The need for obtaining accurate nationwide estimates of diabetes prevalence in India - rationale for a national study on diabetes

According to the World Diabetes Atlas, India is projected to have around 51 million people with diabetes. However, these data are based on small sporadic studies done in some parts of the country. Even a few multi-centre studies that have been done, have several limitations. Also, marked heterogeneity between States limits the generalizability of results. Other studies done at various time periods also lack uniform methodology, do not take into consideration ethnic differences and have inadequate coverage. Thus, till date there has been no national study on the prevalence of diabetes which are truly representative of India as a whole. Moreover, the data on diabetes complications is even more scarce. Therefore, there is an urgent need for a large well-planned national study, which could provide reliable nationwide data, not only on prevalence of diabetes, but also on pre-diabetes, and the complications of diabetes in India. A study of this nature will have enormous public health impact and help policy makers to take action against diabetes in India.

Increased awareness about diabetes and its complications in a whole city: effectiveness of the "prevention, awareness, counselling and evaluation" [PACE] Diabetes Project [PACE-6]

AIMS AND OBJECTIVES

To determine the effectiveness of a large scale multipronged diabetes awareness program provided through community involvement in Chennai.

MATERIAL AND METHODS

Mass awareness and free screening camps were conducted between 2004-2007 at various locations of Chennai as part of the Prevention, Awareness, Counselling and Evaluation [PACE] Diabetes Project. During a 3-year period, 774 diabetes awareness camps were conducted to reach the public directly. After the PACE project was completed, 3000 individuals, representative of Chennai, were surveyed in 2007 using a systematic stratified random sampling technique. The results were compared to a similar survey carried out, as part of the Chennai Urban Rural Epidemiology Study [CURES] in 2001-2002, which served as a measure of baseline diabetes awareness.

RESULTS

Awareness of a condition called "diabetes" increased significantly from 75.5% in 2001-2002 (CURES) to 81% (p < 0.001) in 2007 (PACE). 74.1% of the citizens of Chennai are now aware that the prevalence of diabetes is increasing as compared to 60.2% earlier [p < 0.001]. Significantly more people felt that diabetes could be prevented (p < 0.001), and that a combination of diet and exercise were needed to do so (p < 0.001). Respondents reporting obesity, family history of diabetes, hypertension and mental stress as risk factors increased significantly after PACE (p < 0.001). More people were able to correctly identify the eyes (PACE 38.1% compared to CURES--16.1%, p < 0.001), kidney (PACE 42.3% compared to CURES 16.10%, p < 0.001), heart (PACE 4.6% compared to CURES 5.8%, p < 0.001) and feet (PACE 35.0% vs. CURES 21.9%, p < 0.001) as the main organs affected by diabetes.

CONCLUSION

Through direct public education and mass media campaigns, awareness about diabetes and its complications can be improved even in a whole city. If similar efforts are implemented state-wise and nationally, prevention and control of non-communicable diseases, specifically diabetes and cardiovascular disease, is an achievable goal in India.

Prevention awareness counselling and evaluation (PACE) diabetes project: a mega multi-pronged program for diabetes awareness and prevention in South India (PACE- 5)

OBJECTIVE

The Prevention Awareness Counselling Evaluation (PACE) Diabetes Project is a large scale community based project carried out to increase awareness of diabetes and its complications in Chennai city (population: 4.7 million) through 1) public education 2) media campaigns 3) general practitioner training 4) blood sugar screening and 5) community based "real life" prevention program

METHODS

Education took place in multiple forms and venues over the three-year period of the PACE project between 2004-2007. With the help of the community, awareness programs were conducted at residential sites, worksites, places of worship, public places and educational institutions through lectures, skits and street plays. Messages were also conveyed through popular local television and radio channels and print media. The General Practitioners (GPs) program included training in diabetes prevention, treatment and the advantages of early detection of complications. Free random capillary blood glucose testing was done for individuals who attended the awareness programs using glucose meter.

RESULTS

Over a three-year period, we conducted 774 education sessions, 675 of which were coupled with opportunistic blood glucose screening. A total of 76,645 individuals underwent blood glucose screening. We also set up 176 "PACE Diabetes Education Counters" across Chennai, which were regularly replenished with educational materials. In addition, we trained 232 general practitioners in diabetology prevention, treatment and screening for complications. Multiple television and radio shows were given and messages about diabetes sent as Short Message Service (SMS) through mobile phones. Overall, we estimate that we reached diabetes prevention messages to nearly two million people in Chennai through the PACE Diabetes Project, making it one of the largest diabetes awareness and prevention programs ever conducted in India.

CONCLUSION

Mass awareness and screening programs are feasible and, through community empowerment, can help in prevention and control of non-commuincable diseases such as diabetes and its complications on a large scale.

