Do known risk factors explain the higher coronary heart disease mortality in South Asian compared with European men? Prospective follow-up of the Southall and Brent studies, UK

AIMS/HYPOTHESIS

We examined prospectively whether measured risk factors can explain the higher CHD mortality in South Asians compared with Europeans.

MATERIALS AND METHODS

Conventional CHD risk factors and those associated with insulin resistance were measured in 1,787 European and 1,420 South Asian men aged 40 to 69 years at baseline in the population-based Southall and Brent studies (London) between 1988 and 1990. Participants were followed up for mortality.

RESULTS

By February 2006, there were 202 CHD deaths (108 Asian, 94 European). South Asian men had double the CHD mortality of European men in Cox regression analyses adjusted for age, smoking, and cholesterol (hazard ratio [HR] 2.14, 95% CI 1.56-2.94, p<0.001). Nearly half of all South Asian CHD deaths versus 13% of deaths among Europeans were among persons with diabetes. Asian men had greater CHD mortality than Europeans, both in the with- and the without-diabetes categories at baseline. CHD mortality remained significantly higher in South Asian men in multivariable models that adjusted for conventional risk factors and diabetes and/or impaired glucose regulation, features of insulin resistance, or the metabolic syndrome (HR 1.6-1.9). Accounting for co-morbidity and socio-economic status did not materially alter the findings.

CONCLUSIONS/INTERPRETATION

These data confirm that South Asian men have significantly higher CHD mortality than their European counterparts, while indicating that neither conventional risk factors, nor insulin resistance parameters or metabolic syndrome criteria as currently defined can account for this excess risk. The contribution of unmeasured factors to the elevated vascular risk in South Asians should be addressed in future studies.

Weight gain is associated with improved glycaemic control but with adverse changes in plasma lipids and blood pressure isn Type 1 diabetes

AIMS

To assess the effects of weight gain on metabolic control, plasma lipids and blood pressure in patients with Type 1 diabetes.

METHODS

Patients in the EURODIAB Prospective Complications Study (n = 3250) were examined at baseline and 1800 (55%) were re-examined a mean of 7.3 years later. Patients had Type 1 diabetes, defined as a diagnosis made before age 36 years and with a need for continuous insulin therapy within a year of diagnosis. Patients were aged 15-60 years at baseline and were stratified for age, sex and duration of diabetes.

RESULTS

The change in HbA(1c) from baseline to follow-up examination was significantly more favourable in those who gained 5 kg or more during follow-up ('marked weight gain') than in patients who gained less or no weight or lost weight ('less or no weight gain'). In those with marked weight gain, there was a significantly greater rise in plasma triglycerides and total cholesterol and significantly less favourable changes in low-density lipoprotein and high-density lipoprotein cholesterol compared with those with less or no weight gain, with or without adjustment for HbA(1c). Systolic and diastolic blood pressure also rose significantly more in the group with marked weight gain.

CONCLUSION

Weight gain in patients with Type 1 diabetes has adverse effects on plasma lipids and blood pressure, despite a small improvement in glycaemic control.

Is pregnancy a risk factor for microvascular complications? The EURODIAB Prospective Complications Study

AIMS

To examine the long-term influence of pregnancy on the development and progression of microvascular complications in Type 1 diabetes.

METHODS

In the EURODIAB Prospective Complications Study (PCS), 793 women potentially child bearing at baseline completed the follow-up (7.3 years) and 163 (21%) gave birth during the follow-up period. We compared risk factors [mean levels of age, duration of diabetes, HbA(1c), systolic blood pressure (SBP) and proportion giving birth] between those that did or did not develop microvascular complications during the follow-up period.

RESULTS

For the 425 childless women at baseline, 102 gave birth during follow-up. HbA(1c) was a significant risk factor for progression to microalbuminuria but age, duration of diabetes, systolic blood pressure or giving birth were not. Duration of diabetes and high HbA(1c) were significant risk factors for progression to proliferative retinopathy, whereas giving birth was not. Similar results were obtained for progression to any form of retinopathy. Giving birth was not significantly related to the incidence of neuropathy. Similar results were obtained for women with children at baseline giving birth during follow-up (n = 61/368).

CONCLUSIONS

In this European study, having a first or another pregnancy did not seem to be a risk factor for long-term progression of any microvascular complication. This is in accordance with the findings of the Diabetes Control and Complications Trial (DCCT).

