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1.
The role of the propensity score in estimating dose-response functions   总被引:11,自引:0,他引:11  
Imbens  GW 《Biometrika》2000,87(3):706-710
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2.
BackgroundInjury is a significant cause of childhood death and can result in substantial long-term disability. Injuries are more common in children from socio-economically deprived families, contributing to health inequalities between the most and least affluent. However, little is known about how the relationship between injuries and deprivation has changed over time in the UK.MethodsWe conducted a cohort study of all children under 5 registered in one of 495 UK general practices that contributed medical data to The Health Improvement Network database between 1990–2009. We estimated the incidence of fractures, burns and poisonings by age, sex, socio-economic group and calendar period and adjusted incidence rate ratios (IRR) comparing the least and most socio-economically deprived areas over time. Estimates of the UK annual burden of injuries and the excess burden attributable to deprivation were derived from incidence rates.ResultsThe cohort of 979,383 children experienced 20,804 fractures, 15,880 burns and 10,155 poisonings, equating to an incidence of 75.8/10,000 person-years (95% confidence interval 74.8–76.9) for fractures, 57.9 (57.0–58.9) for burns and 37.3 (35.6–38.0) for poisonings. Incidence rates decreased over time for burns and poisonings and increased for fractures (p<0.001 test for trend for each injury). They were significantly higher in more deprived households (IRR test for trend p<0.001 for each injury type) and these gradients persisted over time. We estimate that 865 fractures, 3,763 burns and 3,043 poisonings could be prevented each year in the UK if incidence rates could be reduced to those of the most affluent areas.ConclusionsThe incidence of burns and poisonings declined between 1990 and 2009 but increased for fractures. Despite these changes, strong socio-economic inequalities persisted resulting in an estimated 9,000 additional medically-attended injuries per year in under-5s.  相似文献   

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4.

Importance

RSV is a common illness among young children that causes significant morbidity and health care costs.

Objective

Routinely collected health administrative data can be used to track disease incidence, explore risk factors and conduct health services research. Due to potential for misclassification bias, the accuracy of data-elements should be validated prior to use. The objectives of this study were to validate an algorithm to accurately identify pediatric cases of hospitalized respiratory syncytial virus (RSV) from within Ontario’s health administrative data, estimate annual incidence of hospitalization due to RSV and report the prevalence of major risk factors within hospitalized patients.

Study Design and Setting

A retrospective chart review was performed to establish a reference-standard cohort of children from the Ottawa region admitted to the Children’s Hospital of Eastern Ontario (CHEO) for RSV-related disease in 2010 and 2011. Chart review data was linked to Ontario’s administrative data and used to evaluate the diagnostic accuracy of algorithms of RSV-related ICD-10 codes within provincial hospitalization and emergency department databases. Age- and sex-standardized incidence was calculated over time, with trends in incidence assessed using Poisson regression.

Results

From a total of 1411 admissions, chart review identified 327 children hospitalized for laboratory confirmed RSV-related disease. Following linkage to administrative data and restriction to first admissions, there were 289 RSV patients in the reference-standard cohort. The best algorithm, based on hospitalization data, resulted in sensitivity 97.9% (95%CI: 95.5–99.2%), specificity 99.6% (95%CI: 98.2–99.8%), PPV 96.9% (95%CI: 94.2–98.6%), NPV 99.4% (95%CI: 99.4–99.9%). Incidence of hospitalized RSV in Ontario from 2005–2012 was 10.2 per 1000 children under 1 year and 4.8 per 1000 children aged 1 to 3 years. During the surveillance period, there was no identifiable increasing or decreasing linear trend in the incidence of hospitalized RSV, hospital length of stay and PICU admission rates. Among the Ontario RSV cohort, 16.3% had one or more major risk factors, with a decreasing trend observed over time.

