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PubMed2002

Cohort effects on gender differences in alcohol dependence.

AIMS: The present study investigated the presence of cohort effects on gender differences in the course, severity and symptomatology of DSM-III-R alcohol dependence in a community-based sample. DESIGN: A comparison of substance-related variables among men and women divided into two groups based on the median birth year of the sample was conducted. PARTICIPANTS: Participants were 468 men and 132 women with life-time alcohol dependence, the vast majority of whom were born between 1941 and 1960. MEASUREMENTS: Substance use and DSM-III-R substance use disorders were assessed by a structured interview administered in person. FINDINGS: Individuals born after 1951 had higher rates of alcohol dependence. Among individuals with alcohol dependence, those born after 1951 had an earlier onset and longer duration of alcohol-related problems. Significant interactions indicated that these effects were stronger for women than men. CONCLUSIONS: Risk for alcohol dependence appears to be rising in younger generations, and particularly for younger women, making them an important target group for prevention and treatment programs.

Adult↗
PubMed2001

Solid waste characterisation study in the Guadalajara Metropolitan Zone, Mexico.

The key findings of a solid waste characterisation study conducted at the Guadalajara Metropolitan Zone, Mexico, are reported. Objectives of the study were to estimate the daily generation rate of household (HSW) and municipal solid waste (MSW), characterise and compare their composition by type of material, determine the proportion that HSW contributes to MSW, explore changes in MSW composition through time after final disposal, and estimate the types and amount of MSW that are sorted out for recycling at final disposal sites. HSW generated during seven days by a sample of 300 households chosen through a two-stage stratified sampling design was collected, weighed and classified. MSW entering the four local disposal sites was recorded for 12 weeks, and materials' sorting was quantified. MSW samples taken by excavating trenches in two final disposal sites were also characterised. The average per capita daily HSW generation rate was 508 g. HSW mainly consisted of putrescible waste (53%), paper (10%) and plastic (9%). The average daily generation rate of MSW was 3119.2 metric tonnes. HSW represented 55.9% of MSW, and the main difference between HSW and MSW was a lower proportion of organic materials (53% vs. 16.5%, respectively). The major changes in MSW composition through time after final disposal, were the result of the quick decomposition of putrescible materials. Only 2.2% of total MSW generated in Guadalajara (mainly package waste) was sorted for recycling.

Cities↗
PubMed2003

Nature and severity of physical harm caused by child abuse and neglect: results from the Canadian Incidence Study.

BACKGROUND: Despite growing public concern about child maltreatment, the scope and severity of this significant public health issue remains poorly understood. This article examines the nature and severity of the physical harm associated with reports of child maltreatment documented in the Canadian Incidence Study of Reported Child Abuse and Neglect (CIS). METHODS: The CIS collected information directly from child welfare investigators about cases of reported child abuse or neglect. A multistage sampling design was used to track child-maltreatment investigations conducted at selected sites from October to December 1998. The analyses were based on the sample of 3780 cases in which child maltreatment was substantiated. RESULTS: Some type of physical harm was documented in 18% of substantiated cases; most of these involved bruises, cuts and scrapes. In 4% of substantiated cases, harm was severe enough to require medical attention, and in less than 1% of substantiated cases, medical attention was sought for broken bones or head trauma. Harm was noted most often in cases of physical abuse compared to other forms of maltreatment. INTERPRETATION: Rates of physical harm were lower than expected. Current emphasis on mandatory reporting, abuse investigations and risk assessment may need to be tempered for cases in which physical harm is not the central concern.

Adolescent↗
PubMedDate not supplied

Tobacco use among school personnel in Orissa.