Differences in the association between type 2 diabetes and impaired microvascular function among Europeans and African Caribbeans

AIMS/HYPOTHESIS

Diabetes is associated with microvascular damage in all populations, but diabetic patients of Black African descent (African Caribbeans) have a greater risk of vascular target organ damage than would be anticipated for any given blood pressure level. We investigated whether this may be due to differences in the microvasculature.

MATERIALS AND METHODS

To assess the maximum hyperaemic response to heating and the post-ischaemic response, Laser Doppler fluximetry was performed on 51 and 100 Europeans, and on 66 and 88 African Caribbeans with and without diabetes, respectively. Subjects were aged between 40 and 65 years and recruited from the general population. Echocardiographic interventricular septal thickness (IVST) was measured as a proxy for vascular target organ damage.

RESULTS

In diabetic subjects of both ethnic groups, the maximum hyperaemic response and peak response to ischaemia were attenuated as compared to the corresponding non-diabetic subjects (p=0.08 for diabetic and 0.03 for non-diabetic Europeans; p=0.03 and 0.1 for African Caribbeans). Adjustment for cardiovascular risk factors, in particular insulin and blood pressure, abolished these differences in Europeans (p=0.8 for diabetic and 0.2 for non-diabetic Europeans), but not in African Caribbeans (p=0.03 and 0.05).

CONCLUSIONS/INTERPRETATION

Persisting microvascular dysfunction in African Caribbeans may contribute to the increased risk of target organ damage observed in diabetes in this population. The weak contribution of conventional cardiovascular risk factors to these disturbances indicates that conventional therapeutic interventions may be less beneficial in these patients. There was a risk-factor-independent, inverse association between IVST and maximal hyperaemia. These ethnic differences in microvascular responses to temperature and arterial occlusion could account for increased target organ damage in African Caribbeans.

Plasma homocysteine and microvascular and macrovascular complications in type 1 diabetes: a cross-sectional nested case-control study

OBJECTIVES

To examine the independent relationship between plasma total homocysteine (tHcy) and microvascular and macrovascular complications.

DESIGN

We performed a cross-sectional nested case-control study from the EURODIAB Prospective Complications Study.

SETTING

A hospital-based multicentre study at 24 centres in 13 European countries.

SUBJECTS

A total of 533 type 1 diabetic patients, diagnosed at <36 years of age. Cases (n=359) were defined as those with one or more complications of diabetes and control subjects (n=174) were all those with no evidence of any complication. Main outcome measures. Retinopathy, albumin excretion rate (AER), glomerular filtration rate (GFR) estimated by Cockcroft-Gault formula, hypertension and cardiovascular disease (CVD) were assessed.

RESULTS

In unadjusted models, tHcy (per 5 micromol L(-1)) was significantly associated with nonproliferative retinopathy (OR=1.45, 95% CI: 1.10-1.91), proliferative retinopathy (OR=1.74, 95% CI: 1.34-2.27), macroalbuminuria (OR=1.90, 95% CI: 1.49-2.42), hypertension (OR=2.23, 95% CI: 1.69-2.93) and CVD (OR=1.59, 95% CI: 1.18-2.14). In multivariate models, tHcy was significantly related to macroalbuminuria (OR=1.66, 95% CI: 1.24-2.24) and hypertension (OR=1.57, 95% CI: 1.19-2.07), independent of age, sex, diabetes duration, GFR, microvascular and macrovascular complications and cardiovascular risk factors. There was a significant relationship between tHcy and decreased GFR, independent of established risk factors. The relationship between tHcy and retinopathy was not independent of albuminuria or GFR. The initial positive relationship with CVD was explained by cardiovascular risk factors.

CONCLUSION

In this large study of European type 1 diabetic subjects, increased concentrations of tHcy were independently related to macroalbuminuria, renal function and hypertension, which suggests that tHcy might play an important role in the pathogenesis of vascular complications in type 1 diabetes.

Metabolic syndrome and coronary heart disease in South Asians, African-Caribbeans and white Europeans: a UK population-based cross-sectional study

AIMS/HYPOTHESIS

The aim of this study was to study differences in the prevalence of the metabolic syndrome and its associations with prevalent CHD according to ethnicity and sex.

