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PubMed2004

[Respiratory syntomatic prevalence, infection and tuberculosis disease and associated factors: population-based study].

A cross sectional survey on TB epidemiological characteristics was carried out in Mitú (Vaupes, Colombia) with the aim of measuring the prevalence of TB cases, the prevalence of TB suspected cases, the coverage with BCG vaccine and the prevalence of infection with Mycobacterium tuberculosis. One hundred and sixty five (165) households were included in the survey using a randomized cluster sampling design (n=20 clusters) which yielded a sample size of 972 subjects. The prevalence of TB suspect cases was 3.6% (C.I.95% 2.6-4.9%); coverage with BCG vaccine was 94%. Vaccinated people had a lower chance of being a TB suspected case (OR=0.37 C.I.95% 0.15-0.95). TB prevalence was 1.4%. People vaccinated with BCG had a lower chance of having been a TB case (OR=3.3 C.I.95% 1.0-14). These data recommend that 10% of people with respiratory symptoms be screened for in the National Control Program,and that the results be reviewed with surveys based at health centers. The data also reinforce the need for better vaccination coverages with BCG in high endemic areas.

Adolescent↗
PubMed1987

Pharmacokinetics and tissue residues of gentamicin in lactating cows after multiple intramuscular doses are administered.

Gentamicin was administered IM to 6 healthy, mature, lactating cows at a dosage of 3.5 or 5 mg/kg of body weight every 8 hours for 10 consecutive days (total, 30 doses). Endometrial biopsies were done at 72, 136 or 144, and 216 hours after the first dose was administered. On the 10th day, just before the last dose of gentamicin was administered, blood samples (designated 10th-day base-line samples) were obtained, and serial blood samples were obtained for 144 hours after the last injection was given. The cows were catheterized on the 10th day, and urine was obtained for 10 to 18 consecutive hours. Milk samples were also obtained. The cows were slaughtered at different times after the last dose was given, and samples were taken from 22 tissues and organs. Serum, milk, urine, and tissue gentamicin concentrations were determined by radioimmunoassay. Serum gentamicin concentrations were best fitted to a 2-compartment open model. The mean half-lives for absorption, distribution, and elimination were 0.16 +/- 0.14, 2.59 +/- 0.53, and 44.91 +/- 9.38 hours, respectively. Total body clearance and renal clearance were 1.65 +/- 0.69 and 1.32 +/- 0.25 ml/min/kg, respectively. The percentage of the dose excreted unchanged in the urine at 8 hours after the last dose was given was 98 +/- 15. As expected, of the tissues examined, the gentamicin concentrations in the kidney cortex and medulla were 1,500 times greater than those in serum. Renal function remained within the baseline range during the 10 days of gentamicin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

The influence of linear elements on plant species diversity of Mediterranean rural landscapes: assessment of different indices and statistical approaches.

This paper mainly aims to study the linear element influence on the estimation of vascular plant species diversity in five Mediterranean landscapes modeled as land cover patch mosaics. These landscapes have several core habitats and a different set of linear elements--habitat edges or ecotones, roads or railways, rivers, streams and hedgerows on farm land--whose plant composition were examined. Secondly, it aims to check plant diversity estimation in Mediterranean landscapes using parametric and non-parametric procedures, with two indices: Species richness and Shannon index. Land cover types and landscape linear elements were identified from aerial photographs. Their spatial information was processed using GIS techniques. Field plots were selected using a stratified sampling design according to relieve and tree density of each habitat type. A 50x20 m2 multi-scale sampling plot was designed for the core habitats and across the main landscape linear elements. Richness and diversity of plant species were estimated by comparing the observed field data to ICE (Incidence-based Coverage Estimator) and ACE (Abundance-based Coverage Estimator) non-parametric estimators. The species density, percentage of unique species, and alpha diversity per plot were significantly higher (p < 0.05) in linear elements than in core habitats. ICE estimate of number of species was 32% higher than of ACE estimate, which did not differ significantly from the observed values. Accumulated species richness in core habitats together with linear elements, were significantly higher than those recorded only in the core habitats in all the landscapes. Conversely, Shannon diversity index did not show significant differences.

