United States. A high level of consistency with the observed disease-rate changes was noted. Similarly, the international data analyses were used to project RRs for the fat intake categories used in specific case-control and cohort studies, while acknowledging measurement error in individual dietary assessment. Although certain exceptions are noted, considerable consistency was found between the aggregate and analytic data results, leaving open the strong possibility that a practical reduction in dietary fat could result in a major reduction in the incidence of several prominent cancers in the United States and in other nations having high fat consumption.
Long-term effects of drug type and other drug use related risk factors on CD4+ cell decline were assessed in 224 HIV-infected injecting drug users (IDUs) from Baltimore (ALIVE), USA, and 63 IDUs from Amsterdam, The Netherlands. Higher frequencies of borrowing used injection equipment since 1980 resulted in a higher CD4+ count already present before seroconversion (P = 0.049). Use of mainly heroin in the seroconversion interval resulted in a sharper CD4+ decline until the first 6 months after seroconversion (P = 0.004), but CD4+ values converged later on. This finding might reconcile earlier discordant epidemiological and laboratory study results regarding the possible effects of heroin.
The relation between the maximal velocity of red blood cell sodium-lithium countertransport and blood pressure/hypertension has been studied in 2,748 men and women aged 25-74 years who participated in the 1983-85 baseline examination of the Gubbio Population Study, an epidemiologic investigation performed in a hill town of north central Italy. Men had a higher sodium-lithium countertransport velocity than women at all ages, and, in both sexes, a higher velocity was observed at successive ages. Hypertensives of both sexes had a higher sodium-lithium countertransport velocity than normotensive individuals, the difference remaining significant after control for age, body mass index and plasma uric acid concentration. Individuals with high sodium-lithium countertransport velocity had significantly greater prevalence of hypertension in both sexes. The data show the existence of a cross-sectional association between sodium-lithium countertransport velocity and hypertension in general population. Prospective study of the Gubbio population is now in progress to investigate the relation between baseline sodium-lithium countertransport velocity, its change over the years and the incidence of hypertension.
In the present nationwide survey, 1,040 new cases of lymphoid malignancy, in most of which expression of cell surface markers had been determined, and 243 controls for a case-control study on adult T-cell leukemia/lymphoma (ATL) and other types of lymphoid malignancies were enrolled during the two years (1982-84) from 24 institutions throughout Japan. Among the 1,040 cases, 197 cases of ATL, 183 cases of T-cell lymphoma and 236 cases of non T-cell lymphoma were used in the detailed analysis of the clinico-pathological and epidemiological findings. Furthermore, 66 cases of ATL and 174 cases of other lymphoid malignancies were used for case-control analysis. In order to standardize the clinico-pathological classification throughout Japan, 20 hematologists and 12 pathologists met once a year and made the final consensus diagnosis in each case of lymphoid malignancy. Five hundred cases of non-Hodgkin's lymphoma were examined for antibody to ATL-associated antigen (ATLA). Clinico-pathological and epidemiological features for these cases were compared according to their anti-ATLA antibody status. The new results obtained from this survey are as follows: All of the patients with ATL in Kyushu had anti-ATLA antibody, but several patients with ATL in other districts had no anti-ATLA antibody, suggesting that there was no association with ATL virus (ATLV) infection in these cases. There was a difference in the histopathological patterns in non-Hodgkin's lymphoma between Kyushu and the other districts, which was due to the difference in distribution of the ATLV-associated lymphoid malignancies, namely ATL, in each area. The histopathological distribution in anti-ATLA negative cases in the Kyushu district was almost the same as that in the other districts.
The strong geographic and social class differences in blood pressure may be related to differences in potassium intake or in the ratio of sodium to potassium intake. "Low salt" populations also have high potassium intake. In Japanese villages, populations with similar salt intake but different blood pressures had different potassium intake. In one study, a significant correlation was found between urinary Na/K ratio and blood pressure. Another study showed a significant negative correlation between potassium excretion and blood pressure. Four studies are available that show that blacks excrete much less potassium than whites. One of these studies also showed, by analyzing duplicate meals, that blacks consumed much less potassium than whites. A high potassium diet tends to be more expensive than a low potassium diet. Potassium intake may be a major factor in the epidemiologic differences of hypertension.