METHODS

We performed a combined analysis of two population-based cross-sectional studies conducted between 1988 and 1991 that followed identical protocols. Participants (aged 40-69 years) comprised 2,346 Europeans (76% male), 1,711 South Asians (83% male) and 803 African-Caribbeans (57% male) resident in west London. Fasting blood, overnight urine collection, clinical and anthropometric measurements were performed. Clinical history or major ECG changes defined prevalent CHD. The metabolic syndrome was defined according to the criteria recommended by the World Health Organization (WHO) and the National Cholesterol Education Programme (NCEP).

RESULTS

The prevalence of the metabolic syndrome was highest in South Asians (WHO, men 46%, women 31%; NCEP, men 29%, women 32%) and lowest in European women (WHO, 9%; NCEP, 14%). The prevalence of CHD was 10% in South Asian men, 9% in European men, 5-6% in African-Caribbeans and European women, and 2% in South Asian women. The metabolic syndrome was associated with prevalent CHD in European men [NCEP, odds ratio (OR)=1.6, 95% CI 1.2-2.4; WHO, OR=1.7, 95% CI 1.2-2.5] and South Asian men (NCEP, OR=2.1, 95% CI 1.5-3.1; WHO, OR=1.6, 95% CI 1.1-2.3). Associations with CHD were weaker in African-Caribbeans and were inconsistent among European women.

CONCLUSIONS/INTERPRETATION

The current definitions of the metabolic syndrome give an inconsistent picture of cardiovascular disease risk when applied to different ethnic groups within the UK. Prospective studies are needed to validate workable ethnic-specific definitions.

Markers of inflammation are cross-sectionally associated with microvascular complications and cardiovascular disease in type 1 diabetes--the EURODIAB Prospective Complications Study

AIMS/HYPOTHESIS

The pathogenesis of vascular complications in type 1 diabetes is poorly understood, but may involve chronic, low-grade inflammation. We investigated the association of markers of inflammation with vascular complications in type 1 diabetes.

METHODS

A cross-sectional nested case-control study of the follow-up data of the EURODIAB Prospective Complications Study. This study included 543 individuals (278 men) with type 1 diabetes diagnosed at <36 years of age. Cases (n=348) had complications of diabetes, controls (n=195) had no complications.

RESULTS

C-reactive protein, interleukin-6 and tumour necrosis factor-alpha levels, which were combined in an inflammatory marker Z-score, were associated with albuminuria, retinopathy and cardiovascular disease. Calculated means (95% confidence intervals) of the marker Z-score were -0.15 (-0.22 to -0.07), 0.10 (-0.05 to 0.25), and 0.28 (0.15 to 0.41), p for trend <0.0001, in individuals with normo-, micro- and macroalbuminuria; -0.23 (-0.33 to -0.13), 0.14 (0.02 to 0.25) and 0.20 (0.07 to 0.32), p for trend <0.0001, in individuals with no, non-proliferative and proliferative retinopathy; and -0.28 (-0.39 to -0.18) and 0.06 (-0.08 to 0.20), p<0.001, in individuals without and with cardiovascular disease. Per 1 SD increase of the inflammatory marker Z-score, GFR decreased by -4.6 (-6.6 to -2.6) ml per min per 1.73 m(2) (p<0.001).

CONCLUSIONS/INTERPRETATION

We have shown that markers of inflammation are strongly and independently associated with microvascular complications and cardiovascular disease in type 1 diabetes. These data suggest that strategies to decrease inflammatory activity may help to prevent the development of vascular complications in type 1 diabetes.

Risk factors for cardiac autonomic neuropathy in type 1 diabetes mellitus

AIMS/HYPOTHESIS

Cardiac autonomic neuropathy (CAN) is associated with increased morbidity and mortality in type 1 diabetes. Apart from glycaemic control, risk factors for CAN have not been extensively studied.

METHODS

As part of the EURODIAB Prospective Complications Study, CAN--defined as either a loss of heart rate variability or postural hypotension on standing--was assessed at baseline and follow-up (7.3+/-0.6 years from baseline) in patients with type 1 diabetes.