Biodiversity↗
PubMed2000

Descriptive anthropometric reference data for older Americans.

OBJECTIVE: To present selected anthropometric data derived from adults aged 60 years and older examined in the third National Health and Nutrition Examination Survey (NHANES III). DESIGN: NHANES III used a complex, stratified, multistage, probability cluster sample design to obtain a nationally representative sample of the US civilian, noninstitutionalized population. Persons aged 60 years and older, Mexican-Americans, and African-Americans were oversampled to produce more reliable estimates for these groups. Trained technicians measured height, weight, skinfold thickness, and circumferences using standardized procedures. SUBJECTS: A total of 5,700 persons aged 60 years and older, and 1,861 persons aged 50 to 59 years. STATISTICAL ANALYSES PERFORMED: Mean and selected percentiles for body weight, body mass index, triceps skinfold thickness, mid upper arm circumference, and arm muscle circumference were calculated by gender, race/ethnicity, and 3 age categories. Weight (lb) per height (in) tables were generated for men and women by age group. RESULTS: Mean body weight was lowest for persons aged 80 years and older. A decline in body mass index occurred that paralleled the direction and magnitude of the progressive decrease observed in weight. Muscle loss with increasing age, as indicated by arm muscle circumference, appeared to be greater among men than women. APPLICATIONS/CONCLUSIONS: In addition to being relatively simple, quick, and inexpensive, anthropometry is the most reliable and specific indicator of malnutrition in the older adult population. The cross-sectional reference data provided can be used by dietitians to interpret anthropometric measurements of persons aged 60 years and older.

Black or African American↗
PubMed1999

Epidemiology for the practicing orthodontist.

Epidemiological principles and biostatistical techniques are essential when performing research in human populations. This article describes the methods used for designing valid and reliable research and the statistical concepts necessary to analyze data from such studies. Specifically, the overview includes the different epidemiological study designs, sampling techniques, sources of bias encountered in research studies, and statistical tests to assess significance. It is hoped that clinical orthodontists will benefit from this review.

Bias↗
PubMed1989

Biostatistics in clinical trials: Part 2. Determining sample sizes for clinical trials.

The appropriate sample size for a clinical trial depends on the objectives of the trial. For Phase II trials, the recommended sample size is generally in the neighborhood of 25-40 patients, regardless of the choice of design. Sample sizes for Phase III trials are much more variable, ranging from less than a hundred to thousands of patients. The methodology of sample size determination for Phase III trials depends on the type of endpoint that is to be the primary focus of analysis. Tables of sample sizes for a variety of situations are presented. Use of sequential designs may reduce the required sample size by permitting early termination of trials whose results become definitive prior to completion of patient entry.

Clinical Trials as Topic↗
PubMed1998

Critical appraisal of the health research literature: prevalence or incidence of a health problem.

This article identifies and discusses criteria that can be used by health professionals to critically appraise research articles that estimate the prevalence or incidence of a disease or health problem. These guidelines will help determine the validity and usefulness of such community assessment studies. The criteria relate to the validity of the study methods (design, sampling frame, sample size, outcome measures, measurement and response rate), interpretation of the results and applicability of the findings. The research question "What is the prevalence of dementia in Canada?" is used as an example for this paper.

Bias↗
PubMed2006

Challenging behaviour and learning disabilities: the relationship between expressed emotion and staff attributions.

