Economic inequalities in decayed, missing, and filled first permanent molars among 8-12 years old Iranian schoolchildren.

BACKGROUND: First permanent molars (FPM) play an important role in the masticatory function and oral health. This study aimed to assess the economic inequalities of FPM health indices among schoolchildren in the northeast of Iran. METHODS: A total of 4051 children aged 8-12 years old were included in the analyses of this cross-sectional study in 2015. Economic status was measured using the principal component analysis on home assets. Concentration index (C) was used to measure economic inequality in FPM health indices, and its contributing factors determined by Wagstaff decomposition technique. RESULTS: The prevalence of having decayed, missing, and filled FPMs among children was 40.9% (95% CI: 38.8-43.0), 1.2% (95% CI: 0.8-1.6%), and 7.8% (95% CI: 6.7-8.9%), respectively. Missing FPM was generally more concentrated among low-economic children (C=-0.158), whereas, filled FPM was more concentrated on high-economic children (C = 0.223). Economic status, mother education, having a housekeeper mother, and overweight/obesity, contributed to the measured inequality in missing FPM by 98.7%, 97.5%, 64.4%, and 11.2%, respectively. Furthermore, 88.9%, 24.1%, 14.5%, and 13.2% of filled FPM inequality was attributable to children's economic status, father education, residence in rural areas, and age, respectively. CONCLUSION: There is a significant economic inequality in both missing and filled FPM. This inequality can be attributed to the economic status of individuals. To reduce FPM extraction, it is important to target low-income and rural children and provide them with FPM restoration services. Additionally, it is necessary to provide training to less-educated parents and housekeeper mothers to address the observed inequalities.

Effective refractive error coverage in adults aged 50 years and older: estimates from population-based surveys in 61 countries.

BACKGROUND: In 2021, WHO Member States endorsed a global target of a 40-percentage-point increase in effective refractive error coverage (eREC; with a 6/12 visual acuity threshold) by 2030. This study models global and regional estimates of eREC as a baseline for the WHO initiative. METHODS: The Vision Loss Expert Group analysed data from 565 448 participants of 169 population-based eye surveys conducted since 2000 to calculate eREC (met need/[met need + undermet need + unmet need]). A binary logistic regression model was used to estimate eREC by Global Burden of Disease (GBD) Study super region among adults aged 50 years and older. FINDINGS: In 2021, distance eREC was 79·1% (95% CI 72·4-85·0) in the high-income super region; 62·1% (54·7-68·8) in north Africa and Middle East; 49·5% (45·0-54·0) in central Europe, eastern Europe, and central Asia; 40·0% (31·7-48·2) in southeast Asia, east Asia, and Oceania; 34·5% (29·4-40·0) in Latin America and the Caribbean; 9·0% (6·5-12·0) in south Asia; and 5·7% (3·1-9·0) in sub-Saharan Africa. eREC was higher in men and reduced with increasing age. Global distance eREC increased from 2000 to 2021 by 19·0%. Global near vision eREC for 2021 was 20·5% (95% CI 17·8-24·4). INTERPRETATION: Over the past 20 years, distance eREC has increased in each super region yet the WHO target will require substantial improvements in quantity and quality of refractive services in particular for near vision impairment. FUNDING: WHO, Sightsavers, The Fred Hollows Foundation, Fondation Thea, Brien Holden Vision Institute, Lions Clubs International Foundation.

Development of glaucoma predictive model and risk factors assessment based on supervised models.

