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

Effectiveness of a Group-Based Culturally Tailored Lifestyle Intervention Program on Changes in Risk Factors for Type 2 Diabetes among Asian Indians in the United States

This study used an experimental, pretest-posttest control group repeated measures design to evaluate the effectiveness of a community-based culturally appropriate lifestyle intervention program to reduce the risk for type 2 diabetes (T2DM) among Gujarati Asian Indians (AIs) in an urban community in the US. Participants included 70 adult AIs in the greater Houston metropolitan area. The primary outcomes were reduction in weight and hemoglobin A1c (HbA1c) and improvement in physical activity. Participants were screened for risk factors and randomly assigned to a 12-week group-based lifestyle intervention program (n = 34) or a control group (n = 36) that received standard print material on diabetes prevention. Participants also completed clinical measures and self-reported questionnaires about physical activity, social, and lifestyle habits at 0, 3, and 6 months. No significant baseline differences were noted between groups. While a significant decline in weight and increase in physical activity was observed in all participants, the intervention group lowered their HbA1c (p < 0.0005) and waist circumference (p = 0.04) significantly as compared to the control group. Findings demonstrated that participation in a culturally tailored, lifestyle intervention program in a community setting can effectively reduce weight, waist circumference, and HbA1c among Gujarati AIs living in the US.

Rural urban differences of cardiovascular disease risk factors in adult Asian Indians

The prevalence of cardiovascular disease (CVD) risk factors in "People of Indian Origin" (PIO) is exceedingly high and strong relationships among elevated blood pressure, increased levels of lipoproteins, visceral obesity, physical inactivity and subsequent high occurrence of coronary heart disease, type 2 diabetes mellitus etc., were evident in many studies. Increasing urbanization with effective changes in lifestyles could be attributed to explain this exaggerated rate. The present community based cross-sectional investigation was aimed to identify rural-urban differences in prevalence of risk factors of CVD in the adult Asian Indians. A total of 350 adult (30 years and above) individuals (184 males and 166 females) belong to urban (n = 193, males = 104, and females = 89) and rural (n = 157, males = 80, and females = 77) areas participated in the study. Anthropometric measures, lipids profiles, fasting blood glucose and blood pressure measures were obtained from participants. The mean body mass index (kg/m2) for male and female was 22.37 +/- 4.09 and 23.20 +/- 4.37, respectively. There existed significant differences for anthropometric, metabolic, and blood pressure variables between rural and urban areas. Habitat (rural vs. urban) had significant impact on central adiposity, lipids, lipoproteins, and blood pressure measures even after adjusted for age and sex. Overall, 84.3% of females had lower HDL level compared with only 20.1% in males. It was also observed that the prevalence of metabolic syndrome was 56.2% in urban females compared with 36.4% in rural females. Effective urbanization and or modernization seem to influence CVD risk factors and warrants intervention as early as adulthood to check this menace.

Insulin response to oral glucose in healthy, lean young women and patients with polycystic ovary syndrome

BACKGROUND AND AIM

Insulin resistance and consequent hyperinsulinemia are common among patients with polycystic ovary syndrome (PCOS). Ethnicity and dietary habits affect insulin levels. There is little published information from India on insulin levels in PCOS patients. Thus the present study aimed to determine the insulin response to oral glucose in women with PCOS and healthy women.

METHODS

In a case-control study design, women with PCOS and lean healthy women without a family history of diabetes mellitus underwent oral glucose tolerance testing. Samples were collected at 0, 1 and 2 h after glucose ingestion.

