National prevalence of vision impairment and blindness and associated risk factors in adults aged 40 years and older with known or undiagnosed diabetes: results from the SMART-India cross-sectional study

BACKGROUND

National estimates of the prevalence of vision impairment and blindness in people with diabetes are required to inform resource allocation. People with diabetes are more susceptible to conditions such as diabetic retinopathy that can impair vision; however, these are often missed in national studies. This study aims to determine the prevalence and risk factors of vision impairment and blindness in people with diabetes in India.

METHODS

Data from the SMART-India study, a cross-sectional survey with national coverage of 42 147 Indian adults aged 40 years and older, collected using a complex sampling design, were used to obtain nationally representative estimates for the prevalence of vision impairment and blindness in people with diabetes in India. Vulnerable adults (primarily those who did not have capacity to provide consent); pregnant and breastfeeding women; anyone deemed too ill to be screened; those who did not provide consent; and people with type 1 diabetes, gestational diabetes, or secondary diabetes were excluded from the study. Vision impairment was defined as presenting visual acuity of 0·4 logMAR or higher and blindness as presenting a visual acuity of 1·0 logMAR or higher in the better-seeing eye. Demographic, anthropometric, and laboratory data along with geographic distribution were analysed in all participants with available data. Non-mydriatic retinal images were used to grade diabetic retinopathy, and risk factors were also assessed.

FINDINGS

A total of 7910 people with diabetes were included in the analysis, of whom 5689 had known diabetes and 2221 were undiagnosed. 4387 (55·5%) of 7909 participants with available sex data were female and 3522 (44·5%) participants were male. The estimated national prevalence of vision impairment was 21·1% (95% CI 15·7-27·7) and blindness 2·4% (1·7-3·4). A higher prevalence of any vision impairment (29·2% vs 19·6%; p=0·016) and blindness (6·7% vs 1·6%; p<0·0001) was observed in those with ungradable images. In known diabetes, diabetic retinopathy (adjusted odds ratio [aOR] 3·06 [95% CI 1·25-7·51]), vision-threatening diabetic retinopathy (aOR 7·21 [3·52-14·75]), and diabetic macular oedema (aOR 5·41 [2·20-13·33]) were associated with blindness in adjusted analysis. Common sociodemographic risk factors for vision impairment and blindness include older age, lower educational attainment, and unemployment.

INTERPRETATION

Based on the estimated 101 million people with diabetes in 2021 and the interpretation of the data from this study, approximately 21 million people with diabetes have vision impairment in India, of whom 2·4 million are blind. Higher prevalence is observed in those from lower socio-economic strata and policy makers should focus on these groups to reduce inequalities in health care.

FUNDING

Global Challenge Research Fund of United Kingdom Research and Innovation through the Medical Research Council.

Low-calorie diets for people with isolated impaired fasting glucose

Thirunavukkarasu et al. discuss how standard lifestyle interventions prove ineffective in preventing type 2 diabetes in individuals with isolated impaired fasting glucose, a highly prevalent prediabetes phenotype globally. They propose low-calorie diets as a promising strategy for diabetes prevention in this high-risk population.

Effect of Conventional Lifestyle Interventions on Type 2 Diabetes Incidence by Glucose-Defined Prediabetes Phenotype: An Individual Participant Data Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To examine whether the effect of conventional lifestyle interventions on type 2 diabetes incidence differs by glucose-defined prediabetes phenotype.

RESEARCH DESIGN AND METHODS

We searched multiple databases until 1 April 2023 for randomized controlled trials that recruited people with isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), and impaired fasting glucose plus impaired glucose tolerance (IFG+IGT). Individual participant data were pooled from relevant trials and analyzed through random-effects models with use of the within-trial interactions approach.

RESULTS

Four trials with 2,794 participants (mean age 53.0 years, 60.7% men) were included: 1,240 (44.4%), 796 (28.5%), and 758 (27.1%) had i-IFG, i-IGT, and IFG+IGT, respectively. After a median of 2.5 years, the pooled hazard ratio for diabetes incidence in i-IFG was 0.97 (95% CI 0.66, 1.44), i-IGT 0.65 (0.44, 0.96), and IFG+IGT 0.51 (0.38, 0.68; Pinteraction = 0.01).

CONCLUSIONS

Conventional lifestyle interventions reduced diabetes incidence in people with IGT (with or without IFG) but not in those with i-IFG.

Retinal microvascular associations with cardiometabolic risk factors differ by diabetes status: results from the UK Biobank

AIMS/HYPOTHESIS

The aim of the study was to examine the association of retinal vessel morphometry with BP, body composition and biochemistry, and to determine whether these associations differ by diabetes status.

METHODS

The UK Biobank ocular assessment included 68,550 participants aged 40-70 years who underwent non-mydriatic retinal photography, BP and body composition measurements, and haematological analysis. A fully automated image analysis program provided measurements of retinal vessel diameter and tortuosity. The associations between retinal vessel morphology and cardiometabolic risk factors by diabetes status were examined using multilevel linear regression, to provide absolute differences in vessel diameter and percentage differences in tortuosity (allowing for within-person clustering).

RESULTS

A total of 50,233 participants (a reduction from 68,550) were included in these analyses. Overall, those with diabetes had significantly more tortuous venules and wider arteriolar diameters compared with those without. Associations between venular tortuosity and cardiometabolic risk factors differed according to diabetes status (p interaction <0.01) for total fat mass index, HbA_1c, C-reactive protein, white cell count and granulocyte count. For example, a unit rise in white cell count was associated with a 0.18% increase (95% CI 0.05, 0.32%) in venular tortuosity for those without diabetes and a 1.48% increase (95% CI 0.90, 2.07%) among those with diabetes. For arteriolar diameter, significant interactions were evident for systolic BP, diastolic BP, mean arterial pressure (MAP) and LDL-cholesterol. For example, a 10 mmHg rise in systolic BP was associated with a -0.92 μm difference (95% CI -0.96 to -0.88 μm) in arteriolar diameter for those without diabetes, and a -0.58 μm difference (95% CI -0.76 to -0.41 μm) among those with diabetes. No interactions were observed for arteriolar tortuosity or venular diameters.

CONCLUSIONS/INTERPRETATION

We provide clear evidence of the modifying effect of diabetes on cardiometabolic risk factor associations with retinal microvascular architecture. These observations suggest the occurrence of preclinical disease processes, and may be a sign of impaired autoregulation due to hyperglycaemia, which has been suggested to play a pivotal role in the development of diabetes-related microvascular complications.

DATA AVAILABILITY

The data supporting the results reported here are available through the UK Biobank ( https://www.ukbiobank.ac.uk/enable-your-research/apply-for-access ).

Cost-effectiveness of a lifestyle intervention in high-risk individuals for diabetes in a low- and middle-income setting: Trial-based analysis of the Kerala Diabetes Prevention Program

BACKGROUND

Data on the cost-effectiveness of lifestyle-based diabetes prevention programs are mostly from high-income countries, which cannot be extrapolated to low- and middle-income countries. We performed a trial-based cost-effectiveness analysis of a lifestyle intervention targeted at preventing diabetes in India.

METHODS

The Kerala Diabetes Prevention Program was a cluster-randomized controlled trial of 1007 individuals conducted in 60 polling areas (electoral divisions) in Kerala state. Participants (30-60 years) were those with a high diabetes risk score and without diabetes on an oral glucose tolerance test. The intervention group received a 12-month peer-support lifestyle intervention involving 15 group sessions delivered in community settings by trained lay peer leaders. There were also linked community activities to sustain behavior change. The control group received a booklet on lifestyle change. Costs were estimated from the health system and societal perspectives, with 2018 as the reference year. Effectiveness was measured in terms of the number of diabetes cases prevented and quality-adjusted life years (QALYs). Three times India's gross domestic product per capita (US$6108) was used as the cost-effectiveness threshold. The analyses were conducted with a 2-year time horizon. Costs and effects were discounted at 3% per annum. One-way and multi-way sensitivity analyses were performed.

