Association between body mass index and diabetic retinopathy in Chinese patients with type 2 diabetes

Predicting vision-threatening diabetic retinopathy in patients with type 2 diabetes mellitus: Systematic review, meta-analysis, and prospective validation study

Background

Delayed diagnosis and treatment of vision-threatening diabetic retinopathy (VTDR) is a common cause of visual impairment in individuals with type 2 diabetes mellitus (T2DM). Identification of VTDR predictors is the key to early prevention and intervention, but the predictors from previous studies are inconsistent. This study aims to conduct a systematic review and meta-analysis of the existing evidence for VTDR predictors, then to develop a risk prediction model after quantitatively summarising the predictors across studies, and finally to validate the model with two Chinese cohorts.

Methods

We systematically retrieved cohort studies that reported predictors of VTDR in T2DM patients from PubMed, Ovid, Embase, Scopus, Cochrane Library, Web of Science, and ProQuest from their inception to December 2023. We extracted predictors reported in two or more studies and combined their corresponding relative risk (RRs) using meta-analysis to obtain pooled RRs. We only selected predictors with statistically significant pooled RRs to develop the prediction model. We also prospectively collected two Chinese cohorts of T2DM patients as the validation set and assessed the discrimination and calibration performance of the prediction model by the time-dependent ROC curve and calibration curve.

Results

Twenty-one cohort studies involving 622 490 patients with T2DM and 57 107 patients with VTDR were included in the meta-analysis. Age of diabetes onset, duration of diabetes, glycosylated haemoglobin (HbA1c), estimated glomerular filtration rate (eGFR), hypertension, high albuminuria and diabetic treatment were used to construct the prediction model. We validated the model externally in a prospective multicentre cohort of 555 patients with a median follow-up of 52 months (interquartile range = 39-77). The area under the curve (AUC) of the prediction model was all above 0.8 for 3- to 10-year follow-up periods and different cut-off value of each year provided the optimal balance between sensitivity and specificity. The data points of the calibration curves for each year closely surround the corresponding dashed line.

Conclusions

The risk prediction model of VTDR has high discrimination and calibration performance based on validation cohorts. Given its demonstrated effectiveness, there is significant potential to expand the utilisation of this model within clinical settings to enhance the detection and management of individuals at high risk of VTDR.

Longitudinal Assessment of Intraretinal Microvascular Abnormalities in Diabetic Retinopathy Using Swept-Source Optical Coherence Tomography Angiography

Purpose

To longitudinally investigate the changes in intraretinal microvascular abnormalities (IRMAs) over time, employing swept-source optical coherence tomography angiography in eyes with diabetic retinopathy.

Methods

In this retrospective, longitudinal study, we evaluated 12 × 12-mm swept-source optical coherence tomography angiography centered on the macula at baseline and last available follow-up visit for (1) IRMA changes during follow-up, defined as (a) stable, (b) regressed, (c) obliterated, and (d) progressed; and the (2) development of new neovascularization (NV) and their origins. Competing-risk survival analysis was used to assess the factors associated with these changes.

Results

In total, 195 eyes from 131 participants with diabetic retinopathy were included. Stable, regressed, obliterated, and progressed IRMA were observed in 65.1%, 12.8%, 11.3%, and 19% of eyes with diabetic retinopathy, respectively. Anti-VEGF injections during the follow-up periods and a slower increase of foveal avascular zone were associated with IRMA regression (P < 0.001 and P = 0.039). Obliterated IRMA were correlated with previous panretinal photocoagulation (P < 0.001) and a lower deep capillary plexus vessel density at baseline (P = 0.007), as well as with follow-up anti-VEGF injections (P = 0.025). A higher baseline ischemia index (ISI) and panretinal photocoagulation during the follow-up periods were associated with IRMA progression (P = 0.049 and P < 0.001). A faster increase in ISI predicted the development of NV elsewhere (NVE) from veins (P < 0.001). No significant factors were found to be associated with NVE originating from IRMA.

Conclusions

Changes in IRMA closely correlated with the severity of retinal ischemia and treatment. Notably, our study confirmed the potential, yet relatively rare, development of NVE from IRMA in a large cohort; however, the risk factors associated with this transformation require further exploration.

Mendelian randomization analysis reveals a causal effect of Streptococcus salivarius on diabetic retinopathy through regulating host fasting glucose

Diabetic retinopathy (DR) is one of leading causes of vision loss in adults with increasing prevalence worldwide. Increasing evidence has emphasized the importance of gut microbiome in the aetiology and development of DR. However, the causal relationship between gut microbes and DR remains largely unknown. To investigate the causal associations of DR with gut microbes and DR risk factors, we employed two-sample Mendelian Randomization (MR) analyses to estimate the causal effects of 207 gut microbes on DR outcomes. Inputs for MR included Genome-wide Association Study (GWAS) summary statistics of 207 taxa of gut microbes (the Dutch Microbiome Project) and 21 risk factors for DR. The GWAS summary statistics data of DR was from the FinnGen Research Project. Data analysis was performed in May 2023. We identified eight bacterial taxa that exhibited significant causal associations with DR (FDR < 0.05). Among them, genus Collinsella and species Collinsella aerofaciens were associated with increased risk of DR, while the species Bacteroides faecis, Burkholderiales bacterium_1_1_47, Ruminococcus torques, Streptococcus salivarius, genus Burkholderiales_noname and family Burkholderiales_noname showed protective effects against DR. Notably, we found that the causal effect of species Streptococcus salivarius on DR was mediated through the level of host fasting glucose, a well-established risk factor for DR. Our results reveal that specific gut microbes may be causally linked to DR via mediating host metabolic risk factors, highlighting potential novel therapeutic or preventive targets for DR.

A Pilot Study of Implementing Diabetic Retinopathy Screening in the Oslo Region, Norway: Baseline Results

PURPOSE

to gain insight into the baseline parameters of a population with diabetes mellitus (DM) included in a pilot diabetic retinopathy (DR) screening program at Oslo University Hospital (OUH), Norway.

