Showing papers by "Saeid Safiri published in 2017"

Health Effects of Overweight and Obesity in 195 Countries over 25 Years.

Abstract: BACKGROUND Although the rising pandemic of obesity has received major attention in many countries, the effects of this attention on trends and the disease burden of obesity remain uncertain. METHOD ...

Global, regional, and national burden of neurological disorders, 1990-2016: A systematic analysis for the Global Burden of Disease Study 2016

Abstract: Summary Background Comparable data on the global and country-specific burden of neurological disorders and their trends are crucial for health-care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study provides such information but does not routinely aggregate results that are of interest to clinicians specialising in neurological conditions. In this systematic analysis, we quantified the global disease burden due to neurological disorders in 2015 and its relationship with country development level. Methods We estimated global and country-specific prevalence, mortality, disability-adjusted life-years (DALYs), years of life lost (YLLs), and years lived with disability (YLDs) for various neurological disorders that in the GBD classification have been previously spread across multiple disease groupings. The more inclusive grouping of neurological disorders included stroke, meningitis, encephalitis, tetanus, Alzheimer's disease and other dementias, Parkinson's disease, epilepsy, multiple sclerosis, motor neuron disease, migraine, tension-type headache, medication overuse headache, brain and nervous system cancers, and a residual category of other neurological disorders. We also analysed results based on the Socio-demographic Index (SDI), a compound measure of income per capita, education, and fertility, to identify patterns associated with development and how countries fare against expected outcomes relative to their level of development. Findings Neurological disorders ranked as the leading cause group of DALYs in 2015 (250·7 [95% uncertainty interval (UI) 229·1 to 274·7] million, comprising 10·2% of global DALYs) and the second-leading cause group of deaths (9·4 [9·1 to 9·7] million], comprising 16·8% of global deaths). The most prevalent neurological disorders were tension-type headache (1505·9 [UI 1337·3 to 1681·6 million cases]), migraine (958·8 [872·1 to 1055·6] million), medication overuse headache (58·5 [50·8 to 67·4 million]), and Alzheimer's disease and other dementias (46·0 [40·2 to 52·7 million]). Between 1990 and 2015, the number of deaths from neurological disorders increased by 36·7%, and the number of DALYs by 7·4%. These increases occurred despite decreases in age-standardised rates of death and DALYs of 26·1% and 29·7%, respectively; stroke and communicable neurological disorders were responsible for most of these decreases. Communicable neurological disorders were the largest cause of DALYs in countries with low SDI. Stroke rates were highest at middle levels of SDI and lowest at the highest SDI. Most of the changes in DALY rates of neurological disorders with development were driven by changes in YLLs. Interpretation Neurological disorders are an important cause of disability and death worldwide. Globally, the burden of neurological disorders has increased substantially over the past 25 years because of expanding population numbers and ageing, despite substantial decreases in mortality rates from stroke and communicable neurological disorders. The number of patients who will need care by clinicians with expertise in neurological conditions will continue to grow in coming decades. Policy makers and health-care providers should be aware of these trends to provide adequate services. Funding Bill & Melinda Gates Foundation.

The global burden of tuberculosis: results from the Global Burden of Disease Study 2015

