The gap of visual impairment between economic groups in Shahroud, Iran: a Blinder-Oaxaca decomposition

PERSIAN Eye Cohort Study (PECS): Design, Methodology

BACKGROUND

To report the study protocol, methodology and latest enrollment data of a large epidemiological multi-central eye cohort named PERSIAN Eye Cohort Study (PECS), originating from the ongoing PERSIAN Cohort Study, to investigate the distribution of ophthalmic disorders in different regions and ethnicities of Iran, and determine their associations with various exposures of ophthalmic and non-ophthalmic nature.

METHODS

A central committee designed the study and equipped six chosen centers (Khameneh, Some'e Sara, Hoveizeh, Yazd, Rafsanjan and Zahedan). A focal point in each center conducted the study under close supervision of the central committee.

RESULTS

This ongoing study was launched in 2014. Out of 65,580 eligible participants of the PERSIAN Cohort, 48,618 individuals aged 35-70 have been enrolled in the PECS (response rate: 74.13%) until June 2021. Slit lamp and fundus photography were performed for 28,702 (59.03%) and 27,437 (56.43%) individuals, respectively.

CONCLUSION

This large epidemiological multi-central eye cohort can improve our epidemiological knowledge of the prevalent ophthalmic disorders in different regions and ethnicities of Iran, and determine their associations with various exposures of ophthalmic and non-ophthalmic nature. This will be very useful for future planned nationwide and global interventions.

Isolated systolic hypertension and its associated risk factors in Iranian middle age and older population: a population-based study

Background

Isolated systolic hypertension (ISH), is the most common form of hypertension in older adults. However, the ISH prevalence is not well known in many developing countries such as Iran. This study was conducted to determine the ISH prevalence and its related risk factors in an Iranian population.

Methods

Data were obtained from the second phase of the Shahroud eye cohort study (ShECS) in 2014. ShECS is a longitudinal population-based study which the first phase had been conducted in 2009 using the stratified multistage cluster sampling design on 5190 people aged 40 to 70 years. The ISH prevalence was determined based on the eighth Joint National Commission guidelines for different demographic variables. The associated risk factors were estimated by multiple logistic regression and a two-tailed p-value less than 0.05 was considered significant.

Results

The ISH prevalence was 15.89% (95% CI: 14.88–16.96). It was 15.68% (14.12–17.39) and 15.87% (14.54–17.29) for men and women, respectively. The prevalence of ISH increased significantly with increasing age. The 65–70 compared to 45–69 year age group (OR = 4.21), body mass index (OR = 1.03), diabetes (OR = 1.64), retirement, compared to practitioner job (OR = 1.53), and waist to hip ratio (WHR) (OR = 9.81) were significantly associated with ISH prevalence.

Conclusions

ISH is highly prevalent among the older adult population in Iran. Given the risk of cardiovascular disease associated with ISH, it is recommended to conduct education and public health interventions to improve the detection, prevention, and treatment of ISH.

Governmental support for achieving "VISION 2020: the Right to Sight" in Iran: the cataract surgical rates

PURPOSE

The aim of this study was evaluate the effect of governmental support in the form of Health Transformation Plan (HTP) on increasing the cataract surgical rate.

METHODS

The number of cataract surgeries was collected from Iranian cataract surgery clinics during 2019. HTP was implemented in 2014. Forty-seven major and forty-five minor surgery centers were selected from all provinces. In each center, sampling was done from 2012, 2013, 2015, and 2016.

RESULTS

On average, 6202 and 7134 cataract surgery rate were performed before and after HTP, respectively. The cataract surgical rate rose by 15.03% after the HTP. After HTP, the proportion of cataract surgery increased by 21.32% in governmental centers and decreased by 17.56%, 24.45%, and 14.89% in private, insurance, and charity centers, respectively. The cataract surgical rate was 4093 and 6026 in the first economic quartile (the poorest), 3669 and 4595 in the second quartile, 5884 and 5928 in the third quartile, and 8427 and 9681 in the fourth quartile (the richest) before and after HTP, respectively. The highest growth in the cataract surgical rate was seen in the first quartile (47.24%) followed by the second (25.26%), fourth (14.88%), and third quartiles (0.74%).

CONCLUSION

The Health Transformation Plan has been successful in increasing the cataract surgical rate in the low-income group and identifying differences in the services as well as the economic groups within the population.