OBJECTIVES: Expressed emotion (EE) and attributions towards challenging behaviour (CB) were explored amongst a group of staff working within a residential and day service placement for people with learning disabilities. DESIGN: Using a cross-sectional related-samples design, EE and attributions were measured amongst all staff working with one client with CB, and one client without CB. METHODS: Fifteen staff members completed the attributional questionnaire and the 5-minute speech sample (FMSS) to allow for EE ratings concerning staff relationships with two clients. One client exhibited CB, while the other did not, giving 2 samples. Attributional and EE ratings for each group were compared. This study did not employ vignette methodology. RESULTS: Staff working with a client with learning disabilities and CB attributed the CB as internal to the client and controllable by the client. Staff reported high levels of EE and made more critical comments towards the client with CB as compared with the client without CB. Furthermore, staff who reported high EE attributed CB as internal to the client and controllable by the client. CONCLUSIONS: Staff working with a client with challenging behaviour appeared to be making the 'fundamental attribution error'. The relationship between expressed emotion and attribution theory is discussed along with the methodological benefits of not relying on vignette methodology in research that examines challenging behaviour.

Adult↗
PubMedDate not supplied

Environmental sampling: a brief review.

Proper application of statistical principles at the onset of an environmental study can make the difference between an effective, efficient study and wasted resources. This review distills some of the thoughts current among environmental scientists from a variety of backgrounds and organizes them according to statistical principles. Collection and review of preliminary information is important for guiding sampling design. Problems must be carefully defined before rational sample selection is possible. Many potential sources of variability exist, and as many of these sources as possible should be identified, assessed, and, ideally, minimized. Sample selection itself will depend on the precise questions that are to be addressed by the study and on what assumptions can be reasonably made about structures and patterns of contaminants in the field. Careful specification of protocols for sample procurement are needed. Choices of statistical analyses will depend on how data are collected, and intended analyses should be predetermined as part of the sampling plan. Proper attention to these principles will substantially increase the quality and efficiency of an environmental sampling program.

Data Collection↗
PubMed2004

Methodologic issues in research on religion and health.

This study examines several methodologic issues in research on religion and health, including the measurement of the concept of religion, research designs, sampling, and statistical controls for assessing the "net" effects of religion on health outcomes. It briefly discusses differences in analytical perspectives that have contributed to the debate about the effects of religion on health. The authors review some of the methodologic problems of past research in this area of study and address what needs to be done to enhance the quality of the research. The authors conclude that the research methodology used in studies of religion and health has improved over time and that it continues to do so.

Epidemiologic Methods↗
PubMed1993

Regression analysis of grouped survival data: informative censoring and double sampling.

To analyze grouped survival data subject to informative censoring, we propose the following two-part model: a logistic regression model for the hazard for failure, given covariates and a logistic regression model for the hazard for informative censoring, given time of failure and covariates. We fit the model to survival data arising from a double sampling design: In a full follow-up (FF) sample subjects are followed after censoring, and in a partial follow-up (PF) sample subjects are not followed after censoring. We illustrate the methodology using data from a study of wound infection in which patients in the PF sample are censored by release from the hospital, whereas patients in the FF sample are followed after hospital release. We discuss identifiability when there is only a PF sample. We also consider how the allocation between the PF and FF samples affects the precision of estimates.

Follow-Up Studies↗
PubMed2005

Adaptive design and estimation in randomized clinical trials with correlated observations.

Clinical trial designs involving correlated data often arise in biomedical research. The intracluster correlation needs to be taken into account to ensure the validity of sample size and power calculations. In contrast to the fixed-sample designs, we propose a flexible trial design with adaptive monitoring and inference procedures. The total sample size is not predetermined, but adaptively re-estimated using observed data via a systematic mechanism. The final inference is based on a weighted average of the block-wise test statistics using generalized estimating equations, where the weight for each block depends on cumulated data from the ongoing trial. When there are no significant treatment effects, the devised stopping rule allows for early termination of the trial and acceptance of the null hypothesis. The proposed design updates information regarding both the effect size and within-cluster correlation based on the cumulated data in order to achieve a desired power. Estimation of the parameter of interest and its confidence interval are proposed. We conduct simulation studies to examine the operating characteristics and illustrate the proposed method with an example.

