Estimating true scores in kinship data

Estimated true scores are occasionally used to provide an estimate of scores which would be obtained if measurement error could be removed from fallible measures. When one knows only a test's relibility and an observed score for each subject, true scores are estimated by regressing observed scores toward the group mean. When relatives' observed scores are also available, estimates of true scores can be improved by using the additional information. Observed scores of subjects and relatives can be used as predictors of subjects' true scores in a multiple regression. The resulting formula is presented for the case in which only one relative's score per subject is known. Estimation of true scores for the general case ofN relatives per subject is also discussed.     

Spatiotemporal reasoning about epidemiological data

OBJECTIVE: In this article, we propose new methods to visualize and reason about spatiotemporal epidemiological data. BACKGROUND: Efficient computerized reasoning about epidemics is important to public health and national security, but it is a difficult task because epidemiological data are usually spatiotemporal, recursive, and fast changing hence hard to handle in traditional relational databases and geographic information systems. METHODOLOGY: We describe the general methods of how to (1) store epidemiological data in constraint databases, (2) handle recursive epidemiological definitions, and (3) efficiently reason about epidemiological data based on recursive and non-recursive Structured Query Language (SQL) queries. RESULTS: We implement a particular epidemiological system called West Nile Virus Information System (WeNiVIS) that enables the visual tracking of and reasoning about the spread of the West Nile Virus (WNV) epidemic in Pennsylvania. In the system, users can do many interesting reasonings based on the spatiotemporal dataset and the recursively defined risk evaluation function through the SQL query interfaces. CONCLUSIONS: In this article, the WeNiVIS system is used to visualize and reason about the spread of West Nile Virus in Pennsylvania as a sample application. Beside this particular case, the general methodology used in the implementation of the system is also appropriate for many other applications. Our general solution for reasoning about epidemics and related spatiotemporal phenomena enables one to solve many problems similar to WNV without much modification.     

Summarizing methacholine bronchoprovocation data in epidemiological surveys

We have performed bronchoprovocation tests with methacholine in 41 patients with asthma due to Western red cedar dust and in 56 office-workers without known respiratory illness. Our purpose was to define a summary statistic for useful bronchial hyperresponsiveness in epidemiologic surveys. We found a significant linear relationship between the concentration of methacholine and the FEV1 response. We noted, in addition, a positive relation between the rate of the FEV1 response per concentration and the level of FEV1. We conclude that a linear dose-response slope, which can be calculated for each individual, provides a comprehensive summary of methacholine bronchoprovocation tests and is useful in epidemiologic surveys.     

Malaria in Vanuatu. Recent epidemiological data

The Republic of Vanuatu, ex-Condominium of New-Hebrides, is an archipelago in the South Pacific, between Solomon Islands and New-Caledonia. Although the health system is quite satisfactory, malaria has become the major health problem in the whole country. Its epidemiological characteristics are reviewed, and particularly the biology of the only known vector, the Anopheles farauti complex. A sudden and severe aggravation of the malaria morbidity since 1980 is then evidenced. This increase of the yearly incidence (from 21% to 183% between 1980 and 1984) has privileged the rising of Plasmodium falciparum which reached 75% of the national paraside index. Moreover, it has clearly followed a geographical progression from north to south within the group during the four years. Various possible causes to this alarming situation are examined, among which the emergence of chloroquin-resistant strains of P. falciparum, and the possibility of modifications in the vector's population, particularly hold the attention.     

Measures and models for causal inference in cross-sectional studies: arguments for the appropriateness of the prevalence odds ratio and related logistic regression

Background  

Several papers have discussed which effect measures are appropriate to capture the contrast between exposure groups in cross-sectional studies, and which related multivariate models are suitable. Although some have favored the Prevalence Ratio over the Prevalence Odds Ratio -- thus suggesting the use of log-binomial or robust Poisson instead of the logistic regression models -- this debate is still far from settled and requires close scrutiny.     

Rising prevalence of food allergies in Taiwan: An epidemiological study

BackgroundFood allergies are becoming more prevalent globally. The purpose of this study was to investigate the epidemiology of food allergies in Taiwan.MethodsIn 2017, a food allergy questionnaire was administered to 6–7-year-old children, 13–14-year-old adolescents, and their parents in Taipei. The results were compared to those from a previous survey conducted in 2004.ResultsA total of 16,200 questionnaires were completed, revealing a rise in the prevalence of food allergies from 7.7% to 10.4% in the pediatric group and from 6.4% to 12.5% in the adult group. Peanut allergies also increased to 1.1%. Shrimp and crabs were the most common allergens, with urticaria being the most common symptom. Shortness of breath or wheezing occurred in 10% of individuals, while 2.1% experienced syncope or shock, and 0.1% were admitted to an intensive care unit. Personal history of allergic rhinitis and atopic dermatitis, as well as family histories of food allergies, were risk factors for food allergy in 6–7-year-old children. In the 13–14-year-old group, personal history of asthma, allergic rhinitis, or atopic dermatitis, recent use of acetaminophen, and living with dogs were risk factors. Females, personal histories of asthma, allergic rhinitis, atopic dermatitis, and moist and damp at home were risk factors in adults. Breastfeeding was a protective factor in 6–7-year-old children.ConclusionThe increasing prevalence of food allergies, including peanut allergies, in Taiwan warrants attention from physicians to provide appropriate care and education to patients with food allergies. The protective effect of breastfeeding against food allergies shall be emphasized.     