Prevalence and Causes of Visual Impairment and Blindness in Elderly Population; an Urgent Geriatric Health Issue: Tehran Geriatric Eye Study (TGES)

PURPOSE

To determine the prevalence of vision impairment (VI) and blindness and their determinants in the elderly population of Tehran.

METHODS

In a cross-sectional study, multi-stage cluster sampling was used to select a sample of over 60 year population of Tehran. Optometric examinations included the measurement of uncorrected visual acuity, objective and subjective refraction, presenting and best corrected visual acuity. Vision impairment is reported according to the WHO definition. Visual acuity worse than 20/60 and 20/400 in the better eye was regarded as low vision and blindness, respectively.

RESULTS

According to presenting visual acuity, VI was found in 14.8% (95%CI: 13.1-16.5) of the participants, including low vision in 13.8% (95%CI: 12.2-15.4) and blindness in 1.1% (95%CI: 0.5-1.6). The prevalence of VI ranged between 7.8% (95%CI: 6.0-9.5) in subjects aged 60-64 years and 40.0% (95%CI: 33.0-47.0) in participants over 80 years (p < .001). Multivariable logistic regression analysis showed that older age (OR = 1.07(per year)), lower education level (illiterate versus college: OR = 3.55), and lower economic status (middle versus rich: OR = 1.30 and poor versus rich; OR = 1.72) had a significant relationship with an increase in the prevalence of VI, and older age (OR = 1.14(Per year increase)) and diabetes (OR = 2.62) had a significant relationship with blindness. Refractive errors (63.1%) was the leading cause of VI followed by cataract (22.5%). However, cataract (48.3%) was the leading cause of blindness.

CONCLUSION

Many older adults suffer from VI. Correction of refractive errors and cataract reduces a large percentage of VI. Age, education level, and economic status are other determinants of VI.

Economic Inequality in Visual Impairment: A Study in Deprived Rural Population of Iran

Purpose:

To determine economic inequality in visual impairment (VI) and its determinants in the rural population of Iran.

Methods:

In this population-based, cross-sectional study, 3850 individuals, aged 3–93 years were selected from the north and southwest regions of Iran using multi-staged stratified cluster random sampling. The outcome was VI, measured in 20 feet. Economic status was constructed using principal component analysis on home assets. The concentration index (C) was used to determine inequality, and the gap between low and high economic groups was decomposed to explained and unexplained portions using the Oaxaca–Blinder decomposition method.

Results:

Of the 3850 individuals that were invited, 3314 participated in the study. The data of 3095 participants were finally analyzed. The C was −0.248 (95% confidence interval [CI]: −0.347 - −0.148), indicating a pro-poor inequality (concentration of VI in low economic group). The prevalence (95% CI) of VI was 1.72% (0.92–2.52) in the high economic group and 10.66% (8.84–12.48) in the low economic group with a gap of 8.94% (6.95–10.93) between the two groups. The explained and unexplained portions comprised 67.22% and 32.77% of the gap, respectively. Among the study variables, age (13.98%) and economic status (80.70%) were significant determinants of inequality in the explained portion. The variables of education (coefficient: −4.41; P < 0.001), age (coefficient: 14.09; P < 0.001), living place (coefficient: 6.96; P: 0.006), and economic status (coefficient: −7.37; P < 0.001) had significant effects on inequality in the unexplained portion.

Conclusions:

The result showed that VI had a higher concentration in the low economic group, and the major contributor of this inequality was economic status. Therefore, policymakers should formulate appropriate interventions to improve the economic status and alleviate economic inequality.

Epidemiology pattern of traumatic injuries of adults older than 15 years in Kashan, Iran: A population-based study in 2018-2019

Background: Trauma is the first leading cause of death and disability in the active population in developing countries. In Iran, traumatic injuries are the second leading cause of death after cardiovascular disease and also the leading cause of years of life lost (YLL). Population-based surveys can estimate all types of injuries. This study aimed to estimate the annual incidence of nonfatal injuries in adults older than 15 years in Kashan.

Methods: In a cross-sectional population-based study, people older than 15 years who were living in Kashan during 2018-2019 were studied. A cluster stratified sampling method was used. Data analysis was performed using SPSS 22 software. Chi-square and t tests and ANOVA were used to analyze the data. Significance level was set as P ≤.05 and confidence interval (CI) at 95%.