RESULTS

Two hundred and eighty-five women with PCOS and 27 lean healthy young women were enrolled into the study. The mean age of controls was 22.8 +/- 4.5 years (range 15-32 years) and their mean body mass index (BMI) was 19.7 +/- 2.6 kg/m(2). Mean blood glucose at 0, 1 and 2 h was 88.2 +/- 7.2, 115.5 +/- 25.5 and 91.8 +/- 20.5 mg/dl, respectively. Corresponding plasma insulin levels were 5.8 +/- 1.1, 32.7 +/- 26.5 and 14.6 +/- 9.6 mIU/l. Peak insulin levels were seen at 1 h and these came down to less than 40% of the peak value by 2 h. Glucose/insulin ratio at 0, 1 and 2 h was 15.6 +/- 3.1, 7.0 +/- 3.1 and 11.4 +/- 7.0. Homeostasis model assessment of insulin resistance (HOMA-IR) was 1.2 +/- 0.2. The age of the PCOS women ranged from 15 to 40 years (mean 23.4 +/- 6.2 years) and their BMI ranged from 16.4 to 50.4 kg/m(2) (mean 27.7 +/- 6.3 kg/m(2)). One hundred and seventy-six (62%) PCOS patients had normal glucose tolerance (NGT), 39 (14%) had impaired fasting glucose (IFG), 49 (17%) had impaired glucose tolerance (IGT) and 21 (7%) had type 2 diabetes mellitus (T2DM). Insulin response was higher in women with PCOS. Peak insulin was observed at 1 h. The difference between 1-h and 2-h post-glucose insulin decreased with worsening glucose tolerance. Both plasma insulin and BMI showed a rising trend from NGT to IFG to IGT. There was no further increase in either insulin or BMI from IGT to T2DM. Glucose/insulin ratio at 0, 1 and 2 h was lower (8.3 +/- 4.2, 2.0 +/- 1.6 and 3.2 +/- 3.5) than that of healthy controls. HOMA-IR was 3.1 +/- 3.0.

CONCLUSION

Women with PCOS had an exaggerated insulin response to glucose. Thirty-eight percent of PCOS women had some form of abnormal glucose tolerance. Greater insulin response was seen with impairment of glucose tolerance. Obesity had no effect on fasting insulin or insulin response to oral glucose in PCOS women with NGT.

A comparative study of the prevalence of the metabolic syndrome and its components in type 2 diabetic patients in two Caribbean islands using the new International Diabetes Federation definition

BACKGROUND AND AIM

Tobago and Trinidad are two Caribbean islands with distinct genetic background and lifestyles; while Tobago is serene and a tourist centre, Trinidad is characterized by a hustling and bustling lifestyle. The study was aimed at determining and comparing the prevalence of the metabolic syndrome (MetS) and its critical components in type 2 diabetic patients using the new International Diabetes Federation (IDF) definition.

METHODS

Four hundred and thirteen (166 Tobago, 247 Trinidad) type 2 diabetic patients visiting 10 lifestyle disease clinics were studied. Blood pressure, anthropometric parameters (height, weight, body mass index and waist circumference) and overnight fasting blood samples were taken. Plasma glucose and serum triglycerides, total cholesterol, LDL- and HDL-cholesterol, insulin, and adiponectin were determined. Insulin resistance (IR) was determined using the HOMA method.

RESULTS

The patients in Tobago were significantly older than patients in Trinidad (p < 0.001) but the duration of diabetes (9.4 +/- 0.5 vs. 11.1 +/- 0.7 yr), medications, generalized (31.7 vs. 38.8%) and central (78.5 vs. 83.7%) obesity were similar (p > 0.05). In comparison with patients in Tobago, diabetic patients in Trinidad, irrespective of gender, had significantly higher prevalence of IDF critical components such as raised BP, raised triglycerides and reduced HDL-cholesterol (all, p < 0.001). Thus, while more patients in Trinidad were diagnosed with MetS based on three or four components, more patients in Tobago were diagnosed based on two components (p < 0.001).

CONCLUSIONS

There were high prevalence rates of the components of the MetS in both the islands of Tobago and Trinidad. Quantitatively, the aggregation of the components is higher in patients in Trinidad, which constitute greater risk for adverse cardiovascular outcome. Controlling central obesity should be the target in preventing MetS in the two islands.