Tobacco use prevalence, knowledge and attitude was assessed among school personnel in Orissa. A single cluster sample design with probability proportional to the enrolment in grades VIII-X was used. Statistical analysis was clone using SUDAAN and the C-sample procedure in Epi-Info. The school response rate was 100%. Over 72% of school personals participated in the survey, the proportion of men being 84%. Current cigarette smoking, bidi smoking and smokeless tobacco use was reported by 26.8%, 30.1% and 38.8% school personnel respectively. Current daily cigarette smoking, bidi smoking and smokeless tobacco use reported by 18.3%, 16.6% and 24.2% school personnel respectively. Men reported significantly more all kinds of daily tobacco use as compared to women. School tobacco control policy on three scales was reported poor (25-39%). However most of the school personnel felt need for such policies (88-98%). Teaching and training on tobacco was reported low (22.7%-35.9%). Most of the school personnel (87-95%) were supportive on different measures on tobacco control issues. Introduction of comprehensive school policies and enforcement on tobacco use may help to reduce adolescent and school personnel tobacco use.

Cluster Analysis↗
PubMed1990

[Narcotic abuse in Jylland. A study based on narcotics and deaths of addicts examined at the Institute of Forensic Medicine, University of Aarhus during the period 1981-1988. 1. Narcotics].

On the basis of analysis of 1,879 samples of narcotics confiscated in Jutland and Funen during the period 1981-1988, the individual types of drugs are described as regards occurrence and quality. Cannabis and heroin were found in the illegal market during the entire period. Amphetamine was rarely observed prior to 1985 but comprised half of the illegal drugs examined in 1988. Cocaine was encountered in only 1% of the samples. Designer drugs were not seen. Heroin occurred relatively most frequently in Aarhus, Odense and Esbjerg while amphetamine and cannabis were found in all parts of Jutland and Funen. The samples of heroin and amphetamine varied greatly as regards strength and the types and quantities of cutting agents. The majority of the samples were adulterated and/or diluted with substances such as caffeine and phenazone and the sugars, glucose and lactose.

Amphetamine↗
PubMed1990

Adjusting for misselection using subsampling in epidemiological studies.

In epidemiological research it is sometimes necessary to conduct a case-control study in a part of the population which is not exposed to certain risk factors. Such a study design may be useful to investigate the risk related to a weak carcinogen in presence of other strong risk factors. It may happen that some individuals are wrongly included in the study group due to misreporting of the true exposure status. This misselection may cause biased odds ratio estimates of the factors of interest. It is therefore recommended that an evaluation study to validate the selection procedure is undertaken. We propose a two-stage sample design, consisting of a case-control study and a validation study in a subsample. Misselection rates in cases and control for different exposure groups may be estimated in the subsample and used to correct the odds ratio estimation from the first stage. It is shown how the total sample size should be attributed to the case-control sample and to the second-stage sample in order to give an unbiased estimate with minimal variance. The allocation is shown to be dependent on a number of parameters which is illustrated numerically and graphically. Efficiency considerations are also addressed.

Case-Control Studies↗
PubMed2003

Aqueous flat cells perpendicular to the electric field for use in electron paramagnetic resonance spectroscopy.

An analytic solution of the Maxwell equations for aqueous flat cells in rectangular TE(102) cavities has led to the prediction of significant (3-6 times) X-band EPR signal improvement over the standard flat cell for a new sample configuration consisting of many flat cells oriented perpendicular to the electric field nodal plane. Analytic full wave solutions in the presence of sample and wall losses have been obtained and numerically evaluated. Observation of the predicted fields led to a classification of three distinct types of sample loss mechanisms, which, in turn inspired sample designs that minimize each loss type. The resulting EPR signal enhancement is due to the presence and centering of a tangential electric field node within each individual sample region. Samples that saturate with the available RF magnetic field and those that do not are considered. Signal enhancement appears in both types. These observations, done for the TE(102) mode, carry over to the uniform field (UF) modes, a relatively new class of microwave cavities for use in EPR spectroscopy developed in this laboratory. Rectangular UF modes have an RF magnetic field magnitude that is uniform in a plane. Based on this analysis, a practical multiple flat-cell design is proposed.

Computer-Aided Design↗
PubMed2005

Crime victimization in adults with severe mental illness: comparison with the National Crime Victimization Survey.