Risk factors for diabetic retinopathy in a South Indian Type 2 diabetic population--the Chennai Urban Rural Epidemiology Study (CURES) Eye Study 4

AIMS

To determine risk factors for diabetic retinopathy (DR) in an urban South Indian Type 2 diabetic population.

METHODS

The Chennai Urban Rural Epidemiology Study is a large cross-sectional study conducted in Chennai, South India. A total of 1736 Type 2 diabetic subjects were recruited for this study, which included 1382 known diabetic subjects (90.4% response rate) and 354 randomly selected, newly detected diabetic subjects diagnosed by oral glucose tolerance test. All subjects underwent four-field stereo retinal colour photography, graded by the Early Treatment Diabetic Retinopathy Study protocol.

RESULTS

Of the 1736 Type 2 diabetic subjects photographed, photographs could be graded in 1715 subjects. Stepwise ordinal logistic regression analysis revealed that male gender (P = 0.041), duration of diabetes (P < 0.0001), glycated haemoglobin (HbA(1c); P < 0.0001), macroalbuminuria (P = 0.0002) and insulin therapy (P = 0.0001) were significantly associated with severity of DR. The risk for developing DR was 7.7 times (95% confidence interval 4.71-12.48, P < 0.0001) for elevated postprandial plasma glucose levels compared with 4.2 times (95% confidence interval 2.78-6.34, P < 0.0001) for elevated fasting plasma glucose when the fourth quartile values were compared with the first quartile glucose values.

CONCLUSIONS

In South Indian Type 2 diabetic subjects, duration of diabetes, HbA1c, male gender, macroalbuminuria and insulin therapy were independent risk factors for severity of DR. Postprandial hyperglycaemia indicated a higher risk for DR compared with elevated fasting plasma glucose levels.

Prevalence and risk factors for diabetic neuropathy in an urban south Indian population: the Chennai Urban Rural Epidemiology Study (CURES-55)

AIMS

This study was conducted to determine the prevalence of, and risk factors for, diabetic neuropathy (DN) in south Indian Type 2 diabetic subjects.

METHODS

Subjects were recruited from the Chennai Urban Rural Epidemiology Study, conducted on a representative cohort from Chennai city. A total of 1629 diabetic subjects were included, of whom 1291 were known to have diabetes (KD) subjects and 338 were randomly selected newly detected diabetic (NDD) subjects. Neuropathy was diagnosed if vibratory perception threshold at the great toe, measured by biothesiometry, exceeded mean + 2 sd of a healthy non-diabetic study population aged 20-45 years (cut point > or = 20 V).

RESULTS

The overall prevalence of DN was 26.1% (age-adjusted 13.1%) with no significant difference in gender. The prevalence of neuropathy was significantly higher in KD subjects compared with NDD subjects (27.8 vs. 19.5%, P = 0.002). The prevalence of diabetic retinopathy (24.1 vs. 15.3%, P < 0.0001) and hypertension (51.1 vs. 40.0%, P < 0.0001) were higher in those with neuropathy compared with those without. The odds ratio for neuropathy in subjects with duration of diabetes > 15 years compared with < or = 5 years was 5.7 (95% confidence interval: 3.52-9.08, P < 0.0001). Regression analysis showed age (P < 0.0001), glycated haemoglobin (P = 0.001) and duration of diabetes (P = 0.045) to be significantly associated with neuropathy.

CONCLUSIONS

This cross-sectional population-based study shows that, among urban south Indian Type 2 diabetic subjects, the prevalence of DN is 26.1% and that DN is significantly associated with age, glycated haemoglobin and duration of diabetes.

Gene-Environment Interactions and the Diabetes Epidemic in India

The prevalence of diabetes is rising rapidly in all developing countries and India already has the largest number of people with diabetes. Evidence for the rising prevalence of diabetes in India comes from recent population-based studies such as the Chennai Urban Population Study (n = 1,262) and the Chennai Urban Rural Epidemiology Study (n = 26,001). These two studies revealed that the current age-standardized prevalence of diabetes in Chennai in adults >/=20 years of age is 14.3%, which is 70% higher than that seen in the year 1989 (8.3%). In the Chennai Urban Population Study, we observed that the higher-income group who consumed excess fat and calorie-rich food had an increased prevalence of diabetes compared to the lowerincome group. There was also a linear increase in the prevalence of diabetes with an increase in visible fat consumption. In addition, we observed that visible fat consumption and physical inactivity showed a cumulative effect on increasing the prevalence of diabetes. We carried out gene-diet interaction studies, which revealed that the adiponectin gene polymorphism (+10211T - G) contributed to insulin resistance and diabetes and this was exaggerated in those consuming diets with higher glycemic loads. These subjects also had an increased risk for hypoadiponectinemia. Similarly, the Ala54Thr polymorphism of the fatty acid-binding protein 2 gene showed a synergistic effect with a high glycemic load increasing the risk for hypertriglyceridemia. These studies indicate that gene-diet interactions could play a major role in increasing the risk for diabetes. However, given the imprecision in measuring dietary intake, very large sample sizes would be needed for meaningful conclusions to be drawn.

