Assessment of the Macular Microvasculature in High Myopes With Swept Source Optical Coherence Tomographic Angiography

Background: The risk of pathologic myopia (PM) increases with worsening myopia and may be related to retinal microvasculature alterations. To evaluate this, we analyzed the macular microvasculature of myopes with swept source-optical coherence tomographic angiography (SS-OCTA) in adolescent and young adult Singaporeans.

Methods: This is a prevalent case-control study including 93 young Chinese from the Strabismus, Amblyopia and Refractive error in Singaporean children (STARS, N = 45) study and the Singapore Cohort Study of Risk Factors for Myopia (SCORM, N = 48) studies. Macular vessel density (VD) measurements were obtained from 3 × 3 mm SS-OCTA scans and independently assessed using ImageJ. These measurements were compared between individuals with non-high myopia [non-HM, N = 40; SE >-5.0 diopter (D)] and HM (SE ≤-5.0D, N = 53).

Results: The mean macular VD was 40.9 ± 0.6% and 38.2 ± 0.5% in the non-HM and HM, groups, respectively (p = 0.01 adjusted for age and gender). Mean FAZ area in the superficial layer was 0.22 ± 0.02 mm² in the HM group, which was smaller compared to non-HM group (0.32 ± 0.03 mm², p = 0.04). Mean deep FAZ area was similar between the two groups (0.45 ± 0.03 mm² and 0.48 ± 0.04 mm² in the HM and non-HM groups, respectively, p = 0.70).

Conclusions: VD was lower and superficial FAZ area was smaller, in adolescents and young adults with HM compared to non-HM. These findings require validation in prospective studies to assess their impact on the subsequent development of PM.

Sleep Duration in Infants Was Not Associated With Myopia at 3 Years

PURPOSE

To investigate the association of sleep duration and quality at 12 months and myopia at 3 years.

DESIGN

Cohort study.

METHODS

The Growing Up in Singapore Towards Healthy Outcomes (GUSTO) birth cohort recruited pregnant women at 2 major public maternity hospitals (n = 1236). We included 376 children of Chinese, Malay, and Indian ethnicity who had completed caregiver questionnaires on the child's sleep at 12 months of age [Brief Infant Sleep Questionnaire (BISQ)] and also completed cycloplegic autorefraction and eye axial length (AL) measurement at 3 years of age. Data on total sleep duration and number of night wakings were collected by BISQ. Univariable and multivariable regression models adjusting for potential confounders (age, sex, ethnicity, parental myopia, maternal education level, outdoor time, near work, and height) were used.

RESULTS

Thirteen (3.5%) participants were myopic and mean spherical equivalent (SE) was 0.89 diopters (D) (SD 0.88) at 3 years. Total sleep duration and number of night wakings at 12 months were not associated with SE at 3 years (P > 0.05). The total sleep duration (P = 0.07) and number of night wakings (P = 0.49) were not associated with AL in the multivariate model. Total sleep duration in tertile 2 was not associated with AL (P = 0.11) compared with tertile 1. Only total sleep duration in tertile 3 was associated with longer AL (P = 0.006), but there was no association with SE.

CONCLUSIONS

Sleep duration and quality at 12 months of age were not associated with refractive error at 3 years.

Vitamin D insufficiency and cognitive impairment in Asians: a multi-ethnic population-based study and meta-analysis

BACKGROUND

The relationship between vitamin D insufficiency and cognitive impairment remains equivocal in Asians. We examined the association between circulating 25-hydroxyvitamin D (25OHD) concentration and cognitive performance in a large multi-ethnic Singaporean population-based study. We also conducted a meta-analysis of 25OHD concentrations amongst cognitively impaired older adults in Asia.

METHODS

Our population-based cross-sectional study included 2273 persons ≥60 years of age from the Singapore Epidemiology of Eye Diseases (SEED) study (mean ± SD age 70.4 ± 6.2 years; 44.7% female), who were categorized according to 25OHD concentration (i.e. ≤10, 10.1-20 and >20 ng mL(-1) ). The 25OHD concentration was measured and adjusted to reflect a deseasonalized value. Cognition was assessed using the total and domain scores of the Abbreviated Mental Test (AMT). Global cognitive impairment was defined as AMT score of ≤6 if 0-6 years of education and AMT score of ≤8 if >7 years of education. Fully adjusted multivariate models were used. We included seven studies in a meta-analysis of 25OHD and cognition in Asia (6068 participants; 1179 cognitively impaired cases).

