ng-Jun Li

Influence of Blood Pressure on Retinal Vascular Caliber in Young Children

OBJECTIVE Prior studies have reported that blood pressure (BP) has a significant influence on retinal vascular caliber both in adults and children aged 6 years and older. This study aimed to examine the association between BP and retinal vascular caliber in Singapore Chinese preschoolers 4 to 5 years of age. DESIGN Population-based, cross-sectional study. PARTICIPANTS A total of 385 eligible and healthy Singapore Chinese children 4 to 5 years of age who were recruited in The Strabismus, Amblyopia and Refractive Error Study in Singaporean Chinese Preschoolers from May 2006 through October 2008 underwent BP measurements and retinal photography. METHODS According to standard protocols, BP was measured with an automatic Omron sphygmomanometer (Omron HEM 705 LP, Omron Healthcare, Inc., Bannockburn, IL) and a retinal photograph was obtained with a Canon 45° digital retinal camera (Model CR6-NM45, Canon, Inc., Tokyo, Japan) after pupil dilation. Anthropometric and optical biometric measurements such as height, weight, and axial length were obtained also. Information regarding sociodemographic status and child birth information was supplied by parents in either English or Chinese questionnaires. MAIN OUTCOME MEASURES The computer imaging program was used to measure the caliber of all retinal arterioles and venules located in zone B. The central retinal arteriolar equivalent and central retinal venular equivalent were estimated by using a revised Knudtson-Parr-Hubbard formula. RESULTS The mean retinal arteriolar and venular calibers were 156.19 μm and 220.01 μm in boys and 161.97 μm and 224.22 μm in girls. Higher systolic BP was associated with narrower retinal arterioles. After adjusting for age, gender, fathers education, body mass index, birth weight, axial length, and caliber of the fellow retinal vessel, each 10-mmHg increase in systolic BP was associated with 2.00 μm (95% confidence interval, 0.39-3.61; P = 0.02) of retinal arteriolar narrowing and 2.51 μm (95% confidence interval, 0.35-4.68; P = 0.02) of retinal venular widening. However, neither diastolic BP nor mean arterial BP was associated with retinal arteriolar or venular caliber. CONCLUSIONS In very young children 4 to 5 years of age, higher systolic BP was associated with narrower retinal arterioles and wider retinal venules. This suggests that elevated BP may affect the retinal microvasculature from early childhood.

The relationship of body fatness indices and retinal vascular caliber in children

OBJECTIVE To examine the association between body fatness indices and retinal vascular calibre in Singapore Chinese children. METHODS We recruited 136 Singapore Chinese children aged 6-16 years from the STARS (The Strabismus, Amblyopia and Refractive Error Study in Singaporean Chinese Preschoolers) Family study in 2008-2010. Anthropometric measurements including weight, height and triceps skinfold (TSF) and right eye retinal photographs were performed. TSF was measured with Holtain-Tanner calliper on the back of the arm and midway between the point of the acromoion and olecranon process while the arm was hanging relaxed. TSF and BMI threshold (cut-off points for overweight and obesity) were defined as 85th and above of age- and gender-specific TSF and BMI standard charts which were based on American representative survey data. RESULTS The mean retinal arteriolar and venular calibres were 155.78 ? 15.02 ?m and 219.66 ? 21.88 ?m, respectively in the STARS Family study. Each standard deviation (SD) increase in TSF (4.49 mm) and BMI (3.52 kg/m(2)) was associated with a 2.94 ?m (p = 0.012) and a 3.40 ?m (p = 0.005) widening in retinal venular calibre, respectively. Compared with children with TSF and BMI below threshold, children with TSF and BMI above threshold had a 10.21 ?m (p = 0.001) and a 9.33 ?m (p = 0.021) increase in retinal venular calibre, respectively. CONCLUSIONS Greater TSF and BMI are associated with wider retinal venular calibre in healthy children aged 6 years and above. These findings suggest a possible effect of abnormal body fatness indices on early retinal vascular changes that reflect microvasculature in children.

Differential Association of Generalized and Abdominal Obesity With Diabetic Retinopathy in Asian Patients With Type 2 Diabetes.