Biometry↗
PubMed2005

Clinical results of a split sample liquid-based cytology (ThinPrep) study of 4,322 patients in a Turkish institution.

PURPOSE: A prospective study was carried out to compare the efficacy of liquid-based cytology (ThinPrep) with the conventional Pap smear using a split-sample design in a Turkish university hospital outpatient gynecology clinic. METHODS: 4,322 consecutive patients were recruited for the study between 2002 and 2003. All the patients underwent conventional Pap tests followed by a ThinPrep test for screening of cervical cancer. The results were evaluated in terms of the Bethesda III classification. All the patients with abnormal tests underwent colposcopy and directed biopsy. RESULTS: While 2.3% of the specimens were unsatisfactory for evaluation in the conventional Pap test group, this rate was 1.7% for the ThinPrep group. Epithelial cell abnormalities were observed in 42 (1.0%) patients in the conventional Pap test group and in 36 (0.8%) patients in the ThinPrep group. ASCUS was observed in 26 patients in the conventional Pap test group whereas the ThinPrep group had 20 cases of ASCUS as the leading cause of abnormal cytology. Biopsy of these cases revealed CIN 1 in two CIN 2-3 in three and cervical/endometrial adenocarcinoma in three patients. The ThinPrep application led to diagnoses of one additional case of CIN 2-3 and one case of adenocarcinoma among the negative or unsatisfactory for evaluation categories of the conventional Pap test group. CONCLUSION: Despite an adverse bias introduced by the split-sample study design, application of ThinPrep showed an improved rate of specimen adequacy and increased sensitivity for more significant cervical precursor lesions over the conventional Pap test.

Adolescent↗
PubMed2006

Music as nursing intervention for pain in five Asian countries.

BACKGROUND: The use of music as intervention for relieving pain has increased in recent years, prompting its growing use among the people of the western world. However, among Asians, music has long been used for this purpose and continues to be so today. Despite this common knowledge, Asians have not generally written about the therapeutic effects of music. Consequently, most of the published research studies supporting this claim were conducted in western settings using western music. PURPOSE: To describe the use of music as intervention in painful conditions as experienced by people in five Asian countries: China, Thailand, Philippines, South Korea and Taiwan. METHOD: Descriptive survey of studies using music as intervention for painful conditions conducted in selected five Asian countries. FINDINGS: Twelve studies including theses and dissertations, published and unpublished, were found; however, only nine met the inclusion criteria. Data were categorized according to research design, sample size, gender, age, duration of music, frequency of music intervention, types of pain and instruments used to measure pain, conceptual or theoretical frameworks and statistical significance of the study. Five of the nine studies declared significant decrease in pain, while three reported mixed results. Fundamentally, the findings of the studies suggested that with music, relief of pain was possible. IMPLICATIONS: The mixed results imply the need for further investigation of the effects of music in painful conditions. Thus, the authors suggest continuing studies on the effects of music as intervention in painful conditions, and encourage increasing global dissemination of these studies, particularly in international journals.

Adult↗
PubMed1995

Screening for stratification in two-phase ('two-stage') epidemiological surveys.

Screening is undertaken not only for the purpose of giving therapeutic treatment to those among screen positive subjects found to be diagnosis positive, but it is also used in epidemiology as the first phase of multi-phase sampling designs. We review the use of such designs in epidemiology, and in psychiatric epidemiology in particular, focusing on two-phase or double sampling. We then compare a variety of approaches to the statistical analysis of data from such designs including the use of sampling weights, Gibbs sampling, full maximum likelihood for random effects logistic regression and a simple E-M algorithm for incomplete data. The methods are illustrated using data from a recent multi-phase study of psychiatric morbidity in northern Spain.

Humans↗
PubMed2026

Haplotype Blocks Are Associated With Rapid Local Adaptation to Environmental Shifts in Wild Barley.

