The Association Between Primary Open Angle Glaucoma and Clustered Components of Metabolic Syndrome

The Association between Cholesterol Levels and Severity of Normal Tension Glaucoma

Purpose

To evaluate the serum lipid levels, including total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) of patients with normal tension glaucoma (NTG) and to investigate the relationship between serum HDL levels and the severity of NTG.

Methods

In this cross-sectional, case-control study, 282 NTG subjects and 202 control subjects were enrolled from the outpatient clinic of the Department of Ophthalmology at Taichung Veterans General Hospital in central Taiwan from 2015 to 2021. Fasting cholesterol, HDL, and LDL levels were evaluated using a biochemical analyzer (ARCHITECT c16000). Glaucoma severity was classified by visual field test as mild (mean deviation [MD] ≥ -6.0dB), moderate (-12dB ≤ MD < -6 dB), and severe (MD < -12dB), based on the mean deviation.

Results

HDL levels were significantly lower in the NTG group compared with the control subjects (47 ± 18mg/dl versus 53 ± 18mg/dl; p = 0.03). There were no statistically significant differences in total cholesterol or LDL levels between the NTG and control subjects (total cholesterol levels: 194 ± 39mg/dl versus 190 ± 32mg/dl; p > 0.05; LDL levels: 113 ± 30mg/dl versus 110 ± 29mg/dl; p > 0.05). The mean serum HDL levels were lowest in the severe group (41 ± 11mg/dl) followed by the moderate (45 ± 16mg/dl) and mild (50 ± 15mg/dl) groups, with significant differences among the three groups (p = 0.02). The multivariate regression analysis revealed a statistically significant negative correlation between HDL and vertical cup-to-disc ratio (VCDR; B =-0.16, p = 0.03) among all NTG patients and a positive correlation between HDL and retinal nerve fiber layer (RNFL; r = 0.34, p = 0.03) among all NTG patients.

Conclusions

A significantly lower serum HDL concentration was found in the NTG patients, which was negatively associated with disease severity. The findings warrant further study to elucidate the role of these phenomena in the pathogenesis of glaucoma.

Plasma metabolite profile for primary open-angle glaucoma in three US cohorts and the UK Biobank

Glaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness worldwide. Primary open-angle glaucoma is the most common form, and yet the etiology of this multifactorial disease is poorly understood. We aimed to identify plasma metabolites associated with the risk of developing POAG in a case-control study (599 cases and 599 matched controls) nested within the Nurses' Health Studies, and Health Professionals' Follow-Up Study. Plasma metabolites were measured with LC-MS/MS at the Broad Institute (Cambridge, MA, USA); 369 metabolites from 18 metabolite classes passed quality control analyses. For comparison, in a cross-sectional study in the UK Biobank, 168 metabolites were measured in plasma samples from 2,238 prevalent glaucoma cases and 44,723 controls using NMR spectroscopy (Nightingale, Finland; version 2020). Here we show higher levels of diglycerides and triglycerides are adversely associated with glaucoma in all four cohorts, suggesting that they play an important role in glaucoma pathogenesis.

Metabolic syndrome and its components are associated with non-arteritic anterior ischaemic optic neuropathy

PURPOSE

To determine whether metabolic syndrome (MetS) is a risk factor for various forms of optic neuropathy including non-arteritic anterior ischaemic optic neuropathy (NAION).

METHODS

This population-based analysis identified patients ≥40 years of age in Olmsted County, Minnesota, USA using the Rochester Epidemiology Project 2005-2018. Patients with MetS were identified if three or more of the five standard criteria for diagnosing MetS were present: systemic hypertension, hyperglycaemia, hypertriglyceridaemia, reduced high-density lipoprotein cholesterol (hypoalphalipoproteinaemia) and central adiposity defined by increased body mass index. Charts of patients identified as having an optic neuropathy were reviewed to record specific diagnoses and compared with patients without ocular pathology other than cataract. The odds ratio (OR) of association with MetS was calculated and adjusted for age, sex and race with multivariate analysis for the various optic neuropathies.