Conclusion

Children hospitalized for RSV-related disease can be accurately identified within population-based health administrative data. RSV is a major public health concern and incidence has not changed over time, suggesting a lack of progress in prevention.  相似文献   

5.
In dogs and cats an assessment of renal function is often needed, however, existing methods including urine and plasma clearances are invasive, cumbersome and time consuming. This pilot study evaluated the feasibility of a transcutaneous glomerular filtration rate (GFR) measurement in dogs and cats. Additionally the optimal dose and location for the transcutaneous measurement device were investigated. Renal elimination of fluorescein-isothiocyanate-labelled sinistrin (FITC-S) was measured transcutaneously for 4 hours. The procedures were performed in awake, freely moving animals using escalating doses of FITC-S (10 mg/kg, 30 mg/kg, 50 mg/kg) with a wash-out period of at least 24 h in between. Multiple devices were placed on each animal. The resulting FITC-S disappearance curves were visually assessed to determine the most suitable location and the appropriate dose to reach an adequate transcutaneous peak signal for kinetic analysis. In both species 30 mg/kg were adequate for kinetic calculation. The most suitable place for the device was the lateral thoracic wall in dogs and the ventral abdominal wall in cats, respectively. Transcutaneous FITC-S clearance was then repeated using the optimal dose and location and in parallel with an additional plasma sinistrin clearance. Plasma elimination half-lives [min] were 26, 31 and 35, and corresponding transcutaneous elimination half-lives [min] were 26, 34 and 55, respectively in the dogs. Plasma elimination half-lives [min] were 51, 60 and 61, and corresponding transcutaneous elimination half-lives [min] were 75, 96 and 83, respectively in the cats. In conclusion, transcutaneous FITC-S clearance is a feasible method for the assessment of GFR in awake dogs and cats. It is noninvasive, well tolerated and easy to perform even in a clinical setting with results being readily available. A dose of 30 mg/kg of FITC-S seems adequate for kinetic assessment. Further studies are now needed to establish reference values and evaluate transcutaneous renal clearance in various conditions.  相似文献   

6.

Background

Psoriasis is a prevalent autoimmune disorder. Various studies have reported on the relationship between psoriasis and chronic diseases but very few have explored the association between psoriasis and subsequent acute infection. This retrospective cohort study aimed to compare the risk of pneumonia between subjects with and those without psoriasis.

Methods

The medical records of 14,022 patients with psoriasis and 14,022 without psoriasis were obtained from the Taiwan Longitudinal Health Insurance Database 2000. Each patient was followed-up for a three-year period. Cox proportional hazard regressions were performed to compare difference of subsequent pneumonia incidence between subjects with and those without psoriasis.

Results

There were 206 (1.47%) subjects with psoriasis and 138 (0.98%) without psoriasis hospitalized for pneumonia. By Cox proportional hazard regressions analysis, the HR (hazard ratio) of pneumonia requiring hospitalization for patients with psoriasis was 1.50 (95% confidence interval [CI]: 1.21–1.86) compared to patients without psoriasis. The adjusted HR was 1.40 (95% CI: 1.12–1.73). The adjusted HR of pneumonia hospitalization for subjects with mild and severe psoriasis was 1.36 (95% CI: 1.09–1.70) and 1.68 (95% CI: 1.12–2.52), respectively, compared to those without psoriasis.

Conclusions

Patients with psoriasis have significantly higher incidence of pneumonia compared to those without psoriasis.  相似文献   

7.

Objective

Death of a parent in childhood can diminish both the nurturing that promotes healthy development, and household income. We consider, for the first time, whether this adverse childhood experience is associated with self-rated health decades later, among seniors and whether this lifelong effect is different for women and men.

Methods

The International Mobility in Aging (IMIAS) study is a prospective cohort with survey information and biophysical measures and markers from 2000 community-dwelling 65–74 year olds in Canada, Colombia, Brazil and Albania. We assessed the independent impact of death of a parent, early hunger, and witnessing violence, while controlling for current income sufficiency and other early adversities on self-rated health using baseline (2012) IMIAS data. Regressions grouping and then separating women and men were compared.