Abstract: Summary Background An understanding of the trends in tuberculosis incidence, prevalence, and mortality is crucial to tracking of the success of tuberculosis control programmes and identification of remaining challenges. We assessed trends in the fatal and non-fatal burden of tuberculosis over the past 25 years for 195 countries and territories. Methods We analysed 10 691 site-years of vital registration data, 768 site-years of verbal autopsy data, and 361 site-years of mortality surveillance data using the Cause of Death Ensemble model to estimate tuberculosis mortality rates. We analysed all available age-specific and sex-specific data sources, including annual case notifications, prevalence surveys, and estimated cause-specific mortality, to generate internally consistent estimates of incidence, prevalence, and mortality using DisMod-MR 2.1, a Bayesian meta-regression tool. We assessed how observed tuberculosis incidence, prevalence, and mortality differed from expected trends as predicted by the Socio-demographic Index (SDI), a composite indicator based on income per capita, average years of schooling, and total fertility rate. We also estimated tuberculosis mortality and disability-adjusted life-years attributable to the independent effects of risk factors including smoking, alcohol use, and diabetes. Findings Globally, in 2015, the number of tuberculosis incident cases (including new and relapse cases) was 10·2 million (95% uncertainty interval 9·2 million to 11·5 million), the number of prevalent cases was 10·1 million (9·2 million to 11·1 million), and the number of deaths was 1·3 million (1·1 million to 1·6 million). Among individuals who were HIV negative, the number of incident cases was 8·8 million (8·0 million to 9·9 million), the number of prevalent cases was 8·9 million (8·1 million to 9·7 million), and the number of deaths was 1·1 million (0·9 million to 1·4 million). Annualised rates of change from 2005 to 2015 showed a faster decline in mortality (−4·1% [−5·0 to −3·4]) than in incidence (−1·6% [−1·9 to −1·2]) and prevalence (−0·7% [−1·0 to −0·5]) among HIV-negative individuals. The SDI was inversely associated with HIV-negative mortality rates but did not show a clear gradient for incidence and prevalence. Most of Asia, eastern Europe, and sub-Saharan Africa had higher rates of HIV-negative tuberculosis burden than expected given their SDI. Alcohol use accounted for 11·4% (9·3–13·0) of global tuberculosis deaths among HIV-negative individuals in 2015, diabetes accounted for 10·6% (6·8–14·8), and smoking accounted for 7·8% (3·8–12·0). Interpretation Despite a concerted global effort to reduce the burden of tuberculosis, it still causes a large disease burden globally. Strengthening of health systems for early detection of tuberculosis and improvement of the quality of tuberculosis care, including prompt and accurate diagnosis, early initiation of treatment, and regular follow-up, are priorities. Countries with higher than expected tuberculosis rates for their level of sociodemographic development should investigate the reasons for lagging behind and take remedial action. Efforts to prevent smoking, alcohol use, and diabetes could also substantially reduce the burden of tuberculosis. Funding Bill & Melinda Gates Foundation.

The effect of dairy consumption on the prevention of cardiovascular diseases: A meta-analysis of prospective studies

Abstract: Introduction: There is no global consensus on the relationship of dairy products with cardiovascular diseases. This study was conducted to evaluate the effect of the consumption of dairy products on cardiovascular diseases, including stroke and coronary heart disease (CHD). Methods: Important electronic databases such as the Scopus, Science Direct, and PubMed were evaluated up to September 2014. All prospective cohort studies that evaluated the relationship between dairy products consumption and cardiovascular diseases were included regardless of their publication date and language. The study participants were evaluated regardless of age, sex, and ethnicity. The STROBE checklist was used to assess quality of the study. Two investigators separately selected the studies and extracted the data. The designated effects were risk ratio (RR) and hazard ratio (HR). The random effect model was used to combine the results. Results: Meta-analysis was performed on 27 studies. There were 8648 cases of cardiovascular diseases (CVD), 11806 cases of CHD, and 29300 cases of stroke. An inverse association was found between total dairy intake and CVD (RR=0.90, 95% CI: 0.81-0.99) and stroke (RR=0.88, 95% CI: 0.82-0.95) while no association was observed between total dairy intake and CHD. The total diary intake was associated with decreased mortality of stroke (RR=0.80, 95% CI: 0.76-0.83) although it had no association with its incidence (RR=0.96, 95% CI: 0.88-1.04). Conclusion: This is the first meta-analysis of the relationship of total dairy intake with CVD. This study showed an inverse relationship between total dairy intake and CVD while no relationship was found for CHD. Considering the limited number of studies in this regard, more studies are required to investigate the effect of different factors on the association of dairy intake and CVD.