RESULTS

Patients with MetS were more likely to have an optic neuropathy than those without (OR 2.2, p<0.001). After adjusting for age, sex and race, the only optic neuropathy found to be significantly associated with MetS was NAION (OR 6.17, p=0.002). For patients with NAION, though each individual component of MetS was individually significantly associated with MetS, further analysis suggested that hypertriglyceridaemia, hypoalphalipoproteinaemia and hyperglycaemia were likely the key drivers in the overall significance between NAION and MetS.

CONCLUSION

Patients with MetS were more likely to have NAION. Further studies are needed to determine whether MetS is a modifiable risk factor for NAION.

Updates on Coronavirus-Related Ocular Manifestations: From the Past to COVID-19 Pandemic

Context: Coronaviruses are the largest RNA viruses associated with some ocular manifestations. There are various contradictory reports about the ocular manifestations of coronaviruses in humans. Different ocular tissues can affect coronavirus-associated infectious diseases. Evidence Acquisition: All manuscripts were collected from PubMed, Google Scholar, and other relevant databases. All searches were done by specific keywords, including "coronavirus," "ocular disease," and "eye." Results: There are various contradictory reports about the ocular effects of coronaviruses in humans. Different ocular tissues are involved in coronavirus-associated infectious diseases. The ductal connection between the upper respiratory tract and eye mucosa through the nasolacrimal duct can be an entrance to respiratory viruses, such as coronaviruses. The coronavirus can infect the retina, conjunctiva, cornea, and uvea of the eye. The primary SARS-CoV-2 receptor, ACE2, is mainly expressed in the posterior tissues of the eye, such as the retina and RPE. Feline CoV, SARS-CoV, MERS-CoV, and infectious bronchitis virus (IBV) are responsible for conjunctiva involvement in coronavirus-related ocular pathogenesis. Also, various studies are held on COVID-19 and the impact of the conjunctiva on diagnosis and medical complications. Given that the cornea has an acceptable expression of ACE2 and TMPRSS2 genes compared to lung tissue, some studies were done on the impact of the cornea in COVID-19. Feline infectious peritonitis virus (FIPV) is also related to uvea complications. The experiments of human and animal models on the effects of coronaviruses on the retina and cornea in the event of various epidemics of coronaviruses and new and unknown ocular complications can be of great help to future studies. Conclusions: Given the importance of investigating the pathogenesis and other routes of SARS-CoV-2 infection, especially in areas other than the respiratory tract, this report attempts to highlight the importance of eye infections caused by the virus, its role in maintaining the virus transmission chain, and its impact on public health.

Prevalence of Primary Open-Angle Glaucoma and its Relationship with Smoking in the Population of the Azar Cohort: A Cross-Sectional Study

PURPOSE

The purpose is to determine the prevalence of primary open-angle glaucoma (POAG) and study the relationship of smoking and other potential risk factors with POAG.

METHODS

This is a cross-sectional study based on the Azar cohort databases (including the eye cohort study) in Iran, including 11,208 participants aged 35-70 years. According to the questionnaire, participants were divided into five groups in terms of smoking. Ophthalmologic examinations were performed in two steps. The first step was performed by an optometrist, and all referred participants underwent a complete ophthalmological examination in the second step, then after POAG cases were diagnosed using Criteria of the International Society of Geographic and Epidemiological Ophthalmology.

RESULTS

Of the participants, 4992 (44.5%) were male and 6216 (55.5%) were female, with a mean age of 50.1 ± 9.27 years. The prevalence of POAG in our study population was 1%, which included 58 (1.2%) males and 58 (0.9%) females. There was no significant difference between the two groups in terms of the prevalence of different smoking categories in both genders. There was a statistically significant difference between the two groups in both genders in terms of diabetes mellitus (DM) after adjusting for age and there was a statistically significant difference between the two groups in the male population in terms of triglycerides ≥150 mg/dl.

CONCLUSION

Findings of this study indicated that there is no association between cigarette smoking in different doses and a history of smoking with POAG. Other factors, such as aging and underlying diseases, including DM and hypertriglyceridemia, have a statistically significant association with POAG.