METHODS

This was a cross-sectional study of a cohort of adult patients (≥18 years) with type 1 or 2 DM (T1D and T2D). We measured the best-corrected visual acuity (BCVA), blood pressure (BP), heart rate (HR), intraocular pressure (IOP), height and weight. We also collected HbA1c, total serum cholesterol and urine-albumin, -creatinine and -albumin-to-creatinine ratio (ACR), as well as socio-demographic parameters, medications and previous screening history. We obtained color fundus photographs, which were graded by two experienced ophthalmologists according to the International Clinical Disease Severity Scale for DR.

RESULTS

The study included 180 eyes of 90 patients: 12 patients (13.3%) had T1D and 78 (86.7%) had T2D. In the T1D group, 5 patients (41.7%) had no DR, and 7 (58.3%) had some degree of DR. In the T2D group, 60 patients (76.9%) had no DR, and 18 (23.1%) had some degree of DR. None of the patients had proliferative DR. Of the 43 patients not newly diagnosed (time of diagnosis > 5 years for T1D and >1 years for T2D), 37.5% of the T1D patients and 5.7% of the T2D patients had previously undergone regular screening. Univariate analyses found for the whole cohort significant associations between DR and age, HbA1c, urine albumin-to-creatinine ratio, body mass index (BMI) and duration of DM. For the T2D group alone, there were significant associations between DR and HbA1c, BMI, urine creatinine, urine albumin-to-creatinine ratio and duration of DM. The analysis also showed three times higher odds for DR in the T1D group than the T2D group.

CONCLUSIONS

This study underscores the need for implementing a systematic DR screening program in the Oslo region, Norway, to better reach out to patients with DM and improve their screening adherence. Timely and proper treatment can prevent or mitigate vision loss and improve the prognosis. A considerable number of patients were referred from general practitioners for not being followed by an ophthalmologist.Among patients not newly diagnosed with DM, 62.8% had never had an eye exam, and the duration of DM for these patients was up to 18 years (median: 8 years).

Patterns of risk for diabetic retinopathy in the Mumbai slums: The Aditya Jyot Diabetic Retinopathy in Urban Mumbai Slums Study (AJ-DRUMSS) Report 3

Diabetes onset precedes diabetic retinopathy (DR) by 5-10 years, but many people with diabetes remain free of this microvascular complication. Our aim was to identify risk factors for DR progression in a unique and diverse population, the slums of Mumbai. We performed a nested case-control study of 1163 diabetics over 40 years of age from slums in 18 wards of Mumbai. Data was collected on 33 variables and assessed for association with DR using both univariate and multivariate analyses. Stratified analyses were also performed on males and females, separately. Among hypertensive individuals we also assessed whether duration of hypertension associated with DR. Of 31 non-correlated variables analysed as risk factors for DR, 15 showed evidence of significant association. The most prominent included sex, where being a female associated with decreased odds of DR, while longer duration of diabetes and poor glycaemic control associated with increased odds. The duration of diabetes effect was partially, but significantly, mediated by age of diabetes diagnoses (8.6% of variance explained, p = 0.012). Obesity as measured by several measures, including body mass index (BMI) and measures of central obesity had a negative association with DR; increased measures of obesity consistently reduced odds of DR. As in most earlier studies, DR was associated with the duration of diabetes and glycaemic control. However, other factors, especially obesity related measures were associated with DR, in ways that contrast with most prior studies. These results indicated that the overall pattern of association in the Mumbai slums was novel. Thus, in previously uncharacterized populations, such as the slums that we examined, it is important to evaluate all risk factors de novo to appropriately assess patterns of association as the patterns of association with DR can be complex and population specific.

Neutrophil–lymphocyte ratio as a reliable marker to predict pre-clinical retinopathy among type 2 diabetic patients

Background

Diabetic retinopathy is now recognized as a neurovascular in lieu of a microvascular complication. Visual evoked potentials (VEPs) are greatly valuable in detecting early diabetic retinal functional changes before the occurrence of structural damage. Low-grade inflammation plays a fundamental part in the development and progression of retinopathy in diabetics. Detecting diabetic patients with early retinopathy before the occurrence of clinical symptoms provides a window of opportunity to ensure the best prognosis for these eyes. Neutrophil–lymphocyte ratio (NLR) has recently been introduced as a novel marker of inflammation in various diseases. Indeed, the presence of a cheap, available, and reliable marker of inflammation that is capable to detect pre-clinical diabetic retinopathy (P-DR) is crucial for early intervention to retard the progression of ocular damage. As far as we know no previous studies investigated the role of NLR in the detection of P-DR. The aim of this study was to investigate the quality of prediction of NLR in detecting pre-clinical retinopathy in type 2 diabetic patients.

Results

In this case–control study, VEPs results showed a significant delay in P100 latencies of the patients’ group compared to the control group. According to the VEPs results, the patient group was further subdivided into two: diabetic with VEPs changes (a group with P-DR) and diabetic without VEPs changes. NLR was significantly elevated in patients with P-DR (p < 0.001). NLR cut-off point ≥ 1.97 is able to predict P-DR with 89.29% sensitivity and 84.37% specificity. Linear regression model revealed that NLR is the only independent factor that predicts P-DR. (odds ratio 3.312; 95% confidence interval 1.262–8.696, p = 0.015*.

Conclusions

Visual evoked potentials have an important role to evaluate the visual pathway in diabetics and to diagnose pre-clinical diabetic retinopathy before the occurrence of structural damage. Neutrophil–lymphocyte ratio is a reliable marker for the detection of pre-clinical diabetic retinopathy with good sensitivity (89.29%) and specificity (84.37%). Finding a reliable available laboratory test to predict P-DR could be of help to save diabetic patients from serious ocular complications.

