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

Ethnicity and diabetic heart disease

Ethnicity is a complex yet important construct and an independent risk factor for diabetic heart disease (DHD) with paramount clinical significance. Clinicians should try to better understand the role of ethnicity through more questions. The risk of DHD is modified by ethnicity through more questions. The risk of DHD is modified by ethnicity, and its management may require a culturally sensitive individualized approach. Findings from Caucasian populations cannot be fully extrapolated to other ethnic groups, thereby emphasizing the importance of future research with ethnicity-based threshold for obesity. Available limited data support the interaction between genetic predisposition, environmental risk, and lifestyle choices and disparities based on ethnicity as the likely cause for ethnic variations in DHD.

Knowledge, attitude and practice of complementary and alternative medicines for diabetes

OBJECTIVES

To investigate the current status of knowledge, attitude and practice of patients with diabetes relating to complementary and alternative medicine (CAM) in an Indian community, and to determine perceptions about the use of CAM and factors influencing knowledge and usage.

SETTING

Endocrine clinic of Swaroop Rani, Nehru Hospital, Allahabad, India.

STUDY DESIGN

Hospital-based cross-sectional study.

PARTICIPANTS

Patients with diabetes attending the clinic for the first time.

SAMPLE SIZE

A sample of 493 study participants selected by systematic sampling from a population of 6094 patients with diabetes.

STUDY VARIABLES

Age, socio-economic status, educational status, religion, family history of disease, knowledge and practice of CAM, reasons for using CAM, method of use and perceived relief.

STATISTICAL ANALYSIS

Normal test of proportions, chi(2) test, Kolomogorov-Smirnov test.

RESULTS

Awareness of CAM among patients was high (71%). High prevalence of CAM use was found (67.7%) among all participants, and 95% among participants aware of CAM, mostly using 'naturopathy' (97.3% among users). No significant gap (P>0.10) between knowledge and practice in different categories was observed. Desire for quick and additional relief was the most common perceived reason for using CAM (86.8%). Higher levels of education and socio-economic status were significant positive correlates of CAM use. Knowledge of CAM was gained mainly from friends and neighbours. About 30% of users adopted CAM without allopathic treatment earlier. Only 42.2% of users perceived some relief by using CAM. Lowering of blood sugar was the most common perceived relief. CAM, along with diet control and exercise, resulted in maximum degree of satisfaction (61.9%) experienced by users. No relief was experienced by 53.6% of users of 'naturopathy'.

CONCLUSIONS AND SUGGESTIONS

Use of CAM in diabetes is highly prevalent despite high levels of disappointment after its use. In this study, we suggest the need for health education relating to CAM and self-care in diabetes. Use of CAM should be explored with patients before clinical decisions are made.

Secular trends in the prevalence of diabetes and impaired glucose tolerance in urban South India--the Chennai Urban Rural Epidemiology Study (CURES-17)

AIMS/HYPOTHESIS

The aim of this study was to determine the secular trends in prevalence of diabetes and IGT in urban India.

MATERIALS AND METHODS

The Chennai Urban Rural Epidemiology Study (CURES) screened 26,001 individuals aged > or =20 years using the American Diabetes Association fasting capillary glucose criteria. The study population, which was representative of Chennai, was recruited by systematic random sampling. Every tenth subject from Phase 1 of CURES was invited to participate in Phase 3 for screening by World Health Organization (WHO) plasma glucose criteria. The response rate was 90.4% (2,350 responders from 2,600 potential subjects). The prevalences of diabetes and IGT in CURES were compared with three earlier studies: two conducted on a representative population of Chennai in 1989 and 1995, and the other the National Urban Diabetes Survey (NUDS) completed in 2000.

RESULTS

The overall crude prevalence of diabetes using WHO criteria in CURES was 15.5% (age-standardised 14.3%), while that of IGT was 10.6% (age-standardised 10.2%). Prevalence of diabetes increased by 39.8% (8.3-11.6%) from 1989 to 1995; by 16.3% (11.6-13.5%) between 1995 and 2000; and by 6.0% (13.5-14.3%) between 2000 and 2004. Thus within a span of 14 years, the prevalence of diabetes increased by 72.3% (chi (2) trend 22.23, p < 0.0001). The prevalence of IGT increased by 9.6% from 1989 to 1995 and by 84.6% between 1995 and 2000 (chi 2 trend 52.9, p < 0.0001). However, it decreased by 39.3% between 2000 and 2004 (p < 0.0001). There was a shift in the age at diagnosis of diabetes to a younger age in CURES compared with NUDS.

CONCLUSIONS/INTERPRETATION

Compared with earlier studies, the prevalence of diabetes in Chennai, representing urban India, has increased while that of IGT has decreased.

Consequences of inadequate food energy and negative energy balance in humans

Energy deficiency is probably best measured in adults by the body mass index (BMI). Acute energy deficiency (AED) is associated with body weight loss, along with changes in body composition, as well as a reduced BMR and physical activity. Chronic energy deficiency (CED) is an inadequacy in food to which individuals adapt, at some cost. Individuals with this have never 'lost' weight: they have simply grown less. They adapt to the decreased food energy by reductions in their total energy expenditure (TEE), linked mainly to a lower body size, and to their physical activity. It seems unlikely that enhanced metabolic efficiency contributes substantially to energy saving in CED. Supplementation of energy deficient individuals is accompanied by significant fat deposition; this may have deleterious consequences. Women in many developing countries achieve a successful outcome to pregnancy in spite of being chronically undernourished. Reductions in basal metabolism and behavioural changes in the form of diminished physical activity could meet most of the extra energy needed for pregnancy. Milk energy output is maintained within the expected range in undernourished lactating mothers. Energy deficiency in children is best measured by height-for-age for stunting, and weight-for-height for wasting. Deficits in behavioural and functional parameters in children exist with undernutrition, and can be reduced by early nutritional supplementation along with the appropriate environment.

Leanness and type 2 diabetes in a population of indigenous Australians

OBJECTIVE

To determine the prevalence of type 2 diabetes and its risk factors in a population of indigenous Australians.

RESEARCH DESIGN AND METHODS

A cross-sectional study of 332 indigenous community residents aged 15 years and over with fasting blood samples and anthropometric measurements.

RESULTS

Almost half of the study population (47.3%) was extremely lean (BMI<22 kg/m(2)). Leanness was particularly pronounced in the youngest age group (15<20 years), 78% of which had a BMI<22 kg/m(2). The prevalence of diabetes was 12%. It was highest in those 45-54 years and declined in older aged people. No cases of diabetes were detected in those aged less than 30 years. Diabetes prevalence was strongly linked to BMI and age (age-adjusted odds ratio=24.1, 95% CI 6.0-96.5, p<0.001) for BMI>or=25 kg/m(2) versus BMI<22 kg/m(2). Those with the lowest diabetes risk profile are lean (BMI<22 kg/m(2)) and/or young (age 15-34 years).

CONCLUSIONS

These results highlight that strategies to prevent or delay the onset of diabetes should focus on the maintenance of leanness from adolescence and throughout adult life whilst young people are still in the process of forming lifelong habits.

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.

Does Body Mass Index Predict Overweight in Native Asian Indians? A Study from a North Indian Population

AIMS

Body mass index (BMI) has been considered as a gold standard for defining overweight and obesity, and in western populations it has correlated with percentage body fat (%BF). However, data in native Asian Indians regarding BMI and %BF is conflicting and questions have been raised to redefine the BMI cut-off values in these subjects.

SUBJECTS AND METHODS

150 healthy volunteers (79 men and 71 women aged 18-78 and 23-75 years respectively) were recruited for the study. Clinical examination was performed to exclude any systemic disease. Anthropometric measurements were done and %BF was calculated from skinfold thickness.

RESULTS

The BMI for men was 24.96 kg/m(2) (+/-3.85) and for women was 25.75 kg/m(2) (+/-4.39).%BF calculated by skinfold thickness was 21.94% (+/-5.92) in men and 35.15% (+/-5.77) in women. Receiver operating characteristic curve analysis showed a higher sensitivity (92%) and higher negative predictive value (95%) for the conventional cut-off value of the BMI (25 kg/m(2)) in identifying subjects with overweight with %BF of more than 25% in men. However, in females a BMI of 23.9 kg/m(2) had a sensitivity of 84% and negative predictive value of 62% thereby decreasing the misclassification by 13% with %BF of more than 30% as compared to conventional BMI cut-off of >25 kg/m(2). A comparison of BF data amongst Caucasians, Blacks and migrant ethnic Asians revealed inconspicuous differences in men.

