Epidemiological Study Of Diabetic Retinopathy In Dongguan City,Guangdong Province

Diabetic retinopathy(DR) is the leading cause of blindness among working-aged adults around the world and one of the main causes of binocular blindness in elderly patients in the developed world.DR has become a serious global public and economic problems. As the prevalence of DM increases and patients live longer in China, the development of DR as a microvascular complication of DM also rises.In mainland China,the total number of people with DM is projected to rise from43.157million in2010to62.253million in2030.The prevalence of DM in economically developed areas in China is close to the developed countries,such as Beijing, Shanghai and the Pearl River Delta.Many previous reports have shown the higher rates of DR in population-based studies in Beijing, Handan Hebei province and Shanghai. These data is important for the formulation of public health policy and allocation of health resources in these area.The occurrence and development of diabetes is influenced by many factors, such as living habits, geographical distribution, economic level and environmental factors.In addition, because of complex mechanism of diabetes, the reasons of low vision and blindness in diabetes mellitus(DM) also has its particularity. Thirty years of reform and opening up, the economy has been developing rapidly in the Pearl River Delta region, including Dongguan.Accelerating the process of urbanization and better conditions of the public health have markedly improved the living condition of people.However, urbanization is associated with changes in lifestyle that lead to physical inactivity,an unhealthful diet(high-calorie, high fat and low fiber), and obesity, all of which have been implicated as contributing factors in the development of diabetes.There are limited researches on DR in the Southern areas in China, especially population-based studies in Guangdong province. Therefore,in order to identify the prevalence and risk factors of DM and DR in economically developed areas in Guangdong, grasp the reasons of blind and low vision in DM patients, we carried out this population-based study which was divided into four parts:Part1Rationale,Methodology, and Baseline Date for a Pupulation-based Study of Eye Dieases in Hengli town, Dongguan city, Guangdong provincePurpose:To describe the rationale and study design of a population-based study of eye dieases in permanent residents aged40years and older in Hengli town, Dongguan city in Southern China. Focus on the prevalence of diabetic retinopathy and blindness and low vision in diabetic patients. Methods:A population-based cross-sectional study. Public Security Bureau provided a list of15987residents aged40years and older from16villages and1community in Hengli town. Excluded4806no long-term residents(more than3years) living in Hengli town due to move outside Hengli town, work outside, immigration to HongKong or abroad and no answer to the telephone survey, the eligible permanent residents is11181people who were invited to the investigation sites by letter, telephone and home visits by village committee staff. Participants underwent standardized interview, physical and ocular examinations including:general message(name, gender and age), social and economic situation(occupation, education level, income), the questionnaire of diabetes and diabetic retinopathy, anthropometry(measurement of height, weight, BMI, waist circumference, hip circumference, waist to hip ratio, body surface area, blood pressure and heart rate), Laboratory examination(fast blood-glucose, OGTT, glycosylated hemoglobin, blood lipid level and urea nitrogen, serum creatinine and blood uric acid). Ocular examination included presenting visual acuity(PVA),best corrected visual acuity(BCVA), intraocular pressure(IOP), anterior and posterior segment examinations, fundus and optic disc photography. Selected participants underwent gonioscopy, visual field testing and optical coherence tomography(OCT). Results:Of11181eligible persons,8592(response rate:80.06%)were examined Among8952participants,3594men (40.1%),5358females (59.9%), mean age55.31±11.44years, Han Chinese(100%). We conducted a telephone survey of2229people who did not participate in the field investigation,1612participates in telephone survey with a response rate of72.32%. Conclusions:This study provides population-based data on major eye condition, the prevalence and risk factors of DR and visual impairment in diabetic patients in Han Chinese in Southern China.Part2Prevalence of Diabetic retinopathy in a Southern Chinese Population with Diabetes Mellitus in Dongguan city, Guangdong ProvincePurpose:To describe the prevalence of DR, diabetic macular edema(DME), clinically significant macular edema(CSME) and vision-threaten diabetic retinopathy (VTDR) in Hengli town, Dongguan city in Southern China. Methods:A population-based cross-sectional study. A total of8952Han Chinese from16villages and a community participated in the census of diabetes. Participants underwent standardized interview, physical and laboratory examination. Ocular examination included PVA and BCVA, IOP, anterior and posterior segment examinations, fundus and optic disc photography. The diagnosis of DM and DR were made according to American Diabetes Association (ADA,2010) for diabetes and international