Previous research updated the mortality experience of North American synthetic rubber industry workers during the period 1944-1998, determined if leukemia and other cancers were associated with several employment factors and carried out Poisson regression analysis to examine exposure-response associations between estimated exposure to 1,3-butadiene (BD) or other chemicals and cancer. The present study used Cox regression procedures to examine further the exposure-response relationship between several unlagged and lagged, continuous, time-dependent BD exposure indices (BD parts per million (ppm)-years, the total number of exposures to BD concentrations >100 ppm ("peaks") and average intensity of BD) and leukemia, lymphoid neoplasms and myeloid neoplasms. All three BD exposure indices were associated positively with leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (beta) from an analysis that controlled only for age was 2.9 x 10(-4) (p
The main objectives of this paper are to compare Aboriginal and Canadian health status and physician use and to identify the factors associated with the use of physician services. Data are drawn from the 1991 Aboriginal Peoples Survey (APS) and the 1991 General Social Survey (GSS), which are weighted random samples of the Aboriginal and total Canadian populations, respectively. The results demonstrate that Aboriginals were much less likely to use physician services, even though Aboriginals rank their health similarly to the total Canadian population. Location becomes an important aspect of both physician use and health status, with Aboriginals residing on-reserve generally having lower levels of self-assessed health and less likely to have seen a physician. While Aboriginals with the poorest health status were more likely to have seen a physician, other factors including education were found to be barriers to use of health care. Aboriginal identity and cultural orientation provided mixed results.
Birch and Abelson  argue that non-income based barriers might explain differences in utilization of health services within and between income groups. Databases which contain utilization data rarely allow for the modelling of geographic variation. In the Ontario Health Survey (OHS), individual observations are georeferenced at the Public Health Unit (PHU) scale, but PHUs cannot easily be used because of the large coefficients of variation. To overcome this problem, a cluster analysis is performed to create a service environment variable, which reflects differences in service availability, population size and rurality. Utilization of health services is then modelled as a logistic regression equation where the independent variables are age, sex, service environment and income to test the Birch and Abelson argument. This argument is then extended by controlling for age, health and income status. Based on the modelling results, the importance of geography to access and utilization is assessed.
The study is based on a sample of 965 children living in Oulu region (Finland), who were monitored for acute middle ear infections from birth to the age of two years. We introduce a nonparametrically defined intensity model for ear infections, which involves both fixed and time dependent covariates, such as calendar time, current age, length of breast-feeding time until present, or current type of day care. Unmeasured heterogeneity, which manifests itself in frequent infections in some children and rare in others and which cannot be explained in terms of the known covariates, is modelled by using individual frailty parameters. A Bayesian approach is proposed to solve the inferential problem. The numerical work is carried out by Monte Carlo integration (Metropolis-Hastings algorithm).
Accurate prediction of survival for patients with end-stage renal disease (ESRD) and multiple comorbid conditions is difficult. In nondialysis patients, the Charlson Comorbidity Index has been used to adjust for comorbidity. The purpose of this study is to assess the validity of the Charlson index in incident dialysis patients and modify the index for use specifically in this patient population.
Subjects included all incident hemodialysis and peritoneal dialysis patients starting dialysis therapy between July 1, 1999, and November 30, 2000. These 237 patients formed a cohort from which new integer weights for Charlson comorbidities were derived using Cox proportional hazards modeling. Performance of the original Charlson index and the new ESRD comorbidity index were compared using Kaplan-Meier survival curves, change in likelihood ratio, and the c statistic.
After multivariate analysis and conversion of hazard ratios to index weights, only 6 of the original 18 Charlson variables were assigned the same weight and 6 variables were assigned a weight higher than in the original Charlson index. Using Kaplan-Meier survival curves, we found that both the original Charlson index and the new ESRD comorbidity index were associated with and able to describe a wide range of survival. However, the new study-specific index had better validated performance, indicated by a greater change in the likelihood ratio test and higher c statistic.
This study indicates that the original Charlson index is a valid tool to assess comorbidity and predict survival in patients with ESRD. However, our modified ESRD comorbidity index had slightly better performance characteristics in this population.
Future adaptation to changes in the environment depends on the existence of additive genetic variances within populations. Recently, considerable attention has also been given to the non-additive component, which plays an important role in inbreeding depression and bottleneck situations. In this study, I used data from a North Carolina II crossing experiment, analysed with restricted maximum-likelihood methods, to estimate the additive and dominance genetic (co)variances for eight quantitative characters in two different-sized populations of Scabiosa canescens, a rare and threatened plant in Sweden. There was no evidence for genetic erosion in the small Hällestad population ( approximately 25 individuals) relative to the large Ahus population ( approximately 5000 individuals). In fact, slightly higher heritabilities were found in the Hällestad population. The additive genetic variance was statistically significant for all traits in both populations, but only a few additive covariances reached significance. The Hällestad population also had higher mean levels and more traits with significant dominance variance than the Ahus population. The variance attributable to maternal effects was too low to be considered significant. There was only a weak correspondence between heritabilities for each trait in the present study and previous estimates based on open-pollinated families of the same populations, but the mean heritability (over characters) was consistent between the studies.