CONCLUSION

Native North Indian men had comparative BMI and %BF as that of their western counterparts.

Review article: diabetes, genetics and ethnicity

The prevalence of insulin resistance and diabetes has increased in the past decades at an alarming rate in all Western countries and in those countries which are adopting a 'western life style'. This trend suggests the impact of environmental factors such as diet, obesity and physical activity on the pathogenesis of diabetes. However it is known that the prevalence and variation of prevalence, as consequence of environmental changes, it is different in various ethnic groups. Studies conducted in multiethnic populations suggest that some ethnic groups, such as Hispanics or Asian Indians, might have a particular predisposition, possibly on genetic basis, to develop insulin resistance and diabetes, when exposed to adverse conditions. According to the 'thrifty gene' hypothesis, a clustering of different genetic defects or polymorphisms, developed as genetic advantage in some populations, could predispose some ethnic groups to insulin resistance and diabetes in presence of an increased food supply. Multiple mutations, associated with small changes in insulin sensitivity, when combined, may induce a significant reduction in insulin sensitivity. This review deals with the possible relevance of genetic factors in the expression of insulin resistance and diabetes in relation to ethnicity.

Type 2 diabetes in rural and urban population: diverse prevalence and associated risk factors in Bangladesh

AIMS

To describe differences in prevalence of Type 2 diabetes mellitus with its associated risk factors between rural and urban populations in Bangladesh. Diagnostic criteria [fasting blood glucose (FBG) and oral glucose tolerance tests (OGTT)] were compared and reviewed for both populations.

METHODS

A total of 1555 subjects from urban and 4757 from rural communities (age > or = 20 years) with similar cultural and ethnic backgrounds were randomly selected in a cross-sectional survey. FBG values were determined from all and 2-h post-glucose capillary blood samples were determined after a 75-g oral glucose load for a selected number (urban 476, rural 1046).

RESULTS

A higher prevalence of diabetes was found in urban (8.1%) compared with rural populations (2.3%). Age, sex and waist-to-hip ratio for men were significant risk factors for both urban and rural subjects following fasting and 2-h post-glucose values adjusted for a number of confounding variables. Poor agreement was observed between FBG and OGTT for both urban (kappa 0.41) and rural (kappa 0.40) areas.

CONCLUSIONS

A higher prevalence of diabetes mellitus (DM) in the urban population was observed compared with rural subjects despite similar body mass indexes (BMI). Differences in obesity, waist/hip ratio or hypertension failed to explain the increasing occurrence of T2DM in the urban population.

ENPP1/PC-1 K121Q polymorphism and genetic susceptibility to type 2 diabetes

Genetic susceptibility modulates the impact of obesity on risk for type 2 diabetes. The present study evaluates the role of ENPP1 K121Q polymorphism in prediction of type 2 diabetes in three populations that differ in susceptibility to diabetes and environmental exposure. The three cohorts included 679 nonmigrant South Asians living in Chennai, India (223 with type 2 diabetes); 1,083 migrant South Asians living in Dallas, Texas (121 with type 2 diabetes); and 858 nonmigrant Caucasians living in Dallas, Texas (141 with type 2 diabetes). Patients with type 2 diabetes were included in these cohorts if they had diabetes onset before the age of 60 years. The prevalence of subjects carrying the polymorphic ENPP1 121Q allele was 25% in the nondiabetic group and 34% in the diabetic group of South Asians living in Chennai (P = 0.01). The prevalence in the nondiabetic and diabetic groups were 33 and 45% (P = 0.01) for the South Asians living in Dallas and 26 and 39% (P = 0.003) for the Caucasians. Although further replication studies are necessary to test the validity of the described genotype-phenotype relationship, our study supports the hypothesis that ENPP1 121Q predicts genetic susceptibility to type 2 diabetes in both South Asians and Caucasians.

The EIF2AK3 gene region and type I diabetes in subjects from South India

Mutations in the EIF2AK3 gene underlie susceptibility to the Wolcott-Rallison syndrome, which is a monogenic disease associated with insulin-deficient neonatal diabetes. Furthermore, suggestive evidence of linkage between type 1 diabetes (T1DM) and the EIF2KA3 chromosomal region has been reported in Scandinavian families. We have investigated the hypothesis that polymorphic variants in and around the EIF2AK3 gene might partially account for susceptibility to T1DM in South Indian subjects. Excess transmission of the common alleles of two polymorphic markers (D2S1786 and 15INDEL, located within the gene) downstream of EIF2AK3, either singly (D2S1786, P = 0.01) and 15INDEL (P = 0.02) or as a combination (P < 0.001), were found in 234 families with a T1DM proband. There was also a clear paternal effect for the 15INDEL marker (P = 0.005) on disease susceptibility. The presence of the common allele of both markers was found in decreased frequency in the subjects with normal glucose tolerance compared to probands with T1DM (both P <or= 0.0001). Major common mutations of the EIF2AK3 gene in T1DM were excluded. In conclusion, this pilot study demonstrates an association between the region around the EIF2AK3 locus and T1DM susceptibility.

Increasing prevalence of Type 2 diabetes mellitus in all ethnic groups in Mauritius

AIMS

To describe the prevalence of different stages of glucose intolerance in a population from Mauritius followed over 11 years.

METHODS

Population-based surveys were undertaken in the multiethnic nation of Mauritius in 1987, 1992 and 1998, with 5083, 6616, and 6291 participants, respectively. Questionnaires, anthropometric measurements, and a 2-h 75-g oral glucose tolerance test were included. Subjects aged between 25 and 75 years with classifiable data were identified; 4991, 6463 and 5392 from 1987, 1992 and 1998, respectively. Glucose tolerance was classified according to WHO 1999 criteria.

RESULTS

The prevalence of Type 2 diabetes increased significantly during the period studied, from 12.8% in 1987, to 15.2% in 1992, and 17.9% in 1998. The increasing prevalence was seen in both men and women, and in all age groups. The prevalence of known diabetes (KDM) increased progressively, and more markedly than the increase in newly diagnosed diabetes (NDM). A diagnosis of impaired glucose tolerance (IGT) was more prevalent amongst women whereas impaired fasting glucose (IFG) was more common amongst men. The prevalences of IGT and IFG did not change markedly during the period. The prevalence of diabetes and IGT was similar for participants of Indian, Creole and Chinese background in each survey, and the increasing prevalence of diabetes was seen in all ethnic groups.

CONCLUSION

In this study, we report an increasing prevalence of diabetes over an 11-year period in Mauritius. This increase was seen in both sexes, and in all age and ethnic groups, and was mainly due to an increase in the numbers of those with known diabetes.

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.

Insulin resistance syndrome (metabolic syndrome) and obesity in Asian Indians: evidence and implications

OBJECTIVES

This review describes prevalence, determinants, and possible pathophysiologic mechanisms and suggests management and research directions for insulin resistance syndrome (metabolic syndrome) in Asian Indians.

METHOD

We reviewed the topic using the terms Asian Indians, Asians, South Asians, and Indians coupled with the terms insulin resistance, hyperinsulinemia, metabolic syndrome, and obesity from the databases Pubmed (National Library of Medicine, Bethesda, MD, USA) and Current Contents (Institute for Scientific Information, Thomson Scientific, Philadelphia, PA, USA) and from non-indexed publications of the medical research and governmental institutions in India.

RESULTS

Asian Indians have a high prevalence of insulin resistance syndrome that may underlie their greater than normal tendency to develop diabetes mellitus and early atherosclerosis. Important reasons could be their excess body fat and adverse body fat patterning including abdominal adiposity even when the body mass index is within the currently defined normal limits. Some of these features have been reported at birth and childhood. Whether Asian Indians also have tendency to develop insulin resistance de novo, independent of total or regional adiposity, needs further investigation. Underlying genetic tendency or early-life adverse events may contribute to such a phenotype, but lifestyle factors alone or modulated by inherited factors appear to play an important role because obesity and dyslipidemia become worse with urbanization and migration. Systemic stress may contribute to insulin resistance syndrome in the intra-country and inter-country migrant Asian Indians.