The Correlation between Waist Circumference and the Pro-Inflammatory Adipokines in Diabetic Retinopathy of Type 2 Diabetes Patients

Central obesity is one of the major risk factors for type 2 diabetes mellitus (DM), and the most common complication of DM is diabetic retinopathy. However, the exact relationship between obesity and DR remains unknown. In this study, we evaluate the effect of obesity on DR by comparing the aqueous humor-derived adipokines. For the analysis, 37 DR patients and 29 non-DR-patients participated. To evaluate the obesity of the patients, body mass index (BMI) and waist circumference (WC) were used. By comparing the concentrations of adipokines obtained from the aqueous humor of the two groups, the relationship between DR and adipokines was analyzed. In addition, by analyzing the correlation between obesity and adipokines in patients, the relationship between central obesity and DR was finally confirmed. The WC was significantly higher in patients than in the non-patient group. The concentrations of all adipokines compared in this study were significantly higher in the DR group than in the non-DM group (p < 0.05). Among them, adiponectin, leptin, TNF-α, Factor D (adipsin), lipocalin-2 (NGAL), Serpin E1 (PAI-1), and CXCL8 (IL-8) were confirmed to have a positive correlation with central obesity (defined as WC). These findings suggest that central obesity is strongly associated with the risk of DR.

Association of Obesity Indices with Diabetic Kidney Disease and Diabetic Retinopathy in Type 2 Diabetes: A Real-World Study

Background

Diabetic microvascular complications mainly include diabetic kidney disease (DKD) and diabetic retinopathy (DR). Obesity was recognized as a risk factor for DKD, while the reported relationship between obesity and DR was inconsistent. Moreover, whether the associations can be attributed to C-peptide levels is unknown.

Methods

Data from 1142 sequential inpatients with T2DM at Xiangyang Central Hospital between June 2019 and March 2022 were extracted retrospectively from the electronic medical record system. The associations between four obesity indices (body mass index (BMI), waist-hip circumference ratio (WHR), visceral fat tissue area (VFA), and subcutaneous fat tissue area (SFA)) and DKD and DR were evaluated. Whether the associations can be attributed to C-peptide levels was also explored.

Results

Obesity was a risk factor for DKD after adjusting for sex, HbA1c, TG, TC, HDL, LDL, smoking history, education, duration of diabetes, and insulin use (obesity indices: BMI (OR 1.050: 95% CI: 1.008-1.094; P = 0.020); WHR (OR 10.97; 95% CI: 1.250-92.267; P = 0.031); VFA (OR 1.005; 95% CI: 1.001-1.008; P = 0.008)), but it became insignificant after further adjusting for fasting C-peptide. The associations between BMI, WHR, VFA, and DKD might be U-shaped. Obesity and FCP tended to protect against DR; however, they became insignificant after adjusting for multiple potential confounders. C2/C0 (the ratio of the postprandial serum C-peptide to fasting C-peptide) was a protective factor for both DKD (OR 0.894, 95% CI: 0.833-0.959, P < 0.05) and DR (OR 0.851, 95% CI: 0.787-0.919; P < 0.05).

Conclusions

Obesity was a risk factor for DKD, and the effect may be attributable to C-peptide, which represents insulin resistance. The protective effect of obesity or C-peptide on DR was not independent and could be confounded by multiple factors. Higher C2/C0 was associated with both decreased DKD and DR.

Novel insights into the consequences of obesity: a phenotype-wide Mendelian randomization study

Obesity is thought to significantly impact the quality of life. In this study, we sought to evaluate the health consequences of obesity on the risk of a broad spectrum of human diseases. The causal effects of exposing to obesity on health outcomes were inferred using Mendelian randomization (MR) analyses using a fixed effects inverse-variance weighted model. The instrumental variables were SNPs associated with obesity as measured by body mass index (BMI) reported by GIANT consortium. The spectrum of outcome consisted of the phenotypes from published GWAS and the UK Biobank. The MR-Egger intercept test was applied to estimate horizontal pleiotropic effects, along with Cochran's Q test to assess heterogeneity among the causal effects of instrumental variables. Our MR results confirmed many putative disease risks due to obesity, such as diabetes, dyslipidemia, sleep disorder, gout, smoking behaviors, arthritis, myocardial infarction, and diabetes-related eye disease. The novel findings indicated that elevated red blood cell count was inferred as a mediator of BMI-induced type 2 diabetes in our bidirectional MR analysis. Intriguingly, the effects that higher BMI could decrease the risk of both skin and prostate cancers, reduce calorie intake, and increase the portion size warrant further studies. Our results shed light on a novel mechanism of the disease-causing roles of obesity.

The Prevalence and Risk Factors of Diabetic Retinopathy: Screening and Prophylaxis Project in 6 Provinces of China

PURPOSE

To investigate the prevalence and associated factors of diabetic retinopathy (DR) and advanced DR in Chinese adults with diabetes mellitus (DM).

PATIENTS AND METHODS

A cross-sectional study was performed on 4831 diabetic patients from 24 hospitals from April 2018 to July 2020. Non-mydriatic fundus of patients were interpreted by an artificial intelligence (AI) system. Fundus photos that were unsuitable for AI interpretation were interpreted by two ophthalmologists trained by one expert ophthalmologist at Beijing Tongren Hospital. Medical history, height, weight, body mass index (BMI), glycosylated hemoglobin (HbA1c), blood pressure, and laboratory examinations were recorded.

RESULTS

A total of 4831 DM patients were included in this study. The prevalence of DR and advanced DR in the diabetic population was 31.8% and 6.6%, respectively. In multiple logistic regression analysis, male (odds ratio [OR], 1.39), duration of diabetes (OR, 1.05), HbA1c (OR, 1.11), farmer (OR, 1.39), insulin treatment (OR, 1.61), region (northern, OR, 1.78; rural, OR, 6.96), and presence of other diabetic complications (OR: 2.03) were associated with increased odds of DR. The factors associated with increased odds of advanced DR included poor glycemic control (HbA1c >7.0%) (OR, 2.58), insulin treatment (OR, 1.73), longer duration of diabetes (OR, 3.66), rural region (OR, 4.84), and presence of other diabetic complications (OR, 2.36), but overweight (BMI > 25 kg/m²) (OR, 0.61) was associated with reduced odds of advanced DR.