RESULTS

Participants with 25OHD levels >20 ng mL(-1) (n = 1302) had higher AMT total scores (mean ± SD 8.5 ± 1.9) and were less likely to have cognitive impairment (14.1%) than participants with lower 25OHD levels (overall P < 0.001, P-trend < 0.001). Deseasonalized 25OHD concentration was associated with AMT score (β = 0.10 per 10 ng mL(-1) , P = 0.035). Vitamin D insufficiency (25OHD ≤20 ng mL(-1) ) was associated with global cognitive impairment (OR 1.56, P = 0.028). Specifically, 25OHD concentration correlated with semantic memory (r = 0.08, P = 0.009) and orientation in time (r = 0.09, P = 0.003). In the meta-analysis, the pooled mean 25OHD difference was -6.83 ng mL(-1) (95% confidence interval -11.36; -2.30), indicating lower 25OHD concentrations amongst cognitively impaired compared to cognitively healthy participants in Asia.

CONCLUSION

Vitamin D insufficiency is associated with a greater likelihood of and more severe cognitive impairment in Asian populations.

Serum C-reactive protein level and prediabetes in two Asian populations

AIMS/HYPOTHESIS

Prediabetes, an early stage in the hyperglycaemic continuum, increases the future risk of developing diabetes and cardiovascular disease (CVD). C-reactive protein (CRP), a marker of inflammation, is associated with diabetes and CVD. However, studies examining the association between CRP and prediabetes among participants without diabetes are limited.

METHODS

We analysed data from two large population-based studies in Singapore: the Singapore Prospective Study Programme (SP2, n = 4,252 Chinese, Malay and Indians aged ≥ 24 years) and the Singapore Malay Eye Study (SiMES, n = 2,337 Malays aged 40-80 years), participants of which were free of diabetes mellitus. Prediabetes was defined as glycated haemoglobin of 5.7-6.4% in SiMES (n = 1,231); fasting plasma glucose of 5.6-6.9 mmol/l in SP2 (n = 386).

RESULTS

Elevated high sensitivity CRP (hsCRP) levels were found to be associated with prediabetes after adjusting for age, sex, race-ethnicity, education, smoking, alcohol consumption, hypertension, BMI and total cholesterol. Comparing those with hsCRP <1 mg/l (referent), the OR (95% confidence interval) of prediabetes in persons with hsCRP 1-3 mg/l and >3 mg/l was 1.31 (0.99-1.74) and 2.17 (1.61-2.92), p (trend) < 0.0001 in SP2; 1.23 (1.00-1.52) and 1.31 (1.06-1.64), p (trend) = 0.02 in SiMES. In subgroup analysis, the association was stronger in women, Chinese and Malays, and participants with BMI < 25 kg/m(2).

CONCLUSIONS

Data from two population-based Asian cohorts suggest that elevated serum hsCRP levels are associated with prediabetes.

Relationship between glycated haemoglobin and microvascular complications: is there a natural cut-off point for the diagnosis of diabetes?

AIMS/HYPOTHESIS

This study was designed to determine whether the relationship of glycated haemoglobin to diabetic microvascular complications shows any natural thresholds that could be useful in diagnosing diabetes.

METHODS

We examined a population-based sample of 3,190 Malay adults aged 40-80 years in Singapore. The microvascular outcomes of interest were: (1) any retinopathy, defined from fundus photographs; (2) mild retinopathy, defined as in (1); (3) moderate retinopathy, defined as in (1); (4) chronic kidney disease, defined from estimated glomerular filtration rate; (5) micro- or macroalbuminuria, defined from urinary albumin to creatinine ratio; and (6) peripheral neuropathy, defined from neurothesiometer or monofilament sensory testing.

RESULTS

Increasing HbA(1c) was associated with all microvascular complications. The optimal cut-off points for detecting mild and moderate retinopathy were 6.6% (87.0% sensitivity, 77.1% specificity and area under the receiver operating characteristics [ROC] curve 0.899) and 7.0% (82.9% sensitivity, 82.3% specificity and area under ROC curve 0.904). The prevalences of mild and moderate retinopathy were <1% below the optimal cut-off points. For other complications, the association with HbA(1c) was linear without evidence of a distinct threshold. Although ROC analysis for these other complications also suggested optimal cut-off points between 6.6% and 7.0%, the sensitivity at these cut-off points was considerably lower than for mild and moderate retinopathy, ranging from 31.8% to 66.5%.

CONCLUSIONS/INTERPRETATION

Higher levels of HbA(1c) were associated with microvascular complications. Our data support use of an HbA(1c) cut-off point of between 6.6 and 7.0% in diagnosing diabetes. Cut-off points in this range were best for the identification of individuals with mild and moderate retinopathy. Any retinopathy, chronic kidney disease, albuminuria and peripheral neuropathy are less well detected at these cut-off points.