CONCLUSIONS

High prevalences of excess body fat, adverse body fat patterning, hypertriglyceridemia, and insulin resistance beginning at a young age have been consistently recorded in Asian Indians irrespective of their geographic locations. These data suggest that primary prevention strategies should be initiated early in this ethnic group.

Polymorphic variations in the neurogenic differentiation-1, neurogenin-3, and hepatocyte nuclear factor-1alpha genes contribute to glucose intolerance in a South Indian population

The neurogenic differentiation-1 (NEUROD1), neurogenin-3 (NEUROG3), and hepatic nuclear factor-1alpha (TCF1) genes are interacting transcription factors implicated in controlling islet cell development and insulin secretion. Polymorphisms of these genes (Ala45Thr [NEUROD1], Ser199Phe [NEUROG3], and Ala98Val [TCF1]) have been postulated to influence the development of type 2 diabetes. We have investigated the role and interaction between these variants using PCR/restriction fragment-length polymorphism assays in 454 subjects recruited as part of a population survey in South India. Additionally, 97 South Indian parent-offspring trios were studied. Polymorphisms of all three genes were associated with either fasting blood glucose (FBG) and/or 2-h blood glucose (BG) in either the total dataset or when restricted to a normoglycemic population. A monotonically increasing effect, dependent on the total number of risk-associated alleles carried, was observed across the whole population (P < 0.0001 for FBG and 2-h BG), raising FBG by a mean of 2.9 mmol/l and 2-h BG by a mean of 4.3 mmol/l. Similarly, an ascending number of the same risk alleles per subject increased the likelihood of type 2 diabetes (P = 0.002). In conclusion, we observed a combined effect of variations in NEUROD1, NEUROG3, and TCF1 in contributing to overall glucose intolerance in a South Indian population.

Lack of excess maternal transmission of type 2 diabetes in a Korean population

The purpose of this study was to assess the familial clustering of type 2 diabetes and to investigate the presence of excess maternal transmission of type 2 diabetes in Korea. The medical records of 56,492 subjects (31,680 men and 24,812 women), who attended the Health Promotion Center were examined. The subjects were questioned about their parents' diabetes status. All study subjects were classified into the three groups (normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetes). Offspring with paternal diabetes (odds ratio 2.54, 95% CI 2.22-2.91, P < 0.001) and those with maternal diabetes (odds ratio 3.10, 95% CI 2.76-3.49, P < 0.001) were at increased risk for diabetes when compared to subjects without parental diabetes and adjusted for other clinical and biochemical variables. Offspring with bilineal parental diabetes were at a greater risk for diabetes (odds ratio 6.09, 95% CI 4.55-8.16, P < 0.001) when compared to subjects without parental diabetes. In both genders, offspring with maternal diabetes showed no increased risk for diabetes (odds ratio 1.22, 95% CI 0.92-1.37, P + 0.266 in men; odds ratio 1.31, 95% CI 0.95-1.81, P = 0.104 in women) when compared with those with paternal diabetes. The data suggested that parental type 2 diabetes was an independent risk factor for offspring type 2 diabetes in this Korean population. Excess maternal transmission of type 2 diabetes was not observed.

Insulin resistance and C-reactive protein as independent risk factors for non-alcoholic fatty liver disease in non-obese Asian men

BACKGROUND AND AIM

Although insulin resistance is often considered the link between obesity and non-alcoholic fatty liver disease (NAFLD), the role of insulin resistance, independent of obesity, as a NAFLD risk factor in non-obese men has been less well established. Systemic inflammation may be accompanied by insulin resistance in healthy subjects. The goal of the present study was to examine if insulin resistance and systemic inflammatory markers are independent predictors of NAFLD in non-obese men.

METHODS

The authors conducted a cross-sectional survey of 120 patients with NAFLD and 240 controls matched by age and body mass index. Controls had no evidence of alcohol abuse, hepatitis B or C, obesity, or previous history of diabetes, fasting hyperglycemia or hypertension. Diagnosis of NAFLD was based on an elevated alanine aminotransferase level and sonographic evidence of a fatty liver. Insulin resistance was determined using a homeostasis model assessment (HOMA-IR).

RESULTS

The age-adjusted risk of developing NAFLD was strongly associated with the elevated levels in measurements of uric acid, fasting blood sugar, triglycerides, apolipoprotein B, C-reactive protein (CRP) and HOMA-IR, and decreased levels of high density lipoprotein cholesterol and apolipoprotein A-I. Multivariate analysis based on univariate analysis indicated that an increase in CRP (odds ratio [OR] = 1.37; 95% confidence interval [CI]: 1.06-1.77) per 1 SD (1.48 mg/L) and HOMA-IR (OR = 2.28; 95% CI: 1.67-3.11) per 1 SD (0.63) were independent risk factors for NAFLD.

CONCLUSION

Insulin resistance and systemic inflammatory response are of key importance for inducing NAFLD, particularly in apparently healthy non-obese men.

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.

The relative effects of obesity and insulin resistance on cardiovascular risk factors in nondiabetic and normotensive men

BACKGROUND

Several reports have documented that Asians have a strong tendency to develop insulin resistance. The aims of this study were to evaluate the relative effects of insulin resistance and obesity on the risk factors for coronary heart disease (CHD) and to clarify whether insulin resistance accentuates these effects in apparently healthy men.

METHODS

We conducted a cross sectional survey on 4,067 apparently healthy Korean men, aged between 20 and 83 years, with body mass indices (BMI) ranging from 15.19 to 40.29 kg/m2. The presence of insulin resistance was defined as a homeostasis model assessment (HOMA-IR) value > 2.23, which is the cutoff for the highest decile in the normal BMI group (BMI < 23 kg/m2; 1,438 subjects).

RESULTS

The prevalence of insulin resistance was 24.7% in the overweight subjects (23 < or = BMI < 25 kg/m2; 1,259 subjects) and 43.9% in the obese subjects (BMI > or = 25 kg/m2; 1,370 subjects). The BMI was identified as the major determinant for total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and waist circumference (WC) as the most important for apolipoprotein B (Apo B), systolic and diastolic blood pressures and C-reactive protein (CRP), and HOMA-IR as the most important for fasting blood sugar, triglyceride (TG), low high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (Apo A-I) and TC/HDL ratio. The presence of insulin resistance was found to accentuate the risk factors for CHD, with the exception of LDL-C and Apo A-I in the obese.

CONCLUSION

WC and HOMA-IR were found to be closely associated with non-traditional markers for CHD, such as high Apo B, hypertriglyceridaemia and the TC/HDL-C ratio, which are predictors for the presence of small, dense LDL particles. The insulin resistance among obese men was more prevalent than expected, and the presence of insulin resistance accentuates the effect of obesity in terms of the risk of CHD.

Temporal changes in prevalence of diabetes and impaired glucose tolerance associated with lifestyle transition occurring in the rural population in India

AIMS/HYPOTHESIS

The rural Indian population is undergoing lifestyle transition due to socio-economic growth. This study was done to determine the temporal changes in prevalence of diabetes and IGT that could have occurred in a rural population in India as a result of the lifestyle transition.

METHODS

A cross-sectional study of 1213 Asian-Indian subjects aged 20 years or over was done to look for the prevalence of diabetes and IGT using the 1999 WHO criteria. The temporal changes were assessed in comparison with a similar study conducted 14 years previously. The factors associated with the temporal changes were also analysed.

RESULTS

Nearly a three-fold increase in age- and sex-adjusted prevalence of diabetes (from 2.20% to 6.36%) was seen in 2003 when compared with a similar study done 14 years before. Prevalence of IGT did not change significantly (7.44% in 1989 vs 7.18% in 2003). Improvement in living conditions had occurred during the period, occupational changes were seen, the number of manual labourers had decreased and economic conditions had improved. BMI and waist circumference had increased. After correcting for age, sex and differences in time periods, waist circumference and physical inactivity showed significant associations with the increased prevalence of diabetes.

CONCLUSIONS/INTERPRETATION

Demographic transition due to improved living conditions in rural India was associated with a three-fold increase in the prevalence of diabetes. Increased upper body adiposity and physical inactivity showed significant association with this phenomenon.