Diabetic retinopathy: an Indian perspective

Diabetic retinopathy (DR) can be defined as damage to microvascular system in the retina due to prolonged hyperglycaemia. The prevalence of DR in the Chennai Urban Rural Epidemiology (CURES) Eye Study in south India was 17.6 per cent, significantly lower than age-matched western counterparts. However, due to the large number of diabetic subjects, DR is likely to pose a public health burden in India. CURES Eye study showed that the major systemic risk factors for onset and progression of DR are duration of diabetes, degree of glycaemic control and hyperlipidaemia. Hypertension did not play a major role in this cross-sectional analysis. The role of oxidative stress, atherosclerotic end points and genetic factors in susceptibility to DR has been studied. It was found that DR was associated with increased intima-media thickness and arterial stiffness in type 2 Indian diabetic subjects suggesting that common pathogenic mechanisms might predispose to diabetic microangiopathy. Curcumin, an active ingredient of turmeric, has been shown to inhibit proliferation of retinal endothelial cells in vivo. Visual disability from DR is largely preventable if managed with timely intervention by laser. It has been clearly demonstrated that in type 2 south Indian diabetic patients with proliferative DR who underwent Pan retinal photocoagulation, 73 per cent eyes with good visual acuity (6/9) at baseline maintained the same vision at 1 yr follow up. There is evidence that DR begins to develop years before the clinical diagnosis of type 2 diabetes. Our earlier study demonstrated that DR is present in 7 per cent of newly diagnosed subjects, hence routine retinal screening for DR even at the time of diagnosis of type 2 diabetes may help in optimized laser therapy. Annual retinal examination and early detection of DR can considerably reduce the risk of visual loss in diabetic individuals.

Association of serum lipids with diabetic retinopathy in urban South Indians--the Chennai Urban Rural Epidemiology Study (CURES) Eye Study--2

AIMS

To study the association of serum lipids with diabetic retinopathy (DR) in Type 2 diabetic subjects.

METHODS

Type 2 diabetic subjects (n = 1736) were randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), which was carried out on a representative population of Chennai in South India. DR was diagnosed by retinal colour photography and classified according to the Early Treatment Diabetic Retinopathy Study (ETDRS) grading system. Classification of lipid abnormalities was done according to the National Cholesterol Education Programme-Adult Treatment Panel III (NCEP-ATP III) Guidelines.

RESULTS

The mean serum cholesterol (P = 0.024), serum triglycerides (P = 0.017) and non-high-density lipoprotein (HDL)-cholesterol (P = 0.025) concentrations were higher in subjects with DR compared with those without DR. Multiple logistic regression analysis revealed that after adjusting for age, gender, duration of diabetes, total cholesterol Standardised regression estimate (SRE) = 1.178, 95% confidence interval (CI) 1.042, 1.331, P = 0.014), non-HDL-cholesterol (SRE = 1.169, 95% CI 1.040, 1.313, P = 0.012) and serum triglycerides (SRE = 1.292, 95% CI 1.136, 1.467, P = 0.001) were associated with DR and non-HDL-cholesterol (SRE = 1.264, 95% CI 1.000, 1.592, P = 0.045) and low-density lipoprotein (LDL)-cholesterol (SRE = 1.453, 95% CI 1.107, 1.896, P = 0.005) with diabetic macular oedema (DME). After adjusting for HbA(1c) and body mass index, only triglycerides maintained a significant association with DR (SRE = 1.137, 95% CI 1.000, 1.291, P = 0.007) and LDL-cholesterol with macular oedema (SRE = 1.358, 95% CI 1.034, 1.774, P = 0.026).

CONCLUSIONS

There is a significant association of serum triglycerides with DR and LDL-cholesterol with DME.

Differential gene expression of NADPH oxidase (p22phox) and hemoxygenase-1 in patients with Type 2 diabetes and microangiopathy

AIMS

While the downstream effects of increased reactive oxygen species (ROS) in the pathogenesis of diabetes were well studied, only a few studies have explored the cellular sources of ROS. We examined whether protection against oxidative stress is altered in patients with diabetes and microangiopathy by examining changes in NADPH oxidase (p22(phox)) and hemoxygenase-1 (HO-1) levels.

METHODS

NADPH oxidase (p22(phox)) and HO-1 gene expression were probed by RT-PCR using leucocytes from patients with Type 2 diabetes without (n = 19) and with microangiopathy (n = 20) and non-diabetic subjects (n = 17). Levels of lipid peroxidation as measured by thiobarbituric reactive substances (TBARS) and protein carbonyl content (PCO) were determined by fluorimetric and spectrophotometric methods, respectively.