Results: In this study, which included 3880 households residing in Kashan during 2018-2019, the incidence of all injuries was estimated to be 70.61(62.60-78.70) per 1000 people in 1 year. For traffic accidents, the incidence was estimated at 36.08 (30.20-42.00) per 1000 in 1 year. Also, 231 (77.7%) of people with trauma were male, 137 (50.0%) aged 20 to 39 years, and 191 (69.7) were married. The most common cause of injuries (n = 140; 51.1%) was related to traffic accidents, and among the traffic accidents, the highest cause was motorcycle accident (n = 99; 70.71%).

Conclusion: The results of this study showed that the highest rate of injuries occurred among men, younger ages, married, and those with primary education. Also, the results showed the most common causes of trauma were injured hand and foot and head, and the most common location in which trauma occurred was street. The findings of this study are important to better explain the epidemiology aspects of injuries in Kashan.

Health equity in Iran: A systematic review

Background: Health inequities are among debatable and challenging aspects of health systems. Achieving equity through social determinants of health approach has been mentioned in most upstream national plans and acts in Iran. This paper reports the findings of a systematic review of the current synthesized evidence on health equity in Iran.

Methods: This is a narrative systematic review. The relevant concepts and terminology in health equity was found through MeSH. We retrieved the relevant studies from PubMed/MedLine, Social Sciences Database, and Google Scholar in English, plus the Jihad University Database (SID), and Google Scholar in Farsi databases from 1979 until the end of January 2018. The retrieved evidence has been assessed primarily based on PICOS criteria and then Ottawa-Newcastle Scale, and CASP for qualitative studies. We used PRISMA flow diagram and a narrative approach for synthesizing the evidence.

Results: We retrieved 172 455 studies. Following the primary and quality appraisal process, 114 studies were entered in the final phase of the analysis. The main part (approximately 95%) of the final phase included cross-sectional studies that had been analyzed through current descriptive inequality analysis indicators, analytical regression, or decomposition-based approaches. The studies were categorized within 3 main groups: health outcomes (40.3%), health utilization (32%), and health expenditures (27%).

Conclusion: As a part of understanding the current situation of health equity in the policymakers’ need to refer the retrieved evidence in this study, they need more inputs specially regarding the social determinants of health approach. It seems that health equity research plan in Iran needs to be redirected in new paths that give appropriate weights to biological, gene-based, environmental and contextbased, economic, social, and political aspects of health as well. We advocate addressing the aspects of Social Determinant of Health (SDH) in analyzing health inequalities.

Decomposition of socioeconomic inequality in growth disorders to its determinants in pediatric population: the CASPIAN IV study

Purpose

The current study aims to evaluate socioeconomic inequality in growth disorders and its determinants in Iranian children and adolescents.

Methods

In this nationwide cross-sectional survey, 14,880 students aged 6-18 years were selected through multistage cluster sampling method from urban and rural areas of 30 provinces of Iran in 2011. Socioeconomic status (SES) was calculated using principle component analysis. Socioeconomic inequality in growth disorders (including; underweight, excess weight, overweight, general obesity, abdominal obesity, and short stature) was assessed using concentration index (C) and slope index of inequality (SII). The Oaxaca Blinder decomposition method was used to determine determinants of this inequality.

Results

Totally, 13,486 students participated in this study (participation rate: 90.6%), comprising 50.8% boys and 75.6% urban inhabitants. Their mean age was 12.47 ± 3.36 years with no significant gender difference. The prevalence of excess weight, overweight, and general and abdominal obesity increased linearly as SES increased, and the prevalence of underweight and short stature decreased linearly as SES increased. The C index for underweight and short stature was negative, which suggests that inequality was in favor of high SES groups, and regarding overweight, excess weight, general and abdominal obesity, the index was positive, indicating that inequality was in favor of in low SES groups.

Conclusion

Our findings show a considerable inequality in prevalence of growth disorders in Iranian children and adolescents. These findings provide practical information for health policies and programs.

Disability and post-trauma stress in the population over 15 years old in Kashan, Iran: A population-based study

PURPOSE

One of the consequences of trauma-related injuries is disability. There are more than one billion people with disabilities worldwide. Disability in people reduces their quality of life. The goal of this study was to determine the rate of post-trauma stress and disability related to trauma in the population over 15 years old in Kashan during a solar year of 2018-2019.

METHODS

This is a cross-sectional population-based study. A cluster sampling method was used in the city of Kashan, and 3880 persons were interviewed with individuals randomly selected in each household. If a person had trauma during one year ago, the World Health Organization Disability Assessment Schedule 2.0 and Post Trauma Stress Disorder (PTSD) Checklist were applied for further interview. Data were analyzed using Chi-square test or t-test.