IMPORTANCE The association between obesity and diabetic retinopathy (DR) is equivocal, possibly owing to the strong interrelation between generalized and abdominal obesity leading to a mutually confounding effect. To our knowledge, no study in Asia has investigated the independent associations of these 2 parameters with DR to date. OBJECTIVE To investigate the associations of generalized (defined by body mass index [BMI], calculated as weight in kilograms divided by height in meters squared) and abdominal obesity (assessed by waist to hip ratio [WHR]) with DR in a clinical sample of Asian patients with type 2 diabetes mellitus. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional clinic-based study was conducted at the Singapore National Eye Centre, a tertiary eye care institution in Singapore, from December 2010 to September 2013. We recruited 498 patients with diabetes. After exclusion of participants with ungradable retinal images and type 1 diabetes, 420 patients (mean [SD] age, 57.8 [7.5] years; 32.1% women) were included in the analyses. EXPOSURES Body mass index and WHR as waist/hip circumference (in centimeters). MAIN OUTCOMES AND MEASURES The presence and severity of DR were graded from retinal images using the modified Airlie House Classification into none (n = 189), mild-moderate (Early Treatment Diabetic Retinopathy Study scale score, 20-41; n = 125), and severe DR (Early Treatment Diabetic Retinopathy Study scale score ≥53; n = 118). The associations of BMI and WHR with DR were assessed using multinomial logistic regression models adjusting for age, sex, traditional risk factors, and mutually for BMI and WHR. RESULTS Among the total of 420 patients, the median (interquartile range) for BMI and WHR were 25.7 (5.7) and 0.94 (0.08), respectively. In multivariable models, BMI was inversely associated with mild-moderate and severe DR (odds ratio [OR], 0.90 [95% CI, 0.84-0.97] and OR, 0.92 [95% CI, 0.85-0.99] per 1-unit increase, respectively), while WHR was positively associated with mild-moderate and severe DR (OR, 3.49 [95% CI, 1.50-8.10] and OR, 2.68 [95% CI, 1.28-5.62] per 0.1-unit increase, respectively) in women (P for interaction = .006). No sex-specific associations were found between BMI and DR (P for interaction >.10). CONCLUSIONS AND RELEVANCE In Asian patients with type 2 diabetes, a higher BMI appeared to confer a protective effect on DR, while higher WHR was associated with the presence and severity of DR in women. Our results may inform future clinical trials to determine whether WHR is a more clinically relevant risk marker than BMI for individuals with type 2 diabetes.

Retinal vascular imaging in early life: insights into processes and risk of cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent years, studies have shown that the origins of CVD may be traced to vascular and metabolic processes in early life. Retinal vascular imaging is a new technology that allows detailed non‐invasive in vivo assessment and monitoring of the microvasculature. In this systematic review, we described the application of retinal vascular imaging in children and adolescents, and we examined the use of retinal vascular imaging in understanding CVD risk in early life. We reviewed all publications with quantitative retinal vascular assessment in two databases: PubMed and Scopus. Early life CVD risk factors were classified into four groups: birth risk factors, environmental risk factors, systemic risk factors and conditions linked to future CVD development. Retinal vascular changes were associated with lower birth weight, shorter gestational age, low‐fibre and high‐sugar diet, lesser physical activity, parental hypertension history, childhood hypertension, childhood overweight/obesity, childhood depression/anxiety and childhood type 1 diabetes mellitus. In summary, there is increasing evidence supporting the view that structural changes in the retinal microvasculature are associated with CVD risk factors in early life. Thus, the retina is a useful site for pre‐clinical assessment of microvascular processes that may underlie the future development of CVD in adulthood.

Relationship of ocular biometry and retinal vascular caliber in preschoolers.

PURPOSE To systematically examine the association between ocular biometry and retinal vascular caliber in Singapore Chinese preschoolers aged 48 to 72 months. METHODS A total of 469 Singapore Chinese children aged 48 to 72 months were recruited through the Strabismus, Amblyopia and Refractive Error Study in Singaporean Chinese Preschoolers (STARS) from 2006 to 2008. According to standardized protocols, cycloplegic autorefraction, ocular biometry measurements, and retinal photography were performed. Retinal vascular caliber was measured quantitatively and was summarized as the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE), respectively. Ocular magnification was corrected by using the Bengtsson formula. RESULTS The mean retinal arteriolar and venular calibers were 156.08 μm and 219.55 μm in boys, and 161.96 μm and 224.25 μm in girls, respectively. In multiple linear regression adjusted for age, sex, fathers education, parental myopia history, mean arterial blood pressure, body mass index, and spherical equivalent, each 1.0 mm increase in axial length was associated with a 3.52 μm decrease in retinal arteriolar caliber (P = 0.023) and a 5.55 μm decrease in retinal venular caliber (P = 0.008). Each 1.00 mm increase in corneal curvature was associated with a 13.79 μm decrease (P = 0.004) in retinal venular caliber. CONCLUSIONS In very young children aged 48 to 72 months, narrower retinal arteriolar and venular caliber was associated with elongated axial length. Narrower retinal venular caliber was associated with larger corneal curvature. This suggests that the major structural correlate of myopia might have an effect on retinal microvasculature from early childhood.

Can the retinal microvasculature offer clues to cardiovascular risk factors in early life

Adulthood cardiovascular diseases (CVD) burdening in adulthood have been suggested to have possible predisposition early in life. We aimed to systematically review the literatures on retinal microvasculature among paediatric population in relation to a range of environmental and systemic changes. Papers with quantitative retinal vascular assessment and epidemiological design were reviewed.

