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At least 613 records · Page 34Linked to original sources
PubMed2006

Evaluating the performance of the Global Registry of Acute Coronary Events risk-adjustment index across socioeconomic strata among patients discharged from the hospital after acute myocardial infarction.

BACKGROUND: Cardiac risk-adjustment indices for acute coronary syndromes have important clinical and research applications, especially if proven to be valid and robust across heterogeneous socioeconomically diverse populations. The objective of this study was to validate the Global Registry of Acute Coronary Events (GRACE) risk-adjustment index for 6-month all-cause mortality across socioeconomic strata. METHODS: The study cohort consisted of patients who were enrolled in the SESAMI study and discharged alive from the hospital between December 1, 1999, and February 28, 2003. Socioeconomic information was obtained through self-report. Hospital chart abstraction was used to ascertain clinical detail required for the derivation of the GRACE risk index. Six-month mortality rates were obtained through data linkage using encrypted health card numbers. The accuracy (c-statistic) and calibration (Hosmer-Lemeshow) characteristics of the GRACE risk index were generated using logistic regression across income and education strata. RESULTS: Predicted and observed mortality rates were significantly higher among patients of lower incomes and education (ie, observed 6-month mortality: 5.1% vs 1.8% among low income vs high income patients, respectively, P < .0001; 4.6% vs 2.9% among low-educated vs highly educated patients, respectively, P = .02). The predicted 6-month mortality as derived using GRACE closely mirrored observed mortality rates with strong accuracy and precision (c-statistic = 0.80 for the overall cohort and within each income and education strata; Hosmer-Lemeshow goodness-of-fit test was not significant within each income and education strata). CONCLUSION: The GRACE risk score for 6-month all-cause mortality is an accurate, well-calibrated, and robust predictor across socioeconomic strata and can be used as a valid risk-adjustment index when examining socioeconomic-mortality differences after acute MI.

Adult↗
PubMed2005

Hormonal and body-size factors in relation to breast cancer risk: a prospective study of 11,889 women in a low-incidence area.

PURPOSE: This prospective cohort study of 11,889 women was conducted to determine significant factors associated with the risk of breast cancer among Chinese women in Taiwan, a low-incidence area. METHODS: In-person interviews were completed for subjects to solicit information on hormonal factors. Measurements of height, weight, and waist-and- hip circumferences were performed by well-trained assistants using standardized techniques. Cox proportional hazards models were employed to estimate relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: During an average follow-up time of 10.3 years (range: 1 to 11 years) with an accumulation of 134,063 person-years, 104 incident breast cancer cases were identified through data linkage with national cancer registry profile. There was a significant elevation in breast-cancer risk with increasing duration of the interval between age at menarche and age at first full-term pregnancy (FFTP). Additionally, central adiposity reflected by hip circumference was a significant predictor of breast cancer in this Chinese female population. CONCLUSIONS: The findings of this study indicated common mechanisms responsible for the higher incidence of breast cancer in Western populations may also explain the risk of breast cancer development in Taiwan, a low-incidence area.

Adolescent↗
PubMed2005

Bone mass effects of a BMP4 gene polymorphism in postmenopausal women.

The pathogenesis of osteoporosis involves both genetic and environmental factors. On the basis of linkage data suggesting gene effects on bone density at chromosome 14q and data locating the BMP4 gene to 14q, we performed a positional candidate study to examine a possible association of BMP4 gene polymorphisms, hip bone density (n = 1012) and fracture rates (n = 1232) in postmenopausal women (mean age 75). On genotype analysis of the three selected single nucleotide polymorphisms (SNP), the 6007C > T polymorphism was associated with total and intertrochanteric hip BMD and BMD was lower in the 32% of subjects homozygous for the C allele. This polymorphism codes for a nonsynonymous amino acid change with the T allele coding for valine, while the C allele codes for alanine. The difference in BMD was 3.1% (TT vs. CC) and 2.3% (CT versus CC) for the total hip (P = 0.023), and 3.7% (TT vs. CC) and 2.8% (CT versus CC) for the intertrochanter site (P = 0.012). Haplotype analysis demonstrated 6 haplotypes of frequency greater than 2%. A major haplotype defined by G-C-T alleles in SNPs -5826G > A, 3564C > T and 6007C > T respectively, showed association with high bone mass. No SNP showed association with fracture rates. We conclude that a polymorphism found in the BMP4 gene, affecting amino acid sequence, is associated with hip bone density in postmenopausal women, presumably via regulation of anabolic effects on the skeleton.