Metabolic syndrome and its components among rheumatoid arthritis patients: A comprehensive updated systematic review and meta-analysis

Abstract: Background Estimating the current global prevalence of metabolic syndrome (MetS), and its components, among rheumatoid arthritis (RA) patients is necessary in order to formulate preventative strategies and to ensure there are adequate community resources available for these patients. Furthermore, the association between RA and MetS is controversial and has not previously been comprehensively assessed. Therefore, the present study aimed to: 1) determine the prevalence of MetS, and its components, among RA patients across the world 2) update the odds ratio of MetS in RA patients, compared to healthy controls, using a comprehensive systematic review and meta-analysis. Methods International databases, including: the Web of Science, PubMed, Scopus, Embase, CINAHL and other relevant databases were searched to identify English language articles which reported the prevalence and risk of MetS in RA patients between January 2000 and August 2016. The meta-analysis only included studies which clearly described the time and location of the study, utilised adequate sampling strategies, and appropriate statistical analyses. Results The meta-analyses of prevalence (70 studies [n = 12612]) and risk (43 studies [n = 35220]) of MetS in RA patients were undertaken separately. The overall pooled prevalence of MetS was 30.65% (95% CI: 27.87–33.43), but this varied from 14.32% (95% CI: 10.59–18.05) to 37.83% (95% CI: 31.05–44.61), based upon the diagnostic criteria used. The prevalence of MetS also varied slightly between males (31.94%, 95% CI: 24.37–39.51) and females (33.03%, 95% CI: 28.09–37.97), but this was not statistically significant. The overall pooled odds ratio (OR) of MetS in RA patients, compared to healthy controls, was 1.44 (95% CI: 1.20–1.74), but this ranged from 0.70 (95% CI: 0.27–1.76) to 4.09 (95% CI: 2.03–8.25), depending on the criteria used. The mean age and diagnostic criteria of MetS were identified as sources of heterogeneity in the estimated odds ratios between studies (P<0.05). Conclusions According to the high prevalence of MetS in RA patients, and high risk of MetS, measuring metabolic syndrome in RA patients is strongly recommended. Furthermore, as high waist circumference (WC) is the most common metabolic syndrome component, more attention must be paid to nutrition and weight loss among those with RA.

Bias in Association between FEV1/FVC% Predicted at 7 Years and Asthma-Chronic Obstructive Pulmonary Disease Overlap Syndrome.

Abstract: 1. Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2. Department of Epidemiology & Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 3. Managerial Epidemiology Research Center, Department of Public Health, School of Nursing and Midwifery, Maragheh University of Medical Sciences, Maragheh, Iran

Is snack consumption associated with meal skipping in children and adolescents? The CASPIAN-IV study

Abstract: The present inquiry set to assess the relationship between snack consumption and meal skipping in Iranian children and adolescents. Overall, 14,880 students, aged 6–18 years, were selected via multistage cluster sampling method from rural and urban areas of 30 provinces of Iran. A validated questionnaire of food behaviors including questions on snacks consumption and taking/skipping meals was completed. Consuming and skipping meals and their related factors were reported in both crude and adjusted models. Overall, 13,486 students with a mean age of 12.47 ± 3.36 years completed the study (90.6% participation rate). Among them, 32.08, 8.89, and 10.90% skipped breakfast, lunch, and dinner, respectively. Compared to their counterpart groups, the frequency of meal skipping was higher in girls, urban inhabitants, and students in higher school grades (P < 0.05). Snack consumption was associated with an increased odds ratio of meal skipping in many types of snack groups. Meal skipping and snack consumption were frequent among Iranian children and adolescents. Evidence based interventions are proposed to improve the students’ eating habits.

Association of passive and active smoking with self-rated health and life satisfaction in Iranian children and adolescents: the CASPIAN IV study

Abstract: Objective To assess the joint association of passive and active smoking with self-rated health and life satisfaction among Iranian children and adolescents. Methods Using a multistage random cluster sampling method, a representative sample of 14 880 school students were selected from urban and rural areas of 30 provinces of Iran. Data were gathered using a questionnaire, a weight scale and metre. Participants were classified into four groups based on their smoking patterns: ‘non-smoker’, ‘only active smoker’, ‘only passive smoker’ and ‘active and passive smoker’. Life satisfaction (LS) and self-rated health (SRH) were assessed by self-administered validated questionnaires based on the WHO-Global School-based student Health Survey (WHO-GSHS). Data were analysed using a t-test, χ2 test and multiple logistic regression. Results A total of 13 486 individuals (6640 girls and 6846 boys) out of 14 880 invited participated in the study (response rate 90.6%). LS and good SRH showed linearly negative associations with smoking status in both sexes. The proportions of LS and SRH categories were significantly different among all subsets of smoking status. Those classified as ‘non-smokers’ had the highest proportions of LS and good SRH, followed by ‘only passive smokers’ and ‘only active smokers’, while those with ‘active and passive smoking’ had the lowest proportions of LS and good SRH. In a multivariate model, students in the ‘active and passive smoking’ group had lower odds of LS (OR 0.43; 95% CI 0.32 to 0.57) and good SRH (OR 0.51; 95% CI 0.38 to 0.68) than those in the ‘non-smoker’ group. Students in the ‘only passive smoker’ group also had lower odds of LS (OR 0.75; 95% CI 0.67 to 0.83) and good SRH (OR 0.72; 95% CI 0.66 to 0.80) compared with the ‘non-smoker’ group. Conclusions Adolescents with different smoking habits and exposure patterns have poorer SRH and LS than non-smokers. Both active and passive smoking status could affect LS and SRH in adolescents. Therefore, smoking prevention strategies should be considered as a health priority in school health services for promoting psychological well-being in children and adolescents.