RESULTS

Baseline characteristics were similar in the two study groups. Over 2 years, the intervention resulted in an incremental health system cost of US$2.0 (intervention group: US$303.6; control group: US$301.6), incremental societal cost of US$6.2 (intervention group: US$367.8; control group: US$361.5), absolute risk reduction of 2.1%, and incremental QALYs of 0.04 per person. From a health system perspective, the cost per diabetes case prevented was US$95.2, and the cost per QALY gained was US$50.0. From a societal perspective, the corresponding figures were US$295.1 and US$155.0. For the number of diabetes cases prevented, the probability for the intervention to be cost-effective was 84.0% and 83.1% from the health system and societal perspectives, respectively. The corresponding figures for QALY gained were 99.1% and 97.8%. The results were robust to discounting and sensitivity analyses.

CONCLUSIONS

A community-based peer-support lifestyle intervention was cost-effective in individuals at high risk of developing diabetes in India over 2 years.

TRIAL REGISTRATION

The trial was registered with Australia and New Zealand Clinical Trials Registry ( ACTRN12611000262909 ). Registered 10 March 2011.

Retinal Vascular Tortuosity and Diameter Associations with Adiposity and Components of Body Composition

OBJECTIVE

The aim of this study was to assess whether adiposity or body composition relates to microvascular characteristics of the retina, indicative of cardiometabolic function.

METHODS

A fully automated QUARTZ software processed retinal images from 68,550 UK Biobank participants (aged 40-69 years). Differences in retinal vessel diameter and tortuosity with body composition measures from the Tanita analyzer were obtained by using multilevel regression analyses adjusted for age, sex, ethnicity, clinic, smoking, and Townsend deprivation index.

RESULTS

Venular tortuosity and diameter increased by approximately 2% (P < 10^-300 ) and 0.6 μm (P < 10^-6 ), respectively, per SD increase in BMI, waist circumference index, waist-hip ratio, total body fat mass index, and fat-free mass index (FFMI). Venular associations with adiposity persisted after adjustment for FFMI, whereas associations with FFMI were weakened by FMI adjustment. Arteriolar diameter (not tortuosity) narrowing with FFMI was independent of adiposity (-0.6 μm; -0.7 to -0.4 μm per SD increment of FFMI), while adiposity associations with arteriolar diameter were largely nonsignificant after adjustment for FFMI.

CONCLUSIONS

This demonstrates, on an unprecedented scale, that venular tortuosity and diameter are more strongly associated with adiposity, whereas arteriolar diameter relates more strongly to fat-free mass. Different attributes of the retinal microvasculature may reflect distinct roles of body composition and fatness on the cardiometabolic system.

Effect of a Peer-led Lifestyle Intervention on Individuals With Normal Weight Obesity: Insights From the Kerala Diabetes Prevention Program

PURPOSE

Normal weight obesity (NWO) is a unique phenotype of obesity associated with high cardiovascular mortality. There is limited literature on assessing the effect of therapeutic interventions on the cardiometabolic health of these individuals. We studied the effect of a peer-led lifestyle intervention on key cardiometabolic parameters (blood glucose, blood pressure, and plasma lipids) in individuals with NWO.

METHODS

This study is a secondary data analysis of the Kerala Diabetes Prevention Program, a cluster-randomized controlled study that involves a peer-led, real-life lifestyle intervention for individuals from the community between the ages of 30 and 60 years with a high diabetes risk. Participants underwent a rigorous cardiometabolic evaluation at baseline and at 2-year follow-up.

FINDINGS

A total of 292 recruited individuals with NWO were randomized into the intervention (n = 159) and control (n = 133) arms. At 2 years of follow-up, there was minimal but statistically significant improvement in systolic blood pressure and serum HDL level in the intervention arm, but no statistical difference was seen in other lipid and glycemic parameters.

IMPLICATIONS

This study provides early evidence of the effect of a lifestyle intervention in a cohort of individuals with NWO. Only systolic blood pressure and serum HDL level had a mild favorable change in the intervention arm when compared with the control arm.

Benefit of lifestyle-based T2DM prevention is influenced by prediabetes phenotype

The prevention of type 2 diabetes mellitus (T2DM) is a target priority for the WHO and the United Nations and is a key priority in the 2018 Berlin Declaration, which is a global call for early actions related to T2DM. Health-care policies advocate that individuals at high risk of developing T2DM undertake lifestyle modification, irrespective of whether the prediabetes phenotype is defined by hyperglycaemia in the postprandial state (impaired glucose tolerance) and/or fasting state (impaired fasting glucose) or by intermediate HbA_1c levels. However, current evidence indicates that diabetes prevention programmes based on lifestyle change have not been successful in preventing T2DM in individuals with isolated impaired fasting glucose. We propose that further research is needed to identify effective lifestyle interventions for individuals with isolated impaired fasting glucose. Furthermore, we call for the identification of innovative approaches that better identify people with impaired glucose tolerance, who benefit from the currently available lifestyle-based diabetes prevention programmes.

Impact of Ideal Cardiovascular Health in Childhood on the Retinal Microvasculature in Midadulthood: Cardiovascular Risk in Young Finns Study

Background

This study examined the association between ideal cardiovascular health (CVH) and the retinal microvasculature in midadulthood.

Methods and Results

The Cardiovascular Risk in Young Finns Study included children from 5 Finnish University cities, who were chosen randomly from the national population register. Participants ranged from 12 to 18 years in childhood (1986) and from 37 to 43 years in midadulthood (2011). Ideal CVH was defined according to the American Heart Association criteria. Retinal microvascular measures included diameters, lengths, length:diameter ratio, and tortuosity. From childhood to adulthood, fasting plasma glucose and blood pressure were significantly higher in those with impaired fasting glucose or diabetes mellitus. Childhood ideal CVH was negatively associated with adult arteriolar tortuosity (β=−0.008; 95% confidence interval [CI], −0.01 to −0.003; P=0.001). Improved ideal CVH from childhood to adulthood was positively associated with adult arteriolar diameter (β=0.122; 95% CI, 0.01–0.24; P=0.033) and negatively associated with adult length:diameter ratio (β=−0.666; 95% CI, −1.25 to −0.08; P=0.026). When stratified by glucose metabolism, among those with diabetes mellitus and impaired fasting glucose, there was a negative association between childhood ideal CVH and adult venular diameter (diabetes mellitus: β=−2.75; 95% CI, −5.46 to −0.04; P=0.047; impaired fasting glucose: β=−2.13; 95% CI, −4.18 to −0.08; P=0.042).

Conclusions

This study is the first to comprehensively examine the impact of CVH from childhood to midadulthood on quantitative measures of the retinal microvasculature. Ideal CVH in childhood and improvement in CVH from childhood to adulthood appears to have a protective effect on the retinal microvasculature in those with, without, and at risk of diabetes mellitus.

Associations of Retinal Microvascular Diameters and Tortuosity With Blood Pressure and Arterial Stiffness: United Kingdom Biobank

Supplemental Digital Content is available in the text.