Association of Metabolic Syndrome With Glaucoma and Ocular Hypertension in a Midwest United States Population

PRCIS

For patients with glaucoma, metabolic syndrome was associated with higher intraocular pressure and greater central corneal thickness. Patients with metabolic syndrome were more likely to have ocular hypertension.

PURPOSE

The purpose of this study was to determine whether glaucomatous optic neuropathy, also known as glaucoma, and ocular hypertension are more likely to occur in patients with metabolic syndrome.

PATIENTS AND METHODS

Patients in Olmsted County, MN, were identified as having metabolic syndrome based on diagnosis codes, laboratory values, and/or medication use to meet 3 or more of the 5 standard criteria for diagnosing metabolic syndrome: systemic hypertension, hyperglycemia, hypertriglyceridemia, reduced high-density lipoprotein cholesterol, and central adiposity defined by increased body mass index. Patients with glaucoma, including primary open angle, low tension, pigment dispersion, and pseudoexfoliation, were identified using diagnostic codes. The charts of patients with glaucoma were individually reviewed to collect visual acuity, intraocular pressure, cup to disc ratio, central corneal thickness, visual field mean deviation, retinal nerve fiber layer thickness, and treatment of intraocular pressure. Patients with ocular hypertension were separately identified and similarly evaluated.

RESULTS

For patients with glaucoma, those with metabolic syndrome had higher intraocular pressure and greater central corneal thickness compared with those without metabolic syndrome. After adjustment for central corneal thickness, there was no longer a significant difference in intraocular pressure between groups. Metabolic syndrome was also associated with the diagnosis of ocular hypertension, and although central corneal thickness trended higher in patients with metabolic syndrome, it did not attain statistical significance.

CONCLUSION

In Olmsted County, though metabolic syndrome was associated with ocular hypertension and higher intraocular pressure in patients with glaucoma, the results were likely related to a thicker central corneal in this patient population.

The Impact of Systemic Health Parameters on Intraocular Pressure in the Western Region of Saudi Arabia

Background

A normal intraocular pressure (IOP) is essential for maintaining the normal structure and function of the eyes. Furthermore, an elevated IOP is a known risk factor for glaucoma. As the results from studies addressing the relationship between IOP and systemic health parameters are conflicting, researchers have not reached a consensus. This study aimed to evaluate the relationship between IOP and health parameters among non-glaucomatous participants in the western region of Saudi Arabia.

Method

We retrospectively reviewed the medical records of 255 participants aged 20 years and above who had not received any medical treatment for ocular hypertension or glaucoma at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia, from January 2019 to April 2021. The patients were categorized into age groups, divided by decades (ranging from 20-29 years to 80+ years); the most prevalent age group was 60-69 years. The data were entered using Microsoft Excel 2016 (Microsoft Corporation, Redmond, Washington), and Statistical Package for the Social Sciences (SPSS) software was used for univariate analysis. The relationship between continuous variables was analyzed by the Pearson correlation coefficient. The differences between continuous and categorical variables were assessed by the t-test and one-way analysis of variance (ANOVA) test, respectively.

Results

The mean (standard deviation) IOP in the right and the left eyes was 15.7 mmHg (4.0) and 15.6 mmHg (3.9), respectively. There were no significant associations between IOP and lipid profile parameters (p > 0.05). There was a statistically significant difference in the right IOP, in relation to the age groups (p = 0.006). Moreover, the mean IOP in the left eye was significantly higher among patients with diabetes than in the patients without diabetes (p = 0.007) as well as in patients with hypertension than in the patients without hypertension (p = 0.023).

Conclusion

The effect of total cholesterol, triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), BMI, and sex on IOP could not be established in our study. However, over the past years, people's diets have incorporated higher cholesterol and fat content, leading to higher BMI levels. Therefore, further studies of the association between BMI and IOP are critical to determine if BMI is certainly a significant risk factor for increased IOP and glaucoma.