Aged↗
PubMed2006

Maternal smoking behavior, background and neonatal health in Finnish children subsequently placed in foster care.

OBJECTIVE: The purpose of this study was to investigate retrospectively neonatal health and maternal background among a sample of children taken into custody and placed in foster care and to investigate the relation between medical and social risk in the neonatal period. METHOD: The data-linkage study combined two registries: the Finnish Medical Birth Registry (MBR), from January 1, 1987 to December 31, 1989, and the Finnish Child Welfare Registry (CWR) from January 1, 1987 to December 31, 1997 using personal identification numbers (n=1,668). As controls all Finnish children born in 1987 were chosen (n=59,727). Infant neonatal health was estimated using the following indicators: birth-weight and birth-length, birth-weight by gestational age, 1-minute Apgar scores, and discharge age from the nursery. Maternal background characteristics included maternal age, parity, marital status, number of antenatal visits at maternity clinics and smoking during pregnancy. RESULTS: We found that the 1,668 children in the study had a lower birth-weight and birth-length, shorter gestational age, lower 1-minute Apgar scores and later discharge from the nursery than the population-based controls. The proportion of teen-age mothers was about four times higher and the proportion of unmarried women was twice as high. A majority of the women (56%) reported smoking during pregnancy, compared with only 15% of the population-based comparisons. Children subsequently taken into custody had poorer health at the time of birth than other children and these differences could only partly be explained by the differences in smoking habits during pregnancy. The women in the study made use of the free health controls at maternity clinics as much as the population-based comparisons. CONCLUSIONS: Our findings indicate that social and medical risks are related in the neonatal period. Since almost all mothers visit maternity clinics, there are possibilities for early intervention.

Adult↗
PubMed2006

Extent of prostate-specific antigen contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC).

OBJECTIVES: The performance of tests outside prostate cancer screening trials (PSA contamination) may affect their statistical power. The present study addressed the extent of PSA contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC) and its impact on biopsy performance and prostate cancer detection. METHODS: Data linkage was performed to address screening-related interventions outside the study. Four databases were used: (1) Spanish ERSPC database (n=4278), (2) laboratory database with all PSA determinations (n=31,140), (3) database of 1608 prostate biopsies, and (4) records of all prostate cancers (n=819) diagnosed at our centre. PSA contamination, biopsy performance, and cancer detection rates were calculated. RESULTS: Median follow-up time was 6.6 yr. A total of 2201 PSA determinations were performed for 1253 men. Cumulative PSA contamination was 29.3% (17% in the control arm during the first 4 yr). A higher proportion of men undergoing biopsies was found in the screening arm (21.3% vs. 2.9% in the control arm, p<0.0001). Similarly, higher cancer detection rates were found in the screening (4.7% vs. 1.2% in the control arm, p<0.0001). CONCLUSIONS: In our experience, the PSA contamination rate has increased during the last years, but its impact on biopsy performance and cancer detection in the control arm of the trial is limited and not likely to compromise the statistical power of the ERSPC trial.

Aged↗
PubMed2006

Rapid genetic mapping in Neurospora crassa.

Forward genetic analysis is the most broadly applicable approach to discern gene functions. However, for some organisms like the filamentous ascomycete Neurospora crassa, genetic mapping frequently represents a limiting step in forward genetic approaches. We describe an efficient method for genetic mapping in N. crassa that makes use of a modified bulked segregant analysis and PCR-based molecular markers. This method enables mapping with progeny from a single cross and requires only 90 PCR amplifications. Genetic distances between syntenic markers have been determined to ensure complete coverage of the genome and to allow interpolation of linkage data. As a result, most mutations should be mapped in less than one month to within 1-5 map units, a level of resolution sufficient to initiate map-based cloning efforts. This system also will facilitate analyses of recombination at a genome-wide level and is applicable to other perfect fungi when suitable markers are available.

DNA Mutational Analysis↗
PubMed2006

Does federal health care policy influence switching between the public and private sectors in individuals?