OBJECTIVES: To develop and to propose a machine learning model for predicting glaucoma and identifying its risk factors. METHOD: Data analysis pipeline is designed for this study based on Cross-Industry Standard Process for Data Mining (CRISP-DM) methodology. The main steps of the pipeline include data sampling, preprocessing, classification and evaluation and validation. Data sampling for providing the training dataset was performed with balanced sampling based on over-sampling and under-sampling methods. Data preprocessing steps were missing value imputation and normalization. For classification step, several machine learning models were designed for predicting glaucoma including Decision Trees (DTs), K-Nearest Neighbors (K-NN), Support Vector Machines (SVM), Random Forests (RFs), Extra Trees (ETs) and Bagging Ensemble methods. Moreover, in the classification step, a novel stacking ensemble model is designed and proposed using the superior classifiers. RESULTS: The data were from Shahroud Eye Cohort Study including demographic and ophthalmology data for 5190 participants aged 40-64 living in Shahroud, northeast Iran. The main variables considered in this dataset were 67 demographics, ophthalmologic, optometric, perimetry, and biometry features for 4561 people, including 4474 non-glaucoma participants and 87 glaucoma patients. Experimental results show that DTs and RFs trained based on under-sampling of the training dataset have superior performance for predicting glaucoma than the compared single classifiers and bagging ensemble methods with the average accuracy of 87.61 and 88.87, the sensitivity of 73.80 and 72.35, specificity of 87.88 and 89.10 and area under the curve (AUC) of 91.04 and 94.53, respectively. The proposed stacking ensemble has an average accuracy of 83.56, a sensitivity of 82.21, a specificity of 81.32, and an AUC of 88.54. CONCLUSIONS: In this study, a machine learning model is proposed and developed to predict glaucoma disease among persons aged 40-64. Top predictors in this study considered features for discriminating and predicting non-glaucoma persons from glaucoma patients include the number of the visual field detect on perimetry, vertical cup to disk ratio, white to white diameter, systolic blood pressure, pupil barycenter on Y coordinate, age, and axial length.

A paradoxical change in economic inequality in presenting visual acuity between 2009 and 2014: a nonuseful decline.

BACKGROUND: Despite the widespread literate on health inequalities and their determinants, changes in health inequalities over time have not received enough attention. AIMS: To measure and decompose the over-time changes in economic inequality in presenting visual acuity measured using Logarithm of the Minimum Angle of Resolution. METHODS: We analysed 4706 participants who had complete data on presenting visual acuity and economic status in 2009 and 2014 in the Shahroud Eye Cohort Study. We measured changes in presenting visual acuity concentration indices and decomposed them the using a longitudinal approach. RESULTS: Both the presenting visual acuity and economic status deteriorated between 2009 and 2014. The mean (standard deviation) for presenting visual acuity and economic status scores in 2009 versus 2014 were 0.090 (0.2) versus 0.103 (0.2) and 0.01 (1.0) versus 0.0005 (1.07), respectively. Presenting visual acuity concentration index (95% confidence interval) in the first versus second phases of the study were -0.245 (-0.212 to -0.278) versus -0.195 (-0.165 to -0.225), respectively. Longitudinal decomposition of this change in concentration indices during the 5-year period indicated that the most important contributor to reduction in economic inequality of presenting visual acuity was deterioration of presenting visual acuity among people with higher economic status due to their ageing. CONCLUSION: Unexpectedly, reduction in economic inequality in presenting visual acuity was due to presenting visual acuity deterioration among the higher economic status group rather than its amelioration among the lower economic status group. Therefore, the needs of all socioeconomic groups should be considered separately to modify presenting visual acuity in each group and, consequently, reduce the economic inequality in presenting visual acuity.

Detection of influenza epidemics using hidden Markov and Serfling approaches.