RESULTS

p22(phox) gene expression (mean +/- SE) was significantly (P < 0.05) higher in diabetic patients with (0.99 +/- 0.04) and without microangiopathy (0.86 +/- 0.05) compared with control subjects (0.66 +/- 0.05). Consistent with the mRNA data, the p22(phox) protein expression and NADPH oxidase activity was also increased in cells from diabetic patients compared with control subjects. However, HO-1 gene expression was significantly (P < 0.05) lower in patients with (0.73 +/- 0.03) and without microangiopathy (0.85 +/- 0.02) compared with control subjects (1.06 +/- 0.03). The mean (+/- SE) levels of TBARS were significantly (P < 0.05) higher in diabetic patients with (14.36 +/- 1.3 nM/ml) and without microangiopathy (12.20 +/- 1.3 nM/ml) compared with control subjects (8.58 +/- 0.7 nM/ml). The protein carbonyl content was also significantly (P < 0.05) higher in diabetic patients with (1.02 +/- 0.04 nmol/mg protein) and without microangiopathy (0.84 +/- 0.06 nmol/mg protein) compared with control subjects (0.48 +/- 0.02 nmol/mg protein). In diabetic subjects, increased p22(phox) gene expression was negatively correlated with HO-1 and positively correlated with TBARS, PCO, HbA(1c) and diabetes duration. In contrast, HO-1 gene expression was correlated negatively with p22phox, TBARS, PCO, HbA(1c) and diabetes duration.

CONCLUSION

Our results indicate that increased oxidative damage is seen in Asian Indians with Type 2 diabetes and microangiopathy and is associated with increased NADPH oxidase (p22(phox)) and decreased HO-1 gene expression.

Rage gene promoter polymorphisms and diabetic retinopathy in a clinic-based population from South India

PURPOSE

The main objective of this study was to evaluate if the -429T/C, -374T/A and 63 bp deletion polymorphisms in the RAGE gene are associated with diabetic retinopathy (DR) among Type 2 diabetic subjects in a clinic-based population from South India.

METHODS

We screened 149 normal glucose tolerant subjects (NGT), 189 Type 2 diabetes subjects without retinopathy (DM) and 190 subjects with DR for these polymorphisms using the PCR-RFLP method. DR was diagnosed by grading color fundus photography. Logistic regression models were used to evaluate the association of individual polymorphisms with DR. Expectation-maximization algorithms were implemented in haplotype tests of association to examine the combined effects of -429T/C and -374T/A polymorphisms on DR.

RESULTS

The allelic frequencies of -429T are 0.83 in NGT, 0.84 in DM and 0.85 in DR subjects, and that of -374T are 0.93 in NGT, 0.92 in DM and 0.88 in DR subjects. The -374 polymorphism was found to be associated with non-proliferative retinopathy when this subgroup was compared to the DM group (OR=1.814, 95% CI=1.005-3.273). However, this association was not obvious when both the subphenotypes of DR (the nonproliferative and proliferative DR groups) were studied jointly. We found no evidence for associations between the -429T/C polymorphism and the DR phenotype. Finally, extension to a 2-SNP haplotype did not reveal any significant statistical difference between the groups (P=0.668).

CONCLUSION

In this study, we found a modest association with the -374T/A polymorphism in the nonproliferative DR subgroup.

Does hypertension play a role in diabetic retinopathy?

Diabetic retinopathy is a common complication of diabetes. It represents one of the frequent causes of visual disability among diabetic subjects during the period of active life. The risk factors for diabetic retinopathy are poor glycemic control, hypertension, duration of diabetes, hyperlipidemia and proteinuria. It has been observed that prevalence of hypertension is higher in diabetic subjects than in the general population and as it also plays a major role in the progression of diabetic retinopathy, so tight control of hypertension is mandatory. The possible mechanisms by which hypertension affects diabetic retinopathy are haemodynamic (impaired autoregulation and hyperperfusion) and secondly through VEGF (Vascular Endothelial Growth Factor), as it has been observed that hypertension independent of hyperglycaemia upregulates the VEGF expression in retinal endothelial cells and ocular fluids. The level of control of blood pressure are debatable but nearer the blood pressure to the normal levels, better the chances of preventing the onset and progression of diabetic retinopathy. The lowering of blood pressure to a normal range is more important than the type of antihypertensive medication used. Diabetic retinopathy is one of the important causes of visual disability in diabetic subjects during the period of active life. It is characterized by gradually progressive alterations in the retinal microvasculature, leading to increased vasopermeability, areas of retinal occlusion and retinal neovascularization. The complications associated with increased vasopermeability and uncontrolled neovascularization can result in severe and permanent visual loss.

