Prevalence of glucose intolerance in Asian Indians. Urban-rural difference and significance of upper body adiposity

Glucose, insulin and lipid metabolism in rural Gambians exposed to early malnutrition

AIMS

There is now substantial evidence to suggest that susceptibility to certain non-communicable diseases may be increased by early undernutrition. In rural Gambia, an annual hungry season reduces birth weight by 200-300 g and increases the prevalence of low birth weight (< 2500 g) from 11% to 24%. The aim of this study was to investigate whether fetal nutritional stress (using season of birth as a proxy measure for prenatal growth retardation) or early childhood malnutrition (using historical anthropometric records) had a residual influence on risk factors for cardiovascular disease in a cohort of rural Gambian adults.

METHODS

Two hundred and nineteen adults (mean age = 35.8 years; mean body mass index = 21.3 kg/m2; women = 181) for whom month of birth and infant anthropometric records were available participated in this study. Risk factors for cardiovascular disease were measured.

RESULTS

No differences were found between season of birth groups (hungry vs. harvest) and fasting measures of glucose, insulin, lipids, fibrinogen or cortisol, or against 30 and 120 min glucose and insulin levels following an oral glucose tolerance test, or blood pressure. Similarly, these risk factors for adult disease were not related to the subjects' weight-for-age as children.

CONCLUSIONS

Moderate-to-severe fetal and childhood malnutrition in rural Gambia caused no detectable impairment of the glucose/insulin axis, or of other cardiovascular disease risk factors in adults remaining lean and fit on a low-fat diet.

Cardiovascular risk in obese and nonobese patients with type 2 diabetes in the West Indies

OBJECTIVE

To evaluate the impact of obesity on glycemic control and the risk of progressing to cardiovascular disease (CVD) in obese and nonobese type 2 diabetic patients in primary care settings.

METHODS

One hundred and ninety patients (64 men, 126 women) with type 2 diabetes (mean duration 9.2 years) were studied after an overnight fast. Weight, height, waist and hip circumferences and blood pressure were measured and blood samples were taken for glucose, glycated hemoglobin (HbA(1c)), total cholesterol, triglyceride, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol and creatinine determinations.

RESULTS

About 85% of the patients had HbA(1c) levels > 7.0%, and 48% had a diastolic blood pressure (BP) >83 mm Hg, while 40% had a total cholesterol/HDL-cholesterol ratio greater than 6. The prevalence rates of hypercholesterolemia, hypertriglyceridemia, high BP and ratios of total cholesterol to HDL-cholesterol between the obese and nonobese patients were similar irrespective of sex (p > 0.05). Multiple linear regression analysis confirmed that ethnicity, sex, age and duration of diabetes had significant impact on the cardiovascular risk in this population.

CONCLUSION

Both obese and nonobese diabetic patients had poor glycemic control and their risk of CVD was not independent of age, sex, ethnicity and duration of diabetes. We suggest strict metabolic control and improved diabetes health education at the primary care level.

Intra-urban differences in the prevalence of the metabolic syndrome in southern India -- the Chennai Urban Population Study (CUPS No. 4)

AIMS

To assess the influence of socioeconomic status on the prevalence of the metabolic syndrome in an urban south Indian population in Chennai.

METHODS

The Chennai Urban Population Study is an epidemiological study involving two residential colonies in Chennai (formerly Madras) in south India representing the middle and lower income groups. All individuals > or = 20 years of age living in the colonies were invited to participate in the study. Of the total 1399 eligible subjects, 1262 individuals (479 belonging the middle income group colony and 783 from the low income group colony) participated in the study. The overall response rate was 90.2%. The main outcome measures were the prevalence rates of the various components of the metabolic syndrome.

RESULTS

There were significant differences in the socioeconomic status and lifestyle of the inhabitants of the two areas. The mean monthly income of the Tirumangalam (middle income) group (Rs8075 +/- 3859) was significantly higher than the T. Nagar (low income) group (Rs1399 +/- 916). The dietary profile of the middle income group showed higher intake of calories, fat and sugar compared to low income group (P < 0.001). The age-standardized prevalence rates of the various components of the metabolic syndrome were significantly higher in the middle compared to the low income group - diabetes (12.4 vs. 6.5%), impaired glucose tolerance (7.5 vs. 2.9%), hypertension (14.9 vs. 8.4%), obesity (males 38 vs. 13.4%, females 33.1 vs. 24.2%), hypercholesterolaemia (24.2 vs. 14.2%) and hyperinsulinaemia (16.7 vs. 6.6%) P < 0.001). Although the prevalence of coronary artery disease and hypertriglyceridaemia were higher in the middle income group, the differences did not reach statistical significance. The relative odds ratio for diabetes and impaired glucose tolerance increased significantly with increase in income while hypercholesterolaemia, hypertriglyceridaemia, hypertension and coronary artery disease showed no significant changes. Logistic regression analysis revealed that geographical area (higher social class) had a strong association with the components of the metabolic syndrome even after inclusion of other risk factors like age and body mass index in the model.

CONCLUSIONS

Significant differences exist in the prevalence of various components of the metabolic syndrome even within an urban environment and this appears to be influenced by socioeconomic status.

Non-industrialised countries and affluence

The prevalence of type 2 diabetes is rising rapidly in all non-industrialised populations. By 2025, three-quarters of the world's 300 million adults with diabetes will be in non-industrialised countries, and almost a third in India and China alone. There is strong evidence that this epidemic has been triggered by social and economic development and urbanisation, which are associated with general improvements in nutrition and longevity, but also with obesity, reduced physical exercise and other diabetogenic factors. There is evidence too that fetal growth retardation and growth failure in infancy, both still widespread in non-industrialised populations, increase susceptibility to diabetes. An additional factor may be intergenerational effects of gestational diabetes occurring in mothers who grew poorly in early life and become obese as adults. Prevention of type 2 diabetes will require measures to promote exercise and reduce obesity in adults and children, alongside programmes to achieve healthy fetal and infant growth.

