The effects of ambient temperature on cerebrovascular mortality: An epidemiologic study in four climatic zones in China

Background Little evidence is available about the association between temperature and cerebrovascular mortality in China. This study aims to examine the effects of ambient temperature on cerebrovascular mortality in different climatic zones in China. Method We obtained daily data on weather conditions, air pollution and cerebrovascular deaths from five cities (Beijing, Tianjin, Shanghai, Wuhan, and Guangzhou) in China during 2004-2008. We examined city-specific associations between ambient temperature and the cerebrovascular mortality, while adjusting for season, long-term trends, day of the week, relative humidity and air pollution. We examined cold effects using a 1°C decrease in temperature below a city-specific threshold, and hot effects using a 1°C increase in temperature above a city-specific threshold. We used a meta-analysis to summarize the cold and hot effects across the five cities. Results Beijing and Tianjin (with low mean temperature) had lower thresholds than Shanghai, Wuhan and Guangzhou (with high mean temperature). In Beijing, Tianjin, Wuhan and Guangzhou cold effects were delayed, while in Shanghai there was no or short induction. Hot effects were acute in all five cities. The cold effects lasted longer than hot effects. The hot effects were followed by mortality displacement. The pooled relative risk associated with a 1°C decrease in temperature below thresholds (cold effect) was 1.037 (95% confidence interval (CI): 1.020, 1.053). The pooled relative risk associated with a 1°C increase in temperature above thresholds (hot effect) was 1.014 (95% CI: 0.979, 1.050). Conclusion Cold temperatures are significantly associated with cerebrovascular mortality in China, while hot effect is not significant. People in colder climate cities were sensitive to hot temperatures, while people in warmer climate cities were vulnerable to cold temperature.

Fractional polynomials and model selection in generalized estimating equations analysis, with an application to a longitudinal epidemiologic study in Australia

In epidemiologic studies, researchers often need to establish a nonlinear exposure-response relation between a continuous risk factor and a health outcome. Furthermore, periodic interviews are often conducted to take repeated measurements from an individual. The authors proposed to use fractional polynomial models to jointly analyze the effects of 2 continuous risk factors on a health outcome. This method was applied to an analysis of the effects of age and cumulative fluoride exposure on forced vital capacity in a longitudinal study of lung function carried out among aluminum workers in Australia (1995-2003). Generalized estimating equations and the quasi-likelihood under the independence model criterion were used. The authors found that the second-degree fractional polynomial models for age and fluoride fitted the data best. The best model for age was robust across different models for fluoride, and the best model for fluoride was also robust. No evidence was found to suggest that the effects of smoking and cumulative fluoride exposure on change in forced vital capacity over time were significant. The trend 1 model, which included the unexposed persons in the analysis of trend in forced vital capacity over tertiles of fluoride exposure, did not fit the data well, and caution should be exercised when this method is used.

Leptin in depressed women : Cross-sectional and longitudinal data from an epidemiologic study

Background There is conflicting evidence regarding levels of leptin in depression. In this study we aimed to investigate the relationship between serum leptin level and depression in a community sample of women using both cross-sectional and longitudinal data.

Methods From among 510 women aged 20–78 yr, 83 were identified with a lifetime history of major depressive disorder or dysthymia, ascertained using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition (SCID-I/NP). Serum leptin levels were measured by radioimmunoassay. Medication use and lifestyle were self-reported and body mass index (BMI) determined from measures of height and weight.

Results Using multiple linear regression, serum leptin levels were greater among women with a lifetime history of depression compared to women without any history of depression, independent of BMI. Adjusted geometric mean values of serum leptin were 16.37 (95%CI 14.70–18.23) ng/mL for depressed and 14.46 (95%CI 13.79–15.16) ng/mL for non-depressed women (P = 0.039). The hazard ratio (HR) for a de novo depressive disorder over five years increased 2.56-fold for each standard deviation increase in log-transformed serum leptin among non-smokers and this was not explained by differences in BMI, medications or other lifestyle factors (HR = 2.56, 95%CI 1.52-4.30). No association was observed for smokers.

Limitations There is potential for unrecognised confounding, recall bias and transient changes in body composition.

Conclusion Women with a lifetime history of depression have elevated levels of serum leptin, and elevated serum leptin predicts subsequent development of a depressive disorder.