RESULTS

Follow-up measurements were available for 956 participants without CAN at baseline (age at baseline 31.3+/-8.9 years, duration of diabetes 13.5+/-8.3 years). During follow-up, 163 (17%) subjects developed CAN, yielding an incidence of 23.4 per 1,000 person-years. Blood pressure, weight, the presence of cardiovascular disease, albuminuria, distal symmetrical polyneuropathy (DSP) and retinopathy at baseline were associated with the incidence of CAN after adjustment for sex, duration of diabetes and HbA(1)c. In a multivariate regression model, baseline factors associated with an increased risk of developing CAN were age [odds ratio (OR)=1.3 per decade, 95% CI 1.1-1.7], HbA(1)c (OR=1.2 per percentage point, 95% CI 1.1-1.4), systolic blood pressure (OR=1.1 per 10 mmHg, 95% CI 1.0-1.3), feeling faint on standing (OR=2.0, 95% CI 1.2-3.2), DSP (OR=1.9, 95% CI 1.2-3.0) and retinopathy (OR=1.7, 95% CI 1.1-2.6).

CONCLUSION/INTERPRETATION

This study confirms the importance of exposure to hyperglycaemia as a risk factor for CAN. A small set of variables, including HbA(1)c, hypertension, DSP and retinopathy, predict the risk of CAN. Clinical trials are needed to address the impact of intensive antihypertensive treatment on CAN in type 1 diabetes.

Ethnic differences and determinants of diabetes and central obesity among South Asians of Pakistan

AIMS

To study the within ethnic subgroup variations in diabetes and central obesity among South Asians.

METHODS

Data from 9442 individuals age > or = 15 years from the National Health Survey of Pakistan (NHSP) (1990-1994) were analysed. Diabetes was defined as non-fasting blood glucose > or = 7.8 mmol/l, or known history of diabetes. Central obesity was measured at the waist circumference. Distinct ethnic subgroups Muhajir, Punjabi, Sindhi, Pashtun, and Baluchi were defined by mother tongue.

RESULTS

The age-standardized prevalence of diabetes varied among ethnic subgroups (P = 0.002), being highest among the Muhajirs (men 5.7%, women 7.9%), then Punjabis (men 4.6%, women 7.2%), Sindhis (men 5.1%, women 4.8%), Pashtuns (men 3.0%, women 3.8%), and lowest among the Baluchis (men 2.9%, women 2.6%). While diabetes was more prevalent in urban vs. rural dwellers [odds ratio (OR) 1.50, 95% confidence interval (CI) 1.24, 1.82], this difference was no longer significant after adjusting for central obesity (OR 1.15, 95% CI 0.95, 1.42). However, the ethnic differences persisted after adjusting for major sociodemographic risk factors (unadjusted OR for Pashtun vs. Punjabi 0.59, 95% CI 0.42, 0.84, adjusted OR 0.54, 95% CI 0.37, 0.78). Ethnic variation was also observed in central obesity, which varied with gender, and did not necessarily track with ethnic differences in diabetes.

CONCLUSIONS

Unmeasured environmental or genetic factors account for ethnic variations in diabetes and central obesity, and deserve further study.

Factors associated with progression to macroalbuminuria in microalbuminuric Type 1 diabetic patients: the EURODIAB Prospective Complications Study

AIMS/HYPOTHESIS

Type 1 diabetic patients who develop microalbuminuria are clearly disadvantaged in terms of their risk of morbidity and mortality from renal and cardiovascular diseases. It is therefore important to identify potential factors that can predict progression to macroalbuminuria.

METHODS

This is a 7-year follow-up study of 352 microalbuminuric Type 1 diabetic patients from 31 European centres. Risk factors at baseline were compared in patients who progressed to macroalbuminuria and in patients who remained microalbuminuric or reverted to normoalbuminuria. Risk factors and albumin excretion rate (AER) were measured centrally.

RESULTS

Over 7.3 years, 13.9% of the microalbuminuric patients progressed to macroalbuminuria, 35.5% remained microalbuminuric and 50.6% reverted to normoalbuminuria. Independent baseline risk factors for progression to macroalbuminuria were HbA(1)c (7.9% vs 6.8%, p=0.004), AER (64.4 vs 44.9 microg/min, p=0.0001) and-after adjusting for diabetes duration, HbA(1)c and AER-body weight (72 vs 67 kg, p=0.05). Independent factors associated with regression to normoalbuminuria were diabetes duration (15 vs 18 years, p=0.004), AER (37.2 vs 44.9 microg/min, p=0.0001) and-after adjusting for diabetes duration, HbA(1)c and AER-waist-to-hip ratio (0.83 vs 0.86, p=0.05) and incidence of peripheral neuropathy at baseline (24% vs 38%, p=0.001). Blood pressure and smoking did not emerge as risk factors at baseline for the outcome of microalbuminuria.