OBJECTIVE: Detection of epidemics is a critical issue in epidemiology of infectious diseases which enable healthcare system to better control it. This study is devoted to investigating the 5-year trend in influenza and severe acute respiratory infection cases in Iran. The epidemics were also detected using the hidden Markov model (HMM) and Serfling model. STUDY DESIGN: In this study, we used SARI data reported in the World Health Organization (WHO) FluNet web-based tool from August 2011 to August 2016. METHODS: SARI data in Iran from August 2011 to August 2016 were used. We applied the HMM and Serfling model for indicating the two epidemic and non-epidemic phases. The registered outbreak activity recorded on the WHO website was used as the gold standard. The coefficient of determination was reported to compare the goodness of fit of the models. RESULTS: Serfling models modified by 30% and 35% of the data had a sensitivity of 91.67% and 95.83%, while for 15%, 20% and 25% were 70.83%, 79.17% and 83.33%, respectively. Sensitivity of HMM and autoregressive HMM (AHMM) was 66.67% and 92.86%. All fitted models have a specificity of over 96%. The R2 for HMM and AHMM was calculated 0.73 and 0.85, respectively, showing better fitness of these models, while R2 was around 50% for different types of Serfling models. CONCLUSIONS: Both modified Serfling and HMM were acceptable models in determining the epidemic points for the detection of weekly SARI. The AHMM had better fitness, higher detection power and more accurate detection of the incidence of epidemics than Serfling model and high sensitivity and specificity. In addition to AHMM, Serfling models with 30% and 35% modification can be used to detect epidemics due to approximately the same accuracy but the simplicity of the calculations.

Sex Differences in 28-Day Mortality of Ischemic Stroke in Iran and Its Associated Factors: A Prospective Cohort Study.

INTRODUCTION: The mortality and morbidity rates of stroke in men and women have been reported differently and its effective factors have been discussed. The purpose of this study was to investigate sex differences in 28-day mortality of ischemic stroke and its associated factors. MATERIALS AND METHODS: This is a prospective cohort study conducted from June 2018 to September 2019 in patients with ischemic stroke referred to Firoozgar, Shariati and Sina hospitals in Tehran. Demographic data, risk factors, disease history, drug use, severity of stroke, and patient functional status were recorded in the hospital. The patients' functional status and severity of stroke were measured using the Modified Ranking Scale (MRS) and the National Institutes of Health Stroke Scale (NIHSS). After 28 days, the patients' survival status was monitored. Logistic regression was used to analyze the data. RESULTS: In this study, 703 patients were enrolled; of them, 260 (37.00%) were female and 443 (63.00%) were male. After 28 days, 21 female cases (8.17%) and 26 male (6.08%) ones died (P = 0.299). Functional status (OR = 4.65; 95%CI: 2.09 to 10.38), diastolic blood pressure (OR = 0.91; 95%CI: 0.85 to 0.96), warfarin use (OR = 0.15; 95%CI: 0.04 to 0.55), and hemoglobin (OR = 1.17; 95%CI: 1.02 to 1.35) were associated with 28-day mortality. Poor functional status in men had a greater association with 28-day mortality than women (OR 4.65 vs. 1.64). High diastolic blood pressure had a negative association with the 28-day mortality of cases and this association is more in women than in men (OR 0.88 vs. 0.91). High hemoglobin is a risk factor in men and a protective factor in 28-day mortality in women (OR 1.73 vs. 0.73). Smoking also had a greater association with 28-day mortality in women than men (OR 2.67 vs. 1.2). DISCUSSION: Twenty eight-day mortality was more in women than in men, but this difference was not significant. Women were older, had more severe stroke and poorer functional status than men. Variables including functional status, diastolic blood pressure, hemoglobin level, and smoking had interaction with sex, and their association with 28-day mortality rate was different between men and women. Sex differences should be considered, so that we can better manage stroke patients.

Socioeconomic inequality in smoking and its determinants in the Islamic Republic of Iran.

BACKGROUND: The role of socioeconomic inequality and related factors has not been well reported in tobacco consumption. AIMS: To investigate the socioeconomic inequality in smoking and its associated factors in the Islamic Republic of Iran. METHODS: Data were collected from surveillance for noncommunicable diseases in 2005, which included 89 404 people aged 15-65 years. Economic status was defined by principal component analysis on variables related to socioeconomic status. Concentration index and slope index of inequality were used to determine the inequality value. The gap between the high and low economic status groups was decomposed using the Oaxaca-Blinder decomposition method for explained and unexplained components. RESULTS: The total prevalence of smoking was 17.0%; 28.0% in males, and 5.8% in females, 15.8% in urban and 19.1% in rural areas. The concentration index was -0.032 in the whole of country; -0.098, in males, -0.246 in females, 0.014 in urban and -0.059 in rural areas and varied in different provinces of country. The smoking rate was 18.0% for the first quintile and 13.5% for the fifth quintile, a gap of 4.5%. The major part of this gap was related to differences in education level, sex, marital status and age in economic groups. CONCLUSION: There was a pro-rich socioeconomic inequality in smoking, especially in females and in the southern provinces. Increase in education level and empowering females of low socioeconomic status are sound interventions for alleviating inequality and for tobacco control.