Results

Approximately 17% of the 1991 participants had experienced early parental loss. Overall 56% rated their health as good however parental loss predicted poorer adult health, as did early hunger but not witnessing violence. Disaggregated analyses revealed that the health consequences of parental loss were significant only among men (p = 0.000 versus p = 0.210 for women) whereas early hunger predicted poor self-rated health for both (p = 0.000).

Conclusion

Parental loss should be considered as a potent adverse childhood experience with life-long consequences for health. The gender difference in its effect, speaks to unidentified and modifiable traits that appear to be more common among women and that may build resilience to long-term harms of early parental death.  相似文献   

8.
BackgroundSeveral studies have found depression and depressive feelings to be associated with subsequent dementia. As dementias typically have a long preclinical development phase, it has been difficult to determine whether depression and depressive feelings reflect a concurrent underlying dementia disease, rather than playing a causative role. Our aim was to investigate hopelessness, one dimension of depressive feelings, and evaluate the likelihood of a prodromal versus a causative role of hopelessness feelings in dementia development.MethodsWe invited a random sample of 2000 survivors from a representative population in Eastern Finland, originally investigated in midlife between 1972 and 1987, for re-examination an average of 21 years later. The age of the 1449 persons who accepted the invitation was between 39 and 64 years (mean 50.4 years) in midlife and between 65 and 80 (mean 71.3) at follow-up. To measure feelings of hopelessness in midlife and at follow-up, the participants indicated their level of agreement to two statements about their own possible future. We used logistic regression to investigate the association between the combined scores from these two items and cognitive health at follow-up, while adjusting for several health and life-style variables from midlife and for apolipoprotein E4 (ApoE4) status, depression and hopelessness feelings at follow-up. We compared the associations with late-life cognitive health when feelings of hopelessness were either measured in midlife or at the follow-up. In addition we analyzed the changes in hopelessness scores from midlife to follow-up in participants who were either cognitively healthy or impaired at follow-up.ResultsWe found higher levels of hopelessness in midlife, but not at follow-up, to be associated with cognitive impairment at follow-up; the adjusted odds ratio for each step of the five-level hopelessness scale was 1.30 (95% confidence interval 1.11–1.51) for any cognitive impairment and 1.37 (1.05–1.78) for Alzheimer’s disease. These associations remained significant also after the final adjustments for depressive feelings and for hopelessness at follow-up. The individual changes in hopelessness scores between midlife and follow-up were not systematically related to cognitive health at the follow-up.ConclusionOur results suggest that feelings of hopelessness already in midlife may have long-term implications for cognitive health and increase the risk of Alzheimer’s disease in later life.  相似文献   

9.
Levels of rabies virus neutralizing antibody in sera from dogs and cats were titrated to endpoint by the Rapid Fluorescent Focus Inhibition Test (RFFIT) and retested by the RFFIT and the Fluorescent Antibody Virus Neutralization test (FAVN). The two tests were compared for their ability to detect the 0.5 international units/ml (I.U.) of antibody required by the World Health Organization and the Office International des Epizooties as the minimum response for proof of rabies immunization. No difference was observed in sensitivity or specificity for either method in tests of 168 sera from unvaccinated animals or 70 sera from vaccinated animals with high levels of neutralizing antibody (an initial RFFIT titre of > or = 1.0 I.U.). Test to test variation occurred for results obtained by both RFFIT and FAVN for 95 sera from vaccinated animals with low to moderate levels of neutralizing antibody (RFFIT titre < 1.0 I.U.). No significant differences were detected for the 95 sera in the frequency for one methodology more often than the other to have a positive response (> or = 0.5 I.U.), nor were significant differences detected for the symmetry (P = 0.43) or the marginal homogeneity (P = 0.39) of results obtained by the two methods. Both methods can adequately identity unvaccinated animals, but false positive and false negative results are possible for either method when a single test is used to measure the antibody response of low-responding vaccinated animals. Nucleotide sequence analysis identified several amino acid differences in stocks of the challenge rabies virus from different laboratories. The small differences in neutralizing antibody titre that may result from mutations in the challenge virus are not important for evaluating immunity induced by vaccines which are themselves prepared from a variety of different rabies virus strains, but differences in the challenge virus, rather than differences in methodology, may account for at least some of the discrepant results reported in inter-laboratory surveys. Comparative studies of serological methods for measuring rabies antibodies should use well-characterized unpassaged virus stocks obtained from a single reference laboratory.  相似文献   