OBJECTIVE: The aim of this study was to determine if changes in Australian Federal health policy have influenced individual behaviour regarding utilisation of private health insurance in Western Australia. METHOD: The WA Data Linkage System was used to extract all hospital morbidity records in Western Australia from 1980 to 2001. For each individual, episodes were grouped into hospital couplets classified according to the mix of public and privately insured events. Logistic regression was used to estimate the likelihood of switching towards or away from the private sector, according to the time between episodes in each of five health care policy eras. RESULTS: The odds of a switch away from the private sector increased by 29% with each additional year between episodes, while the odds of a switch towards the private sector increased by 15% per intra-couplet year. In those with a private first episode the odds of switching decreased approximately exponentially across the five eras whereas the odds of switching in those with a public first episode stabilised after 1985. In the last era (1999-2001) the odds of switching away from the private sector reduced substantially. CONCLUSION: Our analysis suggests that the recent policies supporting PHI (30% rebate and Lifetime Health Cover) appear to have been effective at modifying individual behaviour to reduce the drift away from the private sector. However, the reported increases in utilisation of PHI were only partially explained by switching of existing demand in patients who had been previously hospitalised as public patients, suggesting that the policy reforms had generated, rather than merely shifted, demand for health care. This finding has significant policy implications for Australia.

Adolescent↗
PubMed2005

A multipurpose comorbidity scoring system performed better than the Charlson index.

BACKGROUND AND OBJECTIVES: To develop a comorbidity scoring system that out-performs the Charlson index. METHODS: Population-based cohorts of medical (n=326,456), procedural (n=349,686), and psychiatric (n=16,895) inpatients in Western Australia were followed for 1-year mortality, 30-day readmissions, and length of stay (LOS) using data linkage. Conditions were identified at index admission and over the preceding 12 months. A Multipurpose Australian Comorbidity Scoring System (MACSS) was developed, based on the most frequent 102 comorbid conditions associated with a rate ratio (RR) > or = 1.1 of death or readmission or a LOS difference > or =0.5 days. The performance of MACSS and the Charlson index in predicting mortality, readmission, and LOS, and in controlling confounding by comorbidity, was compared in five test scenarios involving asthma, myocardial infarction, mastectomy, transurethral prostatectomy, and major depressive illness. RESULTS: MACSS performed better than the Charlson index on all three outcomes in all five clinical groups. It reduced the failure of the Charlson index to discriminate on mortality and readmission outcomes by 5-40%, improved R(2) in LOS models by up to fourfold and often doubled the correction of originally confounded effect measures. CONCLUSION: The use of the MACSS and similar alternatives to the Charlson index are a new methodologic standard for adjustment of comorbidity risk.

Adolescent↗
PubMed2003

The genetic epidemiology of multiple sclerosis.

Multiple sclerosis (MS) is a debilitating immunological and neurodegenerative disorder. Epidemiological studies have provided overwhelming evidence of complex genetic susceptibility to MS. However, with the exception of the human leukocyte antigen (HLA) locus, genetic studies have failed to consistently identify significant linkage or association with genes that modulate MS disease expression. Numerous functional candidate gene studies, linkage genomic screens, and locational candidate gene studies have been performed in an attempt to identify additional loci. However, these methods have demonstrated insufficient power to consistently identify genes or epigenetic factors for MS. More current approaches integrate information from a variety of sources (e.g. consistent linkage data, gene expression profiling, and functional characterization studies) and utilize high throughput methods (e.g. genotyping high density markers, utilizing pooling schemes and performing new statistical analyses) in an attempt to overcome power issues. The following article presents a review of MS genetics research and a brief overview of methods that are currently being developed and utilized for fine localization of MS loci, such as the method employed in the Genetic Analysis of Multiple sclerosis in EuropeanS (GAMES) study that is presented elsewhere in this journal. It is the hope of researchers that these methods will lead to the identification of susceptibility genes for MS that aid in elucidating pathogenic mechanisms and potential therapeutic strategies for this debilitating disease.

Genetic Testing↗
PubMed2006

A method for defining and estimating the palliative care population.

Palliative care research is challenged by a disagreement as to what palliative care is, when it should be offered and what conditions warrant specialized palliative care services. These challenges became evident when we used a population-based data linkage to evaluate the delivery of palliative care services in Western Australia. This paper describes the development of a conceptual framework to provide minimal, mid-range, and maximal estimates of a palliative care population. The estimates include nonmalignant conditions; realistically restrict the number and types of conditions; and propose a time frame over which specialized services can be offered. In defining a palliative care population for the purpose of research, development of an estimation method simultaneously addressed the rhetoric of palliative care with the restrictions inherent in both population-based research and service delivery. When applied to a population, the 10 conditions of the minimal estimate provide an acceptable guide to future research and practice.

Chronic Disease↗
PubMed2006

Molecular genetics of addiction vulnerability.