CONCLUSION

This study shows that the prevalence of DR is very high in Chinese adults with DM, highlighting the necessity of early diabetic retinal screening.

Higher Serum Uric Acid Levels Are Associated With an Increased Risk of Vision-Threatening Diabetic Retinopathy in Type 2 Diabetes Patients

Purpose

To investigate the association between serum uric acid (SUA) levels and vision-threatening diabetic retinopathy (VTDR) in patients with type 2 diabetes.

Methods

This cross-sectional study evaluated 3481 patients with type 2 diabetes from four communities in China between 2016 and 2019. VTDR was defined as severe nonproliferative, proliferative diabetic retinopathy, or clinically significant macular edema evaluated by fundus photography and optical coherence tomography. Potential association between SUA and VTDR was examined using multivariable logistic regression. Sub-group analyses based on sex were constructed.

Results

A total of 305 participants had VTDR. Both higher SUA (odds ratio [OR], 1.22 per 100 µmol/L; 95% confidence interval [CI], 1.04–1.44; P = 0.013) and hyperuricemia (OR, 1.47; 95% CI, 1.07–2.04; P = 0.019) were positively associated with VTDR after adjustment for relevant covariates. Compared with those in the lowest SUA quartile, participants in the third (OR, 1.60; 95% CI, 1.07–2.39; P = 0.022) and fourth (OR, 2.05; 95% CI, 1.37–3.08; P = 0.001) sex-specific SUA quartiles showed a significantly increased risk of VTDR after adjustment. No sex-related difference was observed.

Conclusions

Higher SUA levels were associated with an increased risk of VTDR in patients with type 2 diabetes in both sexes, although females seemed to be more sensitive to high SUA than males. Prospective cohort studies are needed to verify SUA as a biomarker for predicting the risk of VTDR. Whether decreased SUA levels could decrease the risk of VTDR also requires further investigation.

Differential associations between body mass index with diabetes and vision-threatening diabetic retinopathy in an adult Chinese population

PURPOSE

To investigate the associations between body mass index (BMI) with diabetes mellitus (DM) and vision-threatening diabetic retinopathy (VTDR).

METHODS

This was a longitudinal study which included DM-free participants aged ≥40 years from the Lingtou Eye Cohort Study at baseline (2008-2010). Physical and ocular examinations were performed at baseline and annual follow-ups under standardised protocol. Two 45° non-mydriatic colour digital retinal photographs were obtained for each eye at all study visits, and presence of VTDR at the 2016 follow-up was graded by a deep-learning algorithm (LableMe) with proved high accuracy for detection of VTDR.

RESULTS

A total of 2934 participants were included with a mean (SD) age of 59.5 (7.3) years (58.3% men). Participants with incident DM (441/2934, 15%) were significantly older (p<0.001), had higher obesity levels (p<0.001), higher systolic blood pressure (SBP) (p<0.001), diastolic blood pressure (p<0.001), fasting plasma glucose (FPG) (p<0.001), triglycerides (p=0.002) and high-density lipoprotein cholesterol (p<0.001), as compared with those without. Participants with incident VTDR (48/2934, 1.63%) were also older (p<0.001), had higher SBP (p=0.013) and FPG (p<0.001), but did not differ in baseline BMI, comparing with those without. Regression analysis showed that higher baseline BMI was significantly related to incident DM (p<0.005), but not incident VTDR, during the follow-up. Subgroup analysis among participants with incident DM also revealed no association between BMI and VTDR.

CONCLUSIONS

Higher baseline BMI increased the risk of incident DM, but was not related to the risk of VTDR in this adult Chinese population.

Associations between obesity and metabolic health with nonalcoholic fatty liver disease in elderly Chinese

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity. However, this association could be influenced by the coexisting metabolic abnormalities. This study aimed to investigate the role of obesity and metabolic abnormalities in NAFLD among elderly Chinese.

METHODS

A cross-sectional study was performed among elderly residents who took their annual health checkups during 2016 in Keqiao District, Shaoxing, China.

RESULTS

A total of 3359 elderly adults were retrospectively included in this study. The overall prevalence of NAFLD was 28.7%. The prevalence of NAFLD were 7.14%, 27.92%, 34.80%, and 61.02% in participants with metabolically healthy normal weight (MHNW), metabolically abnormal normal weight (MANW), metabolically healthy obese (MHO), and metabolically abnormal obese (MAO), respectively. NAFLD patients in MHO group had more unfavorable metabolic profiles than those in MHNW group. Logistic regression analysis showed that sex, body mass index (BMI), fasting blood glucose, and serum uric acid were the risk factors of NAFLD.

CONCLUSIONS

Both obesity and metabolic health were significantly associated with NAFLD in elderly Chinese. Screening for obesity and other metabolic abnormalities should be routinely performed for early risk stratification of NAFLD.

Combination of leflunomide and benazepril reduces renal injury of diabetic nephropathy rats and inhibits high-glucose induced cell apoptosis through regulation of NF-κB, TGF-β and TRPC6

Objective: To investigate effects of combination use of leflunomide and benazepril on diabetic nephropathy (DN) both in vivo and in vitro.

Methods: The streptozotocin (STZ) induced Sprague-Dawley rats were treated with leflunomide (15 mg/kg/d), benazepril (15 mg/kg/d) or both the two drugs. Fasting blood glucose (FBG) and renal function indexes including blood urea nitrogen (BUN), serum creatinine (Scr), and proteinuria and kidney/body weight ratio (KW/BW) were measured. HE staining was used for histological analysis. The rat glomerular mesangial cells (RMCs) were treated with high-glucose (150 mg/ml) and the leflunomide and benazepril with both concentrations of 50 μmol/l were used to treat the high-glucose induced cells. TUNEL assay was used for measurement of cell apoptosis. Western blotting was conducted to determine expression of nuclear factor Kappa B (NF-κB), transforming growth factor-β (TGF-β) and transient receptor potential canonical 6 (TRPC6).