Worldwide inequality in access to full text scientific articles: the example of ophthalmology.

BACKGROUND: The problem of access to medical information, particularly in low-income countries, has been under discussion for many years. Although a number of developments have occurred in the last decade (e.g., the open access (OA) movement and the website Sci-Hub), everyone agrees that these difficulties still persist very widely, mainly due to the fact that paywalls still limit access to approximately 75% of scholarly documents. In this study, we compare the accessibility of recent full text articles in the field of ophthalmology in 27 established institutions located worldwide. METHODS: A total of 200 references from articles were retrieved using the PubMed database. Each article was individually checked for OA. Full texts of non-OA (i.e., "paywalled articles") were examined to determine whether they were available using institutional and Hinari access in each institution studied, using "alternative ways" (i.e., PubMed Central, ResearchGate, Google Scholar, and Online Reprint Request), and using the website Sci-Hub. RESULTS: The number of full texts of "paywalled articles" available using institutional and Hinari access showed strong heterogeneity, scattered between 0% full texts to 94.8% (mean = 46.8%; SD = 31.5; median = 51.3%). We found that complementary use of "alternative ways" and Sci-Hub leads to 95.5% of full text "paywalled articles," and also divides by 14 the average extra costs needed to obtain all full texts on publishers' websites using pay-per-view. CONCLUSIONS: The scant number of available full text "paywalled articles" in most institutions studied encourages researchers in the field of ophthalmology to use Sci-Hub to search for scientific information. The scientific community and decision-makers must unite and strengthen their efforts to find solutions to improve access to scientific literature worldwide and avoid an implosion of the scientific publishing model. This study is not an endorsement for using Sci-Hub. The authors, their institutions, and publishers accept no responsibility on behalf of readers.

The reduction of horizontal inequity in unmet refractive error: The Shahroud Eye Cohort Study, 2009-2014.

PURPOSE: To measure Horizontal Inequity Index (HI) of unmet refractive error and its changes between 2009 and 2014 in Iran. METHODS: The data used in this study was taken from population-based study, Shahroud Eye Cohort Study. The number of participants analyzed in first (2009) and second phases of study (2014) were 5190 and 4737, respectively, and individuals between 40 and 64 years were included. The HI was determined by using the Concentration Index (C) based on the nonlinear (Probit) model, and C was decomposed to identify and quantify the contribution of each factor. RESULTS: After adjusting for need variables, the results demonstrated that the HI in unmet refractive need decreased from -0.288 (95% CI: 0.370, -0.206) in the 2009 to -0.132 (95% CI: 0.290, -0.028) in 2014. Decomposition of the C showed that level of education and economic status were the greatest contributors with shares of 26.2% and 17.9%, respectively, in reducing the amount of HI in unmet refractive error between 2009 and 2014. CONCLUSIONS: The current study demonstrated that unmet refractive error did not have an equal distribution among economic quintiles, despite the same need for correcting refractive errors. Reducing the amount of HI in unmet refractive error between 2009 and 2014 indicated an improvement in the unmet need in the five years period between two phases of study.

Obesity is the Most Important Factor for Gender Inequality in Type 2 Diabetes Incidence in an Iranian Population.