Classical genetic studies document strong complex genetic contributions to abuse of multiple addictive substances, to mnemonic processes that are likely to include those involved in substance dependence, and to the volumes of brain gray matter in regions that are likely to contribute to mnemonic/cognitive and to addictive processes. The working idea that these three heritable phenotypes are likely to share some of the same complex genetic underpinnings is presented. This review contains association-based molecular genetic studies of addiction that largely derive from my laboratory and their fit with linkage data from other laboratories. These combined results now identify many of the loci and genes that contain allelic variants that are likely to provide the heritable components of human addiction vulnerability. These data are also likely to have broad implications for neurotherapeutics. Drugs with potential abuse liabilities are widely used for indications that include pain, anxiety, sleep, seizure, and attentional disorders. There is increasing nonmedical use of these prescribed substances. Increasing information about addiction vulnerability gene variants should help to improve management of risks of dependence in individuals who receive such therapeutics. In addition, since mnemonic components that correlate well with individual differences in brain regional volumes are likely to play major roles in addiction processes, many addiction vulnerability genes are also good candidates to contribute to individual differences in mnemonic processes. Recently elucidation of addiction-associated haplotypes for the "cell adhesion" NrCAM gene illustrate several of these points.

Animals↗
PubMed1992

The problems of monitoring tuberculosis in an inner-city health district: integrated information is required.

This paper discusses the difficulties in monitoring tuberculosis in an inner-city district health authority. Tuberculosis incidence was reviewed between 1981 and 1989 using several data sources: statutory notifications, hospital activity analysis, death certificates and chest clinic records. The overall notification rate declined but remained higher than national rates; the age-sex distribution was similar to national studies. However, interpretation was limited by the problems of small numbers, the difficulty in obtaining reliable numerator and denominator estimates of ethnic groups, the limited data available about sub-groups of concern such as the homeless, and finally by the incompleteness of the data. Improved methods of data linkage are required to facilitate more complete ascertainment and validation of the diagnosis.

Adolescent↗
PubMedDate not supplied

Restricted fetal growth and adverse maternal psychosocial and socioeconomic conditions as risk factors for suicidal behaviour of offspring: a cohort study.

BACKGROUND: Until now, sparse and contradictory results about an association between adverse neonatal, obstetric, and maternal conditions and heightened suicide risk in adolescents have been reported. The aims of this study were to investigate the relations between fetal growth, obstetric complications, and the mother's psychosocial and socioeconomic situation and the risk in early adulthood of suicide and attempted suicide in the offspring. METHODS: Obstetric, neonatal, and maternal risk factors for suicide and attempted suicide in 713370 young adults, born in Sweden between 1973 and 1980, who were followed-up until Dec 31, 1999, were examined by data linkage between Swedish registers. Univariate and multivariate hazard ratios, derived from proportional-hazard models, were estimated. FINDINGS: Significantly raised risk of attempted suicide was reported for individuals of short birth length, adjusted for gestational age (hazard ratio 1.29, 95% CI 1.18-1.41, p<0.0001); born fourth or more in birth order (1.79, 1.62-1.97, p<0.0001); born to mothers with a low educational level (1.36, 1.27-1.46, p<0.0001) (attributable proportion 10.3%); and those who, at time of delivery, had mothers aged 19 years or younger (2.09, 1.89-2.32, p<0.0001). Significant predictors of suicide were low birthweight, adjusted for gestational age (2.23, 1.43-3.46, p<0.0001), and teenage motherhood (2.30, 1.64-3.22, p<0.0001). INTERPRETATION: Multiparity and low maternal education predicted suicide attempt, whereas restricted fetal growth and teenage motherhood were associated with both suicide completion and attempt in offspring.

Adolescent↗
PubMed2003

A school-based randomized controlled trial of peer-led sex education in England.

This article discusses the design of an ongoing cluster-randomized trial comparing two forms of school-based sex education in terms of educational process and sexual health outcomes. Twenty-nine schools in southern England have been randomized to either peer-led sex education or to continue with their traditional teacher-led sex education. The primary objective is to determine which form of sex education is more effective in promoting young people's sexual health. The trial includes an unusually detailed evaluation of the process of sex education as well as the outcomes. The sex education programs were delivered in school to pupils ages 13-14 years who are being followed until ages 19-20. Major trial outcomes are unprotected sexual intercourse and regretted intercourse by age 16 and cumulative incidence of abortion by ages 19-20. We discuss the rationale behind various aspects of the design, including ethical issues and practical challenges of conducting a randomized trial in schools, data linkage for key outcomes to reduce bias, and integrating process and outcome measures to improve the interpretation of findings.

Adolescent↗
PubMed1989

X-inactivation of the Sts locus in the mouse: an anomaly of the dosage compensation mechanism.