Prevalence and risk factors for diabetes in Ho Chi Minh City, Vietnam

AIMS

To determine the prevalence of diabetes and associated risk factors in Ho Chi Minh City, Vietnam.

METHODS

A total of 2932 participants aged 15 and above in Ho Chi Minh City were screened for diabetes in a cross-sectional study. The study was conducted from March-May 2001. Demographic, occupation, anthropometry and blood pressure were recorded. Blood glucose was calculated on fasting capillary and venous blood. The classification of diabetes and impaired fasting glucose (IFG) was carried out according to WHO and American Diabetes Association criteria.

RESULTS

The crude prevalence of diabetes and IFG were 6.6 and 3.2%, respectively. After age, sex-adjustment to the Vietnam population census, the prevalence was 3.8 and 2.5%, respectively; approximately 40% of cases were found to be newly diagnosed diabetes. The crude prevalence of diabetes in the urban area was approximately 2.8 times higher than that recorded in the 1993 study (6.9 vs. 2.5%, respectively). In this study, there was a positive association between diabetes and sex, age, overweight, waist hip ratio (WHR), and having a history of delivering large for gestational age child; there was a negative association between diabetes and physical activity and occupation.

CONCLUSIONS

This study found that the age, sex-adjusted prevalence of diabetes and IFG in Ho Chi Minh City were 3.8 and 2.5%, respectively, a rapid increase in the recent decade. Our study also indicates that ageing, a high WHR level, overweight and a sedentary lifestyle may be important determinants of the increased prevalence of diabetes during this transition period in Vietnam.

Genetic polymorphism PC-1 K121Q and ethnic susceptibility to insulin resistance

Genetic susceptibility may be responsible for high prevalence of insulin resistance in Asian Indians. This study was carried out in samples of local Asian Indians and Caucasians to determine whether plasma cell membrane glycoprotein (PC)-1 K121Q and insulin receptor substrate-1 (IRS-1) G972A polymorphisms contribute significantly to susceptibility to insulin resistance in Asian Indians. The frequency of carrying at least one copy of the PC-1 121Q variant in Asian Indians was significantly higher than that in Caucasians (P = 0.01), but the frequency was similar for IRS-1 972A (6% and 7%). A significantly higher insulin area under the curve during oral glucose tolerance testing (P < 0.0001) and lower insulin sensitivity during hyperinsulinemic-euglycemic clamps (P = 0.04) were found in Asian Indians with PC-1 121Q variant compared with Asian Indians with wild-type PC-1 and with Caucasians with or without the polymorphism. IRS-1 972A was not associated with any change in insulin sensitivity. We conclude that the PC-1 K121Q polymorphism associates with primary insulin resistance in migrant Asian Indians. A relatively high frequency of this polymorphism thus may be one factor contributing to insulin resistance susceptibility in Asian Indians. This finding indicates the need for expanded studies on the association between PC-1 K121Q and insulin resistance in a representative sample of the Asian Indian population.

Lack of association between central adiposity and lipaemia in UK Sikh men

OBJECTIVE

To determine whether the positive statistical associations between measures of total and regional adiposity and measures of glucose, insulin and triacylglycerol (TAG) metabolism reported in Caucasian men, are also observed in UK Sikhs.

DESIGN

A matched cross-sectional study in which each volunteer provided a blood sample after a 12-h overnight fast and had anthropometric measurements taken.

SUBJECTS

A total of 55 healthy Caucasian and 55 healthy UK Sikh men were recruited. The Caucasian and Sikh men were matched for age (48.7+/-10.9 and 48.3+/-10.0 y, respectively) and body mass index (BMI) (26.1+/-2.8 and 26.3+/-3.2 kg/m(2), respectively).

MEASUREMENTS

Anthropometric measurements were performed to assess total and regional fat depots. The concentrations of plasma total cholesterol, high-density cholesterol (HDL-C), low-density cholesterol (LDL-C) and small dense LDL (LDL3), TAG, glucose, fasting insulin (ins) and nonesterified fatty acids (NEFA) were analysed in fasted plasma. Surrogate measures of insulin resistance (HOMA-IR) and insulin sensitivity (RQUICKI) were calculated from insulin and glucose (HOMA-IR) and insulin, glucose and NEFA (RQUICKI) measurements.

RESULTS

The Sikh men had significantly higher body fat, with the sum of the four skinfold measurements (Ssk) (P=0.0001) and subscapular skinfold value (P=0.009) higher compared with the Caucasian men. The Sikh volunteers also had characteristics of the metabolic syndrome: lower HDL-C (P=0.07), higher TAG (P=0.004), higher % LDL3 (P=0.0001) and insulin resistance (P=0.05). Both ethnic groups demonstrated positive correlations between insulin and waist circumference (Caucasian: r=0.661, P=0.0001; Sikh: r=0.477, P=0.0001). The Caucasian men also demonstrated significant positive correlations between central adiposity (r=0.275, P=0.04), other measures of adiposity (BMI and suprailiac skinfold) and plasma TAG, whereas the Sikh men showed no correlation for central adiposity (r=0.019, ns) and TAG with a trend to a negative relationship between other measures (Ssk and suprailiac) which reached near significance for subscapular skinfold and TAG (r=-0.246, P=0.007). The expected positive association between insulin and TAG was observed in the Caucasian men (r=0.318, P=0.04) but not in the Sikh men (r=0.011, ns).

CONCLUSIONS

In the Caucasian men, the expected positive association between plasma TAG and centralized body fat was observed. However, a lack of association between centralized, or any other measure of adiposity, and plasma TAG was observed in the matched Sikh men, although both ethnic groups showed the positive association between centralized body fat and insulin resistance, which was less strong for Sikhs. These findings in the Sikh men were not consistent with the hypothesis that there is a clear causal relationship between body fat and its distribution, insulin resistance, and lipid abnormalities associated with the metabolic syndrome, in this ethnic group.

The prevalence and management of diabetes in Thai adults: the international collaborative study of cardiovascular disease in Asia

OBJECTIVE

The aim of this study was to determine in Thai adults aged >or=35 years the prevalence and management of diabetes and the associations of diabetes with cardiovascular risk factors.

RESEARCH DESIGN AND METHODS

The International Collaborative Study of Cardiovascular Disease in Asia was a complex sample survey. Data from a structured questionnaire, brief physical examination, and blood sample were collected from 5,105 individuals aged >or=35 years (response rate 68%). Population estimates were calculated by applying sampling weights derived from the 2000 Thai census.

RESULTS

The estimated national prevalence of diabetes in Thai adults was 9.6% (2.4 million people), which included 4.8% previously diagnosed and 4.8% newly diagnosed. The prevalence of impaired fasting glucose was 5.4% (1.4 million people). Diagnosed diabetes, undiagnosed diabetes, and impaired fasting glucose were associated with greater age, BMI, waist-to-hip ratio, systolic blood pressure, total cholesterol, and serum creatinine levels. The majority of individuals with diagnosed diabetes had received dietary or other behavioral advice, and 82% were taking oral hypoglycemic therapy. Blood pressure-lowering therapy was provided to 67% of diagnosed diabetic patients with concomitant hypertension.

CONCLUSIONS

Diabetes is common in Thailand, but one-half of all cases are undiagnosed. Because diagnosed diabetes is likely to be treated with proven, low-cost, preventive therapies such as glucose lowering and blood pressure lowering, initiatives that increased diagnosis rates would be expected to produce substantial health benefits in Thailand.

Blood pressure and waist circumference: an empirical study of the effects of waist circumference on blood pressure among Bengalee male jute mill workers of Belur, West Bengal, India

An investigation of 150 adult Bengalee Hindu male jute mill workers in Belur, a suburb of Kolkata, West Bengal, India, was conducted to study the relationship between central obesity and blood pressure. In accordance with their waist circumference measurement, the subjects were divided into two categories: centrally non-obese (CNO) and centrally obese (CO). The participants were classified as the CO group if they had a WC of 80 cm or more. Results showed that none of the CNO subjects was mild hypertensive (SBP>/=140 mmHg and/or DBP>/=90 mmHg) while 85 of the CO subjects (82.5%) were mild hypertensives, the difference being statistically significant (chi-square=9.33; p<0.0025). Moreover, the data also revealed that the CO subjects had much (p<0.001) greater mean weight, body mass index (BMI), systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure than the CNO group members. The significant difference in blood pressure was found even after correcting the confounding effects of age and BMI variables. The results of this study showed that, the Bengalee male jute mill workers in the CO group had significantly higher blood pressure irrespective of age and overall adiposity (BMI). Therefore, the presence of central obesity is deemed a risk factor, for hypertension regardless of age and BMI. Thus, a WC cut-off point of 80 cm could be employed for health promotion among Bengalee men so as to prevent and manage hypertension effectively.