Genomic mechanisms of local adaptation must be highly responsive in geographic regions where climate is changing rapidly. The Levant region is a critical biodiversity hotspot and the distribution edge for many species, including the wild ancestor of domesticated barley. This region is under an accelerated desertification process, thus enforcing a rapid genomic response to the projected environmental changes. To elucidate the genomic basis of rapid local adaptation, we studied wild barley populations using an ecological-genetic sampling design that decouples environmental variation from demographic background. We collected and sequenced 300 wild barley individuals and evaluated the phenotypes of 3600 progeny plants over 3&#x2009;years. Our genomic analyses revealed that local adaptation is associated with clusters of candidate genes forming haplotype blocks. These clusters are enriched with environment and stress responsive genes, including flowering time regulators, drought and heat responsive genes. We identified six candidate adaptive haplotype blocks which span 1-8&#x2009;Mbp and are distributed across chromosomes 1H, 2H, 4H and 5H, each segregating as two major haplotypes. Additionally, we integrated over 2600 occurrence records into ecological and evolutionary modelling to assess the genomic vulnerability of populations to projected future climates. Our study identifies candidate genomic regions and environmental drivers of local adaptation in wild barley and highlights the advantage of haplotype blocks architecture in orchestrating an efficient response to rapid environmental change. We highlight the ecological factors most strongly associated with the observed evolutionary responses and provide insights and guidelines for biodiversity conservation and implementation of crop wild relatives in breeding.

Hordeum↗
PubMed2006

Neighborhood Environment Walkability Scale: validity and development of a short form.

PURPOSE: The aim of this study was to examine the factorial and criterion validity of the Neighborhood Environment Walkability Scale (NEWS) and to develop an abbreviated version (NEWS-A). METHODS: A stratified two-stage cluster sample design was used to recruit 1286 adults. The sample was drawn from residential addresses within eight high- and eight low-walkable neighborhoods matched for socioeconomic status. Subjects completed the NEWS and reported weekly minutes of walking for transport and recreation using items from the International Physical Activity Questionnaire. RESULTS: Multilevel confirmatory factor analysis was used to develop measurement models of the NEWS and NEWS-A. Six individual-level and five blockgroup-level factors were identified. Factors/scales gauging presence of diversity of destinations, residential density, walking infrastructure, aesthetics, traffic safety, and crime were positively related to walking for transport. Aesthetics, mixed destinations, and residential density were associated with walking for recreation. CONCLUSIONS: The NEWS and NEWS-A possess adequate levels of factorial and criterion validity. Alternative methods of scoring for different purposes are presented.

Adult↗
PubMed2003

A national survey of assisted living facilities.

PURPOSE: Throughout the 1990s, assisted living was the most rapidly growing form of senior housing. The purpose of this paper is to describe the existing supply of assisted living facilities (ALFs) and examine the extent to which they matched the philosophy of assisted living. DESIGN AND METHODS: The study involved a multistage sample design to produce nationally representative estimates for the ALF industry. Administrators of nearly 1,500 eligible ALFs were interviewed by telephone. RESULTS: As of 1998, there were an estimated 11,459 ALFs nationwide, with 611,300 beds and 521,500 residents. Nearly 60% offered a combination of low services and low or minimal privacy, whereas only 11% offered relatively high services and high privacy. Seventy-three percent of the resident rooms or apartments were private. Aging-in-place was limited by discharge policies in most ALFs for residents who needed help with transfers, had moderate to severe cognitive impairment, had any behavioral symptoms, or needed nursing care. The industry is largely private pay and unaffordable for low- or moderate-income persons aged >/=75 unless they use assets as well as income to pay. IMPLICATIONS: ALFs differed widely in ownership, size, policies, and the degree to which they manifested the philosophy of assisted living. This diversity represents a challenge for consumers in terms of selecting an appropriate facility and for policy makers in terms of deciding what role they want assisted living to play in long-term care.

Assisted Living Facilities↗