To examine the baseline associations of retinal vessel morphometry with blood pressure (BP) and arterial stiffness in United Kingdom Biobank. The United Kingdom Biobank included 68 550 participants aged 40 to 69 years who underwent nonmydriatic retinal imaging, BP, and arterial stiffness index assessment. A fully automated image analysis program (QUARTZ [Quantitative Analysis of Retinal Vessel Topology and Size]) provided measures of retinal vessel diameter and tortuosity. The associations between retinal vessel morphology and cardiovascular disease risk factors/outcomes were examined using multilevel linear regression to provide absolute differences in vessel diameter and percentage differences in tortuosity (allowing within person clustering), adjusted for age, sex, ethnicity, clinic, body mass index, smoking, and deprivation index. Greater arteriolar tortuosity was associated with higher systolic BP (relative increase, 1.2%; 95% CI, 0.9; 1.4% per 10 mmHg), higher mean arterial pressure, 1.3%; 0.9, 1.7% per 10 mmHg, and higher pulse pressure (PP, 1.8%; 1.4; 2.2% per 10 mmHg). Narrower arterioles were associated with higher systolic BP (−0.9 µm; −0.94, −0.87 µm per 10 mmHg), mean arterial pressure (−1.5 µm; −1.5, −1.5 µm per 10 mmHg), PP (−0.7 µm; −0.8, −0.7 µm per 10 mmHg), and arterial stiffness index (−0.12 µm; −0.14, −0.09 µm per ms/m²). Associations were in the same direction but marginally weaker for venular tortuosity and diameter. This study assessing the retinal microvasculature at scale has shown clear associations between retinal vessel morphometry, BP, and arterial stiffness index. These observations further our understanding of the preclinical disease processes and interplay between microvascular and macrovascular disease.

Targeted screening for prediabetes and undiagnosed diabetes in a community setting in India

BACKGROUND AND OBJECTIVES

Data to support the use of risk scores in screening programs to detect people with prediabetes and undiagnosed diabetes in low- and middle-income countries are limited. We evaluated a targeted screening program involving a diabetes risk score in a community setting in India in terms of its uptake, yield, and costs.

METHODS

In the Kerala Diabetes Prevention Program, 2586 individuals (age 30-60 years) without known diabetes were screened using a two-step procedure. Step 1: screening with the Indian Diabetes Risk Score at participants' homes by trained non-medical staff. Step 2: oral glucose tolerance test (OGTT) among those with IDRS score ≥60 ("screen-positive") at community-based clinics. Screening costs were expressed in 2013 US dollars.

RESULTS

96.3% of those invited for the IDRS screening consented and 79.1% of screen-positives attended clinics for an OGTT. Older age and male gender were associated with higher IDRS uptake. Female gender, higher monthly household expenditure, and higher IDRS score were associated with higher OGTT uptake. The number needed to screen (yield) to detect one person with prediabetes and undiagnosed diabetes was two and six, respectively. The average screening cost of identifying one person with prediabetes and undiagnosed diabetes was $33.8 and $116.5, respectively.

CONCLUSION

This targeted screening program had a high uptake and high yield for prediabetes and undiagnosed diabetes in a community setting in India. Alternative strategies are likely required to enhance the uptake of screening in certain groups.

A peer-support lifestyle intervention for preventing type 2 diabetes in India: A cluster-randomized controlled trial of the Kerala Diabetes Prevention Program

BACKGROUND

The major efficacy trials on diabetes prevention have used resource-intensive approaches to identify high-risk individuals and deliver lifestyle interventions. Such strategies are not feasible for wider implementation in low- and middle-income countries (LMICs). We aimed to evaluate the effectiveness of a peer-support lifestyle intervention in preventing type 2 diabetes among high-risk individuals identified on the basis of a simple diabetes risk score.

METHODS AND FINDINGS

The Kerala Diabetes Prevention Program was a cluster-randomized controlled trial conducted in 60 polling areas (clusters) of Neyyattinkara taluk (subdistrict) in Trivandrum district, Kerala state, India. Participants (age 30-60 years) were those with an Indian Diabetes Risk Score (IDRS) ≥60 and were free of diabetes on an oral glucose tolerance test (OGTT). A total of 1,007 participants (47.2% female) were enrolled (507 in the control group and 500 in the intervention group). Participants from intervention clusters participated in a 12-month community-based peer-support program comprising 15 group sessions (12 of which were led by trained lay peer leaders) and a range of community activities to support lifestyle change. Participants from control clusters received an education booklet with lifestyle change advice. The primary outcome was the incidence of diabetes at 24 months, diagnosed by an annual OGTT. Secondary outcomes were behavioral, clinical, and biochemical characteristics and health-related quality of life (HRQoL). A total of 964 (95.7%) participants were followed up at 24 months. Baseline characteristics of clusters and participants were similar between the study groups. After a median follow-up of 24 months, diabetes developed in 17.1% (79/463) of control participants and 14.9% (68/456) of intervention participants (relative risk [RR] 0.88, 95% CI 0.66-1.16, p = 0.36). At 24 months, compared with the control group, intervention participants had a greater reduction in IDRS score (mean difference: -1.50 points, p = 0.022) and alcohol use (RR 0.77, p = 0.018) and a greater increase in fruit and vegetable intake (≥5 servings/day) (RR 1.83, p = 0.008) and physical functioning score of the HRQoL scale (mean difference: 3.9 score, p = 0.016). The cost of delivering the peer-support intervention was US$22.5 per participant. There were no adverse events related to the intervention. We did not adjust for multiple comparisons, which may have increased the overall type I error rate.

CONCLUSIONS

A low-cost community-based peer-support lifestyle intervention resulted in a nonsignificant reduction in diabetes incidence in this high-risk population at 24 months. However, there were significant improvements in some cardiovascular risk factors and physical functioning score of the HRQoL scale.

TRIAL REGISTRATION

Australia and New Zealand Clinical Trials Registry ACTRN12611000262909.

Cardiometabolic Health Among Adult Offspring of Hypertensive Pregnancies: The Cardiovascular Risk in Young Finns Study

Background

Cardiometabolic health among adult offspring of hypertensive disorders of pregnancy (HDP) is relatively unknown. We hypothesized that offspring of HDP would have abnormalities in the retinal microvasculature and cardiac structure by midadulthood.

Methods and Results

The Cardiovascular Risk in Young Finns Study included randomly selected children from 5 Finnish university cities. The mean age of participants was 40 years (range 34–49 years) at the time of retinal photography and cardiac assessment. Offspring born ≥37 weeks of gestation and appropriate for gestational age (n=1006) were included. Offspring of HDP had higher systolic blood pressure (β=4.68, P<0.001), body mass index (β=1.25, P=0.009), and waist circumference (β=0.25, P=0.042), compared with offspring of normotensive pregnancies. However, no differences in fasting glucose, insulin, lipid profile, carotid intima media thickness, or brachial artery flow‐mediated dilatation were shown. Retinal arteriolar diameters were narrower (β=−0.43, P=0.009) and longer (β=32.5, P=0.023) and the arteriolar length‐to‐diameter ratio was higher (β=2.32, P=0.006) among offspring of HDP, after adjustment for age and sex. Left atrial volume indexed to body surface area (β=1.34, P=0.040) was increased. Adjustment for the confounding effects of birth weight, body mass index, smoking and socioeconomic status, and the mediating effect of hypertension had little impact on the associations.

Conclusions

Abnormalities of the retinal microvasculature and cardiac structure are seen in offspring of HDP in midadulthood. These findings may need to be considered in future primary prevention strategies of cardiovascular disease among offspring of HDP.

Availability and variability in guidelines on diabetic retinopathy screening in Asian countries

BACKGROUND

Diabetic retinopathy (DR) is a blinding yet treatable complication of diabetes. DR screening is highly cost-effective at reducing blindness. Amidst the rapidly growing diabetic population in Asia, the prevalence of DR in the region is relatively less well known.

AIMS

To review existing national DR screening guidelines of 50 countries in Asia, compare them against the International Council of Ophthalmology (ICO) guideline, and summarise the prevalence rates of DR and sight-threatening DR (STDR) in these countries.

METHODS

We systematically searched for published guidelines from the National Guideline Clearinghouse and other databases, and contacted local diabetic and ophthalmological associations of all 50 Asian countries.

RESULTS

Eleven Asian countries have published relevant guidelines, nine of which pertain to general diabetes care and two are DR-specific, covering less than half of Asia's population. The median DR prevalence among patients with diabetes is 30.5% (IQR: 23.2%-36.8%), similar to the USA and the UK. However, rates of STDR are consistently higher. All guidelines from the 11 Asian countries fulfil the ICO standard on when to start and repeat screening, except for screening interval for pregnant patients. However, only 2 of the 11 guidelines fulfil the ICO referral criteria and 6 partially fulfil. A third of the recommendations on screening process, equipment and personnel is either unavailable or incomplete.