CONTEXT: Since deinstitutionalization, most persons with severe mental illness (SMI) now live in the community, where they are at great risk for crime victimization. OBJECTIVES: To determine the prevalence and incidence of crime victimization among persons with SMI by sex, race/ethnicity, and age, and to compare rates with general population data (the National Crime Victimization Survey), controlling for income and demographic differences between the samples. DESIGN: Epidemiologic study of persons in treatment. Independent master's-level clinical research interviewers administered the National Crime Victimization Survey to randomly selected patients sampled from 16 randomly selected mental health agencies. SETTING: Sixteen agencies providing outpatient, day, and residential treatment to persons with SMI in Chicago, Ill. PARTICIPANTS: Randomly selected, stratified sample of 936 patients aged 18 or older (483 men, 453 women) who were African American (n = 329), non-Hispanic white (n = 321), Hispanic (n = 270), or other race/ethnicity (n = 22). The comparison group comprised 32 449 participants in the National Crime Victimization Survey. MAIN OUTCOME MEASURE: National Crime Victimization Survey, developed by the Bureau of Justice Statistics. RESULTS: More than one quarter of persons with SMI had been victims of a violent crime in the past year, a rate more than 11 times higher than the general population rates even after controlling for demographic differences between the 2 samples (P<.001). The annual incidence of violent crime in the SMI sample (168.2 incidents per 1000 persons) is more than 4 times higher than the general population rates (39.9 incidents per 1000 persons) (P<.001). Depending on the type of violent crime (rape/sexual assault, robbery, assault, and their subcategories), prevalence was 6 to 23 times greater among persons with SMI than among the general population. CONCLUSIONS: Crime victimization is a major public health problem among persons with SMI who are treated in the community. We recommend directions for future research, propose modifications in public policy, and suggest how the mental health system can respond to reduce victimization and its consequences.

Adult↗
PubMed1997

The utility of deviant sib pairs in the detection of linkage.

A tripartite sampling design was used to help deduce the genetic structure of a complex biological system. Univariate and multivariate population parameters were estimated from an age/sex stratified sample of unrelated individuals. Estimates of familial resemblance between and within continuous variables were obtained from a sample of randomly ascertained nuclear families. Finally, a sample of highly deviant concordant and discordant independent sib pairs facilitated the discovery of major genes through multipoint linkage analysis. No false positive signals were inferred. The pleiotropic effects of major genes, however, became obscured when linkage analysis was performed on adjusted quantitative variables.

Environment↗
PubMed2005

Exact sample sizes needed to detect dependence in 2 x 3 tables.

Many medical and biological studies entail classifying a number of observations according to two factors, where one has two and the other three possible categories. This is the case of, for example, genetic association studies of complex traits with single-nucleotide polymorphisms (SNPs), where the a priori statistical planning, analysis, and interpretation of results are of critical importance. Here, we present methodology to determine the minimum sample size required to detect dependence in 2 x 3 tables based on Fisher's exact test, assuming that neither of the two margins is fixed and only the grand total N is known in advance. We provide the numerical tools necessary to determine these sample sizes for desired power, significance level, and effect size, where only the computational time can be a limitation for extreme parameter values. These programs can be accessed at . This solution of the sample size problem for an exact test will permit experimentalists to plan efficient sampling designs, determine the extent of statistical support for their hypotheses, and gain insight into the repeatability of their results. We apply this solution to the sample size problem to three empirical studies, and discuss the results with specified power and nominal significance levels.

DNA, Mitochondrial↗
PubMed2004

Distribution of bacteria in a domestic hot water system in a Danish apartment building.