RESULTS

Among the 3880 participants residing in Kashan, 274 (7.1%) reported a history of traumatic injury during one year ago in 2018-2019. Incidence of all injuries was estimated to be 70.61 (62.60-78.70) per 1000 people. For the trauma population, 213 (77.7%) were male and 75.1% were married. About half of them (50.3%, 138/274) aged 21-39 years. The most common cause of injuries was related to traffic accidents: 140 (51.1%). Of the 274 trauma participants, 47 (17.2%) reported PTSD; 244 (89.1%) had a mild disability, and 30 (10.9%) reported moderate disability.

CONCLUSION

One of the main causes of disability in the human community is the traumatic injuries. According to the results of this study, 89.1% of trauma participants have sustained at last mild disability following trauma. These people require follow-up and post-treatment support. It should be noted that psychological complications such as PTSD are as significant as physical symptoms.

Local-Migrant Gaps in Healthcare Utilization Between Older Migrants and Local Residents in China

BACKGROUND

Older migrants in China without local resident registration (hukou) are a vulnerable population and face barriers to receiving local healthcare.

OBJECTIVES

We aimed to quantify the disparities in healthcare utilization between older migrants and local residents in Shanghai, China.

DESIGN

This was a cross-sectional study.

SETTING

The study was conducted in Shanghai, China, in 2016.

PARTICIPANTS

Older adults (aged ≥60 years) were recruited based on a three-stage stratified cluster sampling method (2571 older locals and 1920 older migrants).

MEASUREMENTS

We compared utilization of outpatient care, inpatient care, preventive care, emergency room (ER) admission, and dental care, as well as medication use between older migrants and local residents. The local-migrant gap was parsed into observed and unobserved components using the Blinder-Oaxaca decomposition method.

RESULTS

Older migrants were less likely to utilize outpatient (odds ratio [OR] = 0.757; 95% confidence interval [CI] = 0.617-0.928), inpatient (OR = 0.642; 95% CI = 0.443-0.931), and preventive care (OR = 0.743; 95% CI = 0.643-0.858) and were more likely to use medication (OR = 1.254; 95% CI = 1.089-1.445) than local residents. Differences in ER admissions and dental care utilization were not significant in the regression analysis. The decomposition results indicated that 55% and 71% of the local-migrant gap in outpatient and preventive care utilization were attributable to individual characteristics, like health insurance. Unobserved components, including hukou-related factors and personal heterogeneous preferences, contributed 59% and 63% to utilization of inpatient care and medication use, respectively.

CONCLUSION

We identified local-migrant gaps in healthcare utilization among older adults in China. Further research is needed into integration of the health insurance system, accessibility of public health welfare benefits, and reconstruction of social networks among older migrants. J Am Geriatr Soc 68:1560-1567, 2020.

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.

Using Oaxaca Decomposition to Study Socioeconomic Inequity of Physical Activity among Children Aged 10-12 Years: A Study in West of Iran

Background

Low physical activity (PA) is increasing public health problem. The present study aimed to determine socioeconomic inequality in PA among children aged 10-12 years old in Kurdistan, west of Iran in 2015.

Methods

The present cross-sectional study was conducted on 2506 children aged 10-12 in Sanandaj, Iran, in 2015. Data on the children's level of PA were collected using the Modifiable Activity Questionnaire. The concentration index was used to measure inequality and the Oaxaca decomposition to examine the different determinants of the inequality. The data were analyzed in Stata 13 and SPSS 20.

Results

Of the 2506 participants, 40.90% (38.97-42.82) had insufficient PA. Girls had a lower level of PA than boys (odds ratio [OR] = 0.34; 95% confidence intervals [CI]: 0.28-0.41) and it is directly related to maternal education (OR = 1.71; 95% CI: 1.18-2.47), the family's Socioeconomic status (SES) (OR = 2.18; 95% CI: 1.56-3.05), and the place of residence (OR = 1.68; 95% CI: 1.16-2.44). The concentration index for insufficient PA was -0.25 (95 CI: -0.30 to -0.21), revealing an insufficient PA in the group with a low SES. The prevalence of insufficient PA is 51.38% (95% CI: 48.45-54.31) in poor group and 28.40% (95% CI: 22.80-33.99) in the wealthier group. The Oaxaca decomposition showed maternal education and the place of residence was the most important determinants of inequality.

Conclusions

According to the findings, most of the children especially in the poor groups didn't have sufficient PA and socioeconomic factors could have the important role.