Cosegregation of obesity with familial aggregation of type 2 diabetes mellitus

OBJECTIVE

We have shown that a positive family history of diabetes, and the variables of general and central obesity are independent risk factors for type 2 diabetes in our population. This study was done to evaluate whether a familial predisposition to diabetes resulted in a tendency for adverse anthropometric and haemodynamic profiles in south Indian non-diabetic subjects.

METHODS

The analysis was carried out on 2463 subjects (M: F, 1196: 1267) with normal glucose tolerance (NGT). The study subjects were selected from population surveys for diabetes. Details of age, sex, family history of diabetes, body mass index (b.m.i.), waist-to-hip ratio (WHR) and blood pressure were recorded. Serum cholesterol and triglycerides were estimated.

RESULTS

A positive family history of diabetes was present in 24.7% of our subjects. Mean b.m.i. and percentage of obesity were significantly higher in families with a positive family history (group 2) vs. families with no family history (group 1). Subjects in group 2 had a higher 2-h plasma glucose (p < 0.001) and higher prevalence of hypertension (chi2 = 6.91, p = 0.0086). Factor analysis with principle components analysis (PCA) showed that a family history of diabetes clustered with WHR in men, and with b.m.i. and WHR in women. The b.m.i. formed a different domain with blood pressure in both sexes. WHR and b.m.i. clustered with cholesterol and triglycerides in another domain.

CONCLUSIONS

In this population, general and central obesity are associated with a family history of diabetes. A family history of diabetes may increase the risk of hypertension and hyperlipidaemia indirectly through its connection with b.m.i.

Expenditure on health care incurred by diabetic subjects in a developing country--a study from southern India

The objective of the study was to estimate the direct costs of diabetes care to patients attending secondary care facilities in Madras, India. A total of 596 subjects were studied, at the Private Hospital for Diabetes Mellitus (PHD) (n = 422), and at the Government General Hospital (GGH) (n = 174). A simple interview schedule enabled a face to face interaction with the patients by the research investigator which elicited a frank and true response. The validity of the data collected was established by independent scrutiny of financial records in a sub sample. Payment bills for expenses of 140 subjects chosen on a random basis from the total sample of 422 PHD patients were compared with the costs reported by the subjects. There were no statistically significant differences both in the inpatient and the outpatient cases between the reported cost and actual cost. Median bill value (total costs)=Rs.1010 (range 195-16700) reported value=880 (110-20355) Z = -0.97, P = 0.33 and, for outpatients, median bill value=Rs.800 (195-4560) reported value=Rs. 740 (110-6320) Z = -1.56, P = 0.12. For inpatients, median bill value = Rs. 4235 (1289-16700) reported value=Rs.5459 (1285-20355), Z = -1.27, P5 years duration of diabetes spent more than those who had <5 years of duration; Rs.5570 (360-75200) and Rs.3220, (460-25600), respectively. All differences between these sub-groups were statistically significant. Within the ambit of economic aspects of the population in a developing country, the direct cost on diabetes health care is very high for many people.

High prevalence of type 2 diabetes in an urban settlement in Kerala, India

BACKGROUND

Prevalence of type 2 or non insulin dependent diabetes mellitus is high among Indians living in India as well as abroad. Prevalence among persons of Indian origin in many countries is greater than that of people of other ethnic extraction. The Indian state of Kerala is distinguished by a high level of achievement in the health sector, characterised by both lower mortality rates and greater density of health care institutions that ensure access to most people. These attributes make the prevalence of diabetes and the pattern of its management in Kerala worth studying.

OBJECTIVE

To estimate the prevalence of diabetes among persons 20 years or older in an urban housing settlement in Trivandrum city, the capital of Kerala, as well as study the management of the disease in subjects affected.

DESIGN

Cross sectional survey for detecting diabetes and other chronic diseases in all willing residents of an urban housing settlement in Trivandrum, the capital city of Kerala, as part of a preventive campaign against lifestyle diseases. Fasting plasma glucose, serum triglycerides, cholesterol, height, weight and blood pressure were measured, and a detailed questionnaire administered to ascertain previous diabetic status and management.

RESULTS

Overall prevalence of type 2 diabetes is 16.3%. In the 30-64 age group, age standardised prevalence is 13.7%. Gender differences in prevalence are negligible. Greater prevalence is associated with advancing age, body mass index above 24.99, sedentary habits, serum total cholesterol > 239, serum triglycerides > 149, hypertension and smoking. Compared to non-diabetics, diabetics have greater mean and range of fasting plasma glucose values (8.87 +/- 3.6 mM/l as against 4.34 +/- 0.53 mM/l). 32 out of 38 diabetics among the subjects (82.4%) were already diagnosed even before the survey; of them, 89% were on medication. 3% of subjects had impaired fasting glucose, or FPG level between 110-125 mg/dl.

CONCLUSION

Prevalence of type 2 diabetes among a group of urban residents in Trivandrum city in Kerala is very high. This is associated also with a high detection rate and compliance to treatment.

Type 1 diabetes in the offspring does not increase the risk of parental type 2 diabetes in South Indians

OBJECTIVES

(a) To study whether there was an increased prevalence of glucose intolerance in the parents of probands with Type 1 diabetes and (b) to look for any possible link between the glucose intolerance in the parents with HLA-DQB1 alleles transmitted in excess to the Type 1 diabetes offspring. Study Design and Methods From 215 families of South Indian Type 1 diabetes probands, 336 parents (170 fathers, age 30-70 years; 166 mothers, age 23-72 years) were studied by oral glucose tolerance test (GTT). Glucose intolerance in the parents was compared with the population data available. HLA-DQB1 alleles in 170 of the families were studied by the Olerup method (based on sequence specific primers) and the transmission disequilibrium test (TDT) was used to determine the Type 1 diabetes-associated DQB1 alleles.

RESULTS

Among the parents 11.2% had Type 2 diabetes which was similar to the population data of 11.6%. However there was a male predominence among the diabetic parents (chi(2)=7.0, p=0.008), while in the population there was a female predominence. Prevalence of IGT was significantly more among the parents (13.6%) compared with the population data (9.1%) (chi(2)=6.43, p=0.011). Both HLA-DQB1*0201 (p<0.0001) and DQB1*0302 (p=0.0001) were positively associated with Type 1 diabetes in the probands although 21% of the probands possessed neither DQB1*0201 or DQB1*0302. The distribution of glucose tolerance categories in the parents of the probands differed according to the presence of DQB1*0302 (p= 0.035) whilst no such differences existed for DQB1*0201.