CONCLUSIONS

Countries in Asia need to establish more comprehensive and evidence-based DR screening guidelines to facilitate the execution of robust screening programmes that could help reduce DR-related blindness, improve patient outcomes and reduce healthcare costs.

Gestational diabetes mellitus and retinal microvasculature

Background

Small-vessel dysfunction may be an important consequence of chronic hyperglycemia. We examined the association between gestational diabetes mellitus (GDM), a state of transient hyperglycemia during pregnancy, and retinal microvascular changes in pregnant women at 26–28 weeks of pregnancy.

Methods

A total of 1136 pregnant women with singleton pregnancies were recruited during their first trimester at two major Singapore maternity hospitals in an on-going birth cohort study. Participants underwent an oral glucose tolerance test and retinal imaging at 26–28 weeks gestation (n = 542). We used the 1999 World Health Organization (WHO) criteria to define GDM: ≥7.0 mmol/L for fasting glucose and/or ≥7.8 mmol/L for 2-h post-glucose. Retinal microvasculature was measured using computer software (Singapore I Vessel Analyzer, SIVA version 3.0, Singapore Eye Research Institute, Singapore) from the retinal photographs.

Results

In a multiple linear regression model adjusting for age, ethnicity and maternal education, mothers with GDM had narrower arteriolar caliber (−1.6 μm; 95% Confidence Interval [CI]: −3.1 μm, −0.2 μm), reduced arteriolar fractal dimension (−0.01 Df; 95% CI: −0.02 Df, −0.001 Df;), and larger arteriolar branching angle (1.8°; 95% CI: 0.3°, 3.3°) than mothers without GDM. After further adjusting for traditional risks of GDM, arteriolar branching angle remained significantly larger in mothers with GDM than those without GDM (2.0°; 95% CI: 0.5°, 3.6°).

Conclusions

GDM was associated with a series of retinal arteriolar abnormalities, including narrower caliber, reduced fractal dimension and larger branching angle, suggesting that transient hyperglycemia during pregnancy may cause small-vessel dysfunction.

Recommendations on the Use of Echocardiography in Adult Hypertension: A Report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Recommendations on the use of echocardiography in adult hypertension: a report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)†

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Impact of blood pressure on retinal microvasculature architecture across the lifespan: the Young Finns Study

OBJECTIVE

The present study examined the impact of BP from childhood to mid-adulthood on retinal microvascular architecture.

METHODS

The Cardiovascular Risk in Young Finns Study included children aged 3-18 years, from five Finnish University cities, with participants chosen randomly from the national population registrar from those areas. The age of participants included in the current analyses in childhood (1980) ranged from three to nine years and in mid-adulthood (2011) ranged from 34 to 40 years (complete data n = 657). Measures of retinal microvasculature architecture measured in adulthood included diameters, tortuosity, lengths, and LDR.

RESULTS

Regression analysis showed a strong negative association between childhood systolic BP and adult arteriolar diameter (standardized regression coefficient [β] -0.300; p < 0.001) and with change in systolic BP from childhood to adulthood (β = -0.249; p < 0.001). For arteriolar tortuosity, there was a strong positive association between childhood systolic BP and adult arteriolar tortuosity (β = 0.154; p < 0.001) and no association with change in systolic BP from childhood to adulthood (β = 0.072; p = 0.110).

CONCLUSIONS

High BP in childhood and increased BP from childhood to adulthood impacts on retinal microvascular architecture in mid-adulthood.

Impact of diabetes on eye care service needs: the National Indigenous Eye Health Survey

BACKGROUND

To assess the proportion of Australian Indigenous adults who require eye care services (separately among those with and without diabetes) and determine implications for eye care service planning.

DESIGN

The National Indigenous Eye Health Survey (NIEHS) was a population-based study of 30 randomly selected geographical areas.

PARTICIPANTS

The NIEHS included 1189 Indigenous adults aged 40-80 years.

METHODS

A standardized eye examination was performed.

MAIN OUTCOME MEASURE

The number requiring eye care services by diabetes status.

RESULTS

Those with diabetes were older (median 53 years) than those without diabetes (median age 50 years), P < 0.001. The total estimated population-based need for annual eye care in the NIEHS population was 52% (n = 615), and of those 72% were people with diabetes. Among those with diabetes, 29% required further primary referral for diabetic retinopathy, 12% for cataract, 1% for trachomatous trichiasis and 5% for uncorrected distance refractive error. Among those without diabetes 13% required further primary referral for cataract, 0% for trachomatous trichiasis and 5% for uncorrected distance refractive error.

CONCLUSION

This study has shown that among Indigenous adults, those with diabetes form 72% of those requiring an eye examination in any year. A key strategy to close the gap for vision for Australia's Indigenous population is to ensure those with diabetes undergo annual eye screening, have clearly defined care pathways and receive timely treatment. Establishing care pathways for those who have diabetes would also improve access to eye care services for others in the community.

Retinal arteriolar narrowing and incidence of knee replacement for osteoarthritis: a prospective cohort study

OBJECTIVES

The role of the microcirculation in the pathogenesis of osteoarthritis (OA) remains unclear. This prospective cohort study examined the association between retinal vascular calibre and incidence of knee replacement for OA.

DESIGN

1838 participants of the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study had retinal vascular calibre measured using a nonmydriatic digital fundus camera in 1999-2000 and were aged ≥ 40 years at joint replacement data collection commencement. The incidence of knee replacement for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).

RESULTS

77 participants underwent knee replacement for OA. They had narrower retinal arteriolar calibre compared with those without knee replacement (166.1 ± 24.8 μm vs 174.3 ± 24.5 μm, P = 0.004). For every one standard deviation reduction in retinal arteriolar calibre, the incidence of knee replacement increased by 25% (HR 1.25, 95% confidence interval (CI) 1.00-1.56). Participants in the narrower two-thirds of arteriolar calibre had twice the risk of knee replacement compared with those in the widest one-third (HR 2.00, 95% CI 1.07-3.74, P = 0.03) after adjustment for sex, body mass index (BMI), physical activity and HbA1c. There was no association for retinal venular calibre.

CONCLUSIONS

Retinal arteriolar narrowing is associated with increased risk of knee replacement for OA suggesting that further work is warranted to determine the role of the microcirculation in the pathogenesis of knee OA.

Impact of adiposity on cardiac structure in adult life: the Childhood Determinants of Adult Health (CDAH) study

BACKGROUND

We have examined the association between adiposity and cardiac structure in adulthood, using a life course approach that takes account of the contribution of adiposity in both childhood and adulthood.

METHODS

The Childhood Determinants of Adult Health study (CDAH) is a follow-up study of 8,498 children who participated in the 1985 Australian Schools Health and Fitness Survey (ASHFS). The CDAH follow-up study included 2,410 participants who attended a clinic examination. Of these, 181 underwent cardiac imaging and provided complete data. The measures were taken once when the children were aged 9 to 15 years, and once in adult life, aged 26 to 36 years.

RESULTS

There was a positive association between adult left ventricular mass (LVM) and childhood body mass index (BMI) in males (regression coefficient (β) 0.41; 95% confidence interval (CI): 0.14 to 0.67; p = 0.003), and females (β = 0.53; 95% CI: 0.34 to 0.72; p < 0.001), and with change in BMI from childhood to adulthood (males: β = 0.27; 95% CI: 0.04 to 0.51; p < 0.001, females: β = 0.39; 95% CI: 0.20 to 0.58; p < 0.001), after adjustment for confounding factors (age, fitness, triglyceride levels and total cholesterol in adulthood). After further adjustment for known potential mediating factors (systolic BP and fasting plasma glucose in adulthood) the relationship of LVM with childhood BMI (males: β = 0.45; 95% CI: 0.19 to 0.71; p = 0.001, females: β = 0.49; 95% CI: 0.29 to 0.68; p < 0.001) and change in BMI (males: β = 0.26; 95% CI: 0.04 to 0.49; p = 0.02, females: β = 0.40; 95% CI: 0.20 to 0.59; p < 0.001) did not change markedly.