10.
11.

Background

Both chronic obstructive pulmonary disease (COPD) and tuberculosis (TB) primarily affect the lungs and are major causes of morbidity and mortality worldwide. COPD and TB have common risk factors such as smoking, low socioeconomic status and dysregulation of host defence functions. COPD is a prevalent co-morbid condition, especially in elderly with TB but in contrast to other diseases known to increase the risk of TB, relatively little is known about the specific relationship and impact from COPD on TB-incidence and mortality.

Methods and Findings

All individuals ≥40 years of age, discharged with a diagnosis of COPD from Swedish hospitals 1987–2003 were identified in the Swedish Inpatient Register (n = 115,867). Records were linked to the Swedish Tuberculosis Register 1989–2007 and the relative risk of active TB in patients with COPD compared to control subjects randomly selected from the general population (matched for sex, year of birth and county of residence) was estimated using Cox regression. The analyses were stratified by year of birth, sex and county of residence and adjusted for immigration status, socioeconomic status (SES) and inpatient co-morbidities previously known to increase the risk of TB. COPD patients had a three-fold increased hazard ratio (HR) of developing active TB (HR 3.0 (95% confidence interval 2.4 to 4.0)) that was mainly dependent on an increased risk of pulmonary TB. In addition, logistic regression estimates showed that COPD patients who developed active TB had a two-fold increased risk of death from all causes within first year after the TB diagnosis compared to the general population control subjects with TB (OR 2.2, 95% confidence interval 1.2 to 4.1).

Conclusions

This population-based study comprised of a large number of COPD patients shows that these patients have an increased risk of developing active TB compared to the general population. The results raise concerns that the increasing global burden of COPD will increase the incidence of active TB. The underlying contributory factors need to be disentangled in further studies.  相似文献   

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13.

Background

While an association between zolpidem use and fracture and road accident was previously proposed, this study aimed to further explore the frequency and risk of a wide spectrum of injuries in subjects prescribed with zolpidem in Taiwan.

Methods

We identified 77,036 subjects who received Zolpidem treatment between 2005 and 2007. We randomly selected 77,036 comparison subjects who were frequency-matched based-on their demographic profiles. We individually tracked each subject for a 90-day period to identify those who subsequently suffered an injury. Cox proportional hazards regressions were performed to calculate the hazard ratio of injury between the two groups.

Results

The incidence rate of injury during the 90-day follow-up period for the total subjects was 18.11 (95% CI = 17.69–18.54) per 100 person-years; this was 24.35 (95% CI = 23.66–25.05) and 11.86 (95% CI = 11.39–12.36) for the study and comparison cohort, respectively. After adjusting for demographic variables, the hazard ratio (HR) of injury during the 90-day follow-up period for study subjects was 1.83 (95% CI = 1.73–1.94) that of comparison subjects. Additionally, compared to comparison subjects, the adjusted HR of injury during the 90-day follow-up period for study subjects who were prescribed Zolpidem for >30 days was as high as 2.17 (95% CI = 2.05–2.32). The adjusted HR of injury to blood vessels for study subjects was particularly high when compared to comparison subjects (HR = 6.34; 95% CI = 1.37–29.38).