Estimating WAIS IQ from the Shipley Institute of Living Scale using continuously adjusted age norms

Linear regression techniques and continuous norming were used to develop a procedure to estimate age-adjusted WAIS IQ scores from the Shipley Institute of Living Scale. The estimation procedure was derived on a mixed sample of 86 psychiatric patients and then was replicated on an independent sample of 44 psychiatric outpatients. Estimated scores based on the cross-validation sample correlated .76 and .74, respectively, with WAIS Full Scale scaled scores and IQs and did not over- or underpredict, which indicates a high degree of concordance between these two procedures. Compared to other procedures, such as those employed by Paulson and Lin (1970b), the continuous norm estimates of age-adjusted IQ are more stable because the age norms are smoothed analytically rather than developed on separate age groups. Thus, this estimation procedure is recommended for use in clinical and research settings in which a brief but accurate IQ estimate is desired.     

Six-month prevalence of phobic symptoms in Iceland: An epidemiological postal survey

An epidemiological questionnaire survey of the prevalence of various types of phobias was undertaken among the Icelandic population. Out of 1,000 individuals surveyed, in accord with national census data held in Reykjavík, 775 questionnaires were returned. Results confirmed that among Icelanders, phobic symptoms overall are more prevalent among women than men. Prevalence rates were lower for individuals 45 years or older, suggesting that extinction may occur with ageing. Divorced or separated individuals were most at risk, as were women homemakers, disabled, or unemployed persons. Education was inversely related to the incidence of all types of phobias, with individuals with less than 10 years of education reporting the highest rates of phobia. Most respondents attributed the onset of their phobias to a specific terrifying experience, and in many cases, to observing another person displaying an intense fear reaction in a given situation. Factor analysis of the data indicated that social anxiety phobias accounted for the greatest proportion of variance. © 1998 John Wiley & Sons, Inc. J Clin Psychol 54: 257–265, 1998.     

Evaluation of an automated safety surveillance system using risk adjusted sequential probability ratio testing

Background

Electronic prescribing is now the norm in many countries. We wished to find out if clinical software systems used by general practitioners in Australia include features (functional capabilities and other characteristics) that facilitate improved patient safety and care, with a focus on quality use of medicines.

Methods

Seven clinical software systems used in general practice were evaluated. Fifty software features that were previously rated as likely to have a high impact on safety and/or quality of care in general practice were tested and are reported here.

Results

The range of results for the implementation of 50 features across the 7 clinical software systems was as follows: 17-31 features (34-62%) were fully implemented, 9-13 (18-26%) partially implemented, and 9-20 (18-40%) not implemented. Key findings included: Access to evidence based drug and therapeutic information was limited. Decision support for prescribing was available but varied markedly between systems. During prescribing there was potential for medicine mis-selection in some systems, and linking a medicine with its indication was optional. The definition of 'current medicines' versus 'past medicines' was not always clear. There were limited resources for patients, and some medicines lists for patients were suboptimal. Results were provided to the software vendors, who were keen to improve their systems.

Conclusions

The clinical systems tested lack some of the features expected to support patient safety and quality of care. Standards and certification for clinical software would ensure that safety features are present and that there is a minimum level of clinical functionality that clinicians could expect to find in any system.     

Estimating historical forest-fire frequencies from time-since-last-fire-sample data

A method of estimating historical forest-fire frequencies basedon time-since-last-fire observations at a simple random sampleof points in an area of undisturbed forest is presented. Thehistorical-fire-hazard rate function is assumed to be piecewiseconstant (constant within distinct epochs separated by changepoints). The method is based on maximum likelihood, with thelikelihood function incorporating two sources of randomness—therandom occurrence and spread of fires, and the random selectionof sample points. The fire model includes a contagion effectrelated to the spread of fires and the consequent spatial autocorrelationin the time-since-last-fire. An example using data from WoodBuffalo National Park is presented, and the effects of groupingdata is discussed.     

Estimating dizygotic/monozygotic ratio of twins by general formula

Eight general formulas are presented for estimation of the dizygotic/monozygotic ratio (DMR) for twins of the same sex and blood groups. The derivation of these formulas and example applications for each are given in plain English without complex statistical symbols. The formulas cover all blood group systems including multiallele systems with silent gene(s) as well as the HLA system. Predetermined DMR values for commonly used genetic markers (except HLA) are provided for U.S. white and black persons.     

Genetic epidemiological study of schizophrenia in Palau, Micronesia: prevalence and familiality

We are studying the genetic etiology of schizophrenia in the Republic of Palau, a remote island nation in Micronesia that has been geographically and ethnically isolated for approximately 2,000 years. The first epidemiological phase sought to estimate the lifetime prevalence of schizophrenia and evaluate the familiality of the illness based on complete ascertainment of cases and families segregating schizophrenia. A total of 160 strictly defined cases of schizophrenia were ascertained in a population of 13,750 adults who were 15 years of age and older. The lifetime prevalence of strictly defined schizophrenia in Palau was 1.99% overall and 2.77% in males vs. 1.24% in females. This greater than 2:1 male-to-female risk ratio for schizophrenia was accompanied by an earlier mean age of onset for males (23.3 years) than for females (27.5 years). These 160 cases of strict schizophrenia represent 59 separate families each identified by a single common founder. Eleven of these families have 5 to 14 cases and represent nearly half of the strict schizophrenia cases in Palau. Although schizophrenia is clearly aggregating in these 11 families, cases are distributed sparsely throughout the large sibships. In the entire sample of 160 cases of strict schizophrenia, there were only 11 sib-pairs and 2 sib-trios. When a family was defined to include third-degree relatives, only 11 cases (6.9%) were nonfamilial. The majority of the ascertained cases can be linked together into extended pedigrees with complex multilineal inheritance patterns. These intricately interconnected families may pose challenges for traditional linkage techniques. However, these Palauan families represent a valuable resource for studying the genetic etiology of schizophrenia because there may be fewer susceptibility genes for schizophrenia in this genetic isolate than in the heterogeneous populations that are common throughout the world today.