The Chennai Urban Rural Epidemiology Study (CURES)--study design and methodology (urban component) (CURES-I)

The report of World Health Organization (WHO) shows that India tops the world with the largest number of diabetic subjects. This increase is attributed to the rapid epidemiological transition accompanied by urbanization, which is occurring in India. There is very little data regarding the influence of affluence on the prevalence of diabetes and its complications particularly retinopathy in the Indian population. Furthermore, there are very few studies comparing the urban/rural prevalence of diabetes and its complications. The Chennai Urban Rural Epidemiology Study (CURES) is designed to answer the above questions. CURES is initially planned as a cross-sectional study to evolve later into a longitudinal study. Subjects for the urban component of the CURES have been recruited from within the corporation limits of Chennai City. Chennai (formerly Madras), the largest city in Southern India and the fourth largest in India has been divided into 10 zones and 155 wards. 46 wards were selected by a systematic random sampling method to represent the whole of Chennai. Twenty thousand and one individuals were recruited for the study, this number being derived based on a sample size calculation. The study has three phases. Phase one is a door to door survey which includes a questionnaire, anthropometric, fasting capillary blood glucose and blood pressure measurements. Phase two focussed on the prevalence of diabetic complications particularly retinopathy using standardized techniques like retinal photography etc. Diabetic subjects identified in phase one and age and sex matched non-diabetic subjects will participate in these studies. Phase three will include more detailed studies like clinical, biochemical and vascular studies on a sub-sample of the study subjects selected on a stratified basis from phase one. CURES is perhaps one of the largest systematic population based studies to be done in India in the field of diabetes and its complications like retinopathy, nephropathy and neuropathy.

Familial clustering of diabetic retinopathy in South Indian Type 2 diabetic patients

AIM

The aim of the study was to determine whether there is familial clustering of diabetic retinopathy among South Indian Type 2 diabetic subjects.

METHODS

During the period September 1991 to September 1997, 322 families with at least two diabetic siblings who were registered at our centre and had undergone a retinal examination were selected for the study. The sibling with the longest duration of diabetes was defined as the proband. The prevalence of retinopathy was compared between the siblings of probands with and without retinopathy.

RESULTS

Diabetic retinopathy was diagnosed in 11.2% of the siblings of the probands without diabetic retinopathy and in 35.3% of the siblings of the probands with diabetic retinopathy (P < 0.0001). The increased prevalence of retinopathy among siblings of probands with retinopathy represented all grades of retinopathy, namely non-proliferative diabetic retinopathy with and without maculopathy and proliferative diabetic retinopathy, although the latter did not reach statistical significance due to the small numbers. Hypertension, metabolic control and the duration of diabetes among the probands did not affect the clustering of retinopathy. The odds ratio for retinopathy in the siblings of probands with retinopathy after adjusting for age, glycosylated haemoglobin, duration of diabetes, proteinuria and other confounding variables was 3.37(95% confidence interval 1.56-7.29, P = 0.002).

CONCLUSIONS

Familial clustering of diabetic retinopathy was three times higher in siblings of Type 2 diabetic subjects with diabetic retinopathy.

Prevalence of non-diabetic renal disease in type 2 diabetic patients in a diabetes centre in Southern India

OBJECTIVE

The Aim of Study is to determine the prevalence of non-diabetic renal disease among South Indian type 2 diabetic subjects based on renal biopsy.

METHODS

Three thousand five hundred and ninety subjects with complete records were included for the study. One hundred and forty subjects who had proteinuria but no evidence of retinopathy undertook a 24 hour proteinuric estimation. Of these 140 subjects, 28 subjects had proteinuria > 1,000 mg/day and were subjected to renal imaging. Seven subjects were excluded due to renal calculi, cysts or contracted kidneys. Of the remaining 21 diabetic subjects, one subject was excluded as he had a mild diabetic retinopathy on fundus fluorescein angiography. Of the 20 subjects included 18 participated in the renal biopsy study (response rate--90%). Renal pathology of these subjects were studied.

RESULTS

Of the 18 renal biopsies, two were excluded due to different reasons. Out of 16 patients, eight (50%) had pathological changes suggestive of diabetic etiology, five (33.3%) had classical membranous nephropathy, one (6.2%) had tubulo-interstitial disease and two (12.5%) were categorized as others with minimal changes. The subjects with non-diabetic renal disease had significantly higher creatinine clearance (p = 0.024), serum cholesterol (p = 0.036), triglyceride levels (p = 0.045) and LDL cholesterol (p = 0.048) compared to subjects with diabetic nephropathy.

CONCLUSION

This study suggests that even in subjects clinically suspected to have non-diabetic renal disease many may turn out to have diabetic nephropathy on renal biopsy.