CONCLUSIONS

Adiposity and increased adiposity from childhood to adulthood appear to have a detrimental effect on cardiac structure.

Effect of phacoemulsification on trabeculectomy function

BACKGROUND

To evaluate the effect of phacoemulsification on trabeculectomy function.

DESIGN

Retrospective case-control study.

PARTICIPANTS

Forty-eight patients who underwent trabeculectomy surgery and had at least 2 years of follow up.

METHODS

Patients were classified into two groups: patients who had phacoemulsification subsequent to trabeculectomy (Trab_phaco, n = 18) and patients who were pseudophakic for greater than 6 months preceding their trabeculectomy (Phaco_trab, n = 30). Groups were matched for length of follow up of 2 years from time of trabeculectomy.

MAIN OUTCOME MEASURES

The primary outcome measures were target intraocular pressure of criteria A, ≤12 mmHg; B, ≤15 mmHg; C, ≤18 mmHg with or without additional topical treatment. A separate measure for bleb function failure was also used; with failure defined as the need for additional topical antiglaucoma therapy or surgical intervention to achieve control of intraocular pressure.

RESULTS

There was no significant difference in achieving each intraocular pressure criterion between groups (12 months, P = 1.0; 24 months, P = 0.330). In the first 12 months, significantly more trabeculectomies in the Trab_phaco group failed, requiring additional intervention to control the IOP (39%) compared with the Phaco_trab (10%) group (P = 0.028). Although this trend continued at 24 months, there were no significant differences in failure rates (P = 0.522).

CONCLUSIONS

Phacoemulsification performed after trabeculectomy significantly increased rates of bleb failure in the following 12 months but not at 24 months.

Prevention of type 2 diabetes and its complications in developing countries: a review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a significant global public health problem affecting more than 285 million people worldwide. Over 70% of those with T2DM live in developing countries, and this proportion is increasing annually. Evidence suggests that lifestyle and other nonpharmacological interventions can delay and even prevent the development of T2DM and its complications; however, to date, programs that have been specifically adapted to the needs and circumstances of developing countries have not been well developed or evaluated.

PURPOSE

The purpose of this article is to review published studies that evaluate lifestyle and other non-pharmacological interventions aimed at preventing T2DM and its complications in developing countries.

METHODS

We undertook an electronic search of MEDLINE, PubMed, and EMBASE with the English language restriction and published until 30 September 2009.

RESULTS

Nine relevant publications from seven studies were identified. The reported interventions predominantly used counseling and educational methods to improve diet and physical activity levels. Each intervention was found to be effective in reducing the risk of developing T2DM in people with impaired glucose tolerance, and improving glycemic control in people with T2DM.

CONCLUSIONS

The current evidence concerning the prevention of T2DM and its complications in developing countries has shown reasonably consistent and positive results; however, the small number of studies creates some significant limitations. More research is needed to evaluate the benefits of low-cost screening tools, as well as the efficacy, cost-effectiveness, and sustainability of culturally appropriate interventions in such countries.

Risk of cardiovascular and all-cause mortality: impact of impaired health-related functioning and diabetes: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study

OBJECTIVE

There is an established link between health-related functioning (HRF) and cardiovascular disease (CVD) mortality, and it is known that those with diabetes predominantly die of CVD. However, few studies have determined the combined impact of diabetes and impaired HRF on CVD mortality. We investigated whether this combination carries a higher CVD risk than either component alone.

RESEARCH DESIGN AND METHODS

The Australian Diabetes, Obesity and Lifestyle (AusDiab) study included 11,247 adults aged ≥ 25 years from 42 randomly selected areas of Australia. At baseline (1999-2000), diabetes status was defined using the World Health Organization criteria and HRF was assessed using the SF-36 questionnaire.

RESULTS

Overall, after 7.4 years of follow-up, 57 persons with diabetes and 105 without diabetes had died from CVD. In individuals with and without diabetes, HRF measures were significant predictors of increased CVD mortality. The CVD mortality risks among those with diabetes or impaired physical health component summary (PCS) alone were similar (diabetes only: hazard ratio 1.4 [95% CI 0.7-2.7]; impaired PCS alone: 1.5 [1.0-2.4]), while those with both diabetes and impaired PCS had a much higher CVD mortality (2.8 [1.6-4.7]) compared with those without diabetes and normal PCS (after adjustment for multiple covariates). Similar results were found for the mental health component summary.

CONCLUSIONS

This study demonstrates that the combination of diabetes and impaired HRF is associated with substantially higher CVD mortality. This suggests that, among those with diabetes, impaired HRF is likely to be important in the identification of individuals at increased risk of CVD mortality.

Health behaviours, socioeconomic status and diabetes incidence: the Australian Diabetes Obesity and Lifestyle Study (AusDiab)

AIMS/HYPOTHESIS

To identify the impact of socioeconomic status on incident impaired glucose metabolism and type 2 diabetes and to investigate the mediating role of health behaviours on this relationship using national, population-based data.

METHODS

The Australian Diabetes Obesity and Lifestyle (AusDiab) Study is a national, population-based, longitudinal study of adults aged 25 years and above. A total sample of 4,405 people provided complete baseline (1999-2000) and 5 year follow-up (2004-2005) data relevant for these analyses. Fasting plasma glucose and 2 h plasma glucose were obtained from an OGTT, and demographic, socioeconomic and behavioural data were collected by interview and questionnaire. Multinomial logistic regression examined the role of socioeconomic position in the development of diabetes and mediation analyses tested the contribution of health behaviours in this relationship.

RESULTS

Highest level of education was a stronger predictor of incident impaired glucose tolerance and type 2 diabetes (p = 0.002), compared with household income (p = 0.103), and occupational grade (p = 0.202). Education remained a significant independent predictor of diabetes in fully adjusted models. However, the relationship was attenuated by the health behaviours (smoking and physical activity). Mediation analyses indicated that these behaviours were partial mediators (explaining 27%) of the socioeconomic status-diabetes relationship.

CONCLUSION/INTERPRETATION

Smoking and physical activity partly mediate the relationship between low education and type 2 diabetes. Identification of these modifiable behavioural mediators should facilitate the development of effective health promotion campaigns to target those at high risk of developing type 2 diabetes.

Wave reflection predicts cardiovascular events in hypertensive individuals independent of blood pressure and other cardiovascular risk factors: an ASCOT (Anglo-Scandinavian Cardiac Outcome Trial) substudy

OBJECTIVES

This study investigated whether wave reflection measured by wave intensity analysis predicts future cardiovascular events in individuals with hypertension and sought to establish whether this relationship is independent of other cardiovascular risk factors and is associated with evidence of increased load on the left ventricle.

BACKGROUND

Wave reflection may impose an additional load on the left ventricle, and augmentation index, a surrogate of wave reflection, has been reported to predict cardiovascular events in some, but not all studies.

METHODS

Measurements of brachial and carotid blood pressure (BP) measurement, carotid ultrasound, echocardiography, and blood chemistry analyses were performed on 259 ASCOT (Anglo Scandinavian Cardiac Outcomes Trial) participants approximately 1 year after randomization, and wave intensity analysis was used to calculate wave reflection index (WRI), the ratio of peak forward to peak backward pressure (P(b)/P(f)), and carotid augmentation index (cAI(x)). All participants were followed up for a median period of 5.9 years, accruing 33 cardiovascular events.