CONCLUSIONS

In summary, the presence of Type 1 diabetes in the South Indian offspring does not predict a higher occurrence of Type 2 diabetes in the parents. However, there is an increased occurrence of impaired glucose tolerance (IGT) among the parents. Family based studies demonstrate increased transmission of HLA-DQB1*0201 and HLA-DQB1*0302 with Type 1 diabetes similar to North American and European Caucasian subjects. Furthermore, HLA-DQB1*0302 may be a minor determinant of glucose tolerance in parents of offspring with Type 1 diabetes.

Impacts of urbanisation on the lifestyle and on the prevalence of diabetes in native Asian Indian population

Recent studies from the Asian subcontinent show an increasing prevalence of diabetes. This increase has been attributed to factors related to lifestyle changes related to modernisation. A periurban rural population resembling the rural in their occupation, but with access to certain urban facilities was chosen for this study. The aim of the study was to assess the impact of modernisation on the rising prevalence of diabetes in the native Indians. A total of 1637 adults aged 20 years and above (749 men and 888 women) were tested for diabetes and impaired glucose tolerance (IGT) by 2 h post-glucose challenge. Demographic, anthropometric, dietary and occupational details, were recorded. Dietary habits were similar in all categories of socio-economic strata. In the present study group, the age standardised prevalence of Type 2 diabetes was 5.9%, which was intermediate to that in the urban (11.6%) and rural (2.4%) populations. The prevalence data of the latter two population were available from previous surveys. Prevalence of impaired glucose tolerance (IGT) was high (6.9%) and similar in all three population samples. In the periurban population, a large percentage of subjects were doing only routine household work and had a sedentary life-style. After correcting for the age and BMI, sedentary work and occupation had a significant association with diabetes, suggesting that sedentary lifestyle may be an important determinant for the higher prevalence of diabetes in an urbanising population.

Insulin secretion and action in different stages of glucose tolerance in Asian Indians

AIMS

To evaluate the sequence of changes in insulin secretion and action in different stages of glucose tolerance and the effect of obesity on insulin profile in South Indian adults. Blood samples from 260 consecutive cases with no known history of diabetes were collected. Plasma insulin levels were measured during a 75-g oral glucose tolerance test. Insulin resistance (IR) was calculated, using the homeostasis model assessment (HOMA). An index of insulin secretion was derived as the ratio of incremental insulin at 30 min divided by 30 minute plasma glucose (delta I/G).

RESULTS

Normoglycaemia was present in 164, impaired glucose tolerance (IGT) in 60 and diabetes in 36 subjects. Fasting and 2 h insulin secretion showed bell shaped curves with increasing plasma glucose. The peak values corresponded to the cut-off values used for the diagnosis of clinical diabetes. IR was higher in obese than in nonobese, nondiabetic subjects but the effect of obesity on IR was not found in subjects with diabetes. IGT was associated with higher IR, but not with evidence of a beta-cell defect.

CONCLUSIONS

Evaluation of insulin resistance and beta-cell function in different stages of glucose tolerance indicate that insulin resistance is manifested in the early stage of glucose intolerance in South Indians, i.e. IGT. A beta-cell defect was mostly found in people with diabetes. The beta-cell defect is more common in diabetes among the nonobese.

Familial aggregation of diabetic kidney disease in Type 2 diabetes in south India

The study was done to assess whether there was a familial aggregation of diabetic kidney disease (DKD) in Type 2 diabetic subjects. The profile of associated complications was also studied. Two groups of diabetic siblings of Type 2 diabetic patients, matched for age, body mass index (BMI) and duration of diabetes mellitus were studied. The siblings also had Type 2 diabetes. Group A comprised of siblings of probands with diabetic nephropathy and retinopathy (n = 30, M:F = 20:10) and Group B were siblings of probands without diabetic nephropathy or microalbuminuria (MAU) (n = 30, M:F = 14:16). Anthropometry, measurement of blood pressure and tests for proteinuria, MAU and retinopathy and ECG and biothesiometry were carried out for all study subjects. Persistent proteinuria was present in 15 (50%) siblings in group A and none in group B. MAU was detected in 26.7% (n = 7) in Group A and 3.3% (n = 1) in Group B (P = 0.057). Thus a total of 22 out of 30 cases in Group A had albuminuria. In Group A, seven (23.3%) had proteinuria and hypertension. Hypertension was present in nine (30.0%) in group A, and in five (16.7%) in group B (NS). Occurrence of retinopathy was found to be significantly higher in group A than in group B (33.3 vs 6.7%, chi2 = 5.1, P = 0.023). Abnormal ECG changes were present in 10% and 6.7% in Group A and Group B, respectively. In Group A, one patient had peripheral vascular disease (PVD) while in Group B none had PVD. A comparison of sib pairs, matched for age, duration of diabetes and the level of metabolic control showed that there was strong familial clustering of diabetic kidney disease in south Indians with Type 2 diabetes. This was independent of the familial clustering of diabetes. Prevalence of other vascular complications were also higher in Group A.

Current zinc intake and risk of diabetes and coronary artery disease and factors associated with insulin resistance in rural and urban populations of North India

OBJECTIVE

To determine the association between current zinc intake and prevalence of coronary artery disease (CAD) and diabetes as well as factors associated with insulin resistance.

DESIGN, SUBJECTS AND METHODS

In this cross sectional survey, 3575 subjects, aged 25 to 64 years, including 1769 rural (894 men. 875 women) and 1806 urban (904 men, 902 women) subjects were studied. The survey methods included questionnaires for 7-day food intake record, physical examination, and electrocardiography using World Health Organization criteria.