Conclusions

We found that patients prescribed with Zolpidem were at a higher risk for a wide range of injuries.  相似文献   

14.

Background

Lyme borreliosis (LB) caused by spirochetes of the Borrelia burgdorferi sensu lato complex is the most common tick-borne disease in the northern hemisphere. Data on the distribution and on risk factors in Germany are sketchy.

Methodology/Principal Findings

Blood samples of a nationwide population-based cross-sectional study from 2003–2006 in children and adolescents aged 1 to 17 years in Germany (KiGGS) were analysed (n = 12,614) to assess the seroprevalence of anti-Borrelia antibodies. Data from standardized interviews were used to assess potential risk factors. First, sera were screened for anti-Borrelia antibodies by ELISA. The overall prevalence was 4.8% (95% confidence interval (CI) 4.3–5.4%). Positive and borderline ELISA test results were confirmed by a line blot revealing a combined prevalence of 4.0% (95% CI 3.6–4.5%). Seroprevalence of ELISA was significantly higher in males (odds ratio (OR) = 1.37; CI 1.15–1.63) and in the southern part of Germany (OR = 1.41; CI 1.09–1.83), but significantly lower in children and adolescents with migration background (OR = 0.33; CI 0.24–0.44). Study participants from households with cats had a higher chance of seropositivity (OR = 6.7; CI 5.6–8.0). In a multivariable model the odds of seropositivity increases by 11% for every year of age for boys and 6% for girls.

Conclusions/Significance

This survey is the first nationwide, representative seroprevalence survey of LB in children and young adolescents. The study shows that infections with Borrelia burgdorferi are endemic in all parts of Germany despite regional differences. Even at a young age children are exposed to tick bites including seropositivity. Encouraging a thorough check for ticks and promptly removal of ticks are the key public health strategies to reduce the risk of LB and other tick-borne diseases in children and adolescents. Further epidemiological studies are warranted to better understand the burden of disease related to LB.  相似文献   

15.
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17.

Background

We aimed to calculate 3-year incidence of multimorbidity, defined as the development of two or more chronic diseases in a population of older people free from multimorbidity at baseline. Secondly, we aimed to identify predictors of incident multimorbidity amongst life-style related indicators, medical conditions and biomarkers.

Methods

Data were gathered from 418 participants in the first follow up of the Kungsholmen Project (Stockholm, Sweden, 1991–1993, 78+ years old) who were not affected by multimorbidity (149 had none disease and 269 one disease), including a social interview, a neuropsychological battery and a medical examination.

Results

After 3 years, 33.6% of participants who were without disease and 66.4% of those with one disease at baseline, developed multimorbidity: the incidence rate was 12.6 per 100 person-years (95% CI: 9.2–16.7) and 32.9 per 100 person-years (95% CI: 28.1–38.3), respectively. After adjustments, worse cognitive function (OR, 95% CI, for 1 point lower Mini-Mental State Examination: 1.22, 1.00–1.48) was associated with increased risk of multimorbidity among subjects with no disease at baseline. Higher age was the only predictor of multimorbidity in persons with one disease at baseline.

Conclusions

Multimorbidity has a high incidence at old age. Mental health-related symptoms are likely predictors of multimorbidity, suggesting a strong impact of mental disorders on the health of older people.  相似文献   

18.

Objective

We sought to measure HRQoL in all-cause encephalitis survivors and assess the impact of various socio-clinical factors on outcome.

Methods

We used a prospective cohort study design, using the short-form 36 (SF-36) to measure the HRQoL in patients 15 years and older, and the short-form 10 (SF-10) for patients less than 15 years old. We posted questionnaires to individuals six months after discharge from hospital. All scores were normalised to the age- and sex-matched general population. We used multivariate statistical analysis to assess the relative association of clinical and socio-demographic variables on HRQoL in adults.