Lean, nondiabetic Asian Indians have decreased insulin sensitivity and insulin clearance, and raised leptin compared to Caucasians and Chinese subjects

OBJECTIVE

To study and compare the insulin sensitivity of healthy, nondiabetic Asian Indians with that of two other ethnic groups (Caucasian and Chinese) living in Singapore.

DESIGN

Study of insulin sensitivity using euglycaemic hyperinsulinaemic glucose clamp.

SUBJECTS

A total of 10 healthy, lean, young male subjects of each ethnic group, matched for age, body mass index (BMI) and physical activity. They all had normal glucose tolerance and had no family history of diabetes.

MEASUREMENTS

Anthropometric parameters (BMI, waist-hip ratio (WHR) and percentage body fat (PBF)), fasting lipid profile and leptin concentration, insulin sensitivity index, and insulin clearance.

RESULTS

Healthy lean (BMI 22.1+/-1.5 kg/m(2) (mean+/-s.d.)) Indians had significantly higher fasting serum leptin (5.1+/-2.5 vs Chinese 1.0+/-0.9 vs Caucasian 2.3+/-1.2 ng/ml; P<0.001), lower insulin sensitivity index (9.9+/-3.3 vs Chinese 14.1+/-3.5 vs Caucasian 18.8+/-9.2 mg/min kg fat-free mass/microU/ml; P<0.002), and lower insulin clearance (461.4+/-54.8 vs Chinese 621.0+/-99.3 vs Caucasian 646.9+/-49.2 ml/min m(2); P<0.001). Indians also had a higher PBF (26.5+/-5.2 vs Chinese 19.5+/-2.2 vs Caucasians 22.9+/-1.4%; P<0.001), diastolic blood pressure (P=0.036), fasting insulin (P<0.006) and fasting triglyceride (P=0.022). Stepwise regression analysis showed that ethnicity was the only significant independent determinant variable for the differences in insulin sensitivity index (P=0.008).

CONCLUSION

Healthy lean nondiabetic Indians were more insulin resistant compared to other ethnic groups despite the similarity in living environment. These findings may warrant preventive health-care strategies for type II diabetes and coronary artery disease to target Indians at an earlier stage compared to other ethnic groups.

Developing a screening program to detect sight-threatening diabetic retinopathy in South India

OBJECTIVE

To develop a screening protocol for detection of sight-threatening diabetic retinopathy in south India.

RESEARCH DESIGN AND METHODS

We performed ophthalmic examinations, including posterior segment examination, using indirect ophthalmoscopy to detect sight-threatening retinopathy in patients with diabetes in screening camps targeting a high-risk population.

RESULTS

We examined 3,949 persons with diabetes in 32 screening camps over a 13-month period beginning July 2001. Most of the patients (93.6%) were aware of their diabetic status, and 84.2% of those aware of their diabetes status were on treatment. One-fifth of those screened had evidence for any retinopathy; only 6.1% of these persons had evidence of past ophthalmic treatment for retinopathy. Only one-quarter of those diagnosed with worse than mild retinopathy came for follow-up to the base hospital within 2 months.

CONCLUSIONS

Screening high-risk groups for sight-threatening retinopathy using indirect ophthalmoscopy may be a useful short-term alternative for India until retinal photography becomes affordable. In addition to strategies to improve coverage, strategies for better follow-up of subjects screened also need to be evolved.

Age- and sex-specific prevalence of diabetes and impaired glucose regulation in 11 Asian cohorts

OBJECTIVE

To report the age- and sex-specific prevalence of diabetes and impaired glucose regulation (IGR) according to revised World Health Organization criteria for diabetes in Asian populations.

RESEARCH DESIGN AND METHODS

We performed 11 studies of 4 countries, comprising 24,335 subjects (10,851 men and 13,484 women) aged 30-89 years who attended the 2-h oral glucose tolerance test and met the inclusion criteria for data analysis.

RESULTS

The prevalence of diabetes increased with age and reached the peak at 70-89 years of age in Chinese and Japanese subjects but peaked at 60-69 years of age followed by a decline at the 70 years of age in Indian subjects. At 30-79 years of age, the 10-year age-specific prevalence of diabetes was higher in Indian than in Chinese and Japanese subjects. Indian subjects also had a higher prevalence of IGR in the younger age-groups (30-49 years) compared with that for Chinese and Japanese subjects. Impaired glucose tolerance was more prevalent than impaired fasting glycemia in all Asian populations studied for all age-groups.

CONCLUSIONS

Indians had the highest prevalence of diabetes among Asian countries. The age at which the peak prevalence of diabetes was reached was approximately 10 years younger in Indian compared with Chinese and Japanese subjects. Diabetes and IGR will be underestimated in Asians based on the fasting glucose testing alone.

Cutoff values for normal anthropometric variables in asian Indian adults

OBJECTIVE

Asian Indians have a high risk of developing glucose intolerance with small increments in their BMI. They generally have high upper-body adiposity, despite having a lean BMI. Therefore, this analysis was performed to find out the normal cutoff values for BMI and upper-body adiposity (waist circumference [WC] or waist-to-hip ratio [WHR]) by computing their risk associations with diabetes.

RESEARCH DESIGN AND METHODS

The risk of diabetes with stratified BMI, WC, or WHR was computed in 10,025 adults aged > or =20 years without a history of diabetes, and they were tested by oral glucose tolerance tests, using World Health Organization criteria. The calculations were performed separately in men and women using diabetes as the dependent variable versus normoglycemia (normal glucose tolerance) in multiple logistic regression analyses. Age-adjusted and stratified BMI, WC, or WHR were used as the independent variables, using the first stratum as the reference category. The upper limit of the stratum above which the risk association became statistically significant (P < 0.05) was considered to be the cutoff for normal values.

RESULTS

Normal cutoff values for BMI was 23 kg/m(2) for both sexes. Cutoff values for WC were 85 and 80 cm for men and women, respectively; the corresponding WHRs were 0.88 and 0.81, respectively. Optimum sensitivity and specificity obtained from the receiver operator characteristic curve corresponded to these cutoff values.

CONCLUSIONS

The cutoff value for normal BMI for men and women was 23 kg/m(2). The cutoff values for WC and WHR were lower in women than in men. The values were significantly lower compared with the corresponding values in white populations.

Diabetes and impaired fasting glycemia in a rural population of Bangladesh

OBJECTIVE

To determine the prevalence of type 2 diabetes and impaired fasting glycemia (IFG) in a rural population of Bangladesh.

RESEARCH DESIGN AND METHODS

A cluster sampling of 4,923 subjects >/=20 years old in a rural community were investigated. Fasting plasma glucose, blood pressure, height, weight, and girth of waist and hip were measured. BMI and waist-to-hip ratio (WHR) were calculated. Total cholesterol, triglycerides, and HDL cholesterol were also estimated. We used the 1997 American Diabetes Association diagnostic criteria.

RESULTS

The crude prevalence of type 2 diabetes was 4.3% and IFG was 12.4%. The age-standardized prevalence of type 2 diabetes (95% CI) was 3.8% (3.12-4.49) and IFG was 13.0% (11.76-14.16). The subjects with higher family income had significantly higher prevalence of type 2 diabetes (5.9 vs. 3.5%, P < 0.001) and IFG (15.6 vs. 10.8%, P < 0.001) than those with lower income. Employing logistic regression in different models, we found that wealthy class, family history of diabetes, reduced physical exercise, and increased age, BMI, and WHR were the important predictors of diabetes. Total cholesterol, triglycerides, and HDL cholesterol showed no association with diabetes and IFG.