RESULTS

The prevalence of CAD, diabetes and glucose intolerance was significantly higher among subjects consuming lower intakes of dietary zinc. There was a higher prevalence of hypertension, hypertriglyceridemia and low high-density lipoprotein cholesterol levels which showed significant upward trend with lower zinc intakes. Serum lipoprotein (a) and 2-hour plasma insulin levels also were associated with low zinc intake. Multivariate logistic regression analysis after adjustment for age showed that zinc intake and CAD were inversely associated. Serum zinc (odds ratio:men 0.77, women 0.57), serum triglycerides (men 0.86, women 0.81), blood pressure (0.83 men, women 0.76), diabetes mellitus (men 0.90, women 0.85), central obesity (men 0.88, women 0.87), glucose intolerance (men 0.66, women 0.57) and low high-density lipoprotein cholesterol (men 0.72, women 0.70) were significant risk factors for CAD (explained by tertiles of zinc status) in urban subjects. These associations were not observed in rural subjects.

CONCLUSION

Lower consumption of dietary zinc and low serum zinc levels were associated with an increased prevalence of CAD and diabetes and several of their associated risk factors including hypertension, hypertriglyceridemia and other factors suggestive of mild insulin resistance in urban subjects.

Dietary profile of urban south Indians and its relations with glycaemic status

This study was done to analyse the dietary profile of urban south Indian adults. It was also aimed to study, if the dietary profile influenced the glycaemic and anthropometric data. Dietary details were collected in a representative urban sample of 900 study subjects in the epidemiological survey for diabetes conducted in 1995 in the city of Madras. The details were collected by a 24-h recall method. All the dietary factors were similar in the non-diabetic (NGT) and newly diagnosed diabetic cases, but the values were lower in known diabetic cases due to dietary modifications (P < 0.001 for all compared to NGT and new diabetic cases). For further analysis, known diabetic cases were deleted and the rest were combined as one group. Men consumed higher calories (2066+/-437, range 1028-3662 kcal) than women (1745+/-343, range 870-3260 kcal) (P < 0.01). Older persons consumed lower calories and percentages of the proximate principles in diet were proportionately lower. Higher calorie consumption was due to consumption of higher quantities of food and not any specific dietary factor. BMI, WHR, plasma glucose, serum cholesterol and triglycerides were not significantly influenced by the total calorie consumption. Calorie consumption was higher in persons engaged in strenuous physical activity. Total calories and proportionately the proximate principles of diet were less in the high income group. The similarity in diet in the non-diabetic and the newly diagnosed diabetic persons showed that the development of diabetes was probably not related to changes in dietary habits. Lower consumption of calories and carbohydrates by the known cases of diabetes was due to the dietary modifications introduced in the management of the disease. Lower calorie consumption in women and older people could be related to lower physical activity. This study shows a uniform dietary pattern among the different strata of society with minor variations based on age, gender and physical activity. No difference has been noted in dietary habits of the newly diagnosed diabetic subjects and the non-diabetic adults.

Prevalence of type 2 diabetes mellitus and risk of hypertension and coronary artery disease in rural and urban population with low rates of obesity

OBJECTIVE

To compare the prevalence of type 2 diabetes mellitus (DM) and coronary artery disease (CAD) and hypertension in DM in the rural and urban populations of north India.

DESIGN AND METHODS

Two populations of the same ethnic background were randomly selected for this cross sectional survey. There were 1769 rural (894 men, 875 women) and 1806 urban subjects (904 men, 902 women) between 25-64 years of age. The survey methods included fasting and 2 h blood glucose and electro-cardiogram and blood pressure measurement of all subjects.

RESULTS

Using the criteria of World Health Organization, the prevalence of diabetes mellitus (6.0 vs 2.8%) hypertension (24.0 vs 17.0%) and CAD (9.0 vs 3.2%) was significantly (P<0.001) higher in urban compared to rural subjects. Hypertension and CAD were significantly more frequent among subjects with diabetes compared to nondiabetes. The association of CAD and hypertension with diabetes was greater in urban than rural subjects. Excess body weight and obesity, central obesity, sedentary lifestyle, higher visible fat intake (>25 g/day), and social class 1-3 (higher and middle) were significantly associated with diabetes. Multivariate logistic regression analysis showed that after adjustment of age and sex, body mass index, central obesity, sedentary lifestyle and higher visible fat intake and alcohol intake in men were significant risk factors of diabetes among all the sub-groups.

CONCLUSIONS

The study showed a high prevalence of diabetes in urban north Indian population compared to rural subjects in the same ethnic group. CAD and hypertension were significantly associated with diabetes more in urban than rural subjects. The findings suggest that higher body mass index, waist-hip ratio and visible fat intake and sedentary lifestyle were risk factors of diabetes.

Computed axial tomographic scan measurement of abdominal fat distribution and its correlation with anthropometry and insulin secretion in healthy Asian Indians

Asian Indians have high insulin resistance, hyperinsulinemia, a high prevalence of diabetes, and a high waist to hip ratio (WHR), although the rate of obesity is low. WHR and visceral fat (VF) are highly correlated, and both are associated with insulin resistance. This study was performed to determine the normal ranges of abdominal fat distribution (subcutaneous [SF] and VF) in nondiabetic South Indians and also to study its correlations with WHR, plasma insulin, and metabolic profiles. Fat areas were measured by computed axial tomographic scan at the L4 to L5 level. Mean areas of SF and VF in men and women in this study were similar to the values in white populations. Women had significantly less VF than men. Gender differences were observed in the contribution of fat areas to anthropometric, hormonal, and metabolic variables. In general, in men, total fat (TF) area showed significant independent correlation with body mass index (BMI), WHR, and total cholesterol, and VF correlated with insulin secretion. In women, TF and BMI were correlated and SF showed a correlation with total cholesterol. Insulin secretion in women did not show a correlation with fat areas.