Socioeconomic inequality in childhood obesity and its determinants: a Blinder-Oaxaca decomposition.

Abstract: Objective Childhood obesity has become a priority health concern worldwide. Socioeconomic status is one of its main determinants. This study aimed to assess the socioeconomic inequality of obesity in children and adolescents at national and provincial levels in Iran. Methods This multicenter cross-sectional study was conducted in 2011–2012, as part of a national school-based surveillance program performed in 40,000 students, aged 6–18-years, from urban and rural areas of 30 provinces of Iran. Using principle component analysis, the socioeconomic status of participants was categorized to quintiles. Socioeconomic status inequality in excess weight was estimated by calculating the prevalence of excess weight (i.e., overweight, generalized obesity, and abdominal obesity) across the socioeconomic status quintiles, the concentration index, and slope index of inequality. The determinants of this inequality were determined by the Oaxaca Blinder decomposition. Results Overall, 36,529 students completed the study (response rate: 91.32%); 50.79% of whom were boys and 74.23% were urban inhabitants. The mean (standard deviation) age was 12.14 (3.36) years. The prevalence of overweight, generalized obesity, and abdominal obesity was 11.51%, 8.35%, and 17.87%, respectively. The SII for overweight, obesity and abdominal obesity was −0.1, −0.1 and −0.15, respectively. Concentration index for overweight, generalized obesity, and abdominal obesity was positive, which indicate inequality in favor of low socioeconomic status groups. Area of residence, family history of obesity, and age were the most contributing factors to the inequality of obesity prevalence observed between the highest and lowest socioeconomic status groups. Conclusion This study provides considerable information on the high prevalence of excess weight in families with higher socioeconomic status at national and provincial levels. These findings can be used for international comparisons and for healthcare policies, improving their programming by considering differences at provincial levels.

Profile and outcome of first 109 cases of paediatric acute liver failure at a specialized paediatric liver unit in India: Methodological issues

Abstract: Dear Editor-in-Chief, We have meticulously read the article authored by Alam and colleagues published in the journal of Liver International in 2017.1 The authors purposed to assess the aetiological spectrum and outcome of the paediatric acute liver failure cases. They conducted the study on 109 children with acute liver failure and found that jaundice to encephalopathy interval >7 days (JE interval >7 days) and higher paediatric/model for endstage liver disease scores at 72 hours (PELD at 72 hours) were associated with poor outcome. Although the present investigation makes valuable contribution to the area, some methodological issues need to be taken into account. Firstly, the authors constructed multivariate logistic regression to find the predictors of poor outcomes in the studied population, which is questionable. Two steps ought to be considered in this type of model building.2,3,4 (i) Independent variables should be examined in a univariate model and then the variables with P<.2 be considered to be candidate for the multivariate model. (ii) The multicollinearity must be checked among the candidate independent variables before their entrance into the multivariate model; otherwise, the multivariate models’ findings may be biased due to the multicollinearity among the independent variables. In the study conducted by Alam and colleagues, neither the criterion (P<.2) has been considered to include the variables into the multivariate model nor the multicollinearity has been checked. Hence, the multivariate model constructed by Alam et al., may be biased because variables such as PELD at 24 hours and PELD at 72 hours are highly correlated. Secondly, normally in clinical and epidemiological studies sample size should be calculated to achieve a predetermined precision and power for statistical tests;5 however, the sample size was not calculated in their study. On the other hand, additional observations must be considered for the studies constructing multivariate model to provide at least 10 events per variable (EPV) per variable included into the multivariate model; otherwise, there will be chance of overparameterization and sparse data bias.6 Hence, some significant associations in the Alam et al. study may not be detected as overparameterization saps the statistical power.3 Finally, the multivariate model is subject to sparse data bias when the number of events is low in different combinations of independent variables and outcome. This bias leads to inflated effect estimates and wide confidence intervals which can be found in the multivariate model constructed by Alam and colleagues (Variable: JE interval >7 days; odds ratio=9.16; 95% confidence interval: 1.5553.00). This bias can be decreased or eliminated through using various methods but an advanced method namely penalized estimation via data augmentation has been introduced by Greenland et al., which dilutes the sparse data bias both in univariate and multivariate models, effectively. Hence, it is suggested for Alam and colleagues to reanalyse their data using the aforementioned method.