CONCLUSIONS/INTERPRETATION

A significant fraction of microalbuminuric Type 1 diabetic patients will progress to overt proteinuria. Patients with higher AER values, sub-optimal metabolic control, excess body fat and peripheral neuropathy may carry a particularly high risk of clinical nephropathy requiring aggressive therapeutic intervention.

Risk factors for non-fatal myocardial infarction in young South Asian adults

OBJECTIVE

To determine the risk factors for premature myocardial infarction among young South Asians.

DESIGN AND SETTING

Case-control study in a hospital admitting unselected patients with non-fatal acute myocardial infarction.

METHODS AND SUBJECTS

Risk factor assessment was done in 193 subjects aged 15-45 years with a first acute myocardial infarct, and in 193 age, sex, and neighbourhood matched population based controls.

RESULTS

The mean (SD) age of the subjects was 39 (4.9) years and 326 (84.5%) were male. Current smoking (odds ratio (OR) 3.82, 95% confidence interval (CI) 1.47 to 9.94), use of ghee (hydrogenated vegetable oil) in cooking (OR 3.91, 95% CI 1.52 to 10.03), raised fasting blood glucose (OR 3.32, 95% CI 1.21 to 8.62), raised serum cholesterol (OR 1.67, 95% CI 1.14 to 2.45 for each 1.0 mmol/l increase), low income (OR 5.05, 95% CI 1.71 to 14.96), paternal history of cardiovascular disease (OR 4.84, 95% CI 1.42 to 16.53), and parental consanguinity (OR 3.80, 95% CI 1.13 to 1.75) were all independent risk factors for acute myocardial infarction in young adults. Formal education versus no education had an independently protective effect on acute myocardial infarction (OR 0.04, 95% CI 0.01 to 0.35).

CONCLUSIONS

Tobacco use, ghee intake, raised fasting glucose, high cholesterol, paternal history of cardiovascular disease, low income, and low level of education are associated with premature acute myocardial infarction in South Asians. The association of parental consanguinity with acute myocardial infarction is reported for the first time and deserves further study.

The prevalence of hepatitis C virus antibodies among the voluntary blood donors of New Delhi, India

Infection with hepatitis C virus (HCV) is a major cause of transfusion-associated hepatitis, cirrhosis and hepatocellular carcinoma. The present study was conducted with an objective to evaluate the prevalence of anti-HCV antibody in New Delhi, India using a large number of healthy voluntary blood donors. A total of 15,898 healthy voluntary blood donors were subjected to anti-HCV testing (using a commercially available third generation anti-HCV ELISA kit) and 249 were found to be reactive for anti-HCV antibody, yielding an overall prevalence of 1.57%. No significant difference was found between the HCV positivity rate of male (1.57%; 238/15,152) vs. female (1.47%; 11/746) donors, family (1.58%; 213/13,521) vs. altruistic (1.51%; 36/2377) donors and first-time (1.55%; 180/11,605) vs. repeat (1.61%; 69/4293) donors. The age distribution of anti-HCV reactivity showed a maximum prevalence rate of 1.8% in the age group of 20-29 years. In addition, there was a clear trend of decreasing positivity for anti-HCV with increasing age and this trend was statistically significant. The results of the present study show that the prevalence of anti-HCV antibodies in the healthy voluntary blood donors of New Delhi, India is considerably higher than the reported seroprevalence of HCV in majority of the industrialized nations and this represents a large reservoir of infection capable of inflicting significant disease burden on the society. In addition, donors of New Delhi, India showed a trend of decreasing seroprevalence with increasing age, possibly implying a higher exposure rate to HCV in younger subjects.

