Are excess carbohydrates the main link to diabetes & its complications in Asians?

Dietary carbohydrates form the major source of energy in Asian diets. The carbohydrate quantity and quality play a vital function in the prevention and management of diabetes. High glycaemic index foods elicit higher glycaemic and insulinaemic responses and promote insulin resistance and type 2 diabetes (T2D) through beta-cell exhaustion. This article reviews the evidence associating dietary carbohydrates to the prevalence and incidence of T2D and metabolic syndrome (MS) in control of diabetes and their role in the complications of diabetes. Cross-sectional and longitudinal studies show that higher carbohydrate diets are linked to higher prevalence and incidence of T2D. However, the association seems to be stronger in Asian-Indians consuming diets high in carbohydrates and more marked on a background of obesity. There is also evidence for high carbohydrate diets and risk for MS and cardiovascular disease (CVD). However, the quality of carbohydrates is also equally important. Complex carbohydrates such as brown rice, whole wheat bread, legumes, pulses and green leafy vegetables are good carbs. Conversely, highly polished rice or refined wheat, sugar, glucose, highly processed foods such as cookies and pastries, fruit juice and sweetened beverages and fried potatoes or French fries are obviously 'bad' carbs. Ultimately, it is all a matter of balance and moderation in diet. For Indians who currently consume about 65-75 per cent of calories from carbohydrates, reducing this to 50-55 per cent and adding enough protein (20-25%) especially from vegetable sources and the rest from fat (20-30%) by including monounsaturated fats (e.g. groundnut or mustard oil, nuts and seeds) along with a plenty of green leafy vegetables, would be the best diet prescription for the prevention and management of non-communicable diseases such as T2D and CVD.

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.

Association of hypoadiponectinemia with non-alcoholic fatty liver disease in urban south Indians - (CURES - 81).

Background & objective: Association between adiponectin and non-alcoholic fatty liver disease (NAFLD) has been reported in west. Studies in Indian population are lacking. This study was undertaken to assess the association of hypoadiponectinemia with NAFLD in Asian Indians. Method: In this cross-sectional study, subjects were randomly selected from Phase 5 of the Chennai Urban Rural Epidemiology Study (CURES), an epidemiological study based on a representative population of Chennai in south India. One hundred twenty one subjects without NAFLD and 72 subjects with NAFLD were selected. NAFLD was diagnosed by ultrasonography. Serum adiponectin levels were measured using radioimmunoassay. Insulin resistance was calculated using Homeostasis Assessment model (HOMA-IR). Results: Serum adiponectin values were significantly lower in subjects with NAFLD compared to those without [5.6 μg/ml (95% Confidence Interval (CI) 5.0 - 6.3 μg/ml] vs 7.4 μg/ml (95% CI: 6.7 - 8.1 μg/ml, P<0.01). Adiponectin levels decreased with increasing severity of NAFLD. Subjects with moderate to severe steatosis had significantly lower adiponectin levels (5.1μg/ml, 95% CI: 4.1- 6.4 μg/ml) compared to subjects with mild steatosis (5.9 μg/ml, 95% CI: 5.0 - 6.9 μg/ml; P<0.001) and subjects without NAFLD (7.3 μg/ml, 95% CI: 6.6 - 8.0 μg/ml; P<0.01). Multiple logistic regression analysis revealed adiponectin to be negatively associated with NAFLD [Odds Ratio (OR): 0.865, 95% Confidence Interval (CI): 0.792- 0.944, P=0.001]. This remained statistically significant even after adjusting for confounding factors age, gender, body mass index, insulin resistance, waist circumference, total cholesterol, triglycerides and glucose intolerance (OR: 0.873, 95% CI: 0.793 - 0.961; P=0.005). Interpretation & conclusion: NAFLD is associated with lower serum adiponectin levels independent of conventional cardiovascular risk factors in Asian Indians known to have high prevalence of diabetes and coronary artery disease.

Incidence of diabetes and pre-diabetes in a selected urban south Indian population (CUPS-19).

OBJECTIVES: Several cross-sectional studies have reported on the prevalence of diabetes in India. However, there are virtually no longitudinal population-based studies on the incidence of diabetes from India. The aim of the study was to determine the incidence of diabetes and prediabetes in an urban south Indian population. METHODS: The Chennai Urban Population Study [CUPS], an ongoing epidemiological study in two residential colonies in Chennai [the largest city in southern India, formerly called Madras] was launched in 1996; the baseline study was completed in 1997. Follow-up examination was performed after a mean period of 8 years. At follow-up, 501 [47.0%] subjects had moved out of this colonies and were lost to follow-up. Of the remaining 564 individuals, 513 [90.9%] provided blood samples for biochemical analysis. Regression analysis was done using incident diabetes as dependant variable to identify factors associated with development of diabetes or pre-diabetes. RESULTS: Among subjects with normal glucose tolerance (NGT) at baseline [n=476], 64 (13.4%) developed diabetes and 48 (10.1%) developed pre-diabetes (IGT or IFG). The incidence rate of diabetes was 20.2 per 1000 person years and that of pre-diabetes was 13.1 per 1000 person years among subjects with NGT. Of the 37 individuals who were pre-diabetic at baseline, 15 (40.5%) developed diabetes [incidence rate: 64.8 per 1000 person years], 16 (43.2%) remained as pre-diabetic and 6 (16.2%) reverted to normal during the follow-up period. Regression analysis revealed obesity [Odds Ratio (OR): 2.1, p=0.001], abdominal obesity [OR: 2.23, p<0.001] and hypertension [OR: 2.57, p<0.001] to be significantly associated with incident diabetes. The Indian Diabetes Risk Score (IDRS) showed the strongest association with incident diabetes [OR: 5.14, p<0.001]. CONCLUSION: The study shows that the incidence of diabetes is very high among urban south Indians. While obesity, abdominal obesity and hypertension were associated with incident diabetes, IDRS was the strongest predictor of incident of diabetes in this population.