High prevalence of glucose intolerance even among young adults in south India

India is experiencing an epidemic of Type 2 diabetes mellitus (DM) in young adults. This study reports the prevalence of glucose intolerance, and insulin profiles, and their relationship to lifestyle factors in 2218 young adults (aged 26-32 years; 997 urban, 1221 rural) in south India. They were drawn from a cohort of 10,691 individuals born during 1969-1973 in Vellore and nearby villages. Family history, socio-economic status, physical activity and tobacco and alcohol use were recorded. Oral glucose tolerance tests were performed for diagnosis (WHO recommendations). Insulin resistance and secretion were derived from plasma insulin concentrations. Median BMI was 20.0kg/m(2). The prevalence of Type 2 DM and impaired glucose tolerance (IGT) was higher in urban than in rural subjects (3.7% versus 2.1%, p=0.02; 18.9% versus 14.3%, p=0.002, respectively), while prevalence of impaired fasting glycaemia (IFG) was similar in urban and rural populations (3.8% versus 3.4%, p=0.04). Type 2 DM, IGT, IFG or higher insulin resistance and increment were associated with higher socio-economic status (more household possessions) and higher percentage body fat, body mass index and waist/hip ratio. Insulin increment was lower in men with higher alcohol consumption. Our data suggest high levels of glucose intolerance in young rural and urban adults highlighting an urgent need for preventive action to avert a public health catastrophe in India.

Evolutionary origins of insulin resistance: a behavioral switch hypothesis

BACKGROUND

Insulin resistance, which can lead to a number of diseases including type 2 diabetes and coronary heart disease, is believed to have evolved as an adaptation to periodic starvation. The "thrifty gene" and "thrifty phenotype" hypotheses constitute the dominant paradigm for over four decades. With an increasing understanding of the diverse effects of impairment of the insulin signaling pathway, the existing hypotheses are proving inadequate.

PRESENTATION OF THE HYPOTHESIS

We propose a hypothesis that insulin resistance is a socio-ecological adaptation that mediates two phenotypic transitions, (i) a transition in reproductive strategy from "r" (large number of offspring with little investment in each) to "K" (smaller number of offspring with more investment in each) and (ii) a transition from "stronger to smarter" or "soldier to diplomat" i.e. from relatively more muscle dependent to brain dependent lifestyle. A common switch could have evolved for the two transitions since the appropriate environmental conditions for the two transitions are highly overlapping and interacting.

TESTING THE HYPOTHESIS

Gestational insulin resistance diverts more energy through the placenta, resulting in increased investment per offspring. On the other hand, insulin resistance is associated with reduced ovulation. The insulin signaling pathway is also related to longevity. Insulin resistance diverts more nutrients to the brain as compared to muscle. Also, hyperinsulinemia has direct positive effects on cognitive functions of the brain. The hypothesis gets support from known patterns in human clinical data and recent research on the molecular interactions in the insulin signaling pathway. Further we state many predictions of the hypothesis that can be tested experimentally or epidemiologically.

IMPLICATIONS OF THE HYPOTHESIS

The hypothesis can bring about a significant change in the line of treatment as well as public health policies for the control of metabolic syndrome.

Sib-recruitment for studying migration and its impact on obesity and diabetes

BACKGROUND

Urban-rural comparisons are of limited relevance in examining the effects of urban migration in developing countries where urbanisation is due to growth of existing urban populations, expansion of urban boundaries, and rural in-migration. Cultural, genetic and life-style backgrounds of migrants and host populations further limit the value of rural-urban comparisons. Therefore we evaluated a sib-comparison design intended to overcome the limitations of urban-rural comparisons.

METHODS

Using the framework of a current cardiovascular risk factor screening study conducted in Indian factories, we recruited the non-migrant rural sibs of migrant urban factory workers and the urban sibs of non-migrant factory workers. The response rate, completed interviews and examinations conducted were assessed. Adequacy of generic food frequency questionnaires and WHO quality of life questionnaire were assessed.