Investigation of the Clinical Laboratory Indexes in COVID-19 Patients with Ocular Symptoms in Iran: A Single-Center Experience

Objectives: Ocular symptoms are prevalent in coronavirus infectious disease 2019 (COVID-19) patients, which may be related to clinical/paraclinical conditions. This study investigated the association between laboratory indexes and ocular symptoms in COVID-19 patients. Methods: In this cross-sectional study, 108 polymerase chain reaction (PCR)-confirmed COVID-19 patients admitted to the Rouhani Hospital, Babol, Iran, were enrolled. Ocular symptoms were investigated using standard ophthalmologic examinations. Routine laboratory investigation was done according to the standard management in patients with COVID-19 infection. Results: The erythrocyte sedimentation rate (ESR) and the serum levels of the blood urea nitrogen (BUN) and creatinine (Cr) were significantly higher in COVID-19 patients with ocular discharge and exudate (P = 0.002, 0.045, 0.046, and 0.027, respectively), while the red blood cell (RBC) and albumin were lower in COVID-19 patients with ocular discharge and exudate (P = 0.029 and 0.027, respectively). The serum levels of creatine kinase (CPK) and iron (Fe) were significantly higher in non-photophobic COVID-19 patients than in photophobic patients (P =0.033 and 0.050, respectively). In contrast, the serum level of procalcitonin was lower than photophobic COVID-19 patients (P = 0.024). The serum level of phosphorus (P) was significantly higher in COVID-19 patients with itchy eyes compared to COVID-19 patients without itchy eyes (P = 0.026). Conclusions: The footprint of laboratory indexes was demonstrated in ocular symptoms of COVID-19 patients. The kidney biomarkers were correlated with ocular discharge and exudate, and electrolytes were associated with tear-related symptoms.

Cholesterol and glaucoma: a systematic review and meta-analysis

PURPOSE

Intraocular pressure is the main risk factor for glaucoma; however, additional risk factors may also matter. This systematic review and meta-analysis were conducted to summarize the evidence regarding the association of cholesterol parameters (total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) levels) and glaucoma.

METHODS

Four electronic databases were searched for all publications containing 'glaucoma' and one of various forms of 'cholesterol' or 'lipoprotein'. Two independent reviewers screened abstracts and potentially full texts of identified articles for eligibility. Risk of bias was assessed with the Newcastle-Ottawa Scale. A random-effects meta-analysis was used to investigate the differences in total cholesterol, LDL and HDL levels between patients with and without glaucoma.

RESULTS

Overall, 29 observational studies were included in the systematic review and 26 reported quantitative information to investigate differences in cholesterol parameters between patients with glaucoma (N = 7196) and patients without glaucoma (N = 350 441). Patients with glaucoma had significantly higher total cholesterol levels than patients without glaucoma (Mean Difference (MD) 7.9 mg/dl, 95% CI 3.3 to 12.5, p = 0.001) and lower mean HDL levels (MD -2.0 mg/dl, 95% CI: -3.1 to -0.9, p = 0.001). Patients with glaucoma had higher mean LDL levels than patients without glaucoma, albeit not statistically significant (MD 6.1 mg/dl, 95% CI: -4.3 to 16.4, p = 0.251).

CONCLUSION

This systematic review and meta-analysis of observational studies found an association of glaucoma and high total cholesterol and low HDL levels, respectively. Although this supports the hypothesis that lipid levels pose an additional risk for glaucoma development, heterogeneity was substantial and causality cannot be presumed from identified observational studies.

Risk of Glaucoma Associated with Components of Metabolic Disease in Taiwan: A Nationwide Population-Based Study

PURPOSE

This retrospective cohort study was conducted to determine the glaucoma risk associated with metabolic disease (MetD) using insurance claims data of Taiwan.