Carpal and scaphoid fracture incidence in south-eastern Australia: an epidemiologic study

UNLABELLED: Carpal fractures were identified by the Geelong Osteoporosis Study Fracture Grid for 2006-2007. Incidence rates were higher in males than females. Males had a lower median age of fracture than females. Females had more fractures on the left side than males. Most fractures were the result of a fall. PURPOSE: In this study, we report the incidence of carpal bone fractures (scaphoid and non-scaphoid) amongst residents from the Barwon Statistical Division over 2 years. METHODS: X-ray reports from imaging centres in the region were used to identify incident fractures during 2006 and 2007. Data were collected as part of the Geelong Osteoporosis Study Fracture Grid. RESULTS: During 2006 and 2007, there were 171 and 41 carpal fractures in males and females, respectively. Of these, 131 males and 29 females had fractured the scaphoid bone. Females had a higher proportion of left-sided fractures (>70 %) than males (∼40 %). Most fractures were the result of an accidental fall (>87 %). Patterns of incidence for males showed one major peak around 20-29 years. For females, peaks occurred around age 10-19 years and 70-79 years. Incidence rates for males (per 100,000 persons per year) were 54.6 (95 % confidence interval (CI) 53.6, 55.7) and 15.9 (95 % CI 15.4, 16.5) for scaphoid and non-scaphoid fractures, respectively. In females, the corresponding rates were 10.6 (95 % CI 10.2, 11.1) and 4.5 (95 % CI 4.2, 4.8). CONCLUSION: Almost all fractures were the result of a fall. In males, carpal fractures were sustained mainly during early adulthood and in females during adolescence and after menopause. Incidence rates for males were higher than those in females for both scaphoid and non-scaphoid fractures.

A comparison of participants with non-participants in a population-based epidemiologic study: the Melbourne Visual Impairment Project

PURPOSE: Adequate participation in population-based studies in essential to ensure that the sample is representative of the population under investigation. Participants may differ from non-participants on important variables such as age, sex socioeconomic status, and general health factors. The Melbourne Visual Impairment Project (Melbourne VIP) is a population-based study designed to increase understanding of the prevalence and severity of common ocular disorders affecting people 40 years of age and over. AIM: The aim of this study was to determine the potential for any non-response bias by comparing data from participants and non-participants of the Melbourne VIP. METHODS: Specific demographic and general variables were compared between the two groups. The variables included age, sex, education level, and social status. The reason for non-attendance was also recorded. RESULTS: A total of 3271 (83%) eligible residents from the 9 sample areas were screened; 46% males and 54% females. Language spoken at home was significantly associated with participation. Residents whose main language at home was not English were less likely to attend the screening centre. (OR: 0.60; CI: 0.44-0.81). The main reasons given for non-attendance by eligible residents were lack of interest (6%), too busy to attend (4%), personal illness (2%), and attend own eye specialist (2%). CONCLUSION: We believe these results will not impact significantly on the interpretation of gender and age-specific data from the Melbourne VIP.

Epidemiologic study of anisometropia in students of Natal, Brazil

To perform an epidemiologic study in students in Natal/Brazil,with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropiaTo perform an epidemiologic study in students in Natal/Brazil, with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropia

An epidemiologic study of headaches in brazilian schoolchildren with a focus on pain frequency

O objetivo deste estudo foi avaliar a prevalência e frequência de cefaléia em escolares brasileiros. Um estudo transversal foi conduzido entre Março e Novembro de 2004 em São José do Rio Preto, Estado de São Paulo, Brasil. Uma amostra de 5.232 crianças das escolas foi selecionada utilizando método de amostragem estratificada proporcional. Para a coleta dos dados, um questionário foi entregue nas escolas aos estudantes para ser respondida pelos pais e/ou responsáveis. do total de respostas recebidas, 84,2% relataram cefaléia durante o último ano. Houve diferenças significativas na frequência da queixa de cefaléia entre meninos e meninas. As meninas relataram cefaléias mais frequentes do que os meninos, com prevalência de cefaléias diárias duas vezes maior em meninas. Uma maior frequência de cefaléia foi também relatada com o aumento da idade. O estudo demonstrou que a prevalência de cefaléia foi alta, com uma maior frequência (mensais, semanais e diárias) em meninas e no grupo etário mais velho.