Background: The results of Shahroud Eye Cohort Study (ShECS) showed a high 5-year incidence of diabetes mellitus with female predominance in 40-64 years old Iranian population. The aim of this report was to decompose the observed sex differences in the incidence of diabetes. Methods: Sex-specific incidence rate of diabetes was calculated between the two phases of ShECS (2009-2014). The gap decomposition was done by the twofold Blinder-Oaxaca decomposition model. Results: The results showed that from the total gap (11.19%-15.55% = -4.36%) between the two sexes, 3.46% which forms 79.4% of the total gap is related to the difference in obesity in both genders. In contrast to obesity, age and overweigh status had a decreasing influence on gender inequality. Conclusions: Obesity of Iranian women compared with men is the most important reason for an increase in the incidence of diabetes in women.

Horizontal inequity in the utilization of cataract surgery in Iran: Shahroud Eye Cohort Study, 2009-2014.

Background: Since there was no evidence about economic inequity in utilization of cataract surgery in developing countries, such as Iran, this study was designed to measure horizontal inequity in the utilization of cataract surgery and its changes in an Iranian middleaged population in 2009 and 2014. Methods: Using data from the first and second phases of Shahroud Eye Cohort Study (2009-2014), the economic inequity in the utilization of cataract surgery in an Iranian middle-aged population aged 40-64 years in 2009 and 2014 was evaluated. The horizontal inequity index (HI) was determined using the indirect standardization method based on a nonlinear (probit) model and the concentration index (C) was decomposed into the contribution of each factor. The analyses were performed using STATA software version 12/SE, and significance level was set at less than 0.05. Results: The HI in the utilization of cataract surgery increased from 0.080 (95% CI: 0.011-0.098) in 2009 to 0.166 (95% CI: 0.0821- 0.228) in 2014. Decomposition of changes in the concentration index showed that among need and non-need variables, older age and economic status (being among the wealthiest 20%) were the greatest contributors, with shares of 67.5% and 57.5%%, respectively, which led to pro-rich inequity during the study periods. Conclusion: The present study demonstrated that utilization of cataract surgery did not have an equal distribution among economic quintiles, despite considering equal needs based on cataract severity. Results demonstrated that older age and economic status were the greatest contributors to HI increase in 2009 and 2014.

Multipoint assessment of demarcation line depth after standard and accelerated cross-linking in central and inferior keratoconus.

PURPOSE: To determine the changes in the depth of the demarcation line in the central to peripheral cornea following accelerated compared to standard corneal cross-linking (CXL). METHODS: In this prospective, non-randomized study, 60 eyes with progressive keratoconus underwent accelerated or standard CXL (30 in each group). Anterior segment optical coherence tomography (AS-OCT) was done one month later by two independent masked examiners to measure the depth of the demarcation line in the central cornea and on peripheral rings. RESULTS: The inter-examiner agreement (intra-class correlation coefficient) was >0.75 for all measured points, and average measurements were used in the analysis. The depth of the visualized demarcation line in the center was 223.4 ± 67.4 µm and 354.9 ± 79.0 µm in the accelerated and standard groups, respectively (P < 0.001). The depth significantly decreased from the center to the 7 mm ring in both groups (all P < 0.05). This change was 7.7-26.1% and 2.2%-11.1% in the accelerated and standard groups, respectively. In the accelerated group, the demarcation line was deeper in the central cone sub-group compared to the inferior cone sub-group, but in the standard group, the demarcation line was deeper in the inferior cone sub-group (all P < 0.05). Cases with an inferior cone showed greater inter-group differences in all studied points. CONCLUSIONS: The depth of the demarcation line with accelerated CXL is less than the standard protocol and decreases from the center towards the periphery. Demarcation lines are more homogenized with standard CXL. In cases with an inferior cone, demarcation line depth varies throughout the cornea.

Transition in tobacco use stages and its related factors in a longitudinal study.