Socioeconomic inequality in cardio-metabolic risk factors in a nationally representative sample of Iranian adolescents using an Oaxaca-Blinder decomposition method: the CASPIAN-III study

Objectives

The present research was conducted aiming at assessing the association of socioeconomic inequality in the prevalence of risk factors associated with cardio-metabolic disorders in a sample population of nationally representative Iranian adolescents and to identify its influencing factors.

Methods

This study was conducted as part of a national-based surveillance program performed on 5625 individuals aged 10-18 years in 27 provinces in Iran. To determine the socioeconomic status (SES) of participants, we defined a new variable by applying the principal component analysis. Doing so, the socioeconomic inequality in cardio-metabolic risk factors was examined over the tertiles of SES using concentration index (C). Then, Oaxaca-Blinder decomposition analysis was carried out in order to decide upon the roots of inequality in the health system.

Results

The mean (standard deviation) age of participants was 14.73 (2.41) years. The prevalence of cardio-metabolic parameters had considerable difference across SES tertiles. Elevated fasting blood glucose (FBG), elevated triglycerides (TG), abdominal obesity, elevated total cholesterol (TC), and metabolic syndrome (MetS) increased linearly by increasing SES tertiles. C index for depressed high density lipoprotein- cholesterol (HDL-C) was negative, which was suggestive of inequality in favor of high SES groups and for other cardio-metabolic parameters, it was positive, which indicate inequality was in favor of the lowest SES groups. The highest gap between the first and third tertiles of socioeconomic was for frequency of abdominal obesity; 13.18% of the lowest SES groups and 20.11% of the highest SES groups had abdominal obesity which accounts 6.93% gap in favor of the highest SES groups. The living area could be named as the main variables standing for the inequality of elevated FBS, elevated LDL-c, low HDL-c and abdominal obesity frequency between the first and the last SES group. In addition, BMI could stand as the main independent variable explaining the gap in elevated TG, elevated TC, elevated BP and MetS prevalence across the lowest and the highest SES group.

Conclusions

The study revealed the considerable inequality in the prevalence of cardio-metabolic risk factors between the highest and the lowest SES groups of Iranian adolescents. Living area and BMI are the two main factors which explained inequality in prevalence of cardio metabolic risk factors between SES groups. These estimations could provide health policy markers with practical information for future complementary analyses.

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.

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.

The Use of Decomposition Methods in Real-World Treatment Benefits Evaluation for Patients with Type 2 Diabetes Initiating Different Injectable Therapies: Findings from the INITIATOR Study

BACKGROUND

Determining characteristics of patients likely to benefit from a particular treatment could help physicians set personalized targets.

OBJECTIVES

To use decomposition methodology on real-world data to identify the relative contributions of treatment effects and patients' baseline characteristics.

METHODS

Decomposition analyses were performed on data from the Initiation of New Injectable Treatment Introduced after Antidiabetic Therapy with Oral-only Regimens (INITIATOR) study, a real-world study of patients with type 2 diabetes started on insulin glargine (GLA) or liraglutide (LIRA). These analyses investigated relative contributions of differences in baseline characteristics and treatment effects to observed differences in 1-year outcomes for reduction in glycated hemoglobin A_1c (HbA_1c) and treatment persistence.

RESULTS

The greater HbA_1c reduction seen with GLA compared with LIRA (-1.39% vs. -0.74%) was primarily due to differences in baseline characteristics (HbA_1c and endocrinologist as prescribing physician; P < 0.050). Patients with baseline HbA_1c of 9.0% or more or evidence of diagnosis codes related to mental illness achieved greater HbA_1c reductions with GLA, whereas patients with baseline polypharmacy (6-10 classes) or hypogylcemia achieved greater reductions with LIRA. Decomposition analyses also showed that the higher persistence seen with GLA (65% vs. 49%) was mainly caused by differences in treatment effects (P < 0.001). Patients 65 years and older, those with HbA_1c of 9.0% or more, those taking three oral antidiabetes drugs, and those with polypharmacy of more than 10 classes had higher persistence with GLA; patients 18 to 39 years and those with HbA_1c of 7.0% to less than 8.0% had higher persistence with LIRA.

CONCLUSIONS

Although decomposition does not demonstrate causal relationships, this method could be useful for examining the source of differences in outcomes between treatments in a real-world setting and could help physicians identify patients likely to respond to a particular treatment.