RESULTS

All the urban factory workers and spouses approached agreed to be interviewed. Of the 697 participants interviewed, 293 (42%) had at least one rural dwelling sibling. Twenty (22%) siblings lived further than 100 km from the study site. An additional 21 urban siblings of non-migrant factory workers were also investigated to test the logistics of this element of the study. Obesity (BMI >25 kg/m2) was more common in rural sibs than urban factory workers (age adjusted prevalence: 21.1% (17.1 to 25.0) vs. 16.1% (11.9, 20.3). Diabetes prevalence (fasting plasma glucose greater than 126 mg/dl) was higher than expected (age-adjusted prevalence: 12.5% (22 out of 93) in urban migrants and 4.5% (8 out of 90) in rural non-migrant sibs.

CONCLUSION

The sib-comparison design is robust and has been adopted in the main study. It is possible that simple urban-rural study designs under-estimate the true differences in diabetes risk between migrants and non-migrants.

Low risk threshold for acquired diabetogenic factors in Asian Indians

India is facing an epidemic of type 2 diabetes, with high prevalence in urban areas. Urbanisation and associated life style changes adversely affect the risk factors for diabetes unmasking the high genetic tendency existing in the population. Various epidemiological studies in Indians have shown that the increasing prevalence of diabetes could be attributed to a high genetic risk and lower risk thresholds for acquired risk factors such as age, obesity, abdominal adiposity and a high percentage of body fat. Diabetes occurs at a younger age in Indians compared to Whites. The risk of diabetes increases with a body mass index (BMI) of >23 kg/m(2) and waist circumference of 85 cm for men and 80 cm for women in Asian Indians. For a given BMI, Asian Indians have higher central adiposity. There is also evidence of higher insulin resistance amongst Indians, and this is partly explained by higher body fat percentage. A large proportion of urban adults has the metabolic syndrome also which predisposes them to both diabetes and cardiovascular diseases. Recognition of these conditions and institution of early preventive measures are urgently needed.

Type 2 diabetes in South Asians: a pathophysiologic focus on the Asian-Indian epidemic

There is a high prevalence of type 2 diabetes mellitus and coronary artery disease among urban and migrant Asian Indians, despite the absence of traditional risk factors. Evidence exists that Asian Indians are more insulin resistant than white persons and that insulin resistance may play an important role in the pathogenesis of these diseases. Increased visceral fat in Asian Indians is associated with increased generalized obesity, which is not apparent from their nonobese body mass index. Increased visceral fat is related to dyslipidemia and increased frequency of insulin resistance and may account for the increased prevalence of diabetes mellitus and cardiovascular disease in Asian Indians. In addition, early protein energy deprivation, as indicated by low weight at birth and at 1 year of age, may induce a state of vulnerability to the development of type 2 diabetes in later life, especially if the quantitative and qualitative aspects of nutrition and altered lifestyles during adult years pose an additional challenge.

Markers of endothelial dysfunction in hyperglycaemic Asian Indian subjects

OBJECTIVE

The aims of this study were the following: (1). to determine the levels of endothelin-1(ET1), soluble adhesion molecules like intracellular adhesion molecule-1 (sICAM-1), and vascular cell adhesion molecule-1 (sVCAM-1) in different stages of glucose intolerance and to identify a suitable marker of endothelial dysfunction and (2). to determine the possible association of these biochemical parameters with diabetic complications and with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

In this cross-sectional study, plasma ET1, sICAM-1, and sVCAM-1 were measured by enzyme-linked immunosorbent assay (ELISA) in 20 nondiabetic subjects, in 15 subjects with IGT, in 21 Type 2 diabetic subjects without any complication, and in 21 Type 2 diabetic patients with nephropathy and retinopathy.

RESULTS

Median ET1 levels were significantly elevated (P=.004) in IGT subjects (0.31 fmol/ml) when compared with the nondiabetic subjects (0.11 fmol/ml). Subjects with nephropathy (0.50 fmol/ml) had significantly higher (P=.002) ET1 values when compared with those without complications (0.40 fmol/ml). The levels of sICAM-1 and sVCAM-1 did not show any significant difference among the groups. ET1 showed correlation with age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), 2 h post glucose (2hPG), waist-to-hip ratio (WHR), total white blood corpuscles count, glycosylated haemoglobin (HbA1c), triglycerides (TG), very-low-density lipoprotein cholesterol (VLDLc), and hypertension (HTN). In the multiple linear regression analysis, plasma ET1 was significantly associated with the presence of Type 2 diabetes either with or without complications (P<.0001 and P=.0098, respectively), WHR (P=.0063), and sVCAM-1 (P=.0051). The total variance explained by the above-mentioned parameters was 55%.