Association between screen time and snack consumption in children and adolescents: The CASPIAN-IV study.

Abstract: Background The relationship between screen time (ST) and the frequency of snack consumption in a national sample of Iranian children and adolescents was assessed. The present nationwide survey was conducted on 14,880 school students living in urban and rural areas of 30 provinces in Iran. Trained healthcare providers conducted the physical examination and completed the questionnaire of the World Health Organization - Global School-Based Student Health Survey (WHO-GSHS). Methods The association between ST (total time spent watching TV and using a computer in leisure time) and the frequency of snack consumption was determined using ordinal logistic regression analysis. The subjects were 13,486 students out of the 14,880 invited including 50.8% boys. The mean (SD) age of participants was 12.47 (3.36) years. Results In multivariate models, for students who had prolonged ST (more than 4 h/day), the odds of daily consumption of sweets (odds ratio, OR 1.25; 95% CI 1.14-1.4), salty snacks (OR 1.6; 95% CI 1.5-1.76), soft drinks (OR 1.52; 95% CI 1.4-1.7), canned fruit juice (OR 1.3; 95% CI 1.2-1.4), and fast food (OR 1.53; 95% CI 1.4-1.7) were higher compared to those with low ST. Furthermore, the odds of daily consumption of milk in students who had prolonged ST (more than 4 h/day) were lower compared to those with low ST (OR 0.9; 95% CI 0.8-0.99). Conclusions Prolonged time spent watching TV and using a computer during leisure time might be associated with unhealthy dietary habits. Moreover, inactivity induced by prolonged ST may also lead to unhealthy dietary habits and in turn excess weight in children and adolescents.

Hypertension is the primary component of metabolic syndrome associated with pathologic features of kidney cancer: methodological issues.

Abstract: dependent variable on univariable analysis (P value <0.2) are imported into multiple regression model through backward step-wise method [2]. In the study of Kocher and colleagues, bivariate correlations between independent variables have not been evaluated. It is most likely that their findings are biased by multicollinearity among MetS components. In fact, the preceding studies showed that MetS components are highly correlated [3, 4]. Also, the predictive performance of hypertension on the specific pathologic features of kidney cancer is arguable and optimistic interpretation. Internal and external validation of model must be tested using bootstrapping and split validation or cross-validation, respectively [5]. Notably, predictive performance of MetS components on pathologic features of kidney cancer should be more evaluated. Kocher and colleagues conducted a cross-sectional study, while the longitudinal study is key concern for the clinical prediction. In other words, the clinical risk prediction through associations estimated by non-longitudinal studies is also doubtful and preceding exposure to outcome (temporality) is main assumption for clinical prediction [5].

