Insulin resistance, high prevalence of diabetes, and cardiovascular risk in immigrant Asians. Genetic or environmental effect?

Disparities in the Prevalence of Childhood Obesity-Related Comorbidities: A Systematic Review

Background

Non-communicable diseases among children are serious consequences of childhood obesity. However, less is known about the disparities in childhood obesity comorbidities burden. This review describes the salient pattern of disparities in the prevalence of childhood obesity-related non-communicable diseases and relevant inequalities in both high- and low/medium-income countries.

Method

A systematic literature search was performed in MEDLINE, Embase, CINAHL, PsycInfo, Scopus, and Web of Science databases by two independent reviewers. Inclusion criteria were as follows: age 2–18 years; the prevalence or incidence of childhood obesity comorbidities reported; and studies published in English from January 2010 to date. No restrictions on the setting. The prevalence data were analyzed using range and median for subgroups based on the country's development status, gender, and geographical region.

Results

Our search identified 6,837 articles, out of which we examined 145 full-text articles and included 54 articles in the analysis. The median prevalence of childhood obesity-related hypertension was 35.6 vs. 12.7% among middle- and low-income countries compared with high-income countries; 37.7 vs. 32.9% among boys compared with girls; and 38.6, 25.3, and 20.1% in Asia, South America, and Europe, respectively. For metabolic syndrome, the median prevalence was 26.9 vs. 5.5% among middle- and low-income countries compared with high-income countries; 55.2 vs. 12.0% among boys compared with girls; and 40.3, 25.8, and 7.7% in South America, Asia, and Europe, respectively. The prevalence of childhood obesity-related non-alcoholic fatty liver disease was 47.5 vs. 23% among middle- and low-income countries compared with high-income countries; and 52.1, 39.7, and 23.0% in Asia, South America, and Europe, respectively. The median prevalence of dyslipidemia was 43.5 vs. 63% among middle- and low-income countries compared with high-income countries; 55.2 vs. 12.0% among boys compared to girls; and 73.7 and 49.2% in Australia and Europe, respectively.

Conclusion

There are disparities in the prevalence of childhood obesity-related hypertension, metabolic syndrome, and non-alcoholic fatty liver disease, with middle- and low-income countries, boys, and Asian region having higher prevalence. Implementing targeted interventions for childhood obesity comorbidities should consider socioeconomic disparities and strengthening of research surveillance methods for a better understanding of non-communicable disease burden in the pediatric population.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO, identifier: CRD42021288607.

Incidence and pathophysiology of diabetes in South Asian adults living in India and Pakistan compared with US blacks and whites

INTRODUCTION

We compared diabetes incidence in South Asians aged ≥45 years in urban India (Chennai and Delhi) and Pakistan (Karachi), two low-income and middle-income countries undergoing rapid transition, with blacks and whites in the US, a high-income country.

RESEARCH DESIGN AND METHODS

We computed age-specific, sex-specific and body mass index (BMI)-specific diabetes incidence from the prospective Center for Cardiometabolic Risk Reduction in South Asia Study (n=3136) and the Atherosclerosis Risk in Communities Study (blacks, n=3059; whites, n=9924). We assessed factors associated with incident diabetes using Cox proportional hazards regression.

RESULTS

South Asians have lower BMI and waist circumference than blacks and whites (median BMI, kg/m²: 24.9 vs 28.2 vs 26.0; median waist circumference, cm 87.5 vs 96.0 vs 95.0). South Asians were less insulin resistant than blacks and whites (age-BMI-adjusted homeostatic model assessment of insulin resistance, µIU/mL/mmol/L: 2.30 vs 3.45 vs 2.59), and more insulin deficient than blacks but not whites (age-BMI-adjusted homeostasis model assessment of β-cell dysfunction, µIU/mL/mmol/L: 103.7 vs 140.6 vs 103.9). Age-standardized diabetes incidence (cases/1000 person-years (95% CI)) in South Asian men was similar to black men and 1.6 times higher (1.37 to 1.92) than white men (26.0 (22.2 to 29.8) vs 26.2 (22.7 to 29.7) vs 16.1 (14.8 to 17.4)). In South Asian women, incidence was slightly higher than black women and 3 times (2.61 to 3.66) the rate in white women (31.9 (27.5 to 36.2) vs 28.6 (25.7 to 31.6) vs 11.3 (10.2 to 12.3)). In normal weight (BMI <25 kg/m²), diabetes incidence adjusted for age was 2.9 times higher (2.09 to 4.28) in South Asian men, and 5.3 times (3.64 to 7.54) in South Asian women than in white women.