Lipoprotein(a) in South Indian type 2 diabetic subjects in relation to diabetic vascular complications

OBJECTIVES

Lipoprotein(a) [LP(a)] has been reported to be an independent risk factor for coronary artery disease (CAD). However, its relationship with other vascular complications is not clear. The aim of the study was to determine the relation of lipoprotein(a) with micro- and macrovascular complications seen in type 2 diabetic patients.

METHODS

We studied 725 type 2 diabetic patients with and without diabetic complications at the MV Diabetes Specialities Centre, Chennai. The mean age of the study group was 54 +/- 10 years and 70% were males. Diabetic complications viz retinopathy, proteinuria, peripheral vascular disease and coronary artery disease were diagnosed using standardized definitions. Lipoprotein(a) levels were measured using enzyme linked immunosorbant assay (ELISA). Since the frequency distribution of Lp(a) was skewed Lp(a) values were log transformed and geometric mean was used for statistical analysis.

RESULTS

The mean Lp(a) level of patients with any vascular complication was significantly higher compared to the subjects without any complications. Multiple logistic regression analysis revealed that lipoprotein(a) had as independent association with CAD (Odds Ratio -1.16, p=0.04) and proteinuria (Odds Ratio -1.69, p < 0.001). The association of Lp(a) with retinopathy and PVD turned out to be non-significant when CAD and proteinuria was introduced as cofactors in the regression model.

CONCLUSION

Lp(a) concentrations are found to be higher in those with CAD and proteinuria. There appears to be no association between Lp(a) and retinopathy or PVD in South Indian type 2 diabetic patients.

Prevalence of microalbuminuria in type 2 diabetes mellitus at a diabetes centre in southern India

OBJECTIVE

The aim of this study was to determine the prevalence and risk factors for microalbuminuria among south Indian type 2 diabetic patients attending a diabetes centre.

METHODS

One thousand four hundred and twenty five type 2 diabetic patients attending a diabetes centre in south India were recruited for the study. Urinary albumin concentration was measured by immunoturbodimetric assay. Microalbuminuria was diagnosed if the urinary albumin excretion was >30 mg/g of creatinine.

RESULTS

Overall prevalence of microalbuminuria was 36.3% (95% confidence interval 33.8 to 38.9). The prevalence of microalbuminuria increased with the increase in duration of diabetes. Multivariate regression analysis revealed age, diastolic blood pressure, glycated haemoglobin, fasting plasma glucose, and duration of diabetes to be associated with microalbuminuria.

CONCLUSION

The overall prevalence of microalbuminuria in this south Indian clinic population and its risk factors are similar to that reported in Europeans.

Prevalence of retinopathy at diagnosis among type 2 diabetic patients attending a diabetic centre in South India

AIM

To assess the prevalence of retinopathy in newly diagnosed south Indian type 2 diabetic patients attending a diabetic centre.

METHODS

448 consecutive newly diagnosed type 2 diabetic patients were recruited. Four field retinal colour photography was performed and graded using a modified form of the Early Treatment Diabetic Retinopathy Study grading system.

RESULTS

Of the 438 patients with assessable photographs, 32 (7.3%, 95% confidence interval 5.0 to 10. 2) had retinopathy. None of the variables tested showed a significant association with retinopathy on univariate or multivariate logistic regression analysis.

CONCLUSION

The overall prevalence of retinopathy at diagnosis among clinic based south Indian patients with type 2 diabetes appears to be lower than that reported among Europeans.

Frequency of proteinuria in type 2 diabetes mellitus seen at a diabetes centre in southern India

The frequency of proteinuria was assessed in a cohort of 1848 diabetic patients attending a diabetes centre in south India. A total of 127 (6.9%) patients had evidence of macroproteinuria and 49 (2.5%) patients had microproteinuria. Thus overall 9.4% of patients had diabetes related proteinuria. In addition, 70 patients (3.8%) had evidence of proteinuria with no evidence of retinopathy. The frequency of both microproteinuria and macroproteinuria increased linearly with duration of diabetes. Multiple logistic regression analysis showed that duration of diabetes, serum creatinine, and glycated haemoglobin were risk factors for macroproteinuria.