Bacterial growth in hot water systems seems to cause problems such as bad odor of the water, skin allergies and increased heat transfer resistance in heating coils. In order to establish a basis for long-term suppression of bacterial growth, we studied the distribution of bacteria in a Danish domestic hot water system. Heterotrophic plate counts (HPC) were measured in both water and biofilm samples from various sampling sites in the system. In hot water samples, where the temperature was 55-60 degrees C, the HPC were 10(3)-10(4)CFU/mL at incubation temperatures of 25 degrees C or 37 degrees C and 10(5)CFU/mL at 55 degrees C or 65 degrees C. In the cold water (10 degrees C) supplying the hot water system, the HPC at 25 degrees C or 37 degrees C was lower than in the hot water, and no bacteria were found after incubation at 55 degrees C or 65 degrees C. HPC constituted from 38% to 84% of the AODC results in hot water but only 2% in cold water, which showed a high ratio of culturable bacteria in hot water. Biofilm samples from the hot water tank and the inner surface of the pipes in the cold and hot water distribution system were collected by specially designed sampling devices, which were exposed in the system for 42 days. The quasi-steady-state number of bacteria in the biofilm, measured as the geometric mean of the HPC obtained between 21 and 42 days, was five-fold higher in the hot water pipe (13x10(5)CFU/cm(2) at 55 degrees C) than in the cold water pipe (2.8x10(5)CFU/cm(2) at 25 degrees C). There was no significant difference between the number of bacteria in the biofilm samples from the top, middle and bottom of the hot water tank, and the number of bacteria in the biofilm counted at 55 degrees C ranged from 0.6x10(4) to 1.7x10(4)CFU/cm(2). The surfaces of the sacrificial aluminum anodes and the heating coils in the hot water tank also contained high bacterial numbers. The measured number of bacteria in water and biofilm samples was related to the dimensions of the hot water system, and calculations showed that the majority of bacteria (72%) were located in the biofilm especially in the distribution system, which accounts for the greatest surface area. Free-living bacteria accounted for 26% and only a minor part of the bacteria were in the sludge in the hot water tank (2%).

Aluminum↗
PubMed1998

Two-stage sampling in surveys to substantiate freedom from disease.

Disease in livestock populations tends to cluster at the herd level. In order to account for this--and to overcome the problems of simple random sampling from a very large population--large-scale livestock surveys usually involve two-stage sampling. However, the use of two-stage sampling presents particular problems for sample-size calculation and analysis. We developed a probability formula for two-stage sampling, initially based on the assumption of a perfect test. We used this formula to demonstrate how combinations of first-stage (number of herds) and second-stage (number of animals in selected herds) sample sizes can be altered to achieve a least-cost survey, and used simulation to validate the formula. To overcome the unrealistic assumption of a perfect test, we then applied an exact-probability formula (which takes imperfect tests and finite population sizes into account) to the two-stage sampling design. An example is given which shows how implementing the formula with the FreeCalc computer program allows least-cost first and second-stage sample sizes to be calculated.

Animal Diseases↗
PubMed2002

Eating frequency and body fatness in middle-aged men.

OBJECTIVE: The relationship between eating frequency and body fatness was tested in a population sample. DESIGN: A cross-sectional survey on cardiovascular risk factors and a nutritional survey were carried out from June 1996 to April 1997. SUBJECTS: Population sample of 330 free-living middle-aged men (45-64 y). MEASUREMENTS: Body mass index (BMI), waist-to-hip ratio (WHR) and nutritional survey (3-day record). RESULTS: In the whole sample, BMI and WHR decreased significantly (P<0.05) along with the increase of the number of eating occasions. When low energy records were excluded, the trend for BMI and WHR according to eating categories remained significant. For WHR, averages were 0.98, 0.95, 0.94 and 0.93 for 1-2, 3, 4 or 5 or more feedings a day, respectively. For BMI, mean values were 28.1, 26.2, 26.2 and 24.5 kg/m(2), respectively. After adjustment for confounders (total energy intake or macronutrients, age, educational level, smoking habits, physical activity and restrained diet), the linear trend for BMI and WHR throughout feeding categories was significant when the whole sample was considered. This relationship remained similar when low energy records or when dieters were excluded. CONCLUSION: These results suggest that for an isoenergetic intake the increase of eating frequency is associated with lower body fatness.