OBJECTIVES: Considering the increase in the non-communicable diseases associated with tobacco use in recent decades in Iran, it is necessary to have a general view of the current condition. This study aimed to identify factors associated with tobacco use and to estimate the probability of a 5-year transition in the stages of tobacco use in an adult population. METHODS: In this study, 5190 people in the 40-64-year-old population of Shahroud (North East of Iran) were interviewed in 2009 and 2014 on tobacco smoking. The association of independent variables with tobacco smoking was evaluated using the population-averaged logit model. We calculated smoking transition probabilities from non-smoking to current smoking and past-smoking stages during a 5-year span. RESULTS: The prevalence of current tobacco smoking in 40-69-years age group was 11.1% (95% CI 10.3-12.0), 1% among women (95% CI 0.8-1.3) and 25.6% among men (95% CI 23.7-27.6). During this 5-year period, the probability of transition of a non-smoker to an overall current tobacco smoker was 2.3%. Meanwhile, 18.5% of the overall current tobacco smokers had changed into past smokers. Unemployed (OR = 2), male gender (OR = 53.9), widow/widowers (OR = 5.4), divorces (OR = 3.3), and high economic status (OR = 1.2) are associated to tobacco smoking. CONCLUSIONS: Compared with the other studies, the prevalence of tobacco use in this population is low but transition rate of non-smokers into current smokers or past smokers is high. Conducting interventions on determinants of starting and quitting smoking and education and awareness raising on the risk and harms of smoking seems necessary.

Assessment of Horizontal Inequity in Eye Care Utilization in the Iranian Middle-aged Population.

PURPOSE: The present study was designed to determine the extent that horizontal inequity was realized regarding eye care utilization in a middle-aged population as well as factors affecting this equity. METHODS: Data were obtained from a population-based study (Shahroud Eye Cohort Study) in 2009 that included 5190 participants from 40 to 64 years of age. Horizontal inequity was determined based on the following variables: (i) economic status, (ii) eye care service needs, (iii) non-need variables, and (iv) eye care utilization (visiting an ophthalmologist or optometrist). Decomposition analysis of the concentration index based on a nonlinear model and indirect standardization was used to ascertain the contribution of each factor in inequity of eye care utilization. RESULTS: After adjusting for need variables, the results of our study demonstrated that horizontal inequity in eye care utilization in a middle-aged Iranian population remained positive and significant (horizontal inequity: 0.19; 95% confidence interval: 0.17-0.23) indicating that use of services was focused among participants with a better financial situation. Furthermore, decomposition analysis demonstrated that educational level and economic status had the greatest contribution (54.1% and 41.1%, respectively) in comparison to other variables. CONCLUSION: This study demonstrated that horizontal inequity exists in eye care utilization among the middle-aged Iranian population.

Cardiovascular mortality in a Western Asian country: results from the Iran Cohort Consortium.

OBJECTIVES: Cardiovascular mortality in Western Asia is high and still rising. However, most data documented on risk prediction has been derived from Western countries and few population-based cohort studies have been conducted in this region. The current study aimed to present the process of pooling data and cardiovascular disease (CVD) mortality incidences for four Iranian cohorts. METHODS: From the Iran Cohort Consortium, the Golestan Cohort Study (GCS), Tehran Lipid and Glucose Study, Isfahan Cohort Study (ICS) and the Shahroud Eye Cohort Study (ShECS) were eligible for the current study since they had appropriate data and follow-up visits. Age-standardised CVD mortality rates were estimated for ages 40-80 and 40-65 years. Cox regression was used to compare mortalities among cohorts. Adjusted marginal rates were calculated using Poisson regression. RESULTS: Overall, 61 291 participants (34 880 women) aged 40-80 years, free of CVD at baseline, were included. During 504 606 person-years of follow-up, 1981 CVD deaths (885 women) occurred. Age-standardised/sex-standardised premature CVD mortality rates were estimated from 133 per 100 000 person-years (95% CI 81 to 184) in ShECS to 366 (95% CI 342 to 389) in the GCS. Compared with urban women, rural women had higher CVD mortality in the GCS but not in the ICS. The GCS population had a higher risk of CVD mortality, compared with the others, adjusted for conventional CVD risk factors. CONCLUSIONS: The incidence of CVD mortality is high with some differences between urban and rural cohorts in Iran as a Western Asian country. Pooling data facilitates the opportunity to globally evaluate risk prediction models.