Results: The body weight was significantly lower and all indexes of FBG, BUN, Scr, proteinuria and KW/BW ratio, GFR, as well as inflammatory factors TNF-α and IL-6 were significantly increased in the DN group after STZ treatment for 4 weeks. The treatment with leflunomide, benazepril or the both dramatically reduced the above effects induced by STZ, and the alteration was the most significant in the combination group. Treatment of leflunomide and benazepril significantly reduced expression levels of NF-κB, TGF-β and TRPC6 in renal tissues of DN rats as well as in high-glucose induced RMCs. It was also observed leflunomide and benazepril reduced high-glucose induced cell apoptosis of RMCs.

Conclusion: The combination use of leflunomide and benazepril could improve the renal function and reduce the renal injury of DN rats and could reduce the levels of NF-κb, TGF-β and TRPC6 in both DN rats and high-glucose induced RMCs.

Influence of Diabetic Retinopathy on the Relationship Between Body Mass Index and Mortality in Patients with Poorly Controlled Type 2 Diabetes

PURPOSE

An "obesity paradox" has been observed in patients with type 2 diabetes. However, the optimal body mass index (BMI) for survival may be influenced by the stage of diabetes. We examined the relationship between BMI and mortality in patients with type 2 diabetes and the influence of diabetic retinopathy (DR).

PATIENTS AND METHODS

This is a retrospective cohort composing patients with type 2 diabetes who were admitted due to poor glucose control. Presence of DR was confirmed by ophthalmologists. The primary outcome was all-cause mortality. The association between BMI and mortality was assessed using a Cox proportional hazards model with adjustment for age, sex, and traditional risk factors.

RESULTS

A total of 2053 patients were enrolled. Over median follow-up of 6.7 years, there were 1060 deaths. Patients were classified into five categories based on admission BMI (kg/m²): <18.5, 18.5‒23, 23‒25, 25‒27 (reference), 25‒30 and >30. Mortality risk was significantly higher in the <18.5 kg/m², 18.5-23 kg/m², and 23-25 kg/m² categories than in the reference category (P <0.001). The similar obesity paradox was observed in the subgroup of patients without DR. However, in patients with DR, only patients with BMI <18.5 kg/m² had significantly increased mortality than those in the reference category. The presence of DR significantly modified the shape of the association between BMI and mortality (P = 0.019).

CONCLUSION

The obesity paradox exists in patients with poorly controlled type 2 diabetes. The presence of DR appears to significantly influence the shape of the association between BMI and mortality.

Nomogram for the Risk of Diabetic Nephropathy or Diabetic Retinopathy Among Patients with Type 2 Diabetes Mellitus Based on Questionnaire and Biochemical Indicators: A Cross-Sectional Study

PURPOSE

This study aimed to develop a diabetic nephropathy (DN) or diabetic retinopathy (DR) incidence risk nomogram in China's population with type 2 diabetes mellitus (T2DM) based on a community-based sample.

METHODS

We carried out questionnaire evaluations, physical examinations and biochemical tests among 4219 T2DM patients in Shanghai. According to the incidence of DN and DR, 4219 patients in our study were divided into groups of T2DM patients with DN or DR, patients with both, and patients without any complications. We successively used least absolute shrinkage and selection operator regression analysis and logistic regression analysis to optimize the feature selection for DN and DR. To ensure the accuracy of the results, we carried out multivariable logistic regression analysis of the above significant risk factors on the sample data for both DN and DR. The selected features were included to establish a prediction model. The C-index, calibration plot, curve analysis and internal validation were used to validate the distinction, calibration, and clinical practicality of the model.

RESULTS

The predictors in the prediction model included disease course, body mass index (BMI), total triglycerides (TGs), systolic blood pressure (SBP), postprandial blood glucose (PBG), haemoglobin A1C (HbA1c) and blood urea nitrogen (BUN). The model displayed moderate predictive power with a C-index of 0.807 and an area under the receiver operating characteristic curve of 0.807. In internal verification, the C-index reached 0.804. The risk threshold was 16-75% according to the analysis of the decision curve, and the nomogram could be applied in clinical practice.

CONCLUSION

This DN or DR incidence risk nomogram incorporating disease course, BMI, TGs, SBP, PBG, HbA1c and BUN can be used to predict DN or DR incidence risk in T2DM patients. The research team has developed an online app based on a clinical prediction model incorporating risk factors for rapid and simple prediction.

Is central obesity associated with diabetic retinopathy in Chinese individuals? An exploratory study

Objective

To our knowledge, the independent association between central obesity, defined by waist circumference (WC) or waist-to-hip ratio (WHR), and diabetic retinopathy (DR) remains unknown in Chinese individuals.

Method

The study was conducted in two stages. First, the relationship between WC or WHR and DR was estimated in a case-control set (DR vs. non-DR) for the whole population before and after propensity score matching. Subsequently, a systematic review and meta-analysis was performed on evidence from the literature to validate the relationship.

Results

Of 511 eligible patients, DR (N = 156) and non-DR (N = 156) patients with similar propensity scores were included in the propensity score matching analyses. Central obesity (defined by WC) was associated with risk of DR (odds ratio [OR] 1.07, 95% confidence interval [95% CI] (1.03–1.10). The meta-analysis showed that central obesity significantly increased the risk of DR by 12% (OR 1.12, 95% CI 1.02–1.22). Analysis of data from 18 studies showed a significant association between continuous body mass index and risk of proliferative DR (OR 0.95, 95% CI 0.93–0.98; I² = 50%).

Conclusion

Central obesity, particularly as defined by WC, is associated with the risk of DR in the Chinese population.

Relationship between body fat and diabetic retinopathy in patients with type 2 diabetes: a nationwide survey in Korea

PURPOSE

To evaluate the association of body mass index (BMI), waist circumference, and body fat with diabetic retinopathy (DR) in Korean patients with type 2 diabetes.