Correlation between fasting plasma glucose and two-hour plasma glucose during oral glucose tolerance test in South Indians

The diagnostic criteria for diabetes have been recently revised and the fasting plasma glucose (FPG) level reduced to 126 mg/dL, since the earlier cutoff of 140 mg/dL was considered to correspond to a much higher level than the 2-hour postglucose (2 h PG) value of 200 mg/dL. However, there are few data directly correlating FPG and 2 h PG during an oral glucose tolerance test (OGTT). This study reports on a retrospective analysis of 5,936 OGTTs performed at a diabetes center in South India and attempts to correlate the FPG and 2 h PG values. Using a 2 h PG of 200 mg/dL or higher as the diagnostic criterion, 46.7% of the cohort had diabetes. The corresponding values using the old FPG of 140 mg/dL or higher and the new FPG of 126 mg/dL or higher were 31.7% and 39.8%, respectively. If the FPG was further reduced to 118 mg/dL, the "diabetic yield" increased to 45.8%, ie, it approached the figures based on a 2 h PG of > or =200 mg/dL. Various regression equations were used to correlate FPG and 2 h PG values. When FPG was used as the dependent variable, the semilogarithmic regression equation provided the best fit, and using this model, the 2 h PG of 200 mg/dL corresponds to a FPG of 118 mg/dL. When the 2 h PG was used as the dependent variable, the log-log model provided the best fit, and using this model, a 2 h PG of 200 mg/dL corresponds to a FPG of 118 mg/dL. Thus, a FPG of 118 mg/dL seems to correlate with a 2 h PG of 200 mg/dL in South Indians.

Lipoprotein(a) is an independent risk factor for coronary artery disease in NIDDM patients in South India

OBJECTIVE

Asian Indians have been reported to have very high prevalence rates of coronary artery disease (CAD) in the absence of traditional risk factors. Recently, elevated levels of lipoprotein(a) [Lp(a)] have been reported to be associated with premature CAD in migrant Asian Indians. However, there are very little data regarding Lp(a) in CAD patients from the Indian subcontinent and virtually none in individuals with NIDDM. The objective of this study was to assess the role of Lp(a) as a marker for CAD in South Indian NIDDM patients.

RESEARCH DESIGN AND METHODS

We estimated serum Lp(a) in 100 control subjects, 100 NIDDM patients without CAD, and 100 NIDDM patients with CAD. Lp(a) values were transformed into natural logarithms. Statistical analysis included Student's t test, one-way analysis of variance, and chi2 test. Multiple logistic regression analysis was used to identify associations with CAD.

RESULTS

Lp(a) levels were significantly higher in NIDDM patients with CAD compared with NIDDM patients without CAD and control subjects (geometric mean 24.6, 15.1, and 19.4 mg/dl, respectively, P < 0.05). Results of logistic regression analysis showed that Lp(a), age, and HDL were associated with CAD. In NIDDM patients with CAD, there was no correlation between Lp(a) and serum cholesterol, triglyceride, or HDL cholesterol levels, but there was a weak association with LDL cholesterol and systolic blood pressure.

CONCLUSIONS

The data suggests that serum Lp(a) is an independent risk factor for CAD in NIDDM patients in South India.

Lack of association between serum sialic acid levels and retinopathy in Type 2 diabetic patients

Sialic acid, an acetylated derivative of neuraminic acid, is reported to be a marker of micro- and macrovascular complications in diabetic subjects. The purpose of this study was to investigate the association of serum sialic acid and diabetic retinopathy. Serum sialic acid levels were measured in healthy non-diabetic control subjects, Type 2 diabetic patients without retinopathy (No DR), Type 2 diabetic patients with non-proliferative diabetic retinopathy (NPDR) and Type 2 diabetic patients with proliferative diabetic retinopathy (PDR). There was no significant difference in the serum sialic acid levels between the study groups (controls, 2.1 mmol/l; No DR, 2.5 mmol/l; NPDR, 2.2 mmol/l and PDR, 2.3 mmol/l). These results suggest that there is no association between serum sialic acid levels and diabetic retinopathy.

Clinical profile of lean NIDDM in South India

The majority (> 80%) of patients with non insulin dependent diabetes mellitus (NIDDM) present in Europe and America are obese. In developing countries like India, most NIDDM (> 60%) are non-obese and many are actually lean with a body mass index (BMI) of < 18.5 and are referred to as 'lean NIDDM'. This paper compares the clinical profile of a cohort of 347 lean NIDDM, with a group of 6274 NIDDM of ideal body weight (IBW) and 3252 obese NIDDM attending a diabetes centre at Madras in South India. The lean NIDDM who constituted 3.5% of all NIDDM patients seen at our centre, had more severe diabetes and an increased prevalence of retinopathy (both background and proliferative), nephropathy and neuropathy. Although a larger percentage of the lean NIDDM patients were treated with insulin, 47% of the males and 53% of the females were still on oral hypoglycaemic agents even after a mean duration of diabetes of 9.2 +/- 8.1 years. Studies of GAD antibodies, islet cell antibodies (ICA) and fasting and stimulated C-peptide estimations done in a small subgroup of the lean NIDDM showed that they were distinct from IDDM patients. More studies are needed on metabolic, hormonal and immunological profile of lean NIDDM seen in developing countries like India.