Socioeconomic inequality in health domains in Tehran: a population-based cross-sectional study.

OBJECTIVE: Reduction of socioeconomic inequality in health requires appropriate evidence on health and its distribution based on socioeconomic indicators. The objective of this study was to assess socioeconomic inequality in various health domains and self-rated health (SRH). METHODS: This study was conducted using data collected in a survey in 2014 on a random sample of individuals aged 18 and above in the city of Tehran. The standardised World Health Survey Individual Questionnaire was used to assess different health domains. The age-adjusted prevalence of poor health was calculated for each health domain and SRH based on levels of education and wealth quintiles. Furthermore, the Slope Index of Inequality (SII) and the Relative Index of Inequality (RII) were applied to assess socioeconomic inequality in each of the health domains and SRH. RESULTS: The age-adjusted prevalence of poor health was observed in a descending order from the lowest to the highest wealth quintiles, and from the lowest level of education to the highest. RII also showed varying values of inequality among different domains, favouring rich subgroups. The highest wealth-related RII was observed in the 'Mobility' domain with a value of 4.16 (95% CI 2.01 to 8.62), and the highest education-related RII was observed in the 'Interpersonal Activities' domain with a value of 6.40 (95% CI 1.91 to 21.36). CONCLUSIONS: Substantial socioeconomic inequalities were observed in different health domains in favour of groups of better socioeconomic status. Based on these results, policymaking aimed at tackling inequalities should pay attention to different health domains as well as to overall health.

Economic Inequality in Presenting Vision in Shahroud, Iran: Two Decomposition Methods.

BACKGROUND: Visual acuity, like many other health-related problems, does not have an equal distribution in terms of socio-economic factors. We conducted this study to estimate and decompose economic inequality in presenting visual acuity using two methods and to compare their results in a population aged 40-64 years in Shahroud, Iran. METHODS: The data of 5188 participants in the first phase of the Shahroud Cohort Eye Study, performed in 2009, were used for this study. Our outcome variable was presenting vision acuity (PVA) that was measured using LogMAR (logarithm of the minimum angle of resolution). The living standard variable used for estimation of inequality was the economic status and was constructed by principal component analysis on home assets. Inequality indices were concentration index and the gap between low and high economic groups. We decomposed these indices by the concentration index and BlinderOaxaca decomposition approaches respectively and compared the results. RESULTS: The concentration index of PVA was -0.245 (95% CI: -0.278, -0.212). The PVA gap between groups with a high and low economic status was 0.0705 and was in favor of the high economic group. Education, economic status, and age were the most important contributors of inequality in both concentration index and Blinder-Oaxaca decomposition. Percent contribution of these three factors in the concentration index and Blinder-Oaxaca decomposition was 41.1% vs. 43.4%, 25.4% vs. 19.1% and 15.2% vs. 16.2%, respectively. Other factors including gender, marital status, employment status and diabetes had minor contributions. CONCLUSION: This study showed that individuals with poorer visual acuity were more concentrated among people with a lower economic status. The main contributors of this inequality were similar in concentration index and Blinder-Oaxaca decomposition. So, it can be concluded that setting appropriate interventions to promote the literacy and income level in people with low economic status, formulating policies to address economic problems in the elderly, and paying more attention to their vision problems can help to alleviate economic inequality in visual acuity.

Obesity and its socioeconomic determinants in Iran.