CONCLUSIONS

The prevalence of diabetes and IFG in the rural population was found to be on the increase compared with the previous reports of Bangladesh and other Asian studies. Older age, higher obesity, higher income, family history of diabetes, and reduced physical activity were proved significant risk factors for diabetes and IFG, whereas plasma lipids showed no association with diabetes and IFG. Further study may address whether diabetes is causally associated with insulin deficiency or insulin resistance.

Type 2 diabetes in Asian-Indian urban children

OBJECTIVE

Due to a background of high prevalence of type 2 diabetes and the increasing rate of obesity occurring in relatively young urban children, we felt the need to look for type 2 diabetes in children.

RESEARCH DESIGN AND METHODS

A study of cases of type 2 diabetes with age at diagnosis of </=15 years seen at a diabetes speciality center in Chennai, India, is reported. A total of 18 children (5 boys and 13 girls) aged 9-15 years with insidious onset of diabetes responding to oral antidiabetic agents (ODAs) for periods from 2 months to 12 years were studied. Clinical details, anthropometry, and details of family history of diabetes were elicited. All of them were tested for the presence of anti-GAD(65) antibodies and for pancreatic beta-cell reserve by measuring serum C-peptide response (radioimmunoassay procedures).

RESULTS

All children showed a response to ODAs, had good beta-cell reserve (>/=0.6 pmol/ml on stimulation), and negligible GAD(65) antibodies indicating the presence of type 2 diabetes. The children were nonketotic; nine were obese, four had acanthosis nigricans, and one had polycystic ovary syndrome. Positive family history of diabetes was present in all cases.

CONCLUSIONS

The clinical, immunological, and biochemical profile showed that the children had type 2 diabetes. The profile of type 2 diabetes was similar to that described in children in many other countries. Although less common than type 1 diabetes, type 2 diabetes in children is a condition that needs to be recognized and looked for in Asian-Indians.

Outcome of pregnancy among immigrant women with diabetes

OBJECTIVE

We studied outcome of pregnancy among immigrant women with diabetes. The women came from regions of the world with high incidence of impaired glucose tolerance and type 2 diabetes. Prevalences, secular trends, and sociodemographic risk factors of diabetes were also explored.

RESEARCH DESIGN AND METHODS

Data from the Medical Birth Registry of Norway on all births from 1988 to 1998 for mothers born in South Asia and North Africa (11,268) and Norway (601,785) were analyzed.

RESULTS

The prevalence of pregestational diabetes among the immigrants was 8.9/1,000 births, which was more than twice the rate among ethnic Norwegians (3.6/1,000). Time trends indicated increasing prevalences in both groups. Among the immigrants, diabetes was closely associated with maternal age. Maternal diabetes was associated with a significantly increased risk of pregnancy complications in both study groups. Increased risks were found for low birth weight, macrosomia, preterm birth, preeclampsia, and cesarean sections. Among ethnic Norwegians, maternal diabetes conferred a significantly increased risk of infant perinatal death (odds ratio 2.00, 95% CI 1,44-2.77). In the sample of immigrant women with predominantly type 2 diabetes, maternal diabetes was not significantly associated with perinatal death or congenital malformations in the offspring.

CONCLUSIONS

The high prevalence of diabetes among immigrants from South Asia and North Africa represents a challenge for health care providers. To prevent adverse pregnancy outcomes and later cardiovascular and renal morbidity among these groups, early diagnosis of diabetes, adequate metabolic control, and relevant preventive measures are warranted.

Indices of obesity, dyslipidemia, and insulin resistance in apparently healthy Caribbean subjects

Reports from developing countries indicate that a rise in the socioeconomic level is a risk factor for metabolic disorders. We aimed to assess the indices of obesity, dyslipidemia, and insulin resistance among fairly literate healthy adults in a multidisciplinary institution in Trinidad. The study included 156 volunteers (46 males and 110 females, 17-40 years old). The subjects provided information on age, ethnicity, educational attainment, and occupation in self-administered, closed-ended questionnaires. Waist and hip circumferences (cm), weight (kg), and height (m) were measured. Fasting blood samples were taken for glucose, insulin, and lipid determinations in 78 subjects who volunteered for laboratory measurements. Insulin resistance was determined with homeostasis model assessment (HOMA). Of the 156 subjects studied, 83% had received tertiary education, and had no previous record of body mass index (BMI); 8% were obese, 17% were overweight, and 27% were underweight. Laboratory measurements in 78 subjects revealed 28% hypercholesterolemia and 20% hyperinsulinemia. There were no significant gender-related differences in these prevalence rates (P>0.05). The identification of obesity, underweight, hyperinsulinemia, and hypercholesterolemia in this healthy population suggests that screening for the indices of metabolic disorders in a healthy population would be potentially useful for the early identification and treatment of metabolic-related disorders.

The impact of ethnicity on type 2 diabetes

The rapid increase of diabetes prevalence in the US population and across all westernized world has been associated with environmental changes that promote obesity. Although dietary factors, such as total caloric intake, relative excess of dietary saturated fats content and lack of fibers, together with reduced level of physical activity clearly determine the main features of the "obesogenic" environment typical of "western" societies, the impact of lifestyle factors on obesity and diabetes appears to differ in various ethnic groups. Although ethnic-related differences in lifestyle factors may account for some of the predisposition to obesity and diabetes of various ethnic groups, genetic factors may play a more determinant role. These observations pose important public health questions in regard to strategies for treatment and prevention of diabetes both within the multiethnic US population and in the population of origin of various ethnicities. The elucidation of the pathophysiologic mechanisms responsible for the heterogeneous relationship between obesity and type 2 diabetes in various ethnicities may give important contributions to better understand the complex mechanisms involved in the development of this disease. This review examines epidemiological and pathophysiological aspects of the interaction between environment and ethnic predisposition to type 2 diabetes.

Association of Gly82Ser polymorphism in the RAGE gene with diabetic retinopathy in type II diabetic Asian Indian patients

AIM/HYPOTHESIS

The binding of advanced glycation end products (AGE) to the receptor induces cellular oxidative stress and vascular dysfunction and this is implicated in the pathogenesis of diabetic retinopathy (DR). This study aims to investigate the frequency of Gly82Ser polymorphism in exon 3 of the receptor for AGE (RAGE) gene and its association with DR in Asian Indian patients who have type II diabetes.

METHODS

200 Asian Indian patients with at least 15-year duration of type II diabetes were identified. This group included (1) 100 patients with retinopathy (DR) and (2) 100 patients without retinopathy (DNR). Fifty unrelated healthy controls (CT) were also included in the study. Genotype frequencies of Gly82Ser polymorphism were studied by polymerase chain reaction (PCR) amplification and restriction fragment length polymorphism analysis using AluI enzyme. Later, the nucleotide change was confirmed by DNA sequencing.

RESULTS

The frequency of the Ser82 allele was significantly higher, 18% in the DNR group compared to 7% in the DR group (P=.03). The same genotype was 2% in the CT group.

CONCLUSION/INTERPRETATION

Our result suggests that Ser82 allele in the receptor for AGE gene is a low-risk allele for developing DR in Asian Indian patients who have type II diabetes.

SPINK1 is a susceptibility gene for fibrocalculous pancreatic diabetes in subjects from the Indian subcontinent

Fibrocalculous pancreatic diabetes (FCPD) is a secondary cause of diabetes due to chronic pancreatitis. Since the N34S variant of the SPINK1 trypsin inhibitor gene has been found to partially account for genetic susceptibility to chronic pancreatitis, we used a family-based and case-control approach in two separate ethnic groups from the Indian subcontinent, to determine whether N34S was associated with susceptibility to FCPD. Clear excess transmission of SPINK1 N34S to the probands with FCPD in 69 Bangladeshi families was observed (P<.0001; 20 transmissions and 2 nontransmissions). In the total study group (Bangladeshi and southern Indian) the N34S variant was present in 33% of 180 subjects with FCPD, 4.4% of 861 nondiabetic subjects (odds ratio 10.8; P<.0001 compared with FCPD), 3.7% of 219 subjects with type 2 diabetes, and 10.6% of 354 subjects with early-onset diabetes (aged <30 years) (P=.02 compared with the ethnically matched control group). These results suggest that the N34S variant of SPINK1 is a susceptibility gene for FCPD in the Indian subcontinent, although, by itself, it is not sufficient to cause disease.