METHODS

From the database, we identified patients with newly diagnosed hypertension, diabetes and/or hyperlipidemia from the years 2000 to 2002 as the MetD cohort (N = 42,036) and an age-gender-diagnosis-date matched control cohort without MetD with a two-fold sample size than that of the MetD cohort. Both cohorts were followed until the development of glaucoma, death, or withdrawal, until 31 December 2013. The incidence of glaucoma, and the Cox method estimated hazard ratio (HR) of glaucoma were calculated. Results showed that the incidence of glaucoma was two-fold higher in the MetD cohort than in the controls (1.99 versus 0.99 per 1000 person-years), with an adjusted HR of 1.66 (95% CI: 1.50-1.85). The glaucoma incidence was higher in patients with diabetes than those with hypertension and hyperlipidemia (2.38 versus 1.95 and 1.72 per 1000 person-years, respectively). The incidence increased to 5.67 per 1000 person-years in patients with all three comorbidities, with an aHR of 4.95 (95% CI: 2.35-10.40). We also found higher incidence rates of primary open-angle glaucoma and primary angle-closure glaucoma with aHRs of 2.03 and 1.44, respectively. It was concluded that glaucoma risk increased with the number of MetD. Health providers need to monitor patients with MetD to prevent glaucoma.

CRISPR-Based Genome Editing as a New Therapeutic Tool in Retinal Diseases

Retinal diseases are the primary reasons for severe visual defects and irreversible blindness. Retinal diseases are also inherited and acquired. Both of them are caused by mutations in genes or disruptions in specific gene expression, which can be treated by gene-editing therapy. Clustered regularly interspaced short palindromic repeats (CRISPR-Cas9) system is a frontier of gene-editing tools with great potential for therapeutic applications in the ophthalmology field to modify abnormal genes and treat the genome or epigenome-related retinal diseases. The CRISPR system is able to edit and trim the gene include deletion, insertion, inhibition, activation, replacing, remodeling, epigenetic alteration, and modify the gene expression. CRISPR-based genome editing techniques have indicated the enormous potential to treat retinal diseases that previous treatment was not available for them. Also, recent CRISPR genome surgery experiments have shown the improvement of patient's vision who suffered from severe visual loss. In this article, we review the applications of the CRISPR-Cas9 system in human or animal models for treating retinal diseases such as retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), age-related macular degeneration (AMD), proliferative diabetic retinopathy (PDR), and proliferative vitreoretinopathy (PVR), then we survey limitations of CRISPR system for clinical therapy.

Association of Hypertriglyceridemia and Incident Glaucoma in a Rural Chinese Population: The Handan Eye Study

Purpose

The purpose of this paper was to investigate the association between baseline metabolic risk factors and incident glaucoma over a 5-year period in rural Chinese adults.

Methods

Population-based prospective cohort study. Participants aged 30 years and older without glaucoma at baseline who underwent comprehensive examinations at baseline and after a 5-year interval in the Handan Eye Study were enrolled. Incident glaucoma was defined as people without glaucoma in either eye at baseline that had developed glaucoma in at least one eye in the 5-year follow-up. Five metabolic syndrome components, mean blood pressure, fasting plasma glucose, total cholesterol, triglycerides (TGs), low density lipoprotein cholesterol, high-density lipoprotein cholesterol, and obesity, determined as body mass index ≥30 kg/m2 at baseline were considered as potential metabolic risk factors for incident glaucoma. Univariate and multivariate logistic regression analyses were carried out to determine baseline metabolic risk factors associated with incident glaucoma.

Results

A total of 5184 participants were included in our study. During the 5-year follow-up, incident glaucoma developed in 82 subjects. Age (odds ratio [OR] = 1.060, 95% confidence interval [CI] = 1.034, 1.086, P < 0.001) and TGs level (OR = 1.213, 95% CI = 1.030, 1.429, P = 0.021) were independently and positively associated with incident glaucoma.

Conclusions

Our study revealed that increased age and high TGs level, one of the baseline metabolic features, were independent risk factors for incident glaucoma. The data implied that the metabolic features be involved in the pathogenesis of glaucoma.

Translational Relevance

This study shed the light on that the TGs level was involved in the pathogenesis of glaucoma.