CONCLUSIONS

South Asian adults have lower BMI and are less insulin resistant than US blacks and whites, but have higher diabetes incidence than US whites, especially in subgroups without obesity. Factors other than insulin resistance (ie, insulin secretion) may play an important role in the natural history of diabetes in South Asians.

Genetics of obesity and its measures in India

Obesity is one of the largest global health problems associated with increased morbidity and mortality mediated by its association with several other metabolic disorders. The interaction between the genes and environment plays an important role in the manifestation of obesity. Despite a high heritability (40-70%) of obesity, the search for genetic variants associated with obesity susceptibility has been a challenging task. To date, limited studies have been conducted in India, restricted to the validation of few genetic variants identified by genomewide association studies. In this critical review, we sought to examine the current knowledge of genetic basis of obesity and its measures in the Indian population. A comprehensive literature search was performed using 'PubMed', 'Medline' and 'IndMed' databases to search for citations published until 31st May 2017, using the key terms as 'Genetics' AND 'obesity' AND 'India'. We identified 48 potential studies which fulfilled the eligibility criteria. The findings indicated that FTO, MC4R, TNF-α, PPAR-γ , UCP1, UCP2, LPL, LEPR, AMD1, IL6, APOE, ADIPOQ, DOK5, INSIG2, PBEF1, IL6R, Myostatin, CXCR4, HHEX, IRX3, POMC, NGN3, FOXA2, MTR, TCN and CHDH are some of the important genes studied among the Indian population. Importantly, the role of sexual dimorphism in the genetic regulation of obesity and body fat distribution was also reported in a few studies. Further, seven biological pathways have been identified that contribute to obesity pathogenesis in India. In conclusion, further exploration of pathway-based research on genetics of obesity can be useful for better understanding the pathophysiology of obesity in India.

Nutraceutical approaches to metabolic syndrome

Metabolic Syndrome (MetS), affecting at least 30% of adults in the Western World, is characterized by three out of five variables, from high triglycerides, to elevated waist circumference and blood pressure. MetS is not characterized by elevated cholesterolemia, but is rather the consequence of a complex interaction of factors generally leading to increased insulin resistance. Drug treatments are of difficult handling, whereas well-characterized nutraceuticals may offer an effective alternative. Among these, functional foods, e.g. plant proteins, have been shown to improve insulin resistance and reduce triglyceride secretion. Pro- and pre-biotics, that are able to modify intestinal microbiome, reduce absorption of specific nutrients and improve the metabolic handling of energy-rich foods. Finally, specific nutraceuticals have proven to be of benefit, in particular, red-yeast rice, berberine, curcumin as well as vitamin D. All these can improve lipid handling by the liver as well as ameliorate insulin resistance. While lifestyle approaches, such as with the Mediterranean diet, may prove to be too complex for the single patient, better knowledge of selected nutraceuticals and more appropriate formulations leading to improved bioavailability will certainly widen the use of these agents, already in large use for the management of these very frequent patient groups. Key messages Functional foods, e.g. plant proteins, improve insulin resistance. Pro- and pre-biotics improve the metabolic handling of energy-rich foods. Nutraceutical can offer a significant help in handling MetS patients being part of lifestyle recommendations.