The importance of allocation concealment and patient blinding in osteoarthritis trials: a meta-epidemiologic study

OBJECTIVE: To evaluate the association of adequate allocation concealment and patient blinding with estimates of treatment benefits in osteoarthritis trials. METHODS: We performed a meta-epidemiologic study of 16 meta-analyses with 175 trials that compared therapeutic interventions with placebo or nonintervention control in patients with hip or knee osteoarthritis. We calculated effect sizes from the differences in means of pain intensity between groups at the end of followup divided by the pooled SD and compared effect sizes between trials with and trials without adequate methodology. RESULTS: Effect sizes tended to be less beneficial in 46 trials with adequate allocation concealment compared with 112 trials with inadequate or unclear concealment of allocation (difference -0.15; 95% confidence interval [95% CI] -0.31, 0.02). Selection bias associated with inadequate or unclear concealment of allocation was most pronounced in meta-analyses with large estimated treatment benefits (P for interaction < 0.001), meta-analyses with high between-trial heterogeneity (P = 0.009), and meta-analyses of complementary medicine (P = 0.019). Effect sizes tended to be less beneficial in 64 trials with adequate blinding of patients compared with 58 trials without (difference -0.15; 95% CI -0.39, 0.09), but differences were less consistent and disappeared after accounting for allocation concealment. Detection bias associated with a lack of adequate patient blinding was most pronounced for nonpharmacologic interventions (P for interaction < 0.001). CONCLUSION: Results of osteoarthritis trials may be affected by selection and detection bias. Adequate concealment of allocation and attempts to blind patients will minimize these biases.

Epidemiologic study of anisometropia in students of Natal, Brazil

To perform an epidemiologic study in students in Natal/Brazil,with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropiaTo perform an epidemiologic study in students in Natal/Brazil, with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropia

Epidemiologic study of anisometropia in students of Natal, Brazil

To perform an epidemiologic study in students in Natal/Brazil,with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropiaTo perform an epidemiologic study in students in Natal/Brazil, with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. Methods: A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of ≥ 2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. Results: We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. Conclusions: There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropia

Acute type A aortic dissection and pregnancy: a population-based study

Pregnancy has been reported to be an independent risk factor for 50% of acute aortic dissections recorded in women younger than 45 years of age. The present epidemiologic study aimed to identify whether this putative association of pregnancy and acute type A dissection could be an artifact of selective reporting.

Obesity and overweight as a risk factor for pneumonia in polytrauma patients: a retrospective cohort study

BACKGROUND Obesity is a growing problem in western societies. The aim of this retrospective cohort study was to determine the association between the overweight and obese polytrauma patients and pneumonia after injury. METHODS A total of 628 patients with an Injury Severity Score (ISS) of 16 or greater and 16 years or older were included in this retrospective study. The sample was subdivided into three groups as follows: body mass index (BMI) of less than 25 kg/m2; BMI of 25 kg/m2 to 30 kg/m2; and BMI more than 30 kg/m2. The Murray score was assessed at admission and at its maximum during hospitalization to determine pulmonary problems. Pneumonia was defined as bacteriologically positive sputum with appropriate radiologic and laboratory changes (C-reactive protein and interleukin 6). Data are given as mean ± SEM. One-way analysis of variance and the Kruskal-Wallis test were used for the analyses, and the significance level was set at p < 0.05; Bonferroni-Dunn test was performed as post hoc analysis. RESULTS The Abbreviated Injury Scale (AIS) score for the thorax was 3.2 ± 0.1 in the group with a BMI of less than 25 kg/m2, 3.3 ± 0.1 in the group with a BMI of 25 kg/m2 to 30 kg/m2, and 2.8 ± 0.2 in the group with BMI of more than 30 kg/m2 (p = 0.044). The Murray score at admission was elevated with increasing BMI (0.8 ± 0.8 for BMI < 25 kg/m2, 0.9 ± 0.9 for BMI 25–30 kg/m2, and 1.0 ± 0.8 for BMI > 30 kg/m2; p = 0.137); the maximum Murray score during hospitalization revealed significant differences (1.2 ± 0.9 for BMI < 25 kg/m2, 1.6 ± 1.0 for BMI 25–30 kg/m2, and 1.5 ± 0.9 for BMI > 30 kg/m2; p < 0.001). The incidence of pneumonia also increased with increasing BMI (1.6% for BMI < 25 kg/m2, 2.0% for BMI 25–30 kg/m2, and 3.1% for BMI > 30 kg/m2; p = 0.044). CONCLUSION Obesity leads to an increased incidence of pneumonia in a polytrauma situation. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level IV.