Metabolic syndrome and the aging retina

PURPOSE OF REVIEW

This review explores metabolic syndrome (MetS) as a risk factor that accelerates aging in retinal neurons and may contribute to the neurodegeneration seen in glaucomatous optic neuropathy (GON) and age-related macular degeneration (AMD).

RECENT FINDINGS

Both animal model experiments and epidemiologic studies suggest that metabolic stress may lead to aberrant regulation of a number of cellular pathways that ultimately lead to premature aging of the cell, including those of a neuronal lineage.

SUMMARY

GON and AMD are each leading causes of irreversible blindness worldwide. Aging is a significant risk factor in the specific retinal neuron loss that is seen with each condition. Though aging at a cellular level is difficult to define, there are many mechanistic modifiers of aging. Metabolic-related stresses induce inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, alterations to the unfolded protein response, defects in autophagy, alterations to the microbiome, and deposition of advanced glycation end products that can all hasten the aging process. Due to the number of variables related to metabolic health, defining criteria to enable the study of risk factors at a population level is challenging. MetS is a definable constellation of related metabolic risk factors that includes enlarged waist circumference, dyslipidemia, systemic hypertension, and hyperglycemia. MetS has been associated with both GON and AMD and may contribute to disease onset and/or progression in each disease.

White blood cell count and clustered components of metabolic syndrome: A study in western Iran

Background

White blood cell count (WBC) is one of the objective parameters of systemic inflammation. The aim of present study was to evaluate the relationship between WBC count and metabolic syndrome.

Methods

In this study on Lor population in Borujerd province (West of Iran), from 2011 to 2013, 800 persons were enrolled. MetS was defined based on ATP III criteria. Differences among the quartiles of WBC were examined by one-way analysis of variance.

Results

Only 14.7% did not have any of the five components and 43% of all subjects had metabolic syndrome. The means of WBC count in MetS group were significantly higher than the control group (p<0.0001). In subjects without any MetS components, the means of WBC was 5.321 /µL, and it was 5.664, 5.714, 5.961, 6.302, and 6.572 /µL in subjects with 1, 2, 3, 4, and 5 components, respectively. These differences show a significant increasing trend (p<0.0001).

Conclusion

WBC count was associated with clustered components of metabolic syndrome. It seems that WBC counts could be considered as a predictive factor for metabolic syndrome in preventive medicine.

Metabolic Syndrome Is Associated With Ocular Hypertension and Glaucoma

Glaucoma remains the world's leading cause of irreversible blindness and though intraocular pressure (IOP) is the most prevalent risk factor and only reliable therapeutic target, a number of systemic disease associations have been reported. Metabolic syndrome (MetS) is a constellation of findings that includes systemic hypertension, abdominal obesity, glucose intolerance, and dyslipidemia. MetS is becoming increasingly common worldwide, with prevalence up to 40% in some countries. Not only is MetS a significant cause of morbidity, but it is also associated with an increase in all-cause mortality. Reports have been conflicting regarding the association of individual components of MetS, including systemic hypertension and diabetes, with elevated IOP or glaucoma. However, though limitations in the existing literature are present, current evidence suggests that MetS is associated with IOP as well as glaucoma. Additional studies are needed to clarify this association by incorporating additional metrics including assessment of central corneal thickness as well as optic nerve structure and function. Future studies are also needed to determine whether lifestyle modification or systemic treatment of MetS could reduce the incidence or progression of glaucoma.

Contribution of inflammasome complex in inflammatory-related eye disorders and its implications for anti-inflammasome therapy

Inflammasome complex is regarded as a major molecular regulator that exerts a significant function in caspase-1 activation and consequently, the development of cytokines like interleukin-1β (IL-1β) and interleukin-18 (IL-18). The secretion of these cytokines may induce inflammation. The role of inflammasomes in the pathologic process of eye-related illnesses like glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy has been well studied over the past decade. However, the detailed pathogenic mechanism of inflammasomes in these retinal diseases is still unknown. Therefore, further investigation and understanding various aspects of inflammasome complexes as well as their pivotal roles in the immunopathology of human ocular illnesses are essential. The present review aims to describe the significant involvement of inflammasomes in the immunopathology of important inflammatory retinal illnesses, including glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy focusing on anti-inflammasome therapy as a promising approach in the treatment of inflammation-related eye diseases.