Results

Of 109 individuals followed-up, we received 61 SF-36 and twenty SF-10 questionnaires (response rate 74%). Patients scored consistently worse than the general population in all domains of the SF-36 and SF-10, although there was variation in individual scores. Infectious encephalitis was associated with the worst HRQoL in those aged 15 years and over, scoring on average 5.64 points less than immune-mediated encephalitis (95% CI −8.77– −2.89). In those aged less than 15 years the worst quality of life followed encephalitis of unknown cause. Immuno compromise, unemployment, and the 35–44 age group all had an independent negative association with HRQoL. A poor Glasgow Outcome Score was most strongly associated with a poor HRQoL. Less than half of those who had made a ‘good’ recovery on the score reported a HRQoL equivalent to the general population.

Conclusions

Encephalitis has adverse effects on the majority of survivors’ wellbeing and quality of life. Many of these adverse consequences could be minimised by prompt identification and treatment, and with better rehabilitation and support for survivors.  相似文献   

19.

Background

Amphimerus sp. is a liver fluke which recently has been shown to have a high prevalence of infection among an indigenous group, Chachi, who reside in a tropical rainforest in the northwestern region of Ecuador. Since it is unknown which animals can act as a reservoir and/or definitive hosts for Amphimerus sp. in this endemic area, a study was done to determine the prevalence of infection in domestic cats and dogs. This information is important to understand the epidemiology, life cycle and control of this parasite.

Methodology/Findings

In July 2012, three Chachi communities located on Rio Cayapas, province of Esmeraldas, were surveyed. A total of 89 of the 109 registered households participated in the study. Of the 27 cats and 43 dogs found residing in the communities, stool samples were collected from 14 cats and 31 dogs (total of 45 animals) and examined microscopically for the presence of Amphimerus eggs. The prevalence of infection was 71.4% in cats and 38.7% in dogs, with similar rates of infection in all three communities. Significantly more cats were infected than dogs (p = 0.042).

Conclusions/Significance

The data show a high rate of Amphimerus sp. infection in domestic cats and dogs residing in Chachi communities. It can be concluded that these animals act as definitive and reservoir hosts for this liver fluke and that amphimeriasis is a zoonotic disease. These findings provide important epidemiological data which will aid in the development and implementation of control strategies against the transmission of Amphimerus.  相似文献   

20.

Background

Self-reported health status measures, like the Short Form 36-item Health Survey (SF-36), can provide rich information about the overall health of a population and its components, such as physical, mental, and social health. However, differential item functioning (DIF), which arises when population sub-groups with the same underlying (i.e., latent) level of health have different measured item response probabilities, may compromise the comparability of these measures. The purpose of this study was to test for DIF on the SF-36 physical functioning (PF) and mental health (MH) sub-scale items in a Canadian population-based sample.

Methods

Study data were from the prospective Canadian Multicentre Osteoporosis Study (CaMos), which collected baseline data in 1996–1997. DIF was tested using a multiple indicators multiple causes (MIMIC) method. Confirmatory factor analysis defined the latent variable measurement model for the item responses and latent variable regression with demographic and health status covariates (i.e., sex, age group, body weight, self-perceived general health) produced estimates of the magnitude of DIF effects.

Results

The CaMos cohort consisted of 9423 respondents; 69.4% were female and 51.7% were less than 65 years. Eight of 10 items on the PF sub-scale and four of five items on the MH sub-scale exhibited DIF. Large DIF effects were observed on PF sub-scale items about vigorous and moderate activities, lifting and carrying groceries, walking one block, and bathing or dressing. On the MH sub-scale items, all DIF effects were small or moderate in size.

Conclusions

SF-36 PF and MH sub-scale scores were not comparable across population sub-groups defined by demographic and health status variables due to the effects of DIF, although the magnitude of this bias was not large for most items. We recommend testing and adjusting for DIF to ensure comparability of the SF-36 in population-based investigations.  相似文献   

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