Multiple deprivation, vision loss, and ophthalmic disease in adults: global perspectives

The association between socioeconomic position and morbidity and mortality has long been recognized. We evaluate the evidence for an association between multiple aspects of deprivation and ocular health in a global context. This is a systematic review of studies that evaluated deprivation in the adult population in the context of the major acquired causes of visual loss such as cataract, diabetic eye disease, glaucoma, age-related macular degeneration, and ocular trauma. The search strategy identified relevant studies reported between 1946 and August 2016, with randomized control trials, case-control, cohort, and cross-sectional study designs being selected for inclusion. The studies identified in this review from across the world demonstrate the extent to which the common themes such as low educational attainment and low income may be associated with increased incidence of various sight-threatening conditions and may adversely affect access to specialist assessment and delivery of treatment. Health inequality may always persist, but an increased recognition of the importance of the various impacts of deprivation may empower policy makers to target limited resources to the most vulnerable groups in order to deliver the greatest benefit.

Embodying pervasive discrimination: a decomposition of sexual orientation inequalities in health in a population-based cross-sectional study in Northern Sweden

Background

Studies from Sweden and abroad have established health inequalities between heterosexual and non-heterosexual people. Few studies have examined the underpinnings of such sexual orientation inequalities in health. To expand this literature, the present study aimed to employ decomposition analysis to explain health inequalities between people with heterosexual and non-heterosexual orientation in Sweden, a country with an international reputation for heeding the human rights of non-heterosexual people.

Methods

Participants (N = 23,446) came from a population-based cross-sectional survey in the four northernmost counties in Sweden in 2014. Participants completed self-administered questionnaires, covering sexual orientation, mental and general physical health, social conditions and unmet health care needs, and sociodemographic data was retrieved from total population registers. Sexual orientation inequalities in health were decomposed by Blinder-Oaxaca decomposition analysis.

Results

Results showed noticeable mental and general health inequalities between heterosexual and non-heterosexual orientation groups. Health inequalities were partly explained (total explained fraction 64-74%) by inequalities in degrading treatment (24-26% of the explained fraction), but to a considerable degree also by material conditions (38-45%) and unmet care needs (25-43%).

Conclusions

Psychosocial experiences may be insufficient to explain and understand health inequalities by sexual orientation in a reputedly ‘gay-friendly’ setting. Less overt forms of structural discrimination may need to be considered to capture the pervasive material discrimination that seems to underpin the embodiment of sexual minority inequalities. This ought to be taken into consideration in research, policy-making and monitoring aiming to work towards equity in health across sexual orientations.

Socioeconomic inequality in oral health behavior in Iranian children and adolescents by the Oaxaca-Blinder decomposition method: the CASPIAN- IV study

Background

The present study set to describe the socioeconomic inequality associated with oral hygiene behavior among Iranian pediatric population.

Methods

A representative sample of 13486 school students aged 6–18 years was selected through multistage random cluster sampling method from urban and rural areas of 30 provinces in Iran. Principle Component Analyses (PCA) correlated variables summarized as socioeconomic status (SES). Association of independent variables with tooth brushing was assessed through logistic regression analysis. Decomposition of the gap in tooth brushing between the first and fifth SES quintiles was assessed using the counterfactual decomposition technique. To assess the relation between tooth brushing and each socioeconomic category, Concentration Index (C) and the slope index of inequality (SII) were used, representing the linear regression coefficient.

Results

The participation rate was 90.6 % (50.7 % boys and 75.6 % urban inhabitants). The mean age of participants was 12.47 ± 3.36 years. The frequency of tooth brushing increased across SES quintiles, prevalence of tooth brushing between the first and fifth quintile, under 20 % difference, increased from 58.22 (95 % CI: 56.24,60.20) to 78.61 (95 % CI: 77.00,80.24). Only 3 % of the difference is explained by the factors considered in the study, and 17 % remained unknown. Residence area, family size, and smoking status made a significant contribution to the gap between the first and last SE groups. Residence area [ −2.01 (95 % CI: −3.46, −0.55)] was along the maximum levels of gaps between SE categories.

Conclusions

The findings revealed a socio-economic inequality in oral health behavior in Iranian children and adolescents. Also, factors influencing oral health are addressed to develop and implement complementary public health actions.

Socioeconomic inequalities in functional somatic symptoms by social and material conditions at four life course periods in Sweden: a decomposition analysis

OBJECTIVE

Socioeconomic inequalities in health are deemed a worldwide public health problem, but current research is lacking on key points including determinants of socioeconomic differences in health, and not the least variations of these determinants over the life course. Using a 26-year prospective Swedish community-based cohort, we aim at decomposing socioeconomic inequalities in functional somatic symptoms by social and material life circumstances, at 4 periods of the life course.