Insulin resistance syndrome in Australian aboriginal people

1. Like many indigenous populations, Australian Aboriginal people have developed high rates of obesity, non-insulin-dependent diabetes mellitus (NIDDM) and cardiovascular and renal disease following the transition from a traditional to an 'urbanized' lifestyle. These conditions tend to cluster as part of the insulin resistance syndrome. 2. The prevalence of overweight people and obesity in Australian Aboriginal populations ranges from 0% in communities with a traditionally orientated lifestyle to well over 50% in the worst affected communities. There is a predominantly central pattern of fat deposition in both men and women, which is associated with greater insulin resistance and cardiovascular risk than is peripheral fat deposition. 3. Data from four previously published, population-based surveys in Aboriginal communities were combined to give a cohort of 1079 subjects of 15 years and older. Several conditions of the insulin resistance syndrome had a strong, positive association with increasing body mass index (BMI): NIDDM (both cross-sectionally and longitudinally), hypertension, dyslipidaemia and albuminuria. Remaining lean (BMI < 20 kg/m2) protected even older Aboriginal people from these conditions to a large extent. 4. Community based programmes to increase physical activity and improve dietary quality are likely to be the major means by which conditions associated with insulin resistance can be prevented in Aboriginal populations.

Risk of noninsulin dependent diabetes mellitus conferred by obesity and central adiposity in different ethnic groups: a comparative analysis between Asian Indians, Mexican Americans and Whites

Epidemiological data from Asian Indians from Madras (AI) and Mexican Americans (MA) and non-Hispanic Whites (NHW) from San Antonio heart study were compared to determine the possible contributions by the anthropometric measurements to the varied prevalence of noninsulin dependent diabetes mellitus (NIDDM) in these ethnic groups. MA had the highest rate of obesity (mean body mass index (BMI) 28.9 +/- 5.9 kg/m2) and the highest prevalence of diabetes (men 19.6%; women 11.8%, P < 0.001 vs other groups). NHW although had high rates of obesity (mean BMI 26.2 +/- 5.2 kg/m2) had low prevalence of diabetes (men 4.4%; women 5.7%) than the AI (men 9.9%; women 5.7%) (Mean BMI 22.3 +/- 4.4 kg/m2, P < 0.001). Although AI had lower BMI than MA, the risk conferred by BMI was similarly high in AI and MA and both the ethnic groups had higher risks than NHW. Impaired glucose tolerance (IGT) was also more prevalent in MA than in AI (men, MA vs AI, 11.8 vs 7.5%, P < 0.003; women 16.1 vs 5.5%, P < 0.001). NHW had lower prevalence of IGT in men (5.7%) and women (6.3%) which were significantly lower (P < 0.001) compared to MA only. Age and BMI were predictive factors of NIDDM in all, while waist to hip ratio (WHR) was significant only in AI and MA, although NHW had high WHR. This may be an indicator of differences in genetic susceptibility. This study also highlights the similarity in risk factors between AI and MA living in urban environment and the significance of distribution of adiposity in the comparatively lean AI.

The prevalence of insulin resistance and other cardiovascular disease risk factors in healthy elderly southwestern Nigerians

We assessed the prevalence of coronary heart disease (CHD) risk factors including insulin resistance in 500 (205 males, 295 females) healthy elderly (age > 55 years) indigenous, low socioeconomic group Yorubas residents in either an urban slum (n = 240) or a rural town (n = 260) in southwestern Nigeria. Anthropometric indices, blood pressure and fasting plasma levels of glucose, lipids, insulin and insulin resistance were measured. The results indicated that: (i) gross obesity (4.4%), diabetes (1.6%), hyperlipidaemia (0.2%) and cigarette smoking (4.8%) were relatively uncommon in the population, although the prevalence of hypertension (30%) was higher than previously reported from this population; (ii). the subjects had a relatively high prevalence of multiple CHD risk factors (about 20% had > 4 risk factors), an observation considered paradoxical in view of the reportedly low CHD prevalence in this population; (iii) these CHD risk factors (increased body mass and blood pressure (BP), hyperinsulinaemia and insulin resistance) were more prevalent in the women and in urban residents; (iv) hyperinsulinaemia (20%) and insulin resistance (35%) were common in the population, and were associated, on regression analyses, to such other CHD risk factors as BP and body mass, particularly in women, suggesting, as in Caucasians, that insulin resistance could be an important index of CHD risk; and (v) the excess of multiple CHD risk factors in the women, is due at least in part, to their increased tendency to obesity (8%) and reduced physical activity (83%). This study concludes that: (i) despite the high prevalence of multiple risk factors in this population, CHD prevalence is low, indicating the supremacy of such major risk factors as diabetes and hyperlipidaemia (relatively uncommon here) in the development of CHD; and (ii) potentially the greatest CHD risk is in the elderly women especially if relatively overweight, physically inactive and resident in an urban centre. While further confirmatory studies are necessary in younger subjects and across societal socioeconomic strata, our results nonetheless suggest that attempts to maintain the CHD prevalence at low levels in this population should include efforts directed at reducing excess body weight particularly in women, and advice on maintenance of a traditional diet to keep lipid levels and diabetes prevalence low.

Association of higher saturated fat intake with higher risk of hypertension in an urban population of Trivandrum in south India

Saturated fat intake appears to be a risk factor of insulin resistance which is important in the pathogenesis of diabetes and cardiovascular disease. This study aims to demonstrate whether saturated fat intake may be a risk factor of hypertension. Cross-sectional survey in six randomly selected streets in Trivandrum city in south India was conducted to study 1497 randomly selected subjects (737 males and 760 females) of 25-64 years of age. The prevalence of hypertension by Joint National Committee V criteria (> 140/90 were 34.6% (n = 255) in males and 30.7% (n = 234) in females. The consumption of food groups showed that they were within desirable limits. However, the intake of fruit, vegetable, legume and coconuts was lower and saturated fat intake higher (> 10% kcal/day), although total fat intake was within desirable limits. Total and saturated fat intake, and the consumption of coconut oil and butter, flesh foods, milk and yogurt as well as sugar and jaggery were significantly associated with hypertension. Total visible fat (> 20 g/day) intake was positively associated whereas fruit, vegetable, legume and coconut intake (< 400 g/day) was inversely associated with hypertension. Salt intake (> 8 g/day), smoking and illiteracy were not associated with hypertension. Multivariate logistic regression analysis showed that saturated fat intake, age and body mass index were independently and strongly associated with hypertension whereas fruits, vegetable, legume and coconuts, coconut oil and butter and alcohol (males) intakes were weakly associated with hypertension. The odds ratio indicate higher risk of hypertension due to higher intake of saturated fat in both sexes (mean: odds ratio, 1.07, 95% confidence interval 1.05-1.09; women, 1.08, 1.06-1.12, P < 0.01). Significant determinants of hypertension were higher saturated fat, particularly coconut oil, and lower fruit, vegetable, legume and coconuts, particularly legumes and coconuts in the diet, apart from conventional risk factors.