CONCLUSION

Elevated levels of ET1 were present in subjects with IGT and in Type 2 diabetic subjects. Such associations with sICAM-1 or sVCAM-1 in these subjects were not seen. ET1 could be an early marker of endothelial dysfunction, which appeared to occur even in the subclinical stages of hyperglycaemia.

Association of proinsulin and insulin resistance with coronary artery disease in non-diabetic south Indian men

AIMS

To evaluate the association of plasma proinsulin and insulin resistance (IR) with coronary artery disease (CAD) in non-diabetic subjects.

METHODS

In this case control study, 41 normoglycaemic men with angiographic evidence of CAD were compared with 41 control men matched for age and glycaemia and with no history or evidence of cardiac diseases. Estimations of plasma glucose, lipids, fasting plasma specific insulin (SI) and proinsulin (PI) were performed. IR was calculated by the homeostasis model assessment (HOMA) method. Multiple logistic regression analysis was performed to test the association of the variables with the prevalence of CAD.

RESULTS

Subjects with CAD had a higher body mass index (BMI) (25.4 +/- 4.3 vs. 22.9 +/- 3.2 kg/m2, P = 0.003) and waist to hip ratio (WHR) (0.95 +/- 0.05 vs. 0.89 +/- 0.09, P = 0.001) and a lower high-density lipoprotein (HDL) cholesterol level (0.97 +/- 0.2 vs. 1.1 +/- 0.2 mmol/l, P = 0.002). They also had higher mean SI values (107.5 vs. 62.3 pmol/l, P = 0.002), PI values (19.3 vs. 5.7 pmol/l, P < 0.0001), PI/SI ratios (21.4 vs. 10.3, P < 0.0001) and HOMA IR (4.2 vs. 2.4, P = 0.004) compared with non-CAD subjects. These variables were associated with CAD in the unadjusted multiple regression analysis. In the multiple regression with the forward entry of the variables, WHR and PI only showed independent association with CAD.

CONCLUSIONS

Subjects with CAD had higher levels of obesity and WHR. CAD showed an association with low HDL cholesterol, circulating PI, PI/SI ratios and IR.

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.

Insulin resistance alone does not explain the clustering of cardiovascular risk factors in southern India

AIMS

To determine whether insulin resistance (IR calculated using the HOMA model) has a dominant role in the clustering of cardiovascular risk factors in the Asian Indian population.

METHODS

A total of 654 non-diabetic subjects aged > or =40 years (male 396: female 258) were selected from a population survey. They had estimates of fasting and 2 h plasma glucose, insulin levels, body mass index (BMI), waist-to-hip ratio (WHR) and blood pressure. Factor analysis was carried out using the principle components analysis (PCA) with varimax orthogonal rotation of continuously distributed variables, considered to represent the components of insulin resistance syndrome including the calculated IR.

RESULTS

There were three major clusters of cardiovascular disease (CVD) risk variables in men and four clusters in women. Insulin resistance, 2 h plasma glucose, insulin and obesity aggregated as the major domain. Insulin resistance was not linked with hypertension. BMI was a common link for all the three factors in men, and for three of the four in women.

CONCLUSIONS

Insulin resistance is not the only underlying factor for the clustering of CVD risk factors in south Indians. These findings are consistent with the presence of several distinct physiological domains, as shown in other ethnic groups.

Body fat percent by bioelectrical impedance analysis and risk of coronary artery disease among urban men with low rates of obesity: the Indian paradox

OBJECTIVE

To determine the association between body fat percent and prevalence of coronary artery disease (CAD) and coronary risk factors in subjects with low rates of obesity.

SUBJECTS AND METHODS

We randomly selected 850 men, aged 25 to 64 years. The survey methods were questionnaire and bioelectrical impedance analysis for body composition. Subjects were divided into high-fat (n = 357), over-fat (n = 230), normal-fat (n = 200) and under-fat (n = 63) based on criteria of body-fat percent analysis.