DESIGN

Repeated cross-sectional study.

SETTING

Participants came from the Northern Swedish Cohort (n=1001), who completed questionnaires about occupational class, social and material living conditions, and symptoms at ages 16, 21, 30 and 42. Socioeconomic inequalities were estimated and decomposed using the Blinder-Oaxaca decomposition analysis.

RESULTS

Inequalities in symptoms between blue-collar and white-collar socioeconomic groups increased along the life course in the sample. In the decomposition analysis, a high proportion of the gap between socioeconomic groups could be explained by social and material living conditions at ages 16 (84% explained), 30 (45%) and 42 (68%), but not at age 21. Specific social (parental illness at age 16 and violence at ages 30 and 42) and material (parental unemployment at age 16, and own unemployment and financial strain at ages 30 and 42) factors contributed jointly to the health gaps.

CONCLUSIONS

Socioeconomic inequalities in functional somatic symptoms increased along the life course in this Swedish cohort. A considerable portion of the social gaps in health was explained by concurrent social and material conditions, and the importance of specific adversities was dependent on the life course stage. Our findings suggest that socioeconomic inequalities in functional somatic symptoms may be reduced by addressing both social and material living conditions of disadvantaged families, and also that the life course stage needs to be taken into consideration.

Activity limitations predict health care expenditures in the general population in Belgium

Background

Disability and chronic conditions both have an impact on health expenditures and although they are conceptually related, they present different dimensions of ill-health. Recent concepts of disability combine a biological understanding of impairment with the social dimension of activity limitation and resulted in the development of the Global Activity Limitation Indicator (GALI). This paper reports on the predictive value of the GALI on health care expenditures in relation to the presence of chronic conditions.

Methods

Data from the Belgian Health Interview Survey 2008 were linked with data from the compulsory national health insurance (n = 7,286). The effect of activity limitation on health care expenditures was assessed via cost ratios from multivariate linear regression models. To study the factors contributing to the difference in health expenditure between persons with and without activity limitations, the Blinder-Oaxaca decomposition method was used.

Results

Activity limitations are a strong determinant of health care expenditures. People with severe activity limitations (5.1%) accounted for 16.9% of the total health expenditure, whereas those without activity limitations (79.0%), were responsible for 51.5% of the total health expenditure. These observed differences in health care expenditures can to some extent be explained by chronic conditions, but activity limitations also contribute substantially to higher health care expenditures in the absence of chronic conditions (cost ratio 2.46; 95% CI 1.74-3.48 for moderate and 4.45; 95% CI 2.47-8.02 for severe activity limitations). The association between activity limitation and health care expenditures is stronger for reimbursed health care costs than for out-of-pocket payments.

Conclusion

In the absence of chronic conditions, activity limitations appear to be an important determinant of health care expenditures. To make projections on health care expenditures, routine data on activity limitations are essential and complementary to data on chronic conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1607-7) contains supplementary material, which is available to authorized users.

Prevalence and causes of vision loss in North Africa and the Middle East: 1990-2010

BACKGROUND

To describe the prevalence and causes of visual impairment and blindness in North Africa and the Middle East (NAME) in 1990 and 2010.

METHODS

Based on a systematic review of medical literature, we examined prevalence and causes of moderate and severe vision impairment (MSVI; presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60).

RESULTS

In NAME, the age-standardised prevalence of blindness decreased from 2.1% to 1.1% and MSVI from 7.1% to 4.5%. In 2010, 3.119 million people were blind, and 13.700 million had MSVI. Women were generally more often affected than men. Main causes of blindness were cataract, uncorrected refractive error, macular degeneration and glaucoma. Main causes of MSVI were cataract and uncorrected refractive errors. Proportions of blindness and MSVI from trachoma significantly decreased.

CONCLUSIONS

Although the absolute numbers of people with blindness and MSVI increased from 1990 to 2010, the overall age-standardised prevalence of blindness and MSVI among all ages and among those aged 50 years and older decreased significantly (p<0.05). Cataract and uncorrected refractive error were the major causes of blindness and MSVI.

Economic inequality in presenting near vision acuity in a middle-aged population: a Blinder-Oaxaca decomposition

PURPOSE

To investigate economic inequality and its determinants in near vision, in a middle-aged population.