Helicobacter pylori Infection and Inflammation: Implication for the Pathophysiology of Diabetes and Coronary Heart Disease in Asian Indians

Asian Indians living in the Indian subcontinent or abroad experience high rate of coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM). Asian Indians are also known to suffer from various infections, particularly during their childhood. One such chronic infection is with Helicobacter pylori (H. pylori). Since H. pylori with its specific virulence factor cytotoxin-associated gene A (cagA) has been suggested to be associated with CHD, a role of this H. pylori infection was investigated in the pathogenesis of CHD in Asian Indians living in Bangladesh. H. pylori (CagA) infected subjects with CHD (HP+ve cases, n=21), and without CHD (HP+ve controls, n=20), and non-infected without CHD (HP-ve normal controls, n=21) were included in this study. Thromboxane (TXB), an index of platelet activation, was found to be significantly higher in the HP+ve cases (p=0.05), but not in the HP+ve controls (p=0.88) when compared with HP-ve controls. Analyses of lipid profiles revealed that while triglycerides, total cholesterol and LDL did not show any significant changes, HDL was significantly lower in both the HP+ve cases (p=0.0003) and controls (p=0.005). The mean fasting glucose level in the HP+ve cases was markedly increased (p>0.0001), while it was intermediate in the HP+ve controls, and lowest in the HP-ve controls. HOMA-IR values, a measure of insulin resistance, did not reflect any substantial differences between the HP+ve and HP-ve controls, but they were highly significantly different between the HP+ve cases and HP-ve controls. HOMA-B, indicating insulin secretory dysfunction (ISD), was significantly higher in both the HP+ve groups when compared with the normal controls. The data indicate that H. pylori infection is associated with impaired insulin secretion, and that a component of insulin resistance that occurs independent of H. pylori can then lead to a worsening of glucose tolerance and the development of CHD. This is the first demonstration to our knowledge that H. pylori (CagA) infection is associated with insulin secretory dysfunction in human subjects. Since many Asian Indians contract various other chronic and acute infections, it is important to investigate the role of H. pylori and other infectious agents in the pathogenesis of T2DM and CHD.

Impact of baseline body mass index status on glucose lowering and weight change during sitagliptin treatment for type 2 diabetics

AIMS

This study was designed to evaluate the efficacy of sitagliptin in Taiwanese diabetic subjects with different baseline BMI status.

METHODS

This was a single-center, hospital-based, retrospective chart review in subjects (n=1874) with type 2 diabetes who received sitagliptin. Subjects were classified into subgroups depending upon their baseline BMI by Taiwan national weight classification: normal (BMI<24kg/m(2)) (n=504), overweight (BMI: 24-27kg/m(2)) (n=615), and obese (BMI⩾27kg/m(2)) (n=755). Changes in HbA1c and weight were evaluated over a 12month treatment period.

RESULTS

For all three groups, the HbA1c levels declined over the first three months by about 8%, and subsequently plateaued for the next nine months. Obese subjects were slower in reducing HbA1c compared with normal and overweight subjects (P<0.05), but at nine months the reduction was similar across groups. Mean body weight increased over the first nine months of sitagliptin therapy in subjects with normal BMI (57.12-58.30kg), but there was no change in mean body weight in the overweight group. After three months the obese groups had significantly greater loss in body weight compared with the normal group.

CONCLUSIONS

Baseline BMI status may influence the reduction of HbA1c levels within the first six months of sitagliptin therapy and affect weight change after three months. Being obese was associated with an initial lag in HbA1c reduction and greater weight loss compared with normal and overweight subjects.

Methodological Challenges When Comparing Demographic and Clinical Characteristics of International Observational Registries

OBJECTIVE

Comparisons of data from different registries can be helpful in understanding variations in many aspects of rheumatoid arthritis (RA). The study aim was to assess and improve the comparability of demographic, clinical, and comorbidity data from 5 international RA registries.

METHODS

Using predefined definitions, 2 subsets of patients (main cohort and subcohort) from 5 international observational registries (Consortium of Rheumatology Researchers of North America Registry [CORRONA], the Swedish Rheumatology Quality of Care Register [SRR], the Norfolk Arthritis Register [NOAR], the Institute of Rheumatology Rheumatoid Arthritis cohort [IORRA], and CORRONA International) were evaluated and compared. Patients ages >18 years with RA, and present in or recruited to the registry from January 1, 2000, were included in the main cohort. Patients from the main cohort with positive rheumatoid factor and/or erosive RA who had received ≥1 synthetic disease-modifying antirheumatic drug (DMARD), and switched to or added another DMARD, were included in the subcohort at time of treatment switch.