METHODS

Among the 1130 participants 19 years of age or older with type 2 diabetes enrolled in the nationwide survey, a total of 887 participants were included in the analyses after excluding patients with ungradable fundus images. The presence and severity of DR were graded with seven-field fundus photographs. The associations between DR and anthropometric parameters and total body fat, which was assessed by dual-energy X-ray absorptiometry, were analysed using multivariate logistic regression models.

RESULTS

Patients were divided into three groups according to severity of DR: no DR (n = 702, 79.1%), mild/moderate DR (n = 130, 14.7%), and vision-threatening DR (n = 55, 6.2%). In multivariate-adjusted analyses, higher BMI (adjusted odds ratio [aOR], 0.80; 95% confidence interval [CI], 0.70-0.92; P = 0.001), larger waist circumference (aOR, 0.96; 95% CI, 0.91-1.00; P = 0.047), and higher total body fat (aOR, 0.86; 95% CI, 0.79-0.92; P < 0.001) were significantly associated with a lower risk of vision-threatening DR. In sex-stratified analyses, however, only total body fat in women showed a significant inverse association with the presence of DR (aOR, 0.93; 95% CI, 0.88-0.98; P < 0.001) and independently with the severity of DR (P for trend = 0.004).

CONCLUSION

In Korean patients with type 2 diabetes, obese patients might be less likely to have vision-threatening DR. Total body fat in women appears to be inversely and independently associated with DR prevalence and progression.

Does diabetes increase the risk of periodontitis? A systematic review and meta-regression analysis of longitudinal prospective studies

AIM

Even though the association between diabetes and periodontitis is taken for granted, results on this association are conflicting within the literature. This systematic review assessed whether poorly controlled diabetes was associated with periodontitis onset or progression.

METHODS

Electronic searches were performed in PubMed, Scopus and Embase databases. Hand search was carried out in the reference list of all articles included. Gray literature was investigated with a Google Scholar search. Prospective longitudinal studies on the association between diabetes and periodontitis were considered for this review. Studies should have presented at least two measurements of periodontal conditions over time. Data on study design, crude and adjusted estimates were collected. We used meta-analysis to estimate the pooled effect of hyperglycemia in people with diabetes on periodontitis onset or progression. Meta-regression and subgroup analyses were employed to investigate potential sources of heterogeneity between studies.

RESULTS

Thirteen studies matched the inclusion criteria, comprising 49,262 individuals, including 3197 diagnosed with diabetes. Meta-analyses of adjusted estimates showed that diabetes increased the risk of incidence or progression of periodontitis by 86% (RR 1.86 [95% CI 1.3-2.8]). However, there is scarce information on the association between diabetes and periodontal destruction.

CONCLUSIONS

This study provides evidence that diabetes is associated with increased risk of periodontitis onset and progression in adults. Upcoming prospective longitudinal studies ought to overcome methodological caveats identified in this review.

Is there a relationship between body mass index and diabetic retinopathy in type II diabetic patients? A cross sectional study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is one of the most important leading causes of disability, premature mortality and Diabetic Retinopathy (DR) that is one of the diabetes-related complications in diabetic patients and the most common cause of vision loss in diabetic patients. The aim of the study was to evaluate the association between DR and body mass index (BMI) in those patients with T2DM.

METHODS

This was a central-based, cross-sectional study on 518 diabetic patients. Their medical history and the laboratory data were collected. All the patients received examination of diabetic retinopathy by professional ophthalmologist. Based on their optic fundi findings, they were classified into five groups: No retinopathy, Mild Non-proliferative Diabetic Retinopathy (NPDR), Moderate NPDR, Severe NPDR, Proliferative diabetic retinopathy (PDR). To analysis data SPSS v18 software used. Frequency, percent, mean and standard deviation were used for population description. t test, spearman correlation, partial correlation, analysis of variance (ANOVA) and Chi-square test (χ2) were used for analytic analysis. Multivariate logistic regression was used to estimate the odds ratio.

RESULTS

518 patients with T2DM 198 male (38%), 320 female (62%) included in this study. The mean age of patients was 61.02 ± 10.18 years. The mean age at onset was 49.06 + 10.52 years and the mean duration of diabetes was 12.09 ± 7.81 years. There was a strong relationship between duration of diabetes and DR (P = 0.001). There were strong significant association between the development of DR and Insulin therapy (OR = 5.975). Correlation analysis between Retinopathy and BMI showed that BMI had inverse relationship with DR when BMI considered as a continuous variable (p-value = 0.009 and correlation coefficient = -0.467).

CONCLUSION

BMI in diabetic patient is one of the most important clinical parameter for their health and disease progression. We conclude that BMI had inverse relationship with DR when BMI considered as a continuous variable.

Progression of diabetic retinopathy severity after treatment with dexamethasone implant: a 24-month cohort study the 'DR-Pro-DEX Study'

PURPOSE

Intravitreal anti-vascular endothelial growth factor agents have been shown to reduce diabetic retinopathy (DR) progression; data on the effects of intravitreal corticosteroids on modifying disease severity are limited. This study evaluates the long-term effect of intravitreal dexamethasone implant (DEX) on the severity and progression of non-proliferative DR (NPDR).

METHODS

This was a retrospective cohort study. Sixty eyes from 60 consecutive patients with NPDR and diabetic macular edema (DME) treated with dexamethasone implant (DEX group) and 49 eyes from consecutive 49 patients without DME requiring observation only. Fundus angiography images from baseline and after 24 months were graded by two masked assessors into mild, moderate and severe NPDR and PDR, according to the ETDRS classification. Patients were followed up 1-3 and 4-6 months after each DEX implant. Re-treatment with DEX implant was on a pro re nata basis. Records were reviewed for performance of panretinal photocoagulation. Main outcome was as follows: change of DR ≥ 1 grade and progression to proliferative diabetic retinopathy (PDR).