Physical inactivity and associated factors in Iranian children and adolescents: the Weight Disorders Survey of the CASPIAN-IV study

Abstract: Introduction: This study aims to assess the associated factors of physical inactivity among Iranian children and adolescents at national level. The second objective is to assess the relationship of physical inactivity with anthropometric measures. Methods: Along with a national surveillance program, this survey on weight disorders was conducted among a nationally-representative sample of Iranian children and adolescents, aged 6-18 years. Students were selected by multi-stage cluster sampling from rural and urban areas of 30 provinces of Iran. The Physical Activity Questionnaire for Adolescents (PAQ-A) was used to assess physical activity (PA). Using PAQ-A instrument, PA of past week categorized as; low PA level, that included those who scored between 1 to 1.9 on the PAQ-A instrument and high PA level that included participants with estimated scores between 2-5 PAQ-A. Results: Participants were 23183 school students (50.8% boys) with a mean age of 12.55 ± 3.3 years, without significant difference in terms of gender. Totally, 23.48% of participants (13.84% of boys and 33.42% of girls) were physically inactive. In multivariate logistic regression model, with increased age in children and adolescence, the odds of a physically inactivity increased (OR: 1.08; 95% CI: 1.07-1.10). The odds of prevalence of both obesity and underweight were high in children and adolescents with low PA. There was a decreasing trend in PA in higher school grades. Conclusion: We found a considerably high prevalence of physical inactivity in Iranian children and adolescents, with higher rates among girls and older ages. However, we did not find correlation between PA and socioeconomic status (SES). Because of the positive relationship between PA and ST, future studies should consider the complex interaction of these two items. Multidisciplinary policies should be considered in increasing PA programs among children and adolescents.

Prevalence of cardio-metabolic risk factors in a nationally representative sample of Iranian adolescents: The CASPIAN-III Study.

Abstract: Introduction: The aim of the present study is to explore the prevalence and mean of cardio-metabolic risk factors and liver enzymes of Iranian adolescents living in regions with different socioeconomic status (SES). To the best of our knowledge this is the first study reporting these data at sub-national level in Iran. Methods: This multi-centric study was performed in 2009-2010 on a stratified multi-stage probability sample of 5940 students aged 10-18 years, living in urban and rural areas of 27 provinces of Iran. Trained healthcare professionals measured anthropometric indices, systolic and diastolic blood pressures (SBP, DBP) according to standard protocols. Fasting venous blood was examined for fasting blood sugar (FBS), lipid profile and liver enzymes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST). We classified the country into four sub-national regions based on criteria of the combination of geography and SES. Mean and frequency of risk factors were compared across these regions. Results: The mean of body mass index had linear rise with increase in the regions’ SES (P for trend <0.001). The mean levels of DBP, total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), triglycerides (TG), FBS, ALT, and AST had linear association with regions’ SES in the whole population and in both genders (P for trend < 0.05), whereas the corresponding figure was statistically significant for the mean SBP only in girls (P for trend: 0.03) and for the mean of LDL-C in the whole population and in boys (P for trend <0.001). In total and in both genders, there was an escalating trend in the prevalence of elevated FBS, TC and liver enzymes, low HDL-C, and metabolic syndrome by increase in the SES of the region(P for trend <0.01). Conclusion: This study proposes that in addition to national health policies on preventing cardiometabolic risk factors, specific interventions should be considered according to the regional SES level.

Caregiver-related predictors of thermal burn injuries among Iranian children: A case-control study.

Abstract: Purpose Burns are a common and preventable cause of injury in children. The aim of this study was to investigate child and caregiver characteristics which may predict childhood burn injuries among Iranian children and to examine whether confounding exists among these predictors. Methods A hospital based case-control study was conducted using 281 burn victims and 273 hospital- based controls, which were matched by age, gender and place of residence (rural/ urban). The characteristics of the children and their caregivers were analyzed using crude and adjusted models to test whether these were predictors of childhood burn injuries. Results The age of the caregiver was significantly lower for burn victims than for the controls (P<0.05). Further, the amount of time the caregiver spent outdoors with the child and their economic status had a significant positive association with the odds of a burn injury (P<0.05). A multivariate logistic regression found that Type A behaviour among caregivers was independently associated with the child's odds of suffering a burn injury (OR = 1.12, 95 CI: 1.04-1.21). The research also found that children with ADHD (Inattentive subscale: Crude OR = 2.14, 95 CI: 1.16-3.95, Adjusted OR = 5.65, 95 CI: 2.53-12.61; Hyperactive subscale: Crude OR = 1.73, 95 CI: 1.23-2.41, Adjusted OR = 2.53, 95 CI: 1.65-3.87) also had increased odds of suffering a burn injury. However, several variables were identified as possible negative confounder variables, as the associations were stronger in the multivariate model than in the crude models. Conclusion The caregiver's characteristics which were predictors of burn injuries among Iranian children were: being younger, high socio-economic status, Type A behavioural pattern and spending more time outdoors. In addition, the relationship between a child's ADHD scores and the odds of a burn injury may be negatively confounded by the caregivers predictor variables. © 2017 Sadeghi-Bazargani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Understanding determinants of unequal distribution of stillbirth in Tehran, Iran: a concentration index decomposition approach.