Association between hypertriglyceridemia and open angle glaucoma: A case report

Hypertriglyseridemia is a metabolic disorder that can cause vascular dysfucntion and be causally associated with glaucoma. Herein we present the case of a 16-year-old boy with hypertriglyseridemia with open-angle glaucoma.

Heterogeneity in arterial hypertension and ocular perfusion pressure definitions: Towards a consensus on blood pressure-related parameters for glaucoma studies

PURPOSE

Glaucoma studies have long taken into account the blood pressure (BP) status of patients. This study summarizes and evaluates the impact of the different criteria that have been used for BP-related variables in glaucoma research.

METHODS

Studies included in two meta-analyses that reviewed the role of BP in glaucoma were analyzed. Additional studies published after the search periods of the meta-analyses were also included. Criteria for the definition of arterial hypertension and other BP-related variables, such as mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP), were retrieved.

RESULTS

Sixty-four studies were evaluated. One-third used 140 mmHg as a systolic BP cut-off to define hypertension, 20% used 160 mmHg and the remaining half used various other criteria. Less than 20% of studies reported MAP and/or MOPP. While eight of the ten studies reporting MAP used a correct formula that only happened for five of the eleven studies reporting MOPP. Using as an example average blood pressure values, incorrectly used formulas could have led to an overestimation of more than 100% of the expected values.

CONCLUSION

Considerable heterogeneity exists in BP-related variables in glaucoma research and different definitions can lead to large disparities. Glaucoma research would benefit from a consensus regarding blood pressure parameters.

Prevalence of metabolic syndrome in Iran: A meta-analysis of 69 studies

AIMS

Metabolic syndrome increases the risk of chronic diseases including cardiovascular diseases and diabetes. The present study investigated the prevalence of metabolic syndrome in Iran.

MATERIALS AND METHODS

Published articles in English and Persian during 2000-2016 identified using keywords of prevalence, metabolic syndrome, and Iran in the following databases: Web of Science, PubMed, Scopus, Google scholar, SID and Magiran. Random effect model used to calculate the pooled estimates. Heterogeneity of studies assessed using Q statistic, and geographical distribution of metabolic syndrome demonstrated via GIS map. Data were analyzed by STATA-11.

RESULTS

The overall prevalence of metabolic syndrome was 30.4% (95%CI: 28.3-32.6) with no significant heterogeneity by diagnostic criteria. The lowest frequency was reported in Sistan and Baluchestan Province [18.3% (95% CI: 12.9-25.8)] compared to the highest in Bushehr [57.8% (95% CI: 41.8-80.0)]. It was significantly more prevalent in women [(34.8% (95%CI: 31.2-38.8)] compared to men [25.7% (95%CI: 23.4-28.3)] (P = 0.001)]. A significant increasing trend (P = 0.001) was observed in different age groups, as metabolic syndrome increased from 12.1% (95% CI: 9.37-15.6) in 20-29 years-old age group to 51.7% (95%CI: 47.4-56.4) in the over 60 years-old age group.

CONCLUSIONS

Approximately one-third of Iranian adults have metabolic syndrome which varied by regions, age and gender. Then, appropriate intervention based on behavioral patterns of inhabitants and local conditions may help to reduce the burden of disease.

Review: Impact of Helicobacter pylori on Alzheimer's disease: What do we know so far?

BACKGROUND

Helicobacter pylori has changed radically gastroenterologic world, offering a new concept in patients' management. Over time, more medical data gave rise to diverse distant, extragastric manifestations and interactions of the "new" discovered bacterium. Special interest appeared within the field of neurodegenerative diseases and particularly Alzheimer's disease, as the latter and Helicobacter pylori infection are associated with a large public health burden and Alzheimer's disease ranks as the leading cause of disability. However, the relationship between Helicobacter pylori infection and Alzheimer's disease remains uncertain.