RESULTS

The prevalence of CAD and the coronary-risk factors hypercholesterolemia, hypertension, diabetes, mellitus and sedentary lifestyle were significantly associated with high and moderate body fat percent despite low body-mass index (23.6+/-4.1 kg/m2). Mean total cholesterol, triglycerides and blood pressure were significantly associated with high and moderate body fat percent. The prevalence of smoking was weakly but inversely associated with high body-fat percent. Mean HDL cholesterol was positively associated with high body-fat percent. Body mass index was positively associated with high body-fat percent.

CONCLUSIONS

High and moderate body-fat-percent subjects were associated with high prevalence of CAD and the coronary-risk factors hypertension, diabetes mellitus, higher body-mass index and sedentary lifestyle.

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.

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.

Foetal outcome in gestational diabetes in south Indians

The study was performed to reassess the prevalence of gestational diabetes mellitus (GDM) in south Indians and to study the foetal outcome in women with GDM in comparison with normal pregnancies. In 1036 pregnant women, glucose tolerance was tested with 75-g oral glucose load, in the second or third trimester. Those with 2-h plasma glucose of > or = 200 mg/dl were considered as diabetic (WHO Criteria). Those with 2-h values of 140-199 underwent a 3-h glucose tolerance test (GTT) with 100-g glucose load (O'Sullivan and Mahan criteria). GDM was diagnosed in nine women (0.87%) by this criteria. Foetal outcome in 211 GDM referred to the diabetes centre was compared with the outcome in 853 normal pregnancies. There were no cases of aborted pregnancy among the GDM, while six cases were reported among the normal glucose tolerance (NGT). Still birth and the number of premature babies were higher in GDM. Babies with birth weight > or = 3.5 kg were more among the GDM (P < 0.001). There was no difference in the occurrence of congenital anomalies in the two groups. It was noted that congenital abnormalities in the foetus were more common among those born of mothers with higher plasma glucose (9 versus 1.1%). Multiple linear regression analyses in NGT and GDM showed that the birth weight of the baby was dependent on the plasma glucose and the body mass index of the mothers. The results of the present study show that the prevalence of GDM in urban south India was low, when the NDDG criteria was used. It also indicated that the WHO criteria may be more appropriate as the foetal outcome was determined by even a small rise in maternal plasma glucose. With good metabolic control in GDM, the foetal risks are very much reduced.

Effects of genetic predisposition on proinsulin responses in Asian Indians

This study was done in adult offspring of two diabetic (NIDDM) parents (ODP) to look for changes in specific insulin (insulin) and proinsulin responses due to strong familial background and also in different states of glucose intolerance. Equal numbers (20 in each group) of ODP with normal glucose tolerance (NGT), impaired glucose tolerance (IGT) and diabetes (DM) were chosen. Twenty, age and BMI matched healthy controls, without family history of diabetes, were also studied for comparison. Plasma specific insulin and proinsulin were measured by radioimmunoassays in fasting and 120' plasma samples collected during the GTT. Proinsulin to insulin ratio were calculated. Insulin resistance (IR-HOMA) was calculated. In NGT, fasting proinsulin-insulin ratio was significantly higher than the control value (P = 0.023). Insulin values at 120' was higher than control values, though it did not reach statistical significance. Proinsulin at 120' was higher than controls (P = 0.016). In IGT, the fasting proinsulin to insulin ratio, the 120' proinsulin and insulin values were higher than controls (P = 0.048, 0.0013 and 0.0001, respectively). Fasting proinsulin-insulin ratio in IGT was similar to the value in NGT. In diabetic subjects proinsulin concentrations were significantly higher than controls at fasting (P = 0.0004), and 120' (P = 0.0007). The fasting values were higher compared to NGT also (P = 0.037). Proinsulin-insulin ratios were higher than the values in controls (P = 0.0008), IGT (P = 0.047) and NGT (P = 0.05). Diabetic subjects had higher fasting insulin values compared to the control values although between the groups no statistical significance was found (P = 0.22 by Kruscall Wallis test). At 120' both insulin and proinsulin values increased from NGT to IGT, but with development of diabetes a reduction was seen in the responses. Insulin resistance (IR-HOMA) increased steadily from NGT to diabetes. The difference between NGT and controls in IR was not statistically significant. This study of Asian Indian offspring of diabetic parents has shown that genetic predisposition to diabetes resulted in increased proinsulin to insulin ratio at the fasting state. Absolute hyperproinsulinaemia occurred only with development of diabetes.