Effect of diet and moderate exercise on central obesity and associated disturbances, myocardial infarction and mortality in patients with and without coronary artery disease

OBJECTIVE

To test whether a fat modified and fruit and vegetable enriched diet in conjunction with moderate physical activity reduces the cardiac event rate in patients with coronary artery disease (CAD) and its risk factors in an urban setting in India.

SUBJECTS AND METHODS

480 patients either with CAD or with risk factors. Those with definite or possible CAD including angina pectoris (n = 210) based on World Health Organization criteria and patients with risk factors were assigned to diet A (n = 231) or diet B (n = 232) for a period of 3 years. Both groups were advised to follow a fat modified diet. Group A was also advised to consume at least 400 g/day of fruits, vegetables and legumes according to World Health Organization advice and include moderate physical activity.

RESULTS

Waist-hip ratios, fasting and post-prandial blood glucose, plasma insulin levels, blood pressure and weight fell significantly in patients in group A compared with those in group B. While triglycerides in group A showed a significant decrease, high density lipoprotein cholesterol showed a significant increase. Both groups showed a significant reduction in total and low density lipoprotein cholesterol, although the decrease was greater in group A than group B. Central obesity decreased by 6.2% in group A vs. 1.2% in group B, 95% confidence interval of difference 2.3 to 7.8. The incidence of cardiac events was significantly lower in group A than group B (29 vs. 43 patients, p < 0.01). All-cause mortality also significantly declined in group A compared with group B (16 vs. 24 died, p < 0.05). The group A patients with better adherence to exercise and diet showed greater reduction in central obesity and greater decline in cardiac event rates and total mortality compared to control group B.

CONCLUSIONS

It is possible that moderate physical activity in conjunction with dietary changes in patients with CAD may cause substantial reductions in central obesity and associated disturbances corresponding to a significant decrease in cardiac events and mortality during the follow-up of 3 years.

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.

Biological diversity, indigenous knowledge, drug discovery and intellectual property rights: creating reciprocity and maintaining relationships

When new plant-derived therapeutics based on indigenous knowledge are being explored, it is important that the pharmaceutical companies return benefits to the native populations and the local governments from which the research material was obtained. When a potentially marketable plant product is being developed, it is essential that equitable agreements have already been established between the pharmaceutical companies and the people and/or countries from which this indigenous knowledge was acquired. Equally important is the commitment to provide immediate reciprocity that will enhance the welfare, the biocultural diversity and the well-being of the forest peoples. These measures should commence when a research project begins and continue during its duration. The development of these measures must be based upon the expressed needs of the indigenous communities. The relationship between the stability of the rain forest biocultural diversity, the creation and development of agro-forest resources and the long term benefits to the forest people is highlighted. Examples of initiatives taken by Shaman Pharmaceuticals Inc. and the Healing Forest Conservancy are described and discussed in the context of exploring appropriate use of intellectual property law to address the ethical issues facing all business and research groups working in the tropics.

Diabetic retinopathy at the time of diagnosis of NIDDM in south Indian subjects

Several studies from the U.K. and the U.S. have shown that retinopathy was present at diagnosis of non-insulin dependent diabetes mellitus (NIDDM) indicating the likelihood of a latent phase of hyperglycaemia for a long period. This study looked for the prevalence of retinopathy at diagnosis of NIDDM in South Indian subjects who have a fairly high prevalence of diabetes and also a high rate of undetected diabetes. One thousand NIDDM subjects with varying duration of diabetes underwent detailed ophthalmoscopic examination for retinopathy. It was noted that the prevalence of retinopathy increased linearly with duration of diabetes. Among the 60 newly diagnosed NIDDM, 4 (6.7%) subjects had background diabetic retinopathy. Using a weighted linear regression analysis with percentage of retinopathy in relation to duration, it was estimated that hyperglycaemia could have been present 4.1 years prior to the diagnosis of NIDDM. Although the prevalence of retinopathy at diagnosis in South Indian NIDDM was lower than the other reported values, in view of the high prevalence of diabetes in Indians, a large number of patients would have the risk of microangiopathy even before diagnosis of diabetes is made.

The epidemiology of obesity

An agreed definition of obesity as a body mass index (BMI) of 30 kg/m2 or more seems to be accepted everywhere except in North America. Recent data confirm the importance of setting an upper individual BMI limit of 25 kg/m2 and a population optimum of 20-23 kg/m2. Some adjustment of BMI should be made in individuals and populations with disproportionate shapes, e.g. short or long legs, and morbidity and mortality risks are especially important in those with a waist measurement of about 102 cm or more, the risk increasing from 88 cm. Waist measurements should probably now be substituted for the waist/hip circumference ratio. Diabetes is universally closely linked to increases in BMI, and cardiovascular disease is amplified by obesity, particularly in western societies where other dietary factors contribute substantially. Industrialization with reduced physical activity and higher fat diets lead to obesity first in middle-aged women, then in men, with younger adults and children eventually being affected. Physiological studies display the interaction of physical activity and energy dense, high fat diets and explain the secular, age- and social class-related trends throughout the world. Intergenerational amplification of obesity may be underway, so the public health implications of obesity are immense.