Differing aspects of insulin resistance in diabetes complications: the shape of things to come. RD Lawrence Lecture 2000

The anticipated global epidemic of diabetes, largely as a consequence of increased rates of obesity, will particularly impact on people of South Asian and African Caribbean descent, two populations at elevated risk of insulin resistance. This article contrasts the consequent heightened risk of heart disease on the one hand in South Asians, and the paradoxical protection from heart disease in African Caribbeans on the other. Protection from the hypertriglyceridaemic effects of insulin resistance is likely to account for much of the African Caribbean paradox, although the mechanisms remain unclear. The growing evidence that insulin resistance is commonly observed in people with Type 1 diabetes, as well as those with Type 2 diabetes, and that features of insulin resistance may play a crucial role in the development of microvascular, as well as macrovascular complications, is also discussed. This indicates novel targets for the prevention and treatment of diabetes complications.

Autonomic neuropathy is associated with increased cardiovascular risk factors: the EURODIAB IDDM Complications Study

AIMS

To assess the prevalence of and risk factors for autonomic neuropathy in the EURODIAB IDDM Complications Study.

METHODS

The study involved the examination of randomly selected Type I (insulin-dependent) diabetic patients from 31 centres in 16 European countries. Neuropathic symptoms and two tests of autonomic function (changes in heart rate and blood pressure from lying to standing) were assessed and data from 3007 patients were available for the present analysis. Autonomic neuropathy was defined as an abnormality of at least one of the tests.

RESULTS

The prevalence of autonomic neuropathy was 36% with no sex differences. The frequency of one and two abnormal reflex tests was 30% and 6%, respectively. The R-R ratio was abnormal in 24% of patients while 18% had orthostatic hypotension defined as a fall in systolic blood pressure > 20 mmHg on standing. Significant correlations were observed between autonomic neuropathy and age (P < 0.01), duration of diabetes (P < 0.0001), HbA1c (P < 0.0001), diastolic blood pressure (P < 0.05), lower HDL-cholesterol (P < 0.01), the presence of retinopathy (P < 0.0001) and albuminuria (P < 0.0001). New associations have been identified from the study: the strong relationship of autonomic neuropathy to cigarette smoking (P < 0.01), total cholesterol/HDL-cholesterol ratio (P < 0.05) and fasting triglyceride (P < 0.0001). As a key finding, autonomic neuropathy was related to the presence of cardiovascular disease (P < 0.0001). All analyses were adjusted for age, duration of diabetes and HbA1c. However, data have been only partly confirmed by logistic regression analyses. Frequency of dizziness on standing up was 18%, while only 4% of patients had nocturnal diarrhoea and 5% had problems with bladder control.

CONCLUSION

Cardiovascular reflex tests, even in the form of the two tests applied, rather than a questionnaire, seem to be appropriate for the diagnosis of autonomic neuropathy. The study has identified previously known and new potential risk factors for the development of autonomic neuropathy, which may be important for the development of risk reduction strategies. Our results may support the role of vascular factors in the pathogenesis of autonomic neuropathy.

The retinal renin-angiotensin system: implications for therapy in diabetic retinopathy

Retinopathy is the most common complication of diabetes, and a leading cause of blindness in people of working age. Optimal blood pressure and metabolic control can reduce the risk of diabetic retinopathy, but are difficult to achieve in clinical practice. In the EUCLID Study, the angiotensin converting enzyme (ACE) inhibitor lisinopril reduced the risk of progression of retinopathy by approximately 50%, and also significantly reduced the risk of progression to proliferative retinopathy. These findings are consistent with extensive evidence that the renin-angiotensin system is expressed in the eye, and that adverse effects of angiotensin II on retinal angiogenesis and function can be inhibited by ACE inhibitors or angiotensin II-receptor blockers. However, in the EUCLID Study retinopathy was not a primary end-point and the study was not sufficiently powered for the eye-related outcomes. Hence, the Diabetic Retinopathy Candesartan Trials (DIRECT) programme has been established to determine whether AT(1)-receptor blockade with candesartan can prevent the incidence and progression of diabetic retinopathy. This programme comprises three studies, involving a total of 4500 patients recruited from about 300 centres worldwide. The patients are normotensive or treated hypertensive individuals, and so the DIRECT programme should assess the potential of an AT(1)-receptor blocker to protect against the pathological changes in the eye following diabetes.

Amadori-albumin correlates with microvascular complications and precedes nephropathy in type 1 diabetic patients

BACKGROUND

Amadori-albumin, a major glycated protein, is involved in experimental hyperglycaemia-induced microvascular complications, and is associated with advanced nephropathy in Type I diabetic patients in humans. Our aim was to assess the association of Amadori-albumin with early nephropathy and with retinopathy in Type I diabetic patients and the involvement of chronic low-degree inflammation therein.