clinical classification system of DR and DME(Sydney,2002).Results:1508participants were diagnosed with diabetes mellitus in field investigation, and69diabetic patients were screened out from the telephone survey. The prevalence of diabetes mellitus was17.62%. Among1508diabetic patients,1500were type2diabetes mellitus (T2DM),1072(71.09%) were newly diagnosed and436(28.91%) subjects with known diabetes mellitus(DM). The age and gender standardized prevalence of DR was18.20%in total DM,12.64%in newly diagnosed DM patients and32.87%in patients with known DM. The standardized prevalence of NPDR and PDR was17.33%and0.92%. The age and gender standardize prevalence of DME, CSME and VTDR were2.54%,0.88%and2.62%, respectively. Conclusions:Our study shows a higher rate of DM and a lower prevalence of DR in Southern China. Newly diagnosed DM patients are the majority, accounting for71.09%. NPDR was more common. There is a strong requirement for screening, prevention and treatment to control for DR.Part3Risk Factors for Diabetic Retinopathy in a Southern Chinese Population with Type2Diabetes Mellitus in Dongguan City, Guangdong ProvincePurpose:To describe risk factors associated with DR in type2diabetes mellitus(T2DM) patients aged40years and older in Hengli town, Dongguan city in Southern China. Methods:A population-based cross-sectional study. A total of8952Han Chinese from16villages and a community participated in the census of diabetes. Participants underwent standardized interview, physical and laboratory examination. Ocular examination included PVA and BCVA, IOP, anterior and posterior segment examinations, fundus and optic disc photography. The diagnosis of DM and DR were made according to ADA diagnostic criteria (American,2010) for diabetes and international clinical classification system of DR and DME(Sydney,2002). Univariate and stepwise logistic regression analysis were used to identify independent risk factors. Results:Stepwise logistic regression analysis revealed that male, longer duration of DM, systolic pressure,hyperglycemia and glycosylated hemoglobin were the independent risk factors of DR. Compared with females, males had a higher risk of having any DR,OR=1.914[95%CI(1.382-2.651)].Compared with newly diagnosed DM patients, DM with duration of1-4years,5-9years and≥10years had a higher risk of having any DR,3.336[95%CI(2.322-4.880)],3.890[95%CI(2.327-6.503)] and12.499[95%CI(6.607-23.647)]. Compared with DM patients with BP<120mmHg, DM patients with BP(120-139)mmHg and≥140mmHg had a higher risk of having any DR1.567[95%CI(0.889-2.732)] and2.170[95%CI(1.252-3.761)]; Compared with DM patients with fasting blood glucose<5.6mmol/L, DM patients with (5.6-6.9)mmol/L and≥7.0mmol/L had a higher risk of having any DR,1.567[95%CI(0.889-2.732)]and2.170[95%CI(1.252-3.761)]. Compared with DM patients with glycosylated hemoglobin≥6.5%, DM patients with<6.5%had a higher risk of having any DR, OR=1.577[95%CI(1.105-2.253)].Factors independently associated with newly diagnosed DM patients were male, higher hyperglycemia and higher glycosylated hemoglobin and greater BMI. Conclusions:Our study shows that male, duration of diabetes, systolic pressure, hyperglycemia and glycosylated hemoglobin are independent risk factors of DR in T2DM patients. These findings suggest that controlling hyperglycemia, hypertension and BMI in this population may reduce the high risk of having DR associated with T2DM.Part4Prevalence and Causes of Low vision and Blindness in a T2DM Population in Southern China, in Dongguan City, Guangdong ProvincePurpose:To assess the prevalence and causes of low vision and blindness in a diabetic population in Southern China. Method:A population-based cross-sectional study. There are8592Han Chinese aged40years and older from16villages and1community to participate in the census of diabetes in Hengli town, Dongguan city, Guangdong province, in Southern China.1500T2DM patients were screened according to the diagnostic criteria(ADA,2010).All the diabetic patients underwent a standard interview, a comprehensive eye examination, including PVA and BCVA, intraocular pressure, slit lamp examination(external eye,anterior segment and ocular fundus) and fundus photography. Main outcome measures:Low vision and blindness were defined as VA<20/63to≥20/400and VA<20/400in the better eye following the World Health Organizaion definitions(WHO1973). Results:One thousand three hundred and fifty six(90.46%) of1500T2DM patients anticipated in this study and had VA data available. With best-corrected VA, the prevalence of bilateral low vision and blindness were0.88%and2.58%respectively. Leading causes of visual impairment were cataract (58.06%), other retinal diseases (except DR and AMD,9.68%), corneal opacity (6.45%), pterygium (6.45%), amblyopia (3.87%) and DR (3.23%). The prevalence of bilateral low vision and blindness (PVA) were1.25and7.74%; Cataract was also the principal cause of visual impairment in44.33%diabetic patients. Conclusions:In rapidly urbanized of Dongguan, cataract is still the leading cause of visual impairment in T2DM patients. Therefore, the focus of diabetic blindness prevention work is the intervention in cataract on the basis of the regular screening in DR, especially pay attention to the prevention of visual impairment in diabetic patients with older age and lower education level.