METHODS

In this population-based study, the presenting near vision in the better eye was investigated as the main outcome. If this vision revealed a value ≥1.6 M, the participant was considered to have presenting near vision impairment (PNVI). The effect of variables studied on PNVI was investigated using logistic regression. Economic inequality in PNVI was investigated using the Oaxaca-Blinder decomposition method.

RESULTS

PNVI in the better eye was observed in 18.2% (95% CI 16.8 to 19.6) of participants. The prevalence of PNVI in the high and low economic groups was 11.7% (95% CI 10.3 to 13.0) and 28.5% (95% CI 26.0 to 31.0), respectively. Age and education were observed as the main factors in the explained portion of this gap and were in favour of the high economic group. Gender and eye care utilisation were factors affecting the unexplained portion of this gap and were in favour of the low economic group.

CONCLUSIONS

Economic inequality plays a significant role in PNVI, while age and education are among the main factors affecting this gap. The effect caused by any change in these two factors was found to have a greater effect on women with low economic status.

Cohort profile: Shahroud Eye Cohort Study

The Shahroud Eye Cohort Study was set up to determine the prevalence and incidence of visual impairment and major eye conditions in the 40-64-year-old population of Shahroud as a Middle Eastern population. The first phase of the study was conducted in 2009-10. Using random cluster sampling, 6311 Shahroud inhabitants were invited for ophthalmologic examinations; of these, 5190 participants completed phase 1 (participation rate of 82.2%). All participants were interviewed to collect data on participants' demographics, occupation status, socioeconomic status, history of smoking, and medical and ophthalmic history, as well as history of medication, and the quality and duration of their insurance. DNA and plasma samples, as well as four dots of whole blood were collected from participants. Extensive optometric and ophthalmologic examinations were performed for each participant, including lensometry of current glasses, testing near and far visual acuity; determining objective and subjective refraction; eye motility; cycloplegic refraction; colour vision test; slit-lamp biomicroscopy and intraocular pressure measurement; direct and indirect fundoscopy; perimetry test; ocular biometry; corneal topography; lens and fundus photography; and the Schirmer's (1008 participants) and tear breakup time tests (1013 participants). The study data are available for collaborative research at Noor Ophthalmology Research Center, Tehran, Iran.

Application of the nonlinear Blinder-Oaxaca decomposition to study racial/ethnic disparities in antiobesity medication use in the United States

BACKGROUND

The nonlinear Blinder-Oaxaca (BO) decomposition method is gaining popularity in health services research because of its ability to explain disparity issues. The present study demonstrates the use of this method for categorical variables by addressing antiobesity medication use disparity.

OBJECTIVE

To examine racial/ethnic disparity in antiobesity medication use and to quantify the observed factor contribution behind the disparity using the nonlinear BO decomposition.

METHODS

Medical Expenditure Panel Survey data, 2002-2007, were used in this retrospective cross-sectional study. Adults with body mass index (BMI) >30, or BMI ≥27 and comorbidities such as hypertension, cardiovascular diseases, diabetes, or hyperlipidemia were included in the cohort (N=65,886,625). Multivariable logistic regression was performed to examine racial/ethnic disparity in antiobesity medication use controlling for predisposing, enabling, and need factors. The nonlinear BO decomposition was used to identify the contribution of each predisposing, enabling, and need factors in explaining the racial/ethnic disparity and to estimate the residual unexplained disparity.

RESULTS

Non-Hispanic Blacks were 46% (odds ratio [OR]: 0.54; 95% confidence interval [CI]: 0.35-0.83) less likely to use antiobesity drugs compared with non-Hispanic Whites, whereas no difference was observed between Hispanics and non-Hispanic Whites. A 0.22 percentage point of disparity existed between non-Hispanic Whites and Blacks. The nonlinear BO decomposition estimated a decomposition coefficient of -0.0013 indicating that the observed disparity would have been 58% higher (-0.0013/0.0022) if non-Hispanic Blacks had similar observed characteristics as non-Hispanic Whites. Age, gender, marital status, region, and BMI were significant factors in the decomposition model; only marital status explained the racial/ethnic disparity among all observed characteristics.

CONCLUSIONS

The study revealed that differences in the predisposing, enabling, and need characteristics (except marital status) did not successfully explain the racial/ethnic disparity in antiobesity medication use. Further studies examining racial/ethnic differences in individual beliefs, behavioral patterns, and provider prescription patterns are vital to understand these disparities.