RESULTS

WRI, P(b)/P(f), and to a lesser extent, cAI(x), were correlated. WRI predicted cardiovascular events (hazard ratio: 2.10; 95% confidence interval: 1.10 to 3.99; p = 0.02) in an unadjusted model. Multivariate analysis showed that this association was independent of BP. P(b)/P(f) and cAI(x) did not significantly predict cardiovascular events. WRI was also positively associated with increased left ventricular mass index and elevated B-type natriuretic peptide adjusted for age and sex, and these associations were independent of BP or other cardiovascular risk factors.

CONCLUSIONS

Higher wave reflection predicts future cardiovascular events independent of conventional risk factors in people with treated hypertension.

Differential effects of antihypertensive treatment on left ventricular diastolic function: an ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) substudy

OBJECTIVES

We hypothesized that an amlodipine-based regimen would have more favorable effects on left ventricular (LV) diastolic function.

BACKGROUND

Different antihypertensive therapies may vary in their effect on LV diastolic function.

METHODS

The HACVD (Hypertension Associated Cardiovascular Disease) substudy of ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) collected detailed cardiovascular phenotypic data on a subset of 1,006 participants recruited from 2 centers (St. Mary's Hospital, London, and Beaumont Hospital, Dublin). Conventional and tissue Doppler echocardiography and measurement of plasma B-type natriuretic peptide (BNP) were performed approximately 1 year after randomization to atenolol-based or amlodipine-based antihypertensive treatment to assess LV diastolic function.

RESULTS

On-treatment blood pressure (BP) (mean +/- SD) was similar in both groups: atenolol-based regimen, systolic BP of 137 +/- 17 mm Hg, diastolic BP of 82 +/- 9 mm Hg; amlodipine-based regimen, systolic BP of 136 +/- 15 mm Hg, diastolic BP of 80 +/- 9 mm Hg. Ejection fraction did not differ between groups, but early diastolic mitral annular velocity (E'), a measure of diastolic relaxation, was lower in patients on the atenolol-based regimen: atenolol-based regimen, 7.9 +/- 1.8; amlodipine-based regimen, 8.8 +/- 2.0. A measure of left ventricular filling pressure, E/E', and BNP were significantly higher in patients on the atenolol-based regimen. Differences in E', E/E', and BNP remained significant after adjustment for age and sex. Further adjustment for systolic BP, LV mass index, and heart rate had no impact on differences in mean E' or BNP. The difference in E/E' was attenuated.

CONCLUSIONS

Patients receiving treatment with an amlodipine-based regimen had better diastolic function than patients treated with the atenolol-based regimen. Treatment-related differences in diastolic function were independent of BP reduction and other factors that are known to affect diastolic function.

Is there a link between components of health-related functioning and incident impaired glucose metabolism and type 2 diabetes? The Australian Diabetes Obesity and Lifestyle (AusDiab) study

OBJECTIVE

To determine the longitudinal association of components of health-related functioning (HRF) with incident impaired glucose metabolism and type 2 diabetes.

RESEARCH DESIGN AND METHODS

The Australian Diabetes Obesity and Lifestyle (AusDiab) study is a national, longitudinal study of adults aged > or =25 years from 42 randomly selected areas of Australia. Diabetes status was defined using the World Health Organization criteria, and HRF was assessed using the SF-36 questionnaire in 1999-2000 and 2004-2005.

RESULTS

Incident impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and newly diagnosed type 2 diabetes were associated with increased bodily pain at baseline compared with those with normal glucose tolerance (NGT) (IFG P = 0.005, IGT P < 0.004, and newly diagnosed type 2 diabetes P = 0.005), after adjustment. In addition, those with incident IGT and newly diagnosed type 2 diabetes had significantly reduced physical functioning, general health, mental health, and vitality at baseline compared with those with NGT. After we controlled for factors associated with incident diabetes, those in the lowest quartile of the physical component summary scale at baseline had at least a 50% higher risk of progression to impaired glucose metabolism and diabetes 5 years later.

CONCLUSIONS

These findings show that incident IFG, IGT, and newly diagnosed type 2 diabetes are associated with reduced HRF independent of cardiovascular disease and that this is evident before the onset of these conditions. If future health promotion campaigns are to effectively target those at high risk of developing diabetes, an understanding of the process of declining health before onset of the disease is essential.

Atorvastatin Treatment Is Associated With Less Augmentation of the Carotid Pressure Waveform in Hypertension

Hydroxymethylglutaryl-CoA reductase inhibitors (statins) reduce cardiovascular events in hypertensive subjects, but their effect on carotid BP, pressure augmentation, and wave reflection is unknown. We compared the effect of atorvastatin with placebo in a substudy of the lipid-lowering arm of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT-LLA). Hypertensive patients (n=142; age=43 to 79 years; 127 male) with total cholesterol ≤6.5 mmol/L were randomized to atorvastatin 10 mg or placebo. Carotid BP and flow velocity were measured by tonometry and Doppler ultrasound. Augmentation index (carotid AI x ) was calculated, and waveforms were separated into backward and forward components by wave intensity analysis. Brachial BP was similar in atorvastatin and placebo groups. Carotid AI x and augmentation pressure were significantly less in patients randomized to atorvastatin (mean [SD]: 21.7 [12.1] versus 25.9 [10.3] %; P =0.027 and 10.2 [6.5] versus 13.1 [6.6] mm Hg; P =0.016, respectively), and atorvastatin treatment was associated with significantly less wave reflection from the body. Carotid systolic BP was slightly lower in the atorvastatin group, but there was a statistically significant interaction between lipid-lowering and antihypertensive regimen with lower carotid systolic BP in patients randomized to amlodipine-based therapy and atorvastatin. Carotid wave velocity, timings of waves, and wave intensities did not differ significantly between atorvastatin and placebo groups. Atorvastatin treatment is associated with less augmentation of the carotid BP waveform and less wave reflection from the body. This could contribute to the reduction in risk of cardiovascular events by statins.

Serum amyloid A, C-reactive protein, and retinal microvascular changes in hypertensive diabetic and nondiabetic individuals: an Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) substudy

OBJECTIVE

To study the association of the inflammatory markers serum amyloid A (SAA) and C-reactive protein (CRP) with retinal microvascular parameters in hypertensive individuals with and without type 2 diabetes.

RESEARCH DESIGN AND METHODS

This cross-sectional analysis was a substudy in 711 patients (159 with and 552 without diabetes) of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) based on digital 30-degree images of superior and inferior temporal retinal fields.

RESULTS

SAA was associated with arteriolar length-to-diameter ratio positively in nondiabetic patients (P(trend)= 0.028) but negatively in diabetic patients (P(trend)= 0.005). The difference was unlikely to be a chance finding (P = 0.007 for interaction). Similar results were found for the association of SAA with arteriolar tortuosity (P = 0.05 for interaction). Associations were less pronounced for CRP and retinal parameters.

CONCLUSIONS

Inflammatory processes are differentially involved in retinal microvascular disease in diabetic compared with nondiabetic hypertensive individuals.

Longitudinal association of glucose metabolism with retinopathy: results from the Australian Diabetes Obesity and Lifestyle (AusDiab) study

OBJECTIVE

We determined the longitudinal association of glucose metabolism with retinopathy in a sample of the Australian population.

RESEARCH DESIGN AND METHODS

The Australian Diabetes Obesity and Lifestyle (AusDiab) study is a national, longitudinal study of adults aged > or =25 years from 42 randomly selected areas of Australia. Retinopathy was assessed at baseline in 1999-2000 and 5 years later in 2004-2005 in participants identified as having diabetes (based on self-report and oral glucose tolerance test) and impaired glucose metabolism and in a random sample with normal glucose tolerance. Complete retinal data were available for 1,192 participants. Photographs were graded at two time points according to a simplified version of the Wisconsin grading system.