Abstract: Objective The present inquiry set to determine the economic inequality in history of stillbirth and understanding determinants of unequal distribution of stillbirth in Tehran, Iran. Methods A population-based cross-sectional study was conducted on 5170 pregnancies in Tehran, Iran, since 2015. Principal component analysis (PCA) was applied to measure the asset-based economic status. Concentration index was used to measure socioeconomic inequality in stillbirth and then decomposed into its determinants. Results The concentration index and its 95% CI for stillbirth was −0.121 (−0.235 to −0.002). Decomposition of the concentration index showed that mother’s education (50%), mother’s occupation (30%), economic status (26%) and father’s age (12%) had the highest positive contributions to measured inequality in stillbirth history in Tehran. Mother’s age (17%) had the highest negative contribution to inequality. Conclusions Stillbirth is unequally distributed among Iranian women and is mostly concentrated among low economic status people. Mother-related factors had the highest positive and negative contributions to inequality, highlighting specific interventions for mothers to redress inequality.

Dietary isoflavone intake and all-cause mortality in breast cancer survivors: The Breast Cancer Family Registry-methodological issues.

Abstract: We have read enthusiastically and meticulously the article authored by Zhang et al that was recently published in Cancer. The authors aimed to assess the association between the dietary intake of isoflavone and all-cause mortality in a multi-ethnic cohort of women diagnosed with breast cancer. They found that the risk of all-cause mortality decreased by 21% among the patients in the highest quartile of dietary isoflavone intake in comparison with the patients in the lowest quartile (hazard ratio, 0.79; 95% confidence interval, 0.64-0.97). This significant negative association between the dietary intake of isoflavone and the risk of all-cause mortality was limited to those women who had tumors that were negative for hormone receptors (hazard ratio, 0.49; 95% confidence interval, 0.29-0.83) and those women who did not receive hormone therapy for their breast cancer (hazard ratio, 0.68; 95% confidence interval, 0.51-0.91). Although the study conducted by Zhang et al makes valuable contributions to the field, some methodological issues need to be taken into account. First, combined outcomes such as all-cause mortality are widely used by investigators when the sample size and the power for statistical testing are limited. Some important assumptions, such as the homogeneity of the direction and strength of associations, should be established for the combined outcomes; otherwise, misleading results may be yielded. Zhang et al combined all mortalities into 1 category, and then its association with dietary isoflavone intake was examined; however, the homogeneity of the strength and direction of the association between dietary isoflavone intake and multiple causes of mortality is difficult to establish and was not examined by the authors. Because the aforementioned assumption is hard to establish, Richardson et al proposed a hierarchical regression model that effectively examines a single exposure with multiple specific outcomes such as cause-specific mortality, even in studies with a small sample size. Hence, we propose that this regression model be used by Zhang et al in the current study and future studies to examine the association of dietary isoflavone intake and cause-specific mortalities more accurately. Second, the authors conducted 2 adjusted models in their study. The latter model was adjusted for different covariates (eg, race/ethnicity, education, Health Eating Index, recreational physical activity, body mass index, alcohol use, and smoking) highly associated with dietary isoflavone intake, as reported in Table 2 of their study. In fact, the probability of collinearity is high between the aforementioned covariates and dietary isoflavone intake, and this phenomenon should be examined before construction of the multivariate model. Hence, their finding may be biased by multicollinearity, and some statistically significant associations may not be detected because multicollinearity saps the power of statistical tests. Finally, the authors constructed a Cox proportional hazards regression model, but the main assumption was not checked. The proportional hazards assumption must be initially checked, and variants of Cox proportional hazards regression models such as extended Cox models should be applied when this important assumption is violated. In fact, misleading results may be yielded by a Cox proportional hazards regression model when the proportional hazards assumption is violated.