The behaviour of the X- and Y-borne Sts locus has been studied in male and female mice. There was considerable heterogeneity in STS activity between inbred mouse strains, with a four fold difference in activity between the highest (101/H) and lowest (Ju/Ct) activity strains, which can be interpreted in terms of allelic differences. In all inbred strains male STS levels were higher than those of female STS levels and in the majority of strains tested male STS levels were nearly twice as high as female levels. Reciprocal crosses between C3H/HeH and the STS-deficient substrain, C3H/An, demonstrated that activities of the X- and Y-borne genes in males are essentially the same and this suggested that the lower STS level in females derives from X-inactivation of the locus. The possibility that hormonal differences could instead be responsible for the lower activity in females was ruled out by the findings that (a) castration of males did not reduce their STS levels and (b) sex-reversed males, X/X Sxr, had STS levels typical of females. Final proof that the mouse Sts locus can be subject to the X-inactivation process was provided by the observation that XX females had STS levels that were only slightly (20%) higher than those of XO females. The difference may indicate incomplete inactivation of the locus. Linkage data verifying the location of Sts on the distal end of the X chromosome are provided.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Hepatitis B outbreak at Glenochil prison during January to June 1993.

This data linkage study examined the extent of hepatitis B transmission and co-infection with HIV among 636 former inmates of Glenochil prison, Scotland, during an outbreak of bloodborne diseases in 1993 which was related to needle sharing. Eleven inmates imprisoned during the first half of 1993 presented with hepatitis B infection, of whom co-infection with HIV was detected in six. Based on dates of test results in relation to time of imprisonment, seven definitely acquired their hepatitis B infection within the prison. Only two infections were reported to Scotland's hepatitis B register and neither could be prison-linked. This outbreak of hepatitis B is the first of its kind to be reported but not the first to have occurred. It not only highlights the urgency for measures to prevent further spread of infection among prisoners but also illustrates the need for comprehensive surveillance of hepatitis B infection, and the need for a protocol on how to manage such outbreaks and on how to establish the extent of transmissions when acute hepatitis B occurs in prison.

Adolescent↗
PubMed1998

Electrospray ionization-ion trap mass spectrometry for structural analysis of complex N-linked glycoprotein oligosaccharides.

Electrospray ionization-ion trap mass spectrometry, with its capacity to perform multiple stages of fragmentation (MSn), is demonstrated as an effective method for the structural characterization of permethylated N-linked complex glycoprotein oligosaccharides. Complex glycan structural features, such as N-acetyllactosamine antenane, neuraminic acids, and nonreducing terminal GlcNAc monosaccharides, commonly suppress cross-ring and core saccharide cleavages in traditional MS/MS experiments. Using ion trap mass spectrometry, removal of these substituents permits determination of branching patterns and intersaccharide linkages by MS3 and MS4. Both sequence and linkage data are obtained for N-acetyllactosamine and sialyl-N-acetyllactosamine oligosaccharide antennae from biantennary glycans using MS3, and the location of a bisecting GlcNAc residue is also established after exposing the core pentasaccharide. Higher-order experiments further illustrate the potential of electrospray ionization-quadrupole ion trap mass spectrometry for carbohydrate analysis, as MS8 is used to produce significant and otherwise unobtainable branching information for an oligosaccharide from chicken ovalbumin. These studies constitute further evidence of the unique role that ion trap mass spectrometry can assume in the area of oligosaccharide analysis.

Amino Sugars↗
PubMed1975

Linkage and assembly of polymeric IgA immunoglobulins.

The intersubunit linkage of polymeric IgA immunoglobulins was determined from studies of the products of reductive and cyanogen bromide cleavage. Under conditions of limited dithioerythritol reduction tetramer IgA molecules were cleaved to yield two monomers and a J chain containing dimer. The stability of the dimer and the conservation of the J chain disulfides indicated that the J chain joins two monomer subunits. Evidence confirming the J chain dimer clasp was obtained from the depolymerization of tetramer and dimer IgA by cyanogen bromide treatment. The cleavage studies also showed that (a) the S-S bonds directly joining the other subunits are located at the same penultimate alpha chain half-cystines that constitute the site of J chain attachment and (b) during limited reduction the monomer-monomer bonds undergo interchange to release subunits without a concomitant generation of alpha chain thiols. These linkage data provide strong support for the assembly of IgA and IgM polymers by sequential disulfide exchanges beginning with the formation of a J chain containing dimer.

Chemical Phenomena↗