RESULTS

Age and sex distributions were fairly similar across the registries. The percentage of patients with a high Disease Activity Score in 28 joints score varied between main cohorts (17.5% IORRA, 18.9% CORRONA, 24.7% NOAR, 27.7% CORRONA International, and 36.8% SRR), with IORRA, CORRONA, and CORRONA International including more prevalent cases of RA; the differences were smaller for the subcohort. Prevalence of comorbidities varied across registries (e.g., coronary artery disease ranged from 1.5% in IORRA to 7.9% in SRR), partly due to the way comorbidity data were captured and general cultural differences; the pattern was similar for the subcohorts.

CONCLUSION

Despite different inclusion criteria for the individual RA registries, it is possible to improve the comparability and interpretability of differences across RA registries by applying well-defined cohort definitions.

Ethnic disparities in risk of cardiovascular disease, end-stage renal disease and all-cause mortality: a prospective study among Asian people with Type 2 diabetes

AIM

To study prospectively the ethnic-specific risks of cardiovascular disease, end-stage renal disease and all-cause mortality in patients with Type 2 diabetes mellitus among native Asian subpopulations.

METHODS

A total of 2337 subjects with Type 2 diabetes (70% Chinese, 17% Malay and 13% Asian Indian) were followed for a median of 4.0 years. Time-to-event analysis was used to study the association of ethnicity with adverse outcomes.

RESULTS

Age- and gender-adjusted hazard ratios for cardiovascular disease in ethnic Malay and Asian Indian subjects were 2.01 (1.40-2.88; P<0.0001) and 1.60 (1.07-2.41; P=0.022) as compared with Chinese subjects. Adjustment for conventional cardiovascular disease risk factors, including HbA1c , blood pressure and lipid profile, slightly attenuated the hazards in Malay (1.82, 1.23-2.71; P=0.003) and Asian Indian subjects (1.47, 0.95-2.30; P=0.086); However, further adjustment for baseline renal function (estimated GFR) and albuminuria weakened the cardiovascular disease risks in Malay (1.48, 0.98-2.26; P=0.065) but strengthened that in Asian Indian subjects (1.81, 1.14-2.87; P=0.012). Competing-risk regression showed that the age- and gender-adjusted sub-distribution hazard ratio for end-stage renal disease was 1.87 (1.27-2.73; P=0.001) in Malay and 0.39 (0.18-0.83; P=0.015) in Asian Indian subjects. Notably, the difference in end-stage renal disease risk among the three ethnic groups was abolished after further adjustment for baseline estimated GFR and albuminuria. There was no significant difference in risk of all-cause mortality among the three ethnic groups.

CONCLUSIONS

Risks of cardiovascular and end-stage renal diseases in native Asian subjects with Type 2 diabetes vary substantially among different ethnic groups. Differences in prevalence of diabetic kidney disease may partially explain the ethnic disparities.

The Relationship of Metabolic Syndrome Traits with Beta-Cell Function and Insulin Sensitivity by Oral Minimal Model Assessment in South Asian and European Families Residing in the Netherlands

Background. There are different metabolic syndrome traits among patients with different ethnicities. Methods. We investigated this by studying 44 South Asians and 54 Europeans and classified them in three groups according to the occurrence of metabolic syndrome (MetS) and Type 2 Diabetes (T2D). Insulin sensitivity index (ISI), static, dynamic, and total beta-cell responsivity indices (Φ), and disposition indices (DIs) were calculated with the use of oral minimal model (OMM). Results. In both ethnicities, ISI was lower in the subgroup with MetS and T2D as compared to the subgroup without MetS nor T2D (P < 0.004). South Asians without MetS were more insulin resistant than Europeans without MetS (P = 0.033). In the South Asians, ISI, dynamic DI, and static DI were associated significantly (P < 0.006) with high-density lipoprotein cholesterol and triglycerides. In the Europeans, ISI was associated with waist-to-hip ratio (P = 0.005) and systolic and diastolic blood pressure (P < 0.005), while static DI was related to the systolic blood pressure (P = 0.005). Conclusions. MetS was linked with insulin resistance and reduced capacity to handle glucose regardless of ethnicity. ISI and DIs were associated with lipid traits in South Asians and with blood pressure in Europeans suggesting that insulin resistance enhances different metabolic syndrome traits among different ethnicities.