Hypertension and insulin resistance in a native unindustrialised rural population of India

A cross-sectional survey of 2964 individuals aged 16-70 years from a rural area of North India was carried out to test the hypothesis that a rural unindustrialised hypertensive population of North India has central obesity and hyperinsulinemia. Oral glucose tolerance test was carried out on 68 newly detected hypertensives, 82 age- and sex-matched community controls and 58 genetically related members of hypertensives (family controls). Fasting blood samples were examined for plasma glucose, serum insulin and lipids. Postglucose-load blood samples were examined for plasma glucose and serum insulin. Three blood pressure readings were recorded using Random Zero Sphygmomanometer. Anthropometric measurements (waist-hip ratio, subscapular and triceps skinfold thickness) of all three groups of individuals (hypertensives, community controls and family controls) were also recorded. The hypertensives had significantly higher fasting and postglucose-load serum insulin levels (P<0.05), body mass index (21.3 vs. 19 kg/m2: P<0.05), waist-hip ratio (0.89 vs. 0.85: P<0.001), subscapular (18.5 mm vs. 12.7 mm: P<0.001) and triceps fold thickness (17.6 mm vs. 12.9 mm: P<0.05) than community controls. The family controls had significantly higher systolic blood pressure than community controls (P<0.05). The lipids were not significantly different in all the three groups. Multiple logistic regression showed that both fasting and postglucose-load serum insulin were significantly associated with hypertension independent of waist-hip ratio and body mass index. The results of the present study suggest that hyperinsulinemia is related to hypertension in a rural unindustrialised population of North India.

Specific insulin and proinsulin concentrations in nondiabetic South Indians

The study was performed to determine plasma levels of proinsulin (PI) and specific insulin (SI) in normoglycemic (NGT) Asian Indians and to assess the effect of obesity and impaired glucose tolerance (IGT) on these concentrations. Blood samples from 151 adult nondiabetic South Indian subjects were collected during an epidemiological survey of diabetes. Plasma SI and PI levels were measured in fasting and 30-minute and 120-minute samples of a glucose tolerance test (World Health Organization criteria) using monospecific antibodies. The total insulin (TI) level was also measured by the nonspecific assay. The molar ratio of PI to SI (PI/SI) was calculated. Correlations of the peptides with anthropometry, serum lipids, and blood pressure (BP) were studied by univariate and multivariate analyses. Comparisons were also made in NGT versus IGT groups. As expected, TI values were higher than SI values, but the patterns of response were similar for both. SI and PI responses in NGT were similar to the values found in Mexican-Americans who had a higher body mass index (BMI). Asian Indians were thus found to have a high SI response despite a low BMI. Obesity and IGT produced an increased response of both PI and SI, with normal PI/SI ratios thus showing an absence of hyperproinsulinemia in either condition. Fasting PI showed a strong association with serum triglycerides, and proinsulin at 120 minutes was associated with cholesterol. None of the peptides showed a correlation with BP. Using specific assays for insulin and PI, it is shown that Asian Indians with NGT have a hyperinsulinemic response despite a low BMI. Obesity and mild hyperglycemia in IGT produce a simultaneous increase in PI and SI with no alteration in the PI/SI ratio.

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.

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.

