Epidemiological Study Of Retinal Microvascular Abnormalities And Their Associations With Arterial Hypertension

ObjectiveIn view of the importance retinal microvascular abnormalities may have for the diagnosis of ocular and systemic disease, and because epidemiological data on the retinal vessel morphology in adult Chinese are not available so far, we conducted the present study to assess the retinal microvascular abnormalities in population-based study in rural and urban Beijing, to describe the prevalences of retinal microvascular abnormalities and their distributions, to find their potential risk factors, and to analyse their associations with arterial hypertension.Population and methodsPopulation: The Beijing Eye Study, a population-based study in Beijing defined population, was registered 5324 subjects who were 40 years old or more, in which 4439 (83.4%) subjects attended in the baseline examination in 2001. Before the following-up examination in 2006, there were 146 subjects died, 3251 (75.7%) survival subjects attended in the following-up examination in 2006.Methods: In baseline examination and following-up examination, questionnaires and detail ophthalmological examinations were conducted in every attended subjects. Color photographys of fundus were morphometrically assessed. One eye per person was selected randomly to be assessed. Focal retinal arteriolar narrowing, arteriovenous nicking , and retinopathy were assessed using qualititive methods;generalized retinal arteriolar narrowing was assessed using quantitive methods by computer software. Self-report histories of cardiovascular and cerebrovascular disease and habits of smoking and alcohol drinking were obtained by queastionaire. In following-up examination, height, weight, and blood pressure were measured in setting. And fasting blood samples were collected and analysed by biochemistry test to obtain serum glucose and lipidemia. Considered risk factor included age, gender, area, incomes, educations, hypertension, hyperlipidemia, coronary heart disease, stroke, diabetes, Body Mass Index (BMI), the habits of smoking and alcohol drinking, and fundus diseases(glaucoma, age-ralated macular degeneration, and central/branch retinal vein occlusions, etc).Results1. In the baseline population, the prevalences of focal retinal arteriolar narrowing, arteriovenous nicking, and retinopathy were 7.5%, 7.2%, and 7.5%, respectively. The prevalence of these three abnormalities were increased following the increasing ages (P<0.001); there are no significant difference of the prevalence of generalized retinal arteriolar narrowing among different age groups (P=0.441), but the prevalence was significantly increased in men (24.4%), comparing with in women (17.6%, P<0.001); these four abnormalities were more frequent in rural than in urban population (P<0.001). 2. Using Logistic regression, the risk fators of focal retinal arteriolar narrowing included age (every 10years old increasing, OR=1.383, 95%CI:1.194～1.603), rural (OR=2.062, 95%CI:1.555～2.732), retinal vein occlusion (OR=5.147, 95%CI:2.148～12.336) and hypertension history (OR=1.494, 95%CI:1.120～1.994); the risk factors of arteriovenous nicking included age (every 10 years old increasing, OR=1.447, 95%CI:1.247～1.679), rural (OR=2.674, 95%CI:2.008～3.559), and hypertension history (OR=1.760, 95%CI:1.325～2.338); the risk factors of retinopathy included age (every 10 years old increasing, OR=1.293, 95%CI:1.106～1.513), hypertension history (OR=1.458, 95%CI:1.054～2.017), diabetes history (OR=5.470, 95%CI:3.791～7.893), retinal vein occlusion (OR=39.291, 95%CI:15.073,102.418); the risk factors of generalized retinal arteriolar narrowing included gender (in men, OR=1.553, 95%CI:1.316～1.832), rural (OR=1.437, 95%CI:1.214～1.704), hypertension history (OR=1.544, 95%CI:1.271～1.877), and coronary heart disease history (OR=0.681, 95%CI:0.519～0.893). 3. Controlled by other risk factors, every 10 mmHg mean arterial blood pressure (MABP) increasing, the risks of the prevalences of focal narrowing and arteriovenous nicking were increased 47% and 22% (OR and 95%CI: 1.47, 1.21～1.77 and 1.22, 1.04～1.42); the risks of incidences of focal narrowing, arteriovenous nicking and retinopathy were increased 58%, 55%, and 46%; the regress possibilities of focal narrowing decreased 28% (RR=0.72, 95%CI:0.53 , 0.98). 4. Controlled by other risk factors, in hypertensive patients, comparing with controlled group, the risk of the prevalence of focal narrowing in uncontrolled group and untreated group increased 1.2 times and 1.1times(OR and 95%CI: 2.20, 1.30～3.73; and 2.08, 1.23～3.52); the risk of the incidence of focal narrowing, AV nicking, and retinopathy in uncontrolled group increased 71%,1.1times, and 1.3times, respectively(RR and 95%CI: 1.71, 0.92～3.17; 2.101, 0.734～6.010; and 2.257:1.173～4.342, respectively); the risk of the incidence of focal narrowing, AV nicking, and retinopathy in untreated group increased 1.6times, 2.1times,and 2.3times(RR and 95%CI: 2.595, 1.542～4.368; 3.105, 1.235～7.810; and 2.250, 1.225～4.131); the regress possibilities of focal narrowing in uncontrolled and untreated group were descresed 69% and 87%(RR and 95%CI: 0.314, 0.097～1.020; 0.128, 0.033～0.494).ConclusionRetinal microvascular abnormalities are common in elderly Chinese population aged 40 or more in Beijing defined population in rural and urban area. Retinal microvascular abnormalities are more frequent in rural population than in urban population. The possible causes are the higher prevalence of arterial hypertension, the lower level of medical care and life qualities, and more bad habits in living, such as smoking and alcohol drinking etc. Arterial hypertension is the most important systemic cause of retinal microvascular abnormalities in population without diabetes. Controlled hypertension can decrease the risk of the prevelance and incidence of retinal microvascular abnormalities in hypertensive patients, and can benefit the regress of retinal vascular functional damages in early stage, such as focal retinal arteriolar narrowing.