Risk factors of incident type 2-diabetes mellitus over a 3-year follow-up: Results from a large Australian sample

AIMS

To describe the incidence of type 2 diabetes mellitus (T2DM) among middle-aged and older Australian adults and to examine a broad range of risk factors of T2DM.

METHODS

A large cohort of Australian adults aged 45 and up was sampled from the general population and was followed up for approximately 3 years (n=60,404). Physician-diagnosed T2DM was self-reported at baseline (2006-2008) and follow-up (2010). Incident T2DM was determined as not reporting T2DM at baseline, but reporting T2DM at follow-up. A broad range of risk factors, including socio-demographic characteristics, health status, family history, and lifestyle behaviors were examined at baseline. Multiple logistic regression was used for selecting potential predictors of incident T2DM, and age and reported family history of T2DM were tested as potential effect modifiers.

RESULTS

Of the 54,997 without T2DM at baseline, 888 reported T2DM at follow-up (cumulative incidence 1.6% over 3.4 years, annual incidence rate 0.44%). Adjusted for other risk factors, being male, older age, higher relative socio-economic disadvantage, being born in Asia, lower educational attainment, medical history of hypertension and dyslipidemia, family history of T2DM, overweight/obese, smoking, long sleeping hours, and psychological distress were significantly associated with higher odds of developing T2DM. Particularly, hypertension, dyslipidemia, and overweight/obesity were stronger predictors of T2DM among middle-aged than older adults (≥60 years).

CONCLUSIONS

Understanding risk factors for incident T2DM could help identify at-risk populations and develop upstream preventive strategies to combat the epidemic of diabetes.

The architecture of risk for type 2 diabetes: understanding Asia in the context of global findings

The prevalence of Type 2 diabetes is rising rapidly in both developed and developing countries. Asia is developing as the epicentre of the escalating pandemic, reflecting rapid transitions in demography, migration, diet, and lifestyle patterns. The effective management of Type 2 diabetes in Asia may be complicated by differences in prevalence, risk factor profiles, genetic risk allele frequencies, and gene-environment interactions between different Asian countries, and between Asian and other continental populations. To reduce the worldwide burden of T2D, it will be important to understand the architecture of T2D susceptibility both within and between populations. This review will provide an overview of known genetic and nongenetic risk factors for T2D, placing the results from Asian studies in the context of broader global research. Given recent evidence from large-scale genetic studies of T2D, we place special emphasis on emerging knowledge about the genetic architecture of T2D and the potential contribution of genetic effects to population differences in risk.

A common variant in the FTO locus is associated with waist-hip ratio in Indian adolescents

BACKGROUND

Common variants in the FTO locus, and near MC4R locus, have been shown to have a robust association with obesity in children and adults among various ethnic groups. Associations with obesity traits among Indian adolescents have not been determined.

OBJECTIVE

To study the association of rs9939609 (FTO) and rs17782313 (MC4R) to obesity related anthropometric traits in Indian adolescents.

METHODS

Subjects for the current study were recruited from a cross-sectional cohort of 1,230 adolescents (age mean ± SD: 17.1 ± 1.9 years) from South India.

RESULTS

The variant at the FTO locus was found to be associated with waist-hip ratio (WHR) but not with overall obesity in this population. No significant association was observed for obesity-traits and Mc4R variant rs17782313.

CONCLUSION

The common variant of FTO (rs9939609) is associated with body fat distribution during early growth in Indian adolescents and may predispose to obesity and metabolic consequences in adulthood.

Epigenetic influences in the aetiology of cancers arising from breast and prostate: a hypothesised transgenerational evolution in chromatin accessibility