Glucose intolerance and impairment of insulin secretion in relation to vitamin D deficiency in east London Asians

Vitamin D deficiency reduces insulin secretion and still occurs in East London Asians in whom the prevalence of diabetes mellitus is at least four times that of Caucasians. Vitamin D status was assessed in 44 of 65 non-diabetic subjects 'at risk' of diabetes (spot blood glucose level >6.0 mmol/l <2 h post cibum, or>4.6 mmol/l >2 h post cibum on two separate occasions) and in 15 of 60 age and sex-matched 'low-risk' control subjects who attended for oral glucose tolerance test (OGTT) after screening of 877 omnivorous subjects not known to have diabetes. It was found that 95% of at-risk and 80% of low-risk subjects were vitamin D deficient (serum 25-hydroxy-vitamin D <11 ng/ml). Diabetes was present in 16, impaired glucose tolerance in 12 and normoglycaemia in 19 at-risk subjects, imparied glucose tolerance in 2, and normoglycaemia in 13 low-risk subjects. Correlation of 30-min OGTT blood glucose, specific insulin and C-peptide levels with 25-hydroxy-vitamin D concentrations in 44 at-risk subjects were -0.31 (p=0.04), 0.59 (p=0.0001) and 0.44 (p=0.006). In 15 'not-at-risk' subjects 30-min OGTT specific insulin and C-peptide levels correlated with 25-hydroxy-vitamin D, r=0.39 (p=0.04) and 0.16 (p=0.43), respectively. Serum alkaline phosphatase concentration was higher in at-risk than not-at-risk subjects (59.6 vs 46.5 IU/l, p=0.012); corrected calcium concentrations were comparable (2.38 vs 2.39 mmol/l, p=0.7). Following treatment with 100,000 IU vitamin D by i.m. injection, specific insulin, C-peptide [30 min on OGTT] and 25-hydroxy-vitamin D concentrations had risen 8-12 weeks later [mean +/- DS] from 57 +/- 62 to 96.2 +/- 82.4 mU/l [p=0.0017], 1.0 +/- 0.4 to 1.7 +/- 0.8 pmol/ml [p=0.001] and 3.6 +/- 1.8 to 13.5 +/- 7.4 ng/ml [p=0.0001], (but not to low-risk group values of 179 +/- mU/l, 2.7 +/- 1.14 pmol/ml and 8.16 +/- 6.4 ng/ml), respectively. Both total serum alkaline phosphatase and corrected calcium concentrations rose following vitamin D treatment in the at-risk subjects by 11.1 +/- 8.22 (from 44 to 55 IU/l) and 0.15 +/- 0.18, (2.43 to 2.57 mmol/l), respectively (p=0.004). Abnormal glucose tolerance was unchanged by vitamin D treatment. The value of early and sustained repletion with vitamin D in diabetes prophylaxis should be examined in communities where vitamin D depletion is common.

Diet, central obesity and prevalence of hypertension in the urban population of south India

Central obesity is a strong predictor of higher prevalence of diabetes, hypertension and coronary artery disease among Indian immigrants to Britain. To test this hypothesis in Indians, 1569 adults, between 25 and 64 years of age, from 750 randomly selected households (representative of 0.52 million population of Trivandrum city, Kerala) were selected for this study. The response rate was roughly 95% and the sample consisted of 1497 individuals (737 males and 760 females). The survey methods included dietary diaries for 7-day food intake record, blood pressure measurements using a mercury sphygmo-manometer and anthropometric measurements. The prevalence rates of hypertension between 25 and 64 years was 189/1000 (95% confidence limits 85-360) and between 45 and 64 years was 335/1000 (95% confidence limits 210-460) which is higher than in Western populations. The prevalence was higher in males than females in the younger age groups and comparable in both sexes in the upper age groups. The prevalence of central obesity was significantly higher among male (77.2 vs. 48.9%) and female (84.0 vs. 51.4%) hypertensives compared to non-hypertensive subjects; however, mean body weight, body mass index and waist-hip ratio (WHR) were lower among Indian men compared to a British comparison group. Thus, comparison of Indian men with Britons showed that obesity, salt and alcohol intake, sedentariness, smoking and dietary fat intake do not explain the cause of higher prevalence of hypertension among South Indian men from Kerala.(ABSTRACT TRUNCATED AT 250 WORDS)