Prevalence and Determinants of Suboptimal Vitamin D Levels in a Multiethnic Asian Population

This population-based cross-sectional study examined the prevalence and risk factors of suboptimal vitamin D levels (assessed using circulating 25-hydroxycholecalciferol (25(OH)D)) in a multi-ethnic sample of Asian adults. Plasma 25(OH)D concentration of 1139 Chinese, Malay and Indians (40–80 years) were stratified into normal (≥30 ng/mL), and suboptimal (including insufficiency and deficiency, <30 ng/mL) based on the 2011 Endocrine Society Clinical Practice Guidelines. Logistic regression models were used to assess the associations of demographic, lifestyle and clinical risk factors with the outcome. Of the 1139 participants, 25(OH)D concentration was suboptimal in 76.1%. In multivariable models, age ≤65 years (compared to age >65 years), Malay and Indian ethnicities (compared to Chinese ethnicity), and higher body mass index, HbA1c, education and income levels were associated with suboptimal 25(OH)D concentration (p < 0.05). In a population-based sample of Asian adults, approximately 75% had suboptimal 25(OH)D concentration. Targeted interventions and stricter reinforcements of existing guidelines for vitamin D supplementation are needed for groups at risk of vitamin D insufficiency/deficiency.

Retinal vascular imaging technology to monitor disease severity and complications in type 1 diabetes mellitus: A systematic review

Type 1 diabetes mellitus (T1DM) is a major disease affecting a large number of young patients. In the recent years, retinal vascular imaging has provided an objective assessment of vascular health in patients with T1DM. Our study aimed to review the current literature on retinal vascular parameters in young patients with T1DM in order to understand the following: (i) How retinal vessels are affected in T1DM (ii) How such vascular changes can be predictive of future diabetic microvascular complications

The Impact of Macronutrients on Retinal Microvasculature among Singapore Pregnant Women during the Mid-Late Gestation

Background Imbalanced macronutrient intakes can induce impairment of endothelial and vascular function, and further lead to metabolic and cardiovascular disease. However, little is known about the influence of such diets on endothelial and vascular dysfunction in pregnant women, even though high-fat diet is a known risk for pregnancy complications such as gestational diabetes and pre-eclampsia. Objective We aimed to assess the association between maternal macronutrient intakes (protein, fat and carbohydrates), dietary quality and retinal microvascular changes in a multi-ethnic Asian mother-offspring cohort. Methods Pregnant women (n = 614) with singleton pregnancies were recruited during their first trimester from June 2009 to Sep 2010. Maternal diet quality and macronutrient intakes, expressed as a percentage of total energy during pregnancy, were ascertained using 24 hr recalls and 3 d food diaries at 26–28 weeks gestation. Retinal examination was completed at the same clinic visit. Dietary quality was assessed and scored using the Health Eating Index in Asian Pregnant women (HEI-AP), while macronutrients intakes ware expressed as percentages of total energy and further log transformed for analysis. Associations were examined cross-sectionally by substitution models with the use of multiple linear regression. Results In adjusted model, each 20 points decrease in HEI-AP score was associated with a significant increase of 1.70 μm (p<0.05) in retinal venular calibre. Each 0.1 log increase in percentage of total fat intake was associated with a significant increment of 1.84 μm (p<0.05) in retinal venular caliber. Additionally, each 0.1 log increase in percentage of mono-unsaturated fat intake was associated with an increment of 1.84 μm (p<0.01) in retinal venular caliber. Conclusions In this cross-sectional study, we found that women with higher fat and lower protein intakes, and lower diet quality tended to have wider retinal venular caliber, which is suggestive of suboptimal microvasculature.

Differential Impact of Unilateral and Bilateral Classifications of Diabetic Retinopathy and Diabetic Macular Edema on Vision-Related Quality of Life

PURPOSE To evaluate and compare the impact of unilateral better-eye and bilateral categorizations of diabetic retinopathy (DR) and diabetic macular edema (DME) on vision-related quality of life (VRQoL) in individuals with type 2 diabetes (T2DM). METHODS We recruited 390 subjects (116 females; age range, 22-78 years) of Malay, Indian, and Chinese ethnicities from the Singapore Diabetes Management Project (S-DMP), a cross-sectional clinic-based study conducted from 2010 to 2013. Diabetic retinopathy and DME were graded using the Modified Airlie House and American Academy of Ophthalmology classification systems, respectively. Subjects were categorized, using unilateral better-eye classifications, into no DR (n = 189), any DR only (n = 164), and any DME (n = 37); and with bilateral classifications into no DR (n = 144), DR/DME in one eye only (n = 45), DR in one eye and DR/DME in the other (n = 164), and DME in both eyes (n = 37). Vision-related quality of life was assessed using the composite Rasch-transformed score of the Impact of Visual Impairment (IVI) questionnaire. RESULTS For unilateral better-eye classifications, multivariable linear models revealed a 9% reduction in VRQoL for any DR (β [95% confidence interval (CI)], -0.44 [-0.86, -0.03]) and a 17% reduction for any DME (-0.81 [-1.53, -0.08]) compared to individuals with no DR/DME. Bilateral categorizations revealed significant decrements in VRQoL that occurred only when both eyes had either DR or DME (11%), which worsened when both eyes were affected by DME (22%). CONCLUSIONS Our results suggest that interventions to prevent the onset of DR and/or DME in the second eye are strongly recommended to significantly reduce the bilateral impact of these conditions on VRQoL.