Given the greatly elevated risks of contralateral breast cancer (CBC) observed in breast cancer patients who carry mutations in BRCA1 and BRCA2, it is critical to determine the effectiveness of standard adjuvant therapies in preventing CBC in mutation carriers. The WECARE study is a matched, case-control study of 708 women with CBC as cases and 1,399 women with unilateral breast cancer (UBC) as controls, including 181 BRCA1/BRCA2 mutation carriers. Interviews and medical record reviews provided detailed information on risk factors and breast cancer therapy. All study participants were screened for BRCA1 and BRCA2 mutations using denaturing high-performance liquid chromatography (DHPLC) to detect genetic variants in the coding and flanking regions of the genes. Conditional logistic regression was used to compare the risk of CBC associated with chemotherapy and tamoxifen in BRCA1/BRCA2 mutation carriers and non-carriers. Chemotherapy was associated with lower CBC risk both in non-carriers (RR = 0.6 [95% CI: 0.5-0.7]) and carriers (RR = 0.5 [95% CI: 0.2-1.0]; P value = 0.04). Tamoxifen was associated with a reduced CBC risk in non-carriers (RR = 0.7 [95% CI: 0.6-1.0]; P value = 0.03). We observed a similar but non-significant reduction associated with tamoxifen in mutation carriers (RR = 0.7 [95% CI: 0.3-1.8]). The tests of heterogeneity comparing carriers to non-carriers did not provide evidence for a difference in the associations with chemotherapy (P value = 0.51) nor with tamoxifen (P value = 0.15). Overall, we did not observe a difference in the relative risk reduction associated with adjuvant treatment between BRCA1/BRCA2 mutation carriers and non-carriers. However, given the higher absolute CBC risk in mutation carriers, the potentially greater impact of adjuvant therapy in reducing CBC risk among mutation carriers should be considered when developing treatment plans for these patients.
This brief article provides a description of some new ideas about admission of university engineering students in Sweden. The current system of admission is based on upper-secondary school grades and the Swedish Scholastic Assessment Test. These measures are used for admission to all higher education. For many reasons, ideas for a new admission model have been proposed. This model includes a sector-oriented admission test, which the universities are supposed to use for different purposes, such as selection, eligibility, diagnostics, and recruitment.
Comment On: Psychol Rep. 2003 Oct;93(2):399-40914650662
Women prisoners are known to suffer from an accumulation of factors known to increase the risk for several major health problems. This study examines the prevalence of adverse childhood experiences (ACE) and the relationship between such experiences and suicide attempts and drug use among incarcerated women in Norway.
A total of 141 women inmates (75% of all eligible) were interviewed using a structured interview guide covering information on demographics and a range of ACE related to abuse and neglect, and household dysfunction. The main outcome variables were attempted suicide and adult drug abuse.
Emotional, physical and sexual abuse during childhood was experienced by 39%, 36% and 19%, respectively, and emotional and physical neglect by 31% and 33%, respectively. Looking at the full range of ACE, 17% reported having experienced none, while 34% reported having experienced more than five ACEs. After controlling for age, immigrant background and marital status, the number of ACEs significantly increased the risk of attempted suicide and current drug abuse.
The associations observed between early life trauma and later health risk behaviour indicate the need for early prevention. The findings also emphasize the important role of prison health services in secondary prevention among women inmates.
To investigate age-related differences in health risk behaviors in 11-12-, 13-14-, and 15-16-year-old adolescents with physical disabilities.
Health survey data from 319 adolescents with physical disabilities were compared with the same data from 7,020 adolescents in a national sample.
Significant age-related differences were found for having tried smoking, smoking, having tasted an alcoholic drink, having been drunk, and using prescription drugs for recreational purposes. However, changes were modest and engagement of 15-16-year-old adolescents with physical disabilities was similar to 11-12-year-olds in the general population. Analysis of associations between disability status and health risk behaviors while controlling for age and sex showed that disability is associated with a lower likelihood of having tried smoking, smoking, having tasted an alcoholic drink, drinking, having been drunk, having used drugs, having used prescription drugs for recreational purposes, and eating sweets; a higher likelihood of not engaging in physical exercise, not eating fresh produce, and eating high-fat foods; and non-significant for seat-belt use.
Health promotion programs about health risk behaviours designed for adolescents in the general population may not be appropriate for adolescents with physical disabilities.