Metabolic consequences of obesity and body fat pattern: lessons from migrant studies

Prevalence of non-insulin-dependent diabetes mellitus and mortality from coronary heart disease are higher in people of South Asian (Indian, Pakistani and Bangladeshi) descent living in urban societies than in other ethnic groups. The high prevalence of diabetes is one manifestation of a pattern of metabolic disturbances related to central obesity and insulin resistance, which includes raised plasma very low density lipoprotein triglyceride and low plasma high density lipoprotein-cholesterol. Average waist/hip circumference ratios are higher in South Asians than in Europeans of similar body mass index: in this respect South Asians differ from other populations such as Pima Indians where high prevalence of non-insulin-dependent diabetes mellitus occurs in association with generalized obesity. The high rates of coronary heart disease in South Asians are most easily explained by the effects of this central obesity/insulin resistance syndrome, although ethnic differences in fasting lipids are unlikely to account fully for the excess risk. In Afro-Caribbean migrants, the prevalence of diabetes is almost as high as in South Asians but the lipid disturbances characteristic of the insulin resistance syndrome do not occur to the same extent. This may account for the low rates of coronary heart disease in this group.

Diabetes, impaired glucose tolerance and cardiovascular disease risk factors in the Asian Indian Bhatia community living in Tanzania and in the United Kingdom

A population-based cross-sectional survey was carried out to study potential environmental risk factors contributing to diabetes and cardiovascular risk in the same homogeneous group in the United Kingdom and in Dar es Salaam, Tanzania. In Dar es Salaam, 222 members of the Bhatia community aged 15 years and over were studied. In the UK, 180 randomly selected subjects aged 15 years and over participated. Age, sex, and body mass index adjusted mean levels of fasting glucose (5.5 mmol l-1 vs 5.1 mmol l-1 (p < 0.001)) and 2 h glucose (6.8 mmol l-1 vs 6.0 mmol l-1 (p < 0.001)) were significantly higher in Tanzanian subjects than in UK subjects. Mean levels of serum triglycerides (1.5 mmol l-1 vs. 1.3 mmol l-1 (p < 0.05)) and systolic blood pressure (135 mmHg vs 127 mmHG (p < 0.05) were significantly higher in subjects in the UK. The age and sex adjusted prevalence of impaired glucose tolerance (28.4% vs 11.4% (p < 0.001)), newly diagnosed diabetes (8.6 % vs 1.5% (p < 0.01)), hypercholesterolaemia (9.9% vs 1.5% (p < 0.001)), and smoking (12.1% vs 3.9% (p < 0.01)) were significantly higher in subjects in Tanzania compared to subjects in the UK. The prevalence of known diabetes, hypertriglyceridaemia, hypertension, and obesity did not show significant differences between subjects in Tanzania and those in the UK. Within the same homogeneous community with the same likely genetic predisposition, there are substantial geographical differences in cardiovascular risk factors, the causes of which remain to be determined.

Coronary risk factors in people from the Indian subcontinent living in west London and their siblings in India

Several reports have shown that migrants from southeast Asia tend to have an increased risk of coronary heart disease when settled in their new country. We compared coronary risk factors in a randomly selected group of 247 migrants from the Indian subcontinent of Punjabi origin living in West London and 117 of their siblings living in the Punjab in India. The West London cohort had a greater body mass index (p < 0.001), systolic blood pressure (p = 0.0087), serum cholesterol (p < 0.001), apolipoprotein B (p < 0.001), lower high-density lipoprotein cholesterol (p < 0.05) and higher fasting blood glucose (p < 0.05) than their siblings in the Punjab. Insulin sensitivity, derived from the homoeostatic assessment mathematical model, was lower in men in West London than in their counterparts in India (p < 0.05). Indians in West London had lower beta cell function than those in the Punjab (p < 0.001). Serum lipoprotein (a) concentrations were similar in both the West London and Punjab population, but were significantly higher (p = 0.01) than those of white European populations in the UK. Increases in serum cholesterol after migration from India lead to increased coronary risk conferred by high serum lipoprotein (a) concentrations and greater insulin resistance. Such between-country comparisons are an important means of establishing the importance of coronary risk factors.

Epidemiologic study of diet and coronary risk factors in relation to central obesity and insulin levels in rural and urban populations of north India

In a population survey of 162 rural and 152 urban subjects aged 26-65 years at Moradabad, the findings are compared with existing data on Indian immigrants to Britain and United States. In comparison with rural subjects, urban subjects had a higher prevalence of coronary artery disease (8.6 vs. 3.0%) and diabetes (7.9 vs 2.5%), higher blood pressures, total and low density lipoprotein cholesterol, triglycerides and postprandial 2-h blood glucose and plasma insulin similar to observations made in UK in immigrants compared to Europeans. Fasting plasma insulin and high density lipoprotein cholesterol levels in urban subjects were comparable with rural subjects. Mean body weights were significantly higher in urban women, but not in men, than in rural subjects. However the body mass index (22.9 +/- 4.2 vs. 21.6 +/- 2.4 kg/m2) and waist-hip girth ratio (0.89 +/- 0.10 vs. 0.86 +/- 0.07) were significantly higher in urban men compared to rural men without such differences in women. Underlying these differences in risk factors, urban subjects had three times better socioeconomic status than rural subjects and were eating higher total and saturated fat, cholesterol and refined carbohydrates and lower total and complex carbohydrates compared to rural men and women. Energy expenditure during routine and spare time physical activity was significantly higher in rural compared to urban subjects. Those patients who had risk factors, showed lesser physical activity and had greater adverse factors in the diet compared to subjects without risk factors. Body mass index and waist-hip girth ratio in patients with risk factors were significantly higher than in subjects without risk factors. The findings suggest that decreased consumption of total and saturated fat and increased physical activity may be useful for prevention of coronary artery disease among urbans as well as in immigrants.