DESIGN AND METHODS

Amadori-albumin, the Amadori product of haemoglobin (HbA1c), C-reactive protein, and fibrinogen levels were measured in the EUCLID study, a 2-year randomised, double-blind, placebo-controlled trial of lisinopril in 447 Type I diabetic patients. Retinal photographs were taken in 341 patients at baseline and 294 at follow up.

RESULTS

Amadori-albumin was positively associated with albumin the excretion rate and retinopathy status (P = 0.0001 and P = 0.02 for trend, respectively) and with the progression from normoalbuminuria to (micro)albuminuria (38.6 U mL(-1) in nonprogressors, 44.3 U mL-1 in progressors; P = 0.02), but not with the development or progression of retinopathy during a 2-year follow up. Amadori-albumin levels at baseline were associated with C-reactive protein and fibrinogen (P = 0.0007 and P = 0.0001, respectively). C-reactive protein and fibrinogen were also associated with albumin excretion rates (P = 0.03 and P = 0.01, respectively) and retinopathy status (P = 0.02 and P = 0.0006, respectively). Adjustment for these inflammatory markers did not markedly attenuate the association between Amadori-albumin and the albumin excretion rate, while adjustment for fibrinogen, but not C-reactive protein, abolished the association between Amadori-albumin and retinopathy. Lisinopril had no impact on the association between the levels of Amadori-albumin and albumin excretion rates or retinopathy.

CONCLUSIONS

Amadori-albumin was associated with early nephropathy and with retinopathy in Type I diabetic patients and preceded an increase in albumin excretion rate, but not retinopathy. A chronic low-degree inflammation does not appear to be involved in Amadori-albumin-associated microvascular complications in Type I diabetes.

Risk of diabetes-related amputation in South Asians vs. Europeans in the UK

AIMS

To compare the risk of and risk factors for diabetes-related amputation in South Asians and Europeans.

METHODS

This was a population-based case control study based in the health districts of Bolton, Oldham and Central Manchester in the UK. Cases with diabetes-related amputation performed between 1992 and 1997 (n = 172) and controls with diabetes and no amputation (n = 376) were selected from the primary care-based North-west Diabetes Foot Study database. Risk factor data were also collected.

RESULTS

Age at diagnosis adjusted odds ratio (OR) of amputation in South Asians compared with Europeans was 0.26, 95% confidence interval (CI) 0.11-0.65, P = 0.004. In the control population, South Asians were less likely than Europeans to have peripheral vascular disease (PVD) (9% vs. 24%, P = 0.02), neuropathy (30% vs. 54%, P = 0.003), and less likely to have ever been smokers (31% vs. 57%, P = 0.03). When these factors were added to the model, the OR was attenuated to 0.84, 95% CI 0.23-3.08, P = 0.8.

CONCLUSIONS

South Asians with diabetes have about a quarter of the risk of amputation of Europeans. This is mostly explained by low rates of PVD and neuropathy in South Asians, in part associated with low rates of smoking. The reasons for the South Asian protection from both PVD and neuropathy deserve further exploration.

Birth weight, childhood growth and abdominal obesity in adult life

OBJECTIVE

To examine the relationship of adult abdominal obesity to birth weight, childhood growth and lifetime socioeconomic circumstances.

METHODS

A cohort of 3200 men and women with measured waist and hip circumference, height and weight at age 43 who have been followed since their birth in March 1946 in England, Scotland and Wales. Regression models were used to examine mean waist-hip ratio and waist circumference in relation to prospective measures of birth weight, weight relative to height in childhood at ages 4, 7, 11 and 15 and adult body mass index, and to test the independent and interactive nature of the associations and adjust for childhood and adult social class.

RESULTS

There was a small inverse effect of birth weight on waist-hip ratio (P=0.037) but not waist circumference in women, after adjustment for current body size. Relative weight at age 7 was inversely related to waist-hip ratio and waist circumference in men (P<0.001 for both) and waist circumference in women (P=0.007) after adjustment for current body size. These relationships were attenuated in men of large body mass index (P<0.01 for interactions between relative weight at 7 y and body mass index in both cases) but were not modified by birth weight. Relative weights at other ages showed similar patterns to those observed at age 7, the effect being weakest at age 4. These findings were independent of lifetime socioeconomic circumstances.