Temporal changes in prevalence of type 2 diabetes and impaired glucose tolerance in urban southern India

The prevalence of type 2 diabetes and impaired glucose tolerance (IGT) is increasing in urban areas of developing countries, especially in India. This is a report of the temporal changes in the prevalence of diabetes and IGT in urban areas of Chennai (Madras), India, in adults aged > or =20 years, with an emphasis on identifying the risk factors responsible for the changes. Three urban diabetic surveys conducted in 1989, 1995 and 2000 were compared for the age-standardized prevalence, anthropometric, demographic and lifestyle characteristics of the glucose-intolerant groups. Multiple logistic regression analyses were used for the identification of risk variables associated with diabetes and IGT. The trend was statistically significant for diabetes (chi(2)=18.0, P<0.001) and for IGT (chi(2)=48.2, P<0.001). The period between 1989 and 1995 showed a 40% rise in the prevalence of diabetes and a further increase of 16.4% in the next 5 years. Age increased in each survey for both genders. Waist girth and waist:hip ratio were significantly higher in women, in the 2000 survey. There was no change in the mean body mass index with time in both genders. An increase in IGT was seen in year 2000, especially so in subjects aged <40 years. The prevalence of diabetes and IGT is increasing in India. Increasing age and positive family history showed associations with diabetes.

The lifecycle effects of nutrition and body size on adult adiposity, diabetes and cardiovascular disease

This study was undertaken to review the links between maternal nutrition, offspring's birth weight and the propensity to early insulin resistance and high diabetes rates in Indian adults. Studies included a comparison of maternal size and nutrition with birth weights in Pune, India, and Southampton, UK. In Pune, the growth, insulin resistance and blood pressure of four-year-old children were assessed. Adults >40 years of age, who were resident in rural areas, were compared with adults living in urban areas for size, glucose handling, lipid status and blood pressure. Newly diagnosed diabetic adults living in urban areas were also monitored. Height, weight, head, waist and hip circumferences, skin-fold measurements and blood pressure were routinely measured. Fasting glucose, insulin, total and high-density lipoprotein cholesterol and triglycerides were linked to the glucose and insulin responses during glucose tolerance tests. Cytokine levels were measured in plasma samples of urban and rural adults. Indian babies were lighter, thinner, shorter and had a relatively lower lean tissue mass than the Caucasian babies. However, the subcutaneous fat measurements of these babies were comparable to those of the white Caucasian babies. The Indian mothers were small, but relatively fat mothers produced larger babies. Maternal intake of green vegetables, fruit and milk, and their circulating folate and vitamin C levels, predicted larger fetal size. Rapid childhood growth promoted insulin resistance and higher blood pressure. Rural adults were thin, with a 4% prevalence of diabetes and a 14% prevalence of hypertension, but the risks increased within the normal body mass index (BMI) range. Type 2 diabetes was common in urban adults younger than 35 years of age. Although the average BMI was 23.9 kg m(-2), central obesity and thin limbs were noteworthy. Levels of interleukin-6 and tumour necrosis factor-a were markedly increased in urban dwellers. Hence, there is evidence of a remarkably powerful, intergenerational effect on body size and total and central adiposity. Indians are highly susceptible to insulin resistance and cardiovascular risks, with babies being born small but relatively fat. Insulin resistance is amplified by rapid childhood growth. Dietary factors seem to have profound long-term metabolic influences in pregnancy. Overcrowding with infections and central obesity may amplify cytokine-induced insulin resistance and early diabetes in Indian adults with a low BMI.

Diabetes and impaired glucose tolerance in Aboriginal Australians: prevalence and risk

The prevalence and risk of having impaired glucose tolerance (IGT) and diabetes was estimated relative to body mass index (BMI) among Australian Aboriginal people. A stratified analysis was undertaken of community screening data. Measures included fasting and 2-h glucose concentrations, and BMI (five strata: <22, 22-24.9, 25-29.9, 30-34.9 and >/=35 kg/m(2)). Age was stratified into three groups: 15-34.9, 35-44.9, and >/=45 years. Participants were men and women, ages 15-94 years (n=2626). The prevalence of IGT and diabetes, respectively, adjusted for age and BMI, was 139 and 142 cases/1000 persons among men, and 157 and 152 cases/1000 persons among women. Odds ratios (95% CI) for IGT and diabetes for increasing BMI strata >/=22 kg/m(2) ranged from 1.7 (1.0 to 2.9) to 5.1 (2.4-10.5) for IGT, and from 2.0 (1.2-3.5) to 6.1 (3.3-11.1) for diabetes. For IGT and diabetes, across genders, the population attributable risk percentages (95% CI) for BMI >/=22 kg/m(2) were 34.1% (26.2-41.9%) for IGT, and 46.4% (38.5-54.5%) for diabetes. Diabetes and IGT have reached epidemic proportions among Australian Aboriginal people. An urgent need exists for programmes to reduce the prevalence of diabetes risk factors, especially BMI of 22 kg/m(2) or more, a limit lower than advocated for Euro-American populations.

Clinical, biophysical and biochemical variables from African-heritage subjects with type 2 diabetes

We compared the metabolic profile of two ethnic populations with type 2 diabetes, one from Bantu (n = 23; Ban) and the other from Belgian (n = 314) extraction followed at St Luc Hospital. Further comparison with a Belgian sub-cohort (n = 64; Be) matched for age (52 yrs) and sex distribution (M/F: 61/39%) showed no significant difference between Belgian and Bantu subjects with regards to diabetes duration (9 and 11 yrs; Ban and Be respectively), age at diabetes diagnosis (43 and 42 yrs), HbA1c (8.1 +/- 1.9 vs. 8.5 +/- 1.9%; NS), and achieved education level. BMI was lower in Ban (29 +/- 4 vs. 32 +/- 7 in Be; p < 0.02), as were body fat (33 +/- 12 vs. 37 +/- 11 kg; NS) and waist diameter (99 +/- 9 vs. 106 +/- 16 cm; p < 0.02). Forty-eight and 72% of Ban and Be were on metformin (p < 0.05), while insulin was given to 39 and 34%. Daily insulin dose was lower in Ban (0.31 +/- 0.20 vs. 0.47 +/- 0.18 IU.kg-1.24 h-1; p < 0.001). There was no difference in beta-cell function (% beta; normal: 100%) or insulin sensitivity (%S; normal: 100%) as determined with HOMA between groups. % beta (median [perc 25-75]) was 51 [23-119] and 67 [45-84] in Ban and Be, while %S was 32 [29-37] and 37 [27-45]. Smoking (past & current) prevalence was 5 and 47% in Ban and Be (p < 0.0001). Prevalence of micro- and macroangiopathy did not differ between groups, although Ban had more macroalbuminuria (29 vs. 9%; p < 0.05), and were more often treated with Ca(2+)-channel- and beta-blockers than Be subjects (36 and 39% vs. 16 and 8%; p = 0.07 and < 0.05, respectively). Fasting (F) and interprandial (IP) triglycerides (TG) were lower in Ban: 115 [81-149] vs. 189 [155-325] mg.dL-1 for F-TG and 127 [81-160] vs. 170 [128-305] mg.dL-1 for IP-TG (p < 0.0001), as was total cholesterol (201 +/- 53 vs. 223 +/- 40 mg.dL-1 (p < 0.05), despite lower use of hypolipidaemic drug (13 vs. 44%; p < 0.01). African-heritage subjects with type 2 diabetes have similar degree of diabetes control and complications, in the presence of leaner biophysical status, minimal tobacco exposure and lower fasting and interprandial triglycerides.