RESULTS

Three eyes (5%) in the DEX group and 43 (87.8%) eyes in the control group progressed to PDR (P < 0.0001). Twenty-five eyes (41.7%) in the DEX group but none in the control group demonstrated an improvement in DR severity (P < 0.0001).

CONCLUSION

This study provides the first long-term evidence that DEX implant has the potential to not only delay progression of DR and PDR development, but may also improve DR severity over 24 months. Better understanding of the effects of corticosteroids will help guide its use in the treatment pathway of DR.

HbA1c is Positively Associated with Serum Carcinoembryonic Antigen (CEA) in Patients with Diabetes: A Cross-Sectional Study

INTRODUCTION

To explore the influence of glycemic levels on the serum carcinoembryonic antigen (CEA) levels in patients with diabetes.

METHODS

This is a cross-sectional study. Patients with diabetes aged 18-75 years old were recruited. Those patients with carcinoma, abnormal renal function (serum creatinine ≥ 115 μmol/l), and abnormal hepatic function (serum alanine aminotransferase ≥ 97.5 U/l) were excluded in this study. Blood samples were obtained from every patient after an overnight fasting, and CEA was determined using a chemiluminescent particle immunoassay.

RESULTS

A total of 324 patients with type 1 diabetes and 3019 patients with type 2 diabetes were included in this study. Patients with type 1 diabetes had higher levels of HbA1c (9.5% vs. 8.7%) and CEA (2.79 vs. 2.34 ng/ml), but lower fasting C peptide (0.72 vs. 1.71 ng/ml) than those with type 2 diabetes (all P < 0.001). Data indicated that CEA was higher in patients with smoking, drinking, older age, higher levels of HbA1c, and lower level of fasting C peptide (all P < 0.05). Multiple linear regression analysis indicated that CEA was independently associated with smoking, age, BMI, and HbA1c (all P < 0.05).

CONCLUSION

HbA1c was positively associated with the levels of CEA in patients with diabetes. More studies are warranted to investigate whether elevated CEA is associated with increased carcinoma risk in patients with diabetes.

Prevalence and associated factors of diabetic retinopathy in Beijing, China: a cross-sectional study

OBJECTIVES

The study aimed to determine the exact risk factors for diabetic retinopathy (DR) in the Chinese population using a cohort of 17  985 individuals from Beijing, China.

DESIGN

Cross-sectional study.

SETTING

A hospital.

PARTICIPANTS

17  985 individuals from Beijing, China.

PRIMARY AND SECONDARY OUTCOME MEASURES

This was a cross-sectional study of permanent residents from the Changping area (Beijing, China) recruited from July 2010 to March 2011 and from March 2014 to February 2015 during a routine health examination at the Tongren Hospital of Beijing. Eye examinations were conducted by experienced ophthalmologists. Medical history, height, weight, body mass index (BMI) and blood pressure were recorded. Routine laboratory examinations were performed.

RESULTS

The prevalence of DR was 1.5% in the general study population and 8.1% among individuals with diabetes. Compared with the non-DR group, individuals in the DR group in the diabetes population had longer disease duration, higher systolic blood pressure (SBP), fasting plasma glucose (FPG) and uric acid (UA) (in men) and lower UA (in women) (all p<0.05). The multivariate analysis showed that disease duration (p<0.001), BMI (p=0.046), SBP (p=0.012), creatinine clearance rate (CCR) (p=0.014), UA (p=0.018) and FPG (p<0.001) were independently associated with DR in patients with diabetes.

CONCLUSION

The prevalence of DR was 8.1% among patients with diabetes. Disease duration, BMI, SBP, CCR, UA and FPG were independently associated with DR.

Optical coherence tomography angiography analysis of retinal vascular plexuses and choriocapillaris in patients with type 1 diabetes without diabetic retinopathy

AIMS

To analyze retinal vascular plexuses and choriocapillaris by optical coherence tomography angiography (OCT-A) and retinal nerve fiber layer and ganglion cell layer (GCL) by structural optical coherence tomography (OCT) in patients with type 1 diabetes mellitus (T1DM) without diabetic retinopathy (DR).

METHODS

A total of 25 eyes of 25 consecutive T1DM patients without signs of DR were prospectively recruited and compared to 25 healthy subjects (control eyes). All patients underwent OCT-A (CIRRUS HD-OCT model 5000, Carl Zeiss Meditec, Dublin, CA) and structural OCT. Qualitative and quantitative analyses with vessel density were performed on OCT-A images in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris for all patients.

RESULTS

By means of OCT-A, a rarefaction of the perifoveal capillary network in SCP was detected in 7 out of 25 eyes. No significant difference was found in FAZ area of both SCP and DCP comparing diabetic and control groups. By analyzing the DCP, diabetic eyes revealed a significant decreased vessel density compared to control eyes [0.464 ± 0.016 and 0.477 ± 0.014, respectively (p = 0.005)]. Instead, no significant difference was found in the vessel density of all-retina plexus, SCP and choriocapillaris. By RFNL and GCL thickness analysis, no significant differences were disclosed between diabetics and healthy subjects.

CONCLUSIONS

We demonstrated the ability of OCT-A to disclose early vascular alterations in patients with T1DM diagnosed as without any signs of DR on the basis of fundus biomicroscopy. Our results also suggest that microvascular changes could precede detectable damage of diabetic neuroretinopathy.