Adipose Tissue↗
PubMed2003

Longitudinal study on the prevalence of benzodiazepine (mis)use in a prison: importance of the analytical strategy.

AIMS: This study evaluates the suitability of gas chromatographic-mass spectrometric (GC-MS) analysis to follow-up the extent of benzodiazepine (mis)use in a Belgian prison population and compares it to other analytical strategies (e.g. screening followed by confirmation of the positive samples). DESIGN AND PARTICIPANTS: From February to August 1998, 598 persons were jailed of which 188 (31.4% of the incoming detainees) volunteered to be screened. Urine samples (530 in total) were collected on the day of arrival and after 14, 30 and 90 days of imprisonment. MEASUREMENTS: All samples were screened by EMIT(R) for benzodiazepines and analysed subsequently by GC-MS. FINDINGS: EMIT(R) screening yielded 117 (22.1%) positive samples, a number which increased to 174 (32.8%) after GC-MS analysis. Of these 174 GC-MS positive samples, 119 (68.4%) contained one benzodiazepine while for the remaining samples multiple benzodiazepine (mis)use could be demonstrated. A significant increase in benzodiazepine (mis)use was indicated only from day 0 to day 14 based on the GC-MS results but not on the immunoassay results, even when the latter were complemented with GC-MS analysis of the positively screened samples. The GC-MS data also demonstrated that benzodiazepines are mainly (mis)used by subjects on benzodiazepine prescription as almost 50% of these subjects took additional non-prescribed benzodiazepines. During GC-MS analysis other drugs were co-extracted unintentionally and chromatographed and 23.9% of the volunteers were positive for illegal drugs on the day of arrival. CONCLUSION: Immunoassay results yield an underestimation of the problem of benzodiazepine (mis)use in prison due to the high false negative rate. GC-MS analysis of all samples therefore is the recommended strategy for this type of longitudinal study as it yields more correct and detailed information than the immunoassay results.

Belgium↗
PubMed2005

Psychometric properties and developmental differences in children's ADL item hierarchy: a study of the WeeFIM instrument.

OBJECTIVE: To investigate the measurement properties of the WeeFIM instrument and examine the developmental differences in motor item difficulty in a pediatric inpatient rehabilitation sample. DESIGN: Database approach, retrospective study, using 814 WeeFIM records from 12 facilities. Rasch rating scale analysis was used for all analyses. Data for the complete sample were used to evaluate the dimensionality and item fit of the WeeFIM instrument. Patients were then divided into three age groups, <3 yrs of age (toddlers), 3-7 yrs of age (preschoolers and kindergartners), and >7 yrs of age (school-age children), and their data were used to compare the order of motor items by level of difficulty within and across different age groups. RESULTS: Principal component analysis of the WeeFIM suggests distinct motor and cognitive scales. Within the motor scale, bowel and bladder items misfit, suggesting they measure a distinct aspect of function. The order of motor item difficulty, an indicator of construct validity, varies across age groups, suggesting that motor tasks present different challenges to children at different developmental stages: toileting is the most difficult, whereas locomotion is the easiest motor item for toddlers. For children >3 yrs of age, eating is easiest and stair climbing is most difficult, followed by tub transfer and bathing. CONCLUSIONS: Similar to the adult FIMtrade mark instrument, the WeeFIM instrument has two distinct dimensions. The motor items form a unidimensional construct with acceptable measurement properties. Developmental differences in motor task mastery among children with disabilities are assumed but rarely tested. As evidenced by the age-specific item hierarchies found in this study, developmental differences among children with disabilities mimic that of children without disabilities.

Activities of Daily Living↗
PubMed2004

Current performance of patient sample collection in the UK.