Family studies of non-insulin-dependent diabetes mellitus in South Indians

Though a genetic basis for non-insulin-dependent diabetes mellitus (NIDDM) is clear, the likely mode of inheritance is not known. The segregation of NIDDM was studied in 64 nuclear South Indian pedigrees (449 individuals) ascertained through an affected proband having both parents and more than 1 sibling alive and available for oral glucose tolerance testing. A high proportion of parents were found to be of abnormal glucose tolerance [89 of 128 (70%) diabetic and 11 of 128 (9%) impaired]. Complex segregation analysis was performed using (1) POINTER which implements the mixed model and distinguishes major gene, multifactorial and non-transmitted environmental contributions to affection and (2) COMDS which implements an oligogenic model with major gene, modifier gene and environmental contributions to a) affection and b) diathesis (an ordered polychotomy amongst non-affected family members, based on 2-h plasma glucose level). Using POINTER, there was no formal support for a major gene and the most parsimonious solutions were achieved with multifactorial models. Using COMDS, we found i) significant improvements in models when information on glucose levels in nondiabetic family members (diathesis) was included, ii) support for segregation of a diallelic gene as well as background familial resemblance, and iii) under the best-supported model, this diallelic locus featured incomplete dominance (d = 0.8) and a disease-predisposing allele frequency of 14%. In South Indians, segregation of NIDDM is inadequately described by simple major gene models: more complex models provide more satisfactory descriptions. This finding, if applicable in other populations, has important implications for the search for diabetes-susceptibility genes.

Prevalence of diabetes in pregnant women--a study from southern India

This study was carried out to assess the prevalence of diabetes in southern Indian women during pregnancy. Nine hundred and fifty women having > or = 24 weeks of gestation, attending two general gynaecology centres for antenatal check-ups were screened. Initially, the screening test with 1-h plasma glucose sampling following 50 g glucose load was done and those with glucose values > or = 140 mg/dl were subjected to a 3-h oral glucose tolerance test (OGTT) with 100 g glucose load. Among the 950 women, 6 were known diabetic subjects. Of the other 944, 89 were positive on screening test and 67 of them reported for OGTT. Four were detected to have gestational diabetes mellitus (GDM) (O'Sullivan and Mahan's criteria). Therefore the prevalences of total diabetes and GDM were 1.19% and 0.56%, respectively.

Differences in plasma insulin responses in urban and rural Indians: a study in southern-Indians

Fasting and 2 h post glucose plasma immunoreactive insulin (fasting IRI and 2 h IRI) responses were measured in urban (n = 149) and rural (n = 40) individuals with normal glucose tolerance during an epidemiological survey. In this survey, 900 urban and 1038 rural subjects were screened for glucose intolerance by capillary blood sampling. The respective response rates were 91% and 88%. We had planned to collect venous blood for IRI estimation, i.e. from 180 urban and 200 rural subjects. The compliance for the same was poor from the rural subjects and therefore the number available for IRI estimation was small. The mean +/- SD ages of the urban and rural groups were similar (35.3 +/- 9.9 and 38.6 +/- 13.1 years, respectively). The rural population had lower body mass index (BMI) and subscapular:triceps ratio compared to the urban group (p < 0.001). The total calorie consumption was lower and physical activity was higher in rural population. Fasting and 2 h insulin values in urban population were 16.6 +/- 9.4 mU l-1 and 60.6 +/- 42.5 mU l-1 and in rural 6.7 +/- 5.1 mU l-1 and 32.4 +/- 27.8 mU l-1, respectively; the values being significantly lower in the rural population (p < 0.001). Multiple regression analysis showed that in urban population the fasting insulin was correlated to the BMI and the 2h IRI to 2 h glucose, BMI and the subscapular:triceps ratio. In the rural population, similar results were obtained, except in that the 2 h IRI was influenced by the gender also.(ABSTRACT TRUNCATED AT 250 WORDS)

Fasting plasma glucose in the diagnosis of diabetes mellitus: a study from southern India

The usefulness of fasting plasma glucose (FPG) in the diagnosis of diabetes mellitus was assessed in Asian Indians in South India. Oral GTT values in 570 newly screened adults were studied. Taking the WHO criteria of 2 h plasma glucose (PG) of > or = 11.1 mmol l-1 for diagnosis of diabetes, the validity of a FPG of > or = 7.8 mmol l-1 cut off value for diabetes was assessed. Using the regression analysis, the correlations of the FPG to 2 h PG were examined. Among the 268 with 2h PG value of > or = 11.1 mmol l-1, 205 (76.5%) had FPG > or = 7.8 mmol l-1. Sensitivity of FPG was 76.5% for diagnosis of diabetes and its specificity was 99%. An exponential regression model gave the best fit for FPG vs 2 h PG and using the regression equation, the predicted FPG for a 2 h PG of 11.1 mmol l-1 was 7.05 mmol l-1. Sensitivity increased to 90.3% with FPG of 7.05 mmol l-1 while the specificity remained at 92%. It is concluded that in the south Indian subjects, the sensitivity for diagnosis of diabetes with FPG of > or = 7.8 mmol l-1 was 76.5%; and it increased to 90.3% with FPG of > or = 7.05 mmol l-1.

Positive association in the absence of linkage suggests a minor role for the glucokinase gene in the pathogenesis of type 2 (non-insulin-dependent) diabetes mellitus amongst south Indians

Mutations of the glucokinase gene have been implicated in the development of glucose intolerance in pedigrees with maturity-onset diabetes of the young. However, the contribution of the glucokinase gene to the aetiology of common Type 2 (non-insulin-dependent) diabetes mellitus is uncertain. We have studied the role of the glucokinase gene in the pathogenesis of Type 2 diabetes in South Indians, using both population-association and linkage methodology. A pair of CA-repeat sequences (GCK(3') and GCK(5')) straddling the glucokinase gene were employed as markers, each subject being typed using the polymerase chain reaction and polyacrylamide gel electrophoresis. Comparisons of allele frequencies at these markers were made between 168 Type 2 diabetic subjects and 70 racially-matched control subjects. No differences in allele frequencies were apparent at the GCK(5') marker; however, there were significant differences in allele frequencies at the GCK(3') marker between the Type 2 diabetic subjects and control subjects (chi 2 = 11.6, df = 3, p = 0.009) with an increase of the z allele (78.0% vs 66.4%) and a decrease of the z + 2 allele (13.7% vs 25.0%) amongst the diabetic subjects. Linkage between glucose intolerance and the glucokinase gene was studied in 53 nuclear pedigrees under a variety of genetic models. Linkage was excluded (lod score < -2) at a recombination fraction of zero under five of the ten models used and highly unlikely (-2 < lod score < -1) under the others. The combination of positive association and negative linkage suggests that glucokinase acts as a minor gene influencing the development of Type 2 diabetes within this population.