RESULTS

The 5-year incidences of retinopathy were 13.9 and 3.0% among those with known and newly diagnosed diabetes at baseline, respectively. Of those who developed incident newly diagnosed diabetes at follow-up, 11.9% had retinopathy at baseline compared with 5.6% of those who did not progress to incident newly diagnosed diabetes (P = 0.037). After adjustment for factors identified as risk factors for diabetes, individuals with retinopathy signs at baseline were twice as likely to develop incident newly diagnosed diabetes compared with those who did not have retinopathy signs at baseline.

CONCLUSIONS

The 5-year incidence of retinopathy was 13.9% among individuals with known diabetes. Nondiabetic individuals with retinopathy signs at baseline had a twofold higher risk of developing incident newly diagnosed diabetes 5 years later. This result provides further evidence that mild retinopathy signs may be a preclinical marker of underlying microvascular disease and future diabetes risk.

Relation between fasting glucose and retinopathy for diagnosis of diabetes: three population-based cross-sectional studies

BACKGROUND

The WHO and American Diabetes Association criteria for diagnosing diabetes mellitus assume the presence of a glycaemic threshold with high sensitivity for identifying retinopathy. However, this assumption is based on data from three previous studies that had important limitations in detecting retinopathy. We aimed to provide updated data for the relation between fasting plasma glucose (FPG) and retinopathy, and to assess the diagnostic accuracy of current FPG thresholds in identifying both prevalent and incident retinopathy.

METHODS

We examined the data from three cross-sectional adult populations: those in the Blue Mountains Eye Study (BMES, Australia, n=3162), the Australian Diabetes, Obesity and Lifestyle Study (AusDiab, Australia, n=2182), and the Multi-Ethnic Study of Atherosclerosis (MESA, USA, n=6079). Retinopathy was diagnosed from multiple retinal photographs of each eye, and graded according to the modified Airlie House Classification system. Plasma glucose concentrations were measured from fasting venous blood samples.

FINDINGS

The overall prevalence of retinopathy was 11.5% in BMES (95% CI 10.4-12.6%), 9.6% in AusDiab (8.4-10.9), and 15.8% in MESA (14.9-16.7). However, we found inconsistent evidence of a uniform glycaemic threshold for prevalent and incident retinopathy, with analyses suggesting a continuous relation. The widely used diabetes FPG cutoff of 7.0 mmol/L or higher had sensitivity less than 40% (range 14.8-39.1) for detecting retinopathy, with specificity between 80.8% and 95.8%. The area under receiver operating characteristic curves for FPG and retinopathy was low and ranged from 0.56 to 0.61.

INTERPRETATION

We saw no evidence of a clear and consistent glycaemic threshold for the presence or incidence of retinopathy across different populations. The current FPG cutoff of 7.0 mmol/L used to diagnose diabetes did not accurately identify people with and without retinopathy. These findings suggest that the criteria for diagnosing diabetes could need reassessment.

Retinal arteriolar narrowing predicts incidence of diabetes: the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study

OBJECTIVE

To examine the relationship of retinal vascular caliber to incident diabetes in a population-based cohort.

RESEARCH DESIGN AND METHODS

The Australian Diabetes, Obesity and Lifestyle (AusDiab) Study recruited adults aged 25+ years across Australia in 1999-2000, with a follow-up 5 years later in 2004-2005. Participants' glycemic status was classified using fasting plasma glucose (FPG) and 2-h oral glucose tolerance (2-h plasma glucose [2hPG]) tests. Diabetes was diagnosed if FPG was >or=7.0 mmol/l or 2hPG was >or=11.1 mmol/l. Retinal vascular caliber was measured from baseline retinal photographs using a computer-assisted program.

RESULTS

Of the 803 participants without diabetes at baseline, 108 (13.4%) developed diabetes at follow-up: 7 (2.8%) of 246 participants with normal glucose tolerance, 9 (13.6%) of 66 participants with impaired fasting glucose, and 92 (18.7%) of 491 participants with impaired glucose tolerance. After multivariate analysis, participants with narrower retinal arteriolar caliber had a higher risk of diabetes (odds ratio 2.21 [95% CI 1.02-4.80], comparing smallest versus highest arteriolar caliber tertiles, P = 0.04 for trend). There was no association between retinal venular caliber and incident diabetes.

CONCLUSIONS

Narrower retinal arteriolar caliber predicted risk of diabetes. These data provide further evidence that microvascular changes may contribute to the pathogenesis of diabetes.

Glucose indices, health behaviors, and incidence of diabetes in Australia: the Australian Diabetes, Obesity and Lifestyle Study

OBJECTIVE

This national, population-based study reports diabetes incidence based on oral glucose tolerance tests (OGTTs) and identifies risk factors for diabetes in Australians.

RESEARCH DESIGN AND METHODS

The Australian Diabetes, Obesity and Lifestyle Study followed-up 5,842 participants over 5 years. Normal glycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes were defined using World Health Organization criteria.

RESULTS

Age-standardized annual incidence of diabetes for men and women was 0.8% (95% CI 0.6-0.9) and 0.7% (0.5-0.8), respectively. The annual incidence was 0.2% (0.2-0.3), 2.6% (1.8-3.4), and 3.5% (2.9-4.2) among those with normal glycemia, IFG, and IGT, respectively, at baseline. Among those with IFG, the incidence was significantly higher in women (4.0 vs. 2.0%), while among those with IGT, it was significantly higher in men (4.4 vs. 2.9%). Using multivariate logistic regression, hypertension (odds ratio 1.64 [95% CI 1.17-2.28]), hypertriglyceridemia (1.46 [1.05-2.02]), log fasting plasma glucose (odds ratio per 1 SD 5.25 [95% CI 3.98-6.92]), waist circumference (1.26 [1.08-1.48]), smoking (1.70 [96% CI 1.11-2.63]), physical inactivity (1.56 [1.12-2.16]), family history of diabetes (1.82 [1.30-2.52]), and low education level (1.85 [1.04-3.31]) were associated with incident diabetes. In age- and sex-adjusted models, A1C was a predictor of diabetes in the whole population, in those with normal glycemia, and in those with IGT or IFG.

CONCLUSIONS

Diabetes incidence is 10-20 times greater in those with IGT or IFG than those with normal glycemia. Measures of glycemia, A1C, metabolic syndrome components, education level, smoking, and physical inactivity are risk factors for diabetes.

Impact of size at birth on the microvasculature: the Avon Longitudinal Study of Parents and Children

BACKGROUND

The impact of early life factors on the microvasculature is relatively unknown.

OBJECTIVES

We hypothesized that small birth size may be associated with structural variations in the retinal vasculature in children.

METHODS

The Avon Longitudinal Study of Parents and Children followed a cohort of children born in 1991-1992 from birth. The current study included the first 263 children who were systematically screened in the year-12 follow-up. Complete data were available for 166 children with a gestation of > or = 37 weeks. Retinal circulatory measures were evaluated, including retinal microvascular tortuosity and bifurcation optimality deviance, an indicator of abnormal endothelial function.

RESULTS

Optimality deviance and retinal tortuosity were higher among those with lower birth weight. Linear regression modeling was used to assess the association of retinal microvascular measures with birth weight. The standardized beta coefficient between optimality deviance and birth weight was -.182 adjusted for gender and age in weeks; additional adjustment for systolic blood pressure and heart rate had little impact on the beta coefficient. A similar association was observed for retinal tortuosity.

CONCLUSION

The findings of this study suggest that early life factors may have an important impact on retinal vascular structure, possibly through an adverse effect on endothelial function.

Diagnostic thresholds for diabetes: the association of retinopathy and albuminuria with glycaemia

AIM

We examined the association of fasting plasma glucose (FPG), 2-h plasma glucose (2hPG) and HbA1c with retinopathy and microalbuminuria using both deciles of glycaemia and change point models, to validate current diagnostic criteria for diabetes and to identify therapeutic thresholds for glycaemic control.