CONCLUSION

This study found a small prenatal inverse effect of fetal growth on adult waist-hip ratio due to a reduced hip size. There was also an inverse postnatal effect of childhood growth such that for any given adult body size those who had been lighter in childhood were more at risk of abdominal obesity. These relationships were independent of childhood socioeconomic circumstances and support the idea that insulin resistance may be linked to low weight in childhood.

Differing associations of lipid and lipoprotein disturbances with the macrovascular and microvascular complications of type 1 diabetes

OBJECTIVE

Cardiovascular disease (CVD) is increased in patients with type 1 diabetes, but lipid and lipoprotein patterns remain favorable. In contrast, nephropathy is associated with an adverse distribution. We compared the associations and predictive power of lipid and lipoprotein disturbances with these complications.

RESEARCH DESIGN AND METHODS

A nested case-control study from the EURODIAB cohort of 140 case subjects with evidence of at least one complication and 84 control subjects with no complications were analyzed. Conventional and unconventional lipid and lipoprotein fractions, including apolipoprotein (apo)-A1, lipoprotein (Lp)-A1, LpA1/A2, apoB, and LDL particle size were measured centrally.

RESULTS

CVD was only associated with increased LDL cholesterol (3.6 vs. 3.0 mmol/l, P = 0.02). In contrast, albuminuria was associated with elevated cholesterol, triglyceride, LDL, and apoB and with diminished LDL particle size. No disturbances in HDL and related lipoproteins were noted. In normoalbuminuric patients, CVD was not associated with any significant changes in lipids. CVD in macroalbuminuric patients was associated with increased triglyceride level (2.37 vs. 1.07 mmol/l, P = 0.001; P = 0.02 for CVD/albuminuria interaction) and LDL cholesterol (5.4 vs. 3.3 mmol/l, P = 0.005; P = 0.004 for interaction). Independent associations were observed for total cholesterol and for LDL particle size and albuminuria.

CONCLUSIONS

Abnormalities in lipid and lipoprotein disturbances are more closely related to albuminuria than to CVD in patients with type 1 diabetes. Measurement of conventional parameters provide sufficient risk information. ApoB and LDL particle size offer limited extra information. HDL metabolism remains undisturbed in the presence of complications. These changes reflect associations with glycemic control, which is the key to understanding lipid and lipoprotein disturbances.

Risk factors for progression to proliferative diabetic retinopathy in the EURODIAB Prospective Complications Study

AIMS/HYPOTHESIS

Proliferative diabetic retinopathy (PDR), a leading cause of blindness, cannot be totally prevented by optimizing metabolic and blood pressure control and responds to no specific treatment other than partially destructive retinal photocoagulation. Recognizing risk factors using large-scale epidemiological studies could help identify targets for treatment. The EURODIAB Prospective Complications Study (PCS) includes the largest cohort so far of patients with Type I (insulin-dependent) diabetes mellitus.

METHODS

Baseline data were collected between 1989 and 1991 on 3250 patients who were recalled for follow-up. Physical examination, biochemical tests and assessment of complications were done on both occasions. In particular, 1249 patients had retinal photographs taken both basally and after an average of 7.3 years.

RESULTS

Proliferative retinopathy had developed in 157 patients (cumulative incidence 17.3/1000 patient-years; 95%-CI: 13.6-21.1). HbA(1c) (standardized regression estimate--SRE = 3.03, CI 2.49-3.69), diabetes duration (1.71, 1.42-2.06), age at diagnosis < 12 (1.66, 1.11-2.50), diastolic blood pressure less than or equal to 83 (1.50, 1.03-2.20) and waist-to-hip ratio (1.50, 1.03-2.20) were all independent predictors for progression to PDR when entered simultaneously into a logistic regression model. Including retinopathy at baseline maintained the effects of metabolic control and pre-pubertal onset only. Including the albumin excretion rate maintained the effect of control but reduced SRE for pre-pubertal onset to 1.49 (0.94-2.33). There was no evidence for a threshold effect for HbA(1c)concentrations at baseline and progression to proliferative retinopathy.

CONCLUSION/HYPOTHESIS

Metabolic control and duration of diabetes are strong indicators of progression to proliferative retinopathy. Onset of diabetes before puberty could be an additional independent risk factor.