Haplotype combinations of calpain 10 gene polymorphisms associate with increased risk of impaired glucose tolerance and type 2 diabetes in South Indians

Haplotype combination 112/121 and its intrinsic variants (UCSNP43, -19, and -63) identified within the calpain 10 gene are associated with increased risk of type 2 diabetes in Mexican-Americans. We evaluated whether this haplotype combination and its constituent haplotypes and variants contribute to increased susceptibility to impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) and type 2 diabetes in a South Indian population. Two study groups were used: 95 families ascertained through a proband with type 2 diabetes and 468 subjects recruited as part of an urban survey (69.1% with normal glucose tolerance, 12.8% with IFG/IGT, and 18.2% with type 2 diabetes). The four-locus haplotype combination 1112/1121 (UCSNP44, -43, -19, and -63) in South Indians conferred both a 10.7-fold increased risk for IFG/IGT (P = 0.001) and a 5.78- to 6.52-fold increased risk for type 2 diabetes in the two study groups (families P = 0.025, urban survey P = 0.015). A combination of the 1112 haplotype with the 1221 haplotype also appeared to increase risk for both IFG/IGT and type 2 diabetes. Contrary to what might be expected, quantitative trait analysis in the families found that transmission of the disease-related 1121 and 1112 haplotypes was associated with a reduced hip size and lower waist-to-hip ratio, respectively. This study supports the paradigm that specific haplotype combinations of calpain 10 variants increase risk of both IFG/IGT and type 2 diabetes. However, the relative infrequency of the "at-risk" combinations in the South Indian population suggests that calpain 10 is not a common determinant of susceptibility to type 2 diabetes.

Cardiovascular diseases in the developing countries: dimensions, determinants, dynamics and directions for public health action

The global burden of disease due to cardiovascular diseases (CVDs) is escalating, principally due to a sharp rise in the developing countries which are experiencing rapid health transition. Contributory causes include: demographic shifts with altered population age profiles; lifestyle changes due to recent urbanisation, delayed industrialisation and overpowering globalisation; probable effects of foetal undernutrition on adult susceptibility to vascular disease and possible gene-environment interactions influencing ethnic diversity. Altered diets and diminished physical activity are critical factors contributing to the acceleration of CVD epidemics, along with tobacco use. The pace of health transition, however, varies across developing regions with consequent variations in the relative burdens of the dominant CVDs. A comprehensive public health response must integrate policies and programmes that effectively impact on the multiple determinants of these diseases and provide protection over the life span through primordial, primary and secondary prevention. Populations as well as individuals at risk must be protected through initiatives that espouse and enable nutrition-based preventive strategies to protect and promote cardiovascular health. An empowered community, an enlightened policy and an energetic coalition of health professionals must ensure that development is not accompanied by distorted nutrition and disordered health.

Impact of poverty on the prevalence of diabetes and its complications in urban southern India

AIM

The impact of poverty on the profile of diabetes and its complications was studied.

METHODS

A comparative study of low income group (LIG) (family income Rs. < 30,000/annum (approx. 432 pounds sterling) and high income group (HIG) (family income Rs. greater-than-or-equal 60,000/annum (approx. pounds sterling) subjects of > or = 40 years was done in Madras, India. By screening 1748 LIG subjects (M/W 844/904) 301 diabetic subjects were identified and 218 underwent tests for diabetic complications. Population data available in 635 (M/W 309/326) HIG subjects from the survey were used for comparison of glucose tolerance profile. Complications were studied in 221 diabetic HIG subjects.

RESULTS

Age-standardized prevalences of diabetes (12.6% vs. 25.5%; chi(2) = 56.9, P < 0.0001) and impaired glucose tolerance (IGT) (8.9% vs. 19.0%) were significantly lower (chi(2) = 57.7; P < 0.0001) in the LIG. Hypertension was more common in LIG (53.7% vs. 40.0% in HIG; chi(2) = 34.9; P < 0.0001). LIG subjects were more physically active; 73.8% did not go to school. Parameters significantly associated with diabetes were body mass index (BMI), age, higher income, waist--hip ratio and physical inactivity. Higher income, BMI and age were associated with IGT. Diabetic LIG subjects had a higher prevalence of cardiac disease, neuropathy and cataract and a lower prevalence of retinopathy than HIG subjects. The risk variables such as hyperglycaemia, dyslipidaemia, hypertension, smoking and alcohol consumption were more in the LIG group.

CONCLUSIONS

The urban poor in the developing world has a lower prevalence of diabetes than the urban poor in developed societies. However, they have higher rates of complications of diabetes.

Global burden of cardiovascular diseases: Part II: variations in cardiovascular disease by specific ethnic groups and geographic regions and prevention strategies

This two-part article provides an overview of the global burden of atherothrombotic cardiovascular disease. Part I initially discusses the epidemiological transition which has resulted in a decrease in deaths in childhood due to infections, with a concomitant increase in cardiovascular and other chronic diseases; and then provides estimates of the burden of cardiovascular (CV) diseases with specific focus on the developing countries. Next, we summarize key information on risk factors for cardiovascular disease (CVD) and indicate that their importance may have been underestimated. Then, we describe overarching factors influencing variations in CVD by ethnicity and region and the influence of urbanization. Part II of this article describes the burden of CV disease by specific region or ethnic group, the risk factors of importance, and possible strategies for prevention.

Ethnicity and type 2 diabetes: focus on Asian Indians

Though the overall prevalence of type 2 diabetes is increasing in US and in all other westernized countries, significant differences are noted among different ethnic groups. The reasons for ethnic differences in the risk of type 2 diabetes are not entirely understood. For example, Asian Indians (people from India, Pakistan, and Bangladesh) have remarkably high prevalence of type 2 diabetes compared to Caucasians. However, the incidence of obesity, an important risk factor in the development of type 2 diabetes, is significantly lower in Asian Indians compared to Caucasians. Though westernization of lifestyle with dietary changes and lack of exercise may play a role in increased prevalence of type 2 diabetes in migrant Asian Indians, various epidemiological studies have shown that these factors alone are not sufficient to explain this trend. One important factor contributing to increased type 2 diabetes in Asian Indians is excessive insulin resistance compared to Caucasians. This difference in the degree of insulin resistance may be explained by either an environmental or a genetic factor or by combination of both. The understanding of the etiology and mechanisms causing increased insulin resistance in Asian Indians will provide clues to more effective prevention and treatment of diabetes in this ethnic group. Furthermore, the information may help in understanding the pathophysiology of type 2 diabetes in other ethnic groups and improve methods of treatment and prevention in all ethnic groups. Since the ethnic mix of the US population is changing rapidly and it is estimated that by the year 2020, over 50% of US population will include non-Caucasian ethnicity, the identification of the mechanism involved in the excessive development of type 2 diabetes in non-Caucasians becomes important. In this review, possible etiology of excessive insulin resistance and role of free fatty acids (FFA) in insulin resistance in Asian Indians is discussed. Finally, the role of targeting insulin resistance in prevention and treatment of diabetes is discussed.

Tumor necrosis factor allelic polymorphism with diabetic retinopathy in India

The association of tumor necrosis factor (TNF) with diabetic retinopathy (DR) has been described previously. A total of 207 Asian Indian patients of 15-year duration of type 2 diabetes were identified. This group included (i) 100 patients with DR and (ii) 107 patients without retinopathy (DNR). In this study, we correlated the length of the (GT)n microsatellite di-nucleotide repeat upstream to the promoter region of TNF gene with susceptibility for the development of retinopathy. The microsatellite was polymerase chain reaction amplified and electrophoresed on polyacrylamide gel and silver stained. In our study population, there were 18 alleles ranging from 97 to 131 base pairs (bp). Allele 4 (103 bp) had a higher prevalence (9.81%) in the DNR group compared to that (2.5%) in the DR group (P=0.002). Patients with retinopathy and allele 8 (111 bp) had a tendency to develop proliferative diabetic retinopathy (PDR). In this study of Indian subjects, it is suggested that allele 4 is a low risk allele for developing retinopathy and allele 8 (111 bp) shows an association with PDR.

The genetics of type 2 diabetes

Type 2 diabetes mellitus is not a single disease but a genetically heterogeneous group of metabolic disorders sharing glucose intolerance. The precise underlying biochemical defects are unknown and almost certainly include impairments of both insulin secretion and action. The rapidly increasing prevalence of T2D world wide makes it a major cause of morbidity and mortality. Understanding the genetic aetiology of T2D will facilitate its diagnosis, treatment and prevention. The results of linkage and association studies to date demonstrate that, as with other common diseases, multiple genes are involved in the susceptibility to T2D, each making a modest contribution to the overall risk. The completion of the draft human genome sequence and a brace of novel tools for genomic analysis promise to accelerate progress towards a more complete molecular description of T2D.