METHODS

We performed a narrative review regarding a possible connection between Helicobacter pylori and Alzheimer's disease. All accessible relevant (pre)clinical studies written in English were included. Both affected pathologies were briefly analyzed, and relevant studies are discussed, trying to focus on the possible pathogenetic role of this bacterium in Alzheimer's disease.

RESULTS

Data stemming from both epidemiologic studies and animal experiments seem to be rather encouraging, tending to confirm the hypothesis that Helicobacter pylori infection might influence the course of Alzheimer's disease pleiotropically. Possible main mechanisms may include the bacterium's access to the brain via the oral-nasal-olfactory pathway or by circulating monocytes (infected with Helicobacter pylori due to defective autophagy) through disrupted blood-brain barrier, thereby possibly triggering neurodegeneration.

CONCLUSIONS

Current data suggest that Helicobacter pylori infection might influence the pathophysiology of Alzheimer's disease. However, further large-scale randomized controlled trials are mandatory to clarify a possible favorable effect of Helicobacter pylori eradication on Alzheimer's disease pathophysiology, before the recommendation of short-term and cost-effective therapeutic regimens against Helicobacter pylori-related Alzheimer's disease.

Peripapillary choroidal thickness by enhanced depth imaging optical coherence tomography: the impact of metabolic syndrome

PURPOSE

To assess the impact of metabolic syndrome (MetS) on the peripapillary choroidal thickness (PPCT) and to characterize the PPCT in a Portuguese population.

METHODS

This prospective study included 104 eyes. Detailed medical and ophthalmic examinations were performed; the PPCT was measured by spectral-domain optical coherence tomography (SD-OCT) using enhanced depth imaging (EDI) modality. The PPCT changes with MetS, as well as with other clinical and demographic factors, were investigated.

RESULTS

The mean PPCT was 142.4 ± 54.0 µm (58-303 µm); it was thickest superiorly, followed by the temporal, nasal, and inferior sectors. The PPCT was significantly associated with axial length (p<0.001), age (p = 0.001), intraocular pressure (IOP) (p = 0.041), weight (p = 0.015), and arterial hypertension (p = 0.044). The presence of MetS was associated with thinner PPCT in all sectors, being statistically significant in the temporal (p = 0.032) and inferotemporal (p = 0.034) sectors.

CONCLUSIONS

The choroidal thickness was significantly less in temporal and inferotemporal sectors in patients with MetS than in controls. This may suggest vascular insufficiency around the optic nerve head.

The Association between Adiposity and the Risk of Glaucoma: A Meta-Analysis

Purpose

This meta-analysis was conducted to determine the potential association between adiposity and glaucoma incidence.

Materials and Methods

A comprehensive literature search was performed in PubMed and ISI Web of Science. A meta-analysis was conducted using STATA software.

Results

Fifteen eligible studies involving 2,445,980 individuals were included to investigate the association between adiposity and glaucoma incidence. The relative risks (RRs) were pooled with 95% confidence intervals (CI) by using a random-effects model. The pooled RR between adiposity and elevated intraocular pressure (IOP) was 1.73 (95% CI, 1.18–2.54), whereas that between adiposity and open-angle glaucoma (OAG) was 0.97 (95% CI, 0.83–1.13). The pooled RR between abdominal adiposity and glaucoma was 1.28 (95% CI, 1.15–1.41), whereas that between general adiposity and glaucoma was 1.09 (95% CI, 0.87–1.37). Results of subgroup analysis by sex indicated the association between adiposity and glaucoma in the female group (RR, 1.31; 95% CI, 1.05–1.64), but not in the male group (RR, 1.11; 95% CI, 0.77–1.60). The pooled RR of cohort studies and cross-sectional studies were 1.00 (95% CI, 0.84–1.20) and 1.22 (95% CI, 0.89–1.66), respectively.

Conclusions

Adiposity has a higher risk of elevated IOP, and abdominal adiposity has a positive association with glaucoma, especially in female patients.