Prevalence of retinopathy in non insulin dependent diabetes mellitus at a diabetes centre in southern India

A cohort of 6792 NIDDM patients attending a diabetes centre at Madras in South India was screened using a combination of retinal photography and clinical examination by retinal specialists. A total of 2319 patients (34.1%) had evidence of retinopathy. This included 2090 patients (30.8%) with non-proliferative diabetic retinopathy including 435 patients (6.4%) with maculopathy and 229 patients (3.4%) with proliferative diabetic retinopathy. Multiple logistic regression analyses showed that duration of diabetes, glycosylated haemoglobin, type of treatment (insulin treatment versus non-insulin treatment), systolic and diastolic blood pressures and serum creatinine, showed a positive association with retinopathy while body mass index (BMI) showed an inverse association. The prevalence rates of retinopathy in Southern Indians are comparable to those seen in Europeans. However in view of the high prevalence of diabetes in the Indian sub-continent, diabetic retinopathy could become a formidable challenge in the future.

Acute phase serum proteins in diabetic retinopathy

The serum concentration of various acute phase reactants were studied in patients with non-insulin dependent mellitus with and without retinopathy and in control subjects. The serum levels of haptoglobin was elevated in diabetics with retinopathy and the levels were highest in those with proliferative diabetic retinopathy. The levels of serum albumin, alpha-1 acid glycoprotein, alpha-1 antitrypsin and caeruloplasmin were not significantly different between the patients with retinopathy and controls. Haptoglobin increases serum viscosity and this could be the mechanism by which it plays a role in pathogenesis of diabetic retinopathy. These preliminary observations need to be confirmed by studies based on larger number of patients. Longitudinal studies on acute phase reactants in various stages of development of diabetic retinopathy would also provide valuable information.

An association in non-insulin-dependent diabetes mellitus subjects between susceptibility to retinopathy and tumor necrosis factor polymorphism

In IDDM an association between diabetic retinopathy and polymorphic markers of MHC has been described. However, these associations are complicated by a primary association between the MHC and IDDM. Because the pathogenesis of retinopathy is likely to be the same in IDDM and NIDDM, NIDDM subjects with retinopathy would be the ideal population to study for an association with MHC markers. The following South Indian subjects were therefore studied: unselected NIDDM (n = 76), unselected IDDM (n = 99), non-diabetic controls (n = 96), NIDDM subjects with maculopathy (MAC), n = 55, NIDDM subjects with proliferative retinopathy (PR), n = 53, and without retinopathy (LTD), n = 46. DNA was amplified and studied using a microsatellite polymorphism located 3.5 kb upstream of TNF-beta within the MHC class III region on the short arm of chromosome 6. No differences in allelic distribution were observed between the random NIDDM subjects and controls (p = 0.17). Differences in allelic distribution were found between unselected IDDM and controls (P = 0.016) and between the NIDDM subjects with maculopathy and/or proliferative retinopathy and no retinopathy (P = 0.006). This association could be accounted for by those patients with proliferative retinopathy (MAC vs LTD, p = 0.23; MAC vs PR, p = 0.07; and PR vs LTD, p = 0.002).

Vascular complications in long-term south Indian NIDDM of over 25 years' duration

The prevalence of vascular complications was assessed in 726 South Indian non-insulin dependent diabetes mellitus (NIDDM) patients with over 25 years' duration of diabetes. Retinopathy was detected in 52.0% of patients which included 41.7% with non-proliferative and 10.3% with proliferative diabetic retinopathy. Nephropathy was present in 12.7% and neuropathy in 69.8% of patients. While 32.8% of patients had ischaemic heart disease, the prevalence of peripheral vascular disease was only 15.4%. Multivariate logistic regression analyses showed that serum creatinine was associated with retinopathy, creatinine and post-prandial plasma glucose with nephropathy and post-prandial plasma glucose and age with neuropathy. This is one of the first reports on vascular complications in long-term diabetes from the Indian sub-continent.

Does oxidant stress play a role in diabetic retinopathy?

The role of oxidant stress in the causation of chronic tissue damage is being increasingly recognized. Oxidant stress is usually countered by abundant supply of antioxidants. If concomitant antioxidant deficiency occurs, oxidant stress may produce tissue damage. We took up a study on antioxidant status in non-insulin dependent diabetes mellitus (NIDDM) patients with and without retinopathy and compared them with a control non-diabetic group. The levels of superoxide dismutase (SOD) were significantly reduced in all diabetic patients, i.e., those with and without retinopathy. However, the lowest levels were found in the diabetic patients with retinopathy. Vitamin E and vitamin C levels were also markedly lower in the diabetic patients. There was a paradoxical rise in the catalase and glutathione peroxidase (GPx) in the diabetic patients with retinopathy. This may be a compensatory mechanism by the body to prevent tissue damage by increasing the levels of the two alternative antioxidant enzymes.