OBJECTIVE: To investigate the socioeconomic inequality of obesity and its determinants in Iran. METHODS: Data was from Iran's surveillance system for risk factors of non-communicable diseases which was conducted on 89,400 individuals aged 15-64 years in 2005. Principal component analysis was used to create a new variable for defining socioeconomic status of participants. We assessed inequality by calculating a slop index of inequality and concentration index for obesity. Oaxaca-Blinder decomposition analysis was used to determine the determinants of inequality. RESULTS: The slop index of inequality and concentration index for obesity was -13.1 (95% Confidence Intervals [CI]: -16.3 to -9.8) percentage points and -0.123, respectively. The level of inequality varied widely between different provinces in Iran and was more severe in women and urban population. Obesity persisted in 20.2% (95% CI: 19.4-20.9) of the low-socioeconomic group and 11.0% (95% CI: 10.5-11.6) of the high-socioeconomic group. More than 90% of this gap was due to differences of independent variables (mainly age, gender and marital status) in two socioeconomic status groups. CONCLUSIONS: A pro-rich inequality existed in the obesity in Iran. Older age, female gender and rural residency contributed most to the economic inequality of obesity.

Fee Splitting among General Practitioners: A Cross-Sectional Study in Iran.

BACKGROUND: Fee splitting is a process whereby a physician refers a patient to another physician or a healthcare facility and receives a portion of the charge in return. This survey was conducted to study general practitioners' (GPs) attitudes toward fee splitting as well as the prevalence, causes, and consequences of this process. METHODS: This is a cross-sectional study on 223 general practitioners in 2013. Concerning the causes and consequences of fee splitting, an unpublished qualitative study was conducted by interviewing a number of GPs and specialists and the questionnaire options were the results of the information obtained from this study. RESULTS: Of the total 320 GPs, 247 returned the questionnaires. The response rate was 77.18%. Of the 247 returned questionnaires, 223 fulfilled the inclusion criteria. Among the participants, 69.1% considered fee splitting completely wrong and 23.2% (frequently or rarely) practiced fee splitting. The present study showed that the prevalence of fee splitting among physicians who had positive attitudes toward fee splitting was 4.63 times higher than those who had negative attitudes. In addition, this study showed that, compared to private hospitals, fee splitting is less practiced in public hospitals. The major cause of fee splitting was found to be unrealistic/unfair tariffs and the main consequence of fee splitting was thought to be an increase in the number of unnecessary patient referrals. DISCUSSION: Fee splitting is an unethical act, contradicts the goals of the medical profession, and undermines patient's best interest. In Iran, there is no code of ethics on fee splitting, but in this study, it was found that the majority of GPs considered it unethical. However, among those who had negative attitudes toward fee splitting, there were physicians who did practice fee splitting. The results of the study showed that physicians who had a positive attitude toward fee splitting practiced it more than others. Therefore, if physicians consider fee splitting unethical, its rate will certainly decrease. The study claims that to decrease such practice, the healthcare system has to revise the tariffs.

Assets as a Socioeconomic Status Index: Categorical Principal Components Analysis vs. Latent Class Analysis.

BACKGROUND: Some variables like Socioeconomic Status (SES) cannot be directly measured, instead, so-called 'latent variables' are measured indirectly through calculating tangible items. There are different methods for measuring latent variables such as data reduction methods e.g. Principal Components Analysis (PCA) and Latent Class Analysis (LCA). OBJECTIVES: The purpose of our study was to measure assets index- as a representative of SES- through two methods of Non-Linear PCA (NLPCA) and LCA, and to compare them for choosing the most appropriate model. METHODS: This was a cross sectional study in which 1995 respondents filled the questionnaires about their assets in Tehran. The data were analyzed by SPSS 19 (CATPCA command) and SAS 9.2 (PROC LCA command) to estimate their socioeconomic status. The results were compared based on the Intra-class Correlation Coefficient (ICC). RESULTS: The 6 derived classes from LCA based on BIC, were highly consistent with the 6 classes from CATPCA (Categorical PCA) (ICC = 0.87, 95%CI: 0.86 - 0.88). CONCLUSION: There is no gold standard to measure SES. Therefore, it is not possible to definitely say that a specific method is better than another one. LCA is a complicated method that presents detailed information about latent variables and required one assumption (local independency), while NLPCA is a simple method, which requires more assumptions. Generally, NLPCA seems to be an acceptable method of analysis because of its simplicity and high agreement with LCA.