METHODS

The Australian Diabetes Obesity and Lifestyle study (AusDiab), conducted in 1999-2000, included adults aged > or =25 years from 42 randomly selected areas of Australia. Retinopathy and albuminuria were assessed in participants identified as having diabetes (based on self report and oral glucose tolerance test), impaired fasting glucose, impaired glucose tolerance and in a random sample with normal glucose tolerance. Data were available for 2,182 participants with retinal photographs and 2,389 with urinary albumin/creatinine results.

RESULTS

The prevalence of retinopathy in the first 8 deciles of FPG and HbA1c and the first 9 deciles of 2hPG were 7.2, 6.6, and 6.3%, respectively and showed no variation with increasing glucose or HbA1c. Above these levels, the prevalence rose markedly to 18.6% in the top 2 deciles of FPG, 21.3% in the top 2 deciles of HbA1c and 10.9% in the top decile of 2hPG. The thresholds for increasing prevalence of retinopathy were 7.1 mmol/l for FPG, 6.1% for HbA1c and 13.1 mmol/l for 2hPG. The prevalence of microalbuminuria rose gradually across deciles of each glycaemic measure. Thresholds were less clear than for retinopathy, but were seen at a FPG of 7.2 mmol/l and HbA1c of 6.1%, with no evidence of a threshold effect for 2hPG.

CONCLUSIONS

The prevalence of retinopathy rose dramatically in the highest deciles of each glycaemic measure, while for microalbuminuria the increase of prevalence was more gradual. The FPG values corresponded well with the WHO diagnostic cut-point for diabetes, however the 2hPG value did not. HbA1c thresholds were similar for both retinopathy and microalbuminuria and compared well to values shown in other studies. These results support current targets for FPG and HbA1c in preventing microvascular complications.

Six year incidence and progression of diabetic retinopathy: results from the Mauritius diabetes complication study

AIMS

To determine the incidence, progression and risk factors for diabetic retinopathy in the multiethnic population of Mauritius.

METHOD

A longitudinal, population-based study was conducted in Mauritius, during 1987, 1992 and 1998. Participants identified through the study as having diabetes (both known and newly diagnosed, by self-report and oral glucose tolerance test) and one in four participants with impaired glucose tolerance (IGT) underwent complications screening in 1992 and 1998. Retinal photographs were taken using a TRC-50VT retinal camera in three fields of the right eye (centred on the optic disc; macula (temporal to the optic disc); and nasal to disc). Photographs were graded according to a simplified version of the Wisconsin grading system.

RESULTS

The 6-year incidence of diabetic retinopathy was 23.8% (sight-threatening in 0.4%). Among those with known diabetes mellitus (KDM) and free of retinopathy at baseline the incidence of non-proliferative diabetic retinopathy (NPDR) was 29.2% and proliferative diabetic retinopathy (PDR) was 1.0%. Among those with newly diagnosed diabetes mellitus (NDM) at baseline the incidence of NPDR was 19.1% (no incident cases of PDR were found). Independent risk factors for retinopathy using the baseline population characteristics were duration of diabetes and fasting plasma glucose.

CONCLUSIONS

This is one of the few recent population-based studies of diabetic retinopathy undertaken in a developing nation. The incidence of retinopathy in Mauritius was high among those with NDM at baseline, with one in five developing retinopathy over 6 years. These results support the concept that screening for diabetes is important.

Association of glucose metabolism, smoking and cardiovascular risk factors with incident peripheral arterial disease: the DESIR study

AIMS

We determined the 6-year incidence of peripheral arterial disease (PAD) in a French population and assessed the association of glucose metabolism, smoking, cardiovascular risk factors and physical activity with incident PAD.

METHODS

Participants from the French Data from a Epidemiological Study on the Insulin Resistance Syndrome (DESIR) were studied. Participants analysed were 30-65 years (at baseline) and had complete data (n=3805) after 6 years of follow-up. Diabetes was diagnosed according to the 1999 WHO criteria on the basis of fasting plasma glucose results or previous diagnosis of diabetes mellitus. The ankle brachial pressure index (ABPI) and a claudication question were used to classify PAD.

RESULTS

The 6-year incidence of PAD (defined by ABPI<0.9 and or claudication present) among those with normal fasting glucose (NFG) and free of PAD at baseline was 5.1%. Among those with impaired fasting glucose (IFG) at baseline the incidence of PAD was 4.9% and among those with diabetes mellitus at baseline the incidence of PAD was 9.8%. The incidence of PAD among those who maintained NFG over 6 years was 4.7% and among those who progressed to diabetes over 6 years was 10.2%. Those who progressed from NFG or IFG to diabetes over 6 years were twice as likely to develop PAD compared to those who maintained NFG over 6 years, after adjustment for age and sex (OR (95% CI), 2.22 (1.12-4.42)). Independent risk factors for incident PAD using baseline population characteristics were diabetes (OR (95% CI) 2.11 (1.25-3.55)), systolic BP 122-135mmHg 1.06 (0.70-1.60), >135mmHg 1.54 (1.04-2.27) and current smoking 1.60 (1.10-2.34) after multivariate adjustment for age, sex, cholesterol, triglycerides and waist circumference.

CONCLUSIONS

This French study shows that those who progress to diabetes are twice as likely to develop PAD, compared to those who maintain NFG. Peripheral arterial disease is a treatable condition and more aggressive management of atherosclerotic risk factors could reduce the numbers of people who develop PAD.

Retinopathy in persons with impaired glucose metabolism: the Australian Diabetes Obesity and Lifestyle (AusDiab) study

PURPOSE

To describe risk factors and vascular disease associations of retinopathy in people with impaired glucose metabolism.

DESIGN

Population-based cross-sectional study.

METHODS

Retinal photographs taken of participants with impaired glucose tolerance and impaired fasting glucose were graded for retinopathy. Risk factors and cardiovascular outcomes were ascertained.

RESULTS

Retinopathy was present in 69 (6.7%) of 1027 participants with impaired glucose tolerance or impaired fasting glucose. After multivariate adjustment, retinopathy was associated with prevalent stroke (odds ratio 4.2, 95% confidence interval, 1.8 to 9.7).

CONCLUSIONS

Retinopathy is common in persons with impaired glucose metabolism and may be associated with prevalent stroke.

Albuminuria is evident in the early stages of diabetes onset: results from the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab)

BACKGROUND

Albuminuria is a common complication of diabetes and a leading cause of end-stage renal disease. We determined the prevalence of and factors associated with albuminuria in an Australian population and examined the association of albuminuria with glucose tolerance.

METHODS

The Australian Diabetes, Obesity, and Lifestyle Study included 11,247 adults aged 25 years and older from 42 randomly selected areas of Australia. Microalbuminuria is defined as an albumin-creatinine ratio of 22 to 220 mg/g (2.5 to 25 mg/mmol) in men and 31 to 220 mg/g (3.5 to 25 mg/mmol) in women, and macroalbuminuria is defined as an albumin-creatinine ratio of 220 mg/g or greater (> or =25.0 mg/mmol).

RESULTS

Overall, 25.3% of patients with diabetes mellitus (known [KDM] and newly diagnosed [NDM], type 1 and type 2) had evidence of albuminuria (21.0%, microalbuminuria; 4.3%, macroalbuminuria). Prevalence increased with increasing glycemia (normal glucose tolerance [NGT], 5.1%; impaired fasting glucose [IFG], 9.3%; impaired glucose tolerance, 11.0%; NDM, 17.8%; and KDM, 32.6% [type 2 only]). Patients with diabetes (KDM and NDM) and IFG had an increased risk for albuminuria compared with those with NGT independent of age, sex, and other known risk factors for albuminuria. Logistic regression modeling identified age, duration of diabetes, systolic blood pressure, current smoking, body mass index, and glycated hemoglobin level as independent risk factors for albuminuria.

CONCLUSION

This Australian population-based study shows that albuminuria is common among patients with established diabetes, is present before the onset of diabetes, and becomes more prevalent with worsening glucose tolerance.