Collection of the patient sample for pretransfusion testing begins a complex chain of events in the transfusion process. Hospitals in England and North Wales were surveyed to compare local policies against recommendations of the British Committee for Standards in Haematology (BCSH). Hospitals also measured the frequency of rejected and miscollected samples [designated as wrong blood in tube (WBIT)]. 185 of 360 (51.4%) hospitals returned questionnaires and 182 of 185 (98%) hospitals reported that a policy for sample collection existed. Apart from frequent omission of the gender of the patient, there was 96% compliance with all mandatory identifiers of the BCSH guidelines. Practice allowing additions or changes to labelling on sample tubes and request forms varied. 3.2% (14 114/445 726) of samples submitted were rejected for various reasons, the most frequent being incomplete or missing information (49.5% of the total rejected samples). The corrected mean frequency for WBIT in the 27 hospitals with one or more observed WBIT was 1 in 1501 samples (95% CI: < or =1129.09 to < or =1872.91), and the median corrected frequency for WBIT was 1 in 1303 samples. This study has identified great variation in the policy and practice for sample collection for pretransfusion testing. Regular tracking of the rates of sample rejection and WBIT could be used to identify poor performance in individual hospitals requiring investigation and action.

Blood Specimen Collection↗
PubMed2005

Issues in the epidemiological investigation of dry mouth.

Despite decades of research, much remains unanswered about the epidemiology of dry mouth. This review aims to provide an overview of the condition's epidemiology and the issues to consider when planning an epidemiological study of dry mouth. The latter can be broadly grouped into: study design; sampling and statistical power considerations; the measurement of dry mouth; and the selection, nature and measurement of relevant exposure measures, including medications and potential confounding variables. Each of these is discussed, in order to provide guidance for prospective researchers based on experience with past research. Finally, an agenda for further epidemiological research into dry mouth is proposed.

Aged↗
PubMed1999

Maternal and fetal angiotensinogen gene allele sharing in pre-eclampsia.

OBJECTIVE: To compare the angiotensinogen genotypes in normotensive and pre-eclamptic pregnancies in maternal and fetal samples. DESIGN: Prospective observational study. SETTING: University Hospital, Queen's Medical Centre, Nottingham. POPULATION: Forty-three women with pre-eclampsia and 84 normotensive pregnant women. Fetal samples were available for genotyping from 96% of the pregnancies. METHODS: Maternal and fetal DNA was genotyped at angiotensinogen codon 235 and at a dinucleotide repeat polymorphism in the 3' flanking region of the gene. Angiotensinogen and renin concentrations were measured in maternal plasma by radioimmunoassay. RESULTS: In contrast to earlier studies, no association was demonstrated between the angiotensinogen 235 Thr variant and pre-eclampsia. Normotensive pregnant women homozygous for this variant had significantly lower plasma angiotensinogen concentrations (median 2.2 ng AI/mL; IQR 1.8-3.0) than women homozygous for the 235 Met allele (3.6 ng AI/mL; IQR 2.5-4.1; P = 0.04). In pre-eclamptic pregnancies, 79% (11/14) of mothers heterozygous for the dinucleotide repeat allele designated A9 transmitted this allele to the fetus, more frequently than would be expected by chance (P = 0.02). The A9 allele was associated with low plasma angiotensinogen concentrations (P = 0.001) and high renin concentrations (P = 0.02) in normotensive women. CONCLUSIONS: There is no evidence that the angiotensinogen 235 Thr allele is associated with pre-eclampsia in the Nottingham population. The angiotensinogen 235 Thr allele is associated with low plasma angiotensinogen concentrations in normotensive pregnant women, in contrast to the high levels associated with this variant in non-pregnant women, suggesting that regulation of angiotensinogen expression in normal pregnancy may differ significantly from that in the non-pregnant state. There is preliminary evidence that maternal-fetal transmission of an angiotensinogen allele associated with low plasma angiotensinogen concentrations is associated with pre-eclampsia. Impaired generation of angiotensin II at the maternal-fetal interface may be a factor in the pathogenesis of pre-eclampsia.

Adult↗