Body mass index and risk of diabetic retinopathy: A meta-analysis and systematic review

Diabetic retinopathy (DR) is a frequent cause of acquired blindness worldwide. Various studies have reported the effects of body mass index (BMI) on the risk of DR, but the results remain controversial. Therefore, a meta-analysis was performed to evaluate the relationship between BMI and the risk of DR.A systematic search was performed using the Cochrane Library, PubMed, and Embase databases to obtain articles published through December 2016. Articles regarding the association between BMI and the risk of DR were retrieved. The adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) were included and then pooled with a random effects model.A total of 27 articles were included in this meta-analysis. When BMI was analyzed as a categorical variable, neither being overweight (OR = 0.89, 95% CI 0.75-1.07; P = .21; I = 65%) nor obesity (OR = 0.97, 95% CI 0.73-1.30; P = .86) were associated with an increased risk of DR when compared with normal weight. When BMI was analyzed as a continuous variable, a higher BMI was not associated with an increased risk of DR (OR = 0.99, 95% CI 0.97-1.01; P = .25; I2 = 79%). The pooled results did not significantly change after the sensitivity analysis.Based on the current publications, neither being overweight nor obesity is associated with an increased risk of DR. Further studies should confirm these findings.

Retinal neurodegeneration in patients with type 1 diabetes mellitus: the role of glycemic variability

AIMS

Recent studies have identified neuroretinal abnormalities in persons affected by diabetes mellitus, before the onset of microvascular alterations. However, the role of glycemic variability (GV) on early retinal neurodegeneration is still not clarified.

METHODS

To explore the relationship between glycemic control and neuroretinal characteristics, 37 persons with Type 1 diabetes mellitus (Type 1 DM) divided into two groups with no signs (noRD) and with mild non-proliferative diabetic retinopathy (NPDR) compared to 13 healthy control participants (C) were recruited. All persons underwent an optical coherence tomography with automatic segmentation of all neuroretinal layers. Measurements of mean of nasal (N)/temporal (T)/superior (S)/inferior (I) macular quadrants for individual layer were also calculated. Metabolic control was evaluated by glycated hemoglobin (HbA1c), and indexes of GV were calculated from continuous glucose monitoring.

RESULTS

The difference among the three groups in terms of RNFL thickness was significantly dependent on quadrant (F(6;132) = 2.315; p = 0.037). This interaction was due to a specific difference in RNFL-N thickness, where both Type 1 DM groups showed a similar reduction versus C (-3.9 for noDR and -4.9 for NPDR), without any relevant difference between them (-1.0). Inner nuclear layer (INL) was increased in all quadrants in the two Type 1 DM groups compared to C (mean difference = 7.73; 95% CI: 0.32-15.14, p = 0.043; mean difference = 7.74; 95% CI: 0.33-15.15, p = 0.043, respectively). A negative correlation between RNFL-N and low blood glucose index (r = -0.382, p = 0.034) and positive correlation between INL and continuous overall net glycemic action -1, -2, -4 h (r = 0.40, p = 0.025; r = 0.39, p = 0.031; r = 0.41, p = 0.021, respectively) were observed in Type 1 DM patients. The triglycerides were positively and significantly correlated to INL (r = 0.48, p = 0.011), in Type 1 DM subjects. GV and triglycerides resulted both independent predictors of increased INL thickness. No correlation was found with HbA1c.

CONCLUSIONS

Early structural damage of neuroretina in persons with Type 1 DM patients is related to glucose fluctuations. GV should be addressed, even in the presence of a good metabolic control.

TLR4 is a link between diabetes and Alzheimer's disease

Recently, more and more studies have shown that there is an essential link between diabetes mellitus (DM) and Alzheimer's disease (AD). In addition, innate immunity plays an important role in the occurrence and development of DM and AD, which increase the risk of developing type 2 diabetes (T2D) and AD. Although the pathogenesis of those diseases is still a matter of debate, the important role of Toll-like receptor 4 (TLR4) in the two diseases has been receiving much attention at present. TLR4 and insulin resistance do have close ties, and chronic TLR4 activation may contribute to the insulin resistance. Aside from this, TLR4-mediated chronic inflammation also causes many DM complications such as diabetic nephropathy, diabetic retinopathy and diabetic neuropathy and has a profound impact on the internal environment of the body and brain's microenvironment. In parallel, TLR4 is widely distributed in the brain and also has an important role in the central nervous system (CNS) via regulation of neuroinflammation. The cerebrum under the circumstances of insulin resistance may lead to mitochondrial dysfunction in neurons. Interestingly, in the initial stage, the activation of TLR4 has a useful scavenging effect on amyloid beta (Aβ), but chronic long-term activation leads to Aβ deposition in the brain. Therefore we speculate that the TLR4 signaling pathway may be a potential link between DM and AD.

The association of peroxisome proliferator-activated receptor α with diabetic retinopathy, and additional gene-obesity interaction in Chinese type 2 diabetes mellitus patients

AIMS

To investigate the impact of peroxisome proliferator-activated receptor α (PPAR α) SNPs and gene-obesity interaction on diabetic retinopathy (DR) susceptibility in a Chinese Han population.

METHODS

A total of 812 patients (373men, 439 women) with type 2 diabetes mellitus (T2DM), with a mean age of 53.3±14.0 years old, were selected, including 402 diabetic retinopathy patients and 410 controls. Three single nucleotide polymorphisms (SNPs) were selected for genotyping in the case-control study: rs4253778, rs135539 and rs1800206. Generalised multifactor dimensionality reduction (GMDR) and logistic regression model was used to examine the association and interaction between SNP and obesity on DR, odds ratio (OR) and 95% confident interval (95%CI) were calculated.

RESULTS

The carriers of homozygous mutant of rs1800206 SNP revealed decreased DR risk than those with wild-type homozygotes, OR (95%CI) was 0.78 (0.66-0.94). GMDR analysis indicated a significant two-locus model (p=0.0107) involving rs1800206 and abdominal obesity, indicating a potential interaction among rs1800206 and abdominal obesity. Overall, the two-locus models had a cross-validation consistency of 10 of 10, and had the testing accuracy of 60.72%. We also found that subjects with abdominal obesity and LV or VV genotype have lowest DR risk, compared to subjects with normal WC and LL genotype, OR (95%CI) was 0.39 (0.30-0.74), after covariates adjustment.

CONCLUSIONS

Our results support an important association between rs1800206 minor allele of PPAR α and DR, and the interaction analysis also shown a combined effect of Leu162 allele-abdominal obesity interaction on DR.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.