Epidemiological studies have consistently supported the notion that environmental and/or dietary factors play a central role in the aetiology of cancers of the breast and prostate. However, for more than five decades investigators have failed to identify a single cause-and-effect factor, which could be implicated; identification of a causative entity would allow the implementation of an intervention strategy in at-risk populations. This suggests a more complex pathoaetiology for these cancer sites, compared to others. When one examines the increases or decreases in incidence of specific cancers amongst migrant populations, it is notable that disease arising in colon or stomach requires one or at most two generations to exhibit a change in incidence to match that of high-incidence regions, whereas for breast or prostate cancer, at least three generations are required. This generational threshold could suggest a requirement for nonmutation-driven epigenetic alterations in the F0/F1 generations (parental/offspring adopting a more westernized lifestyle), which then predisposes the inherited genome of subsequent generations to mutagenic/genotoxic alterations leading to the development of sporadic cancer in these target sites. As such, individual susceptibility to carcinogen insult would not be based per se on polymorphisms in activating/detoxifying/repair enzymes, but on elevated accessibility of crucial target genes (e.g., oncogenes, tumour suppressor genes) or hotspots therein to mutation events. This could be termed a genomic susceptibility organizational structure (SOS). Several exposures including alcohol and heavy metals are epigens (i.e., modifiers of the epigenome), whereas others are mutagenic/genotoxic, for example, heterocyclic aromatic amines; humans are continuously and variously exposed to mixtures of these agents. Within such a transgenerational multistage model of cancer development, determining the interaction between epigenetic modification to generate a genomic SOS and genotoxic insult will facilitate a new level of understanding in the aetiology of cancer.

Common genetic variants and central adiposity among Asian-Indians

Recent studies have identified common genetic variants that are unequivocally associated with central adiposity, BMI, and/or fasting plasma glucose among individuals of European descent. Our objective was to evaluate these associations in a population of Asian-Indians. We examined 16 single-nucleotide polymorphisms (SNPs) from loci previously linked to waist circumference, BMI, or fasting glucose in 1,129 Asian-Indians from New Delhi and Trivandrum. Trained medical staff measured waist circumference, height, and weight. Fasting plasma glucose was measured from collected blood specimens. Genotype-phenotype associations were evaluated using linear regression, with adjustments for age, gender, religion, and study region. For gene-environment interaction tests, total physical activity (PA) during the past 7 days was assessed by the International Physical Activity Questionnaire (IPAQ). The T allele at the FTO rs3751812 locus was associated with increased waist circumference (per allele effect of +1.58 cm, P(trend) = 0.0015) after Bonferroni adjustment for multiple testing (P(adj) = 0.04). We also found a nominally statistically significant FTO-PA interaction (P(interaction) = 0.008). Among participants with <81 metabolic equivalent (MET)-h/wk of PA, the rs3751812 variant was associated with increased waist size (+2.68 cm; 95% confidence interval (CI) = 1.24, 4.12), but not among those with 212+ MET-h/wk (-1.79 cm; 95% CI = -4.17, 0.58). No other variant had statistically significant associations, although statistical power was modest. In conclusion, we confirmed that an FTO variant associated with central adiposity in European populations is associated with central adiposity among Asian-Indians and corroborated prior reports indicating that high PA attenuates FTO-related genetic susceptibility to adiposity.

Acute myocardial infarction: Clinical features and outcomes in young adults in Singapore

AIM

To investigate the clinical features and in-hospital outcomes of young adults with acute myocardial infarction (AMI) in Singapore.

METHODS

Between January 2005 to September 2010, 333 consecutive patients aged ≤ 45 years old were diagnosed to have AMI at our institution. As Singapore is a multi-ethnic society, we also analysed whether ethnic differences exist between the three dominant ethnic groups, Malay, Chinese and Indian with regards to the clinical features. Clinical data was collected retrospectively on demographic characteristics, presenting signs and symptoms, blood investigation, angiographic findings and in-hospital clinical outcomes.

RESULTS

The mean age at presentation was 40.2 ± 4.0 years with male predominance (94%). The majority of patients were Chinese (51%) followed by Indians (31%) and Malays (18%). The most common risk factor was smoking (74%) followed by hypertension (28.5%) and hyperlipidemia (20.0%). 37% of patients were obese. The majority of patients had single vessel disease (46%) on coronary angiography. The mean total cholesterol, low-density lipoprotein and high-density lipoprotein levels were 5.6 ± 1.2 mmol/L, 3.8 ± 1.1 mmol/L and 0.93 ± 0.25 mmol/L respectively. The mean left ventricular function was 44% ± 10% with the incidence of heart failure 3% and cardiogenic shock 4.5%. Overall in-hospital mortality was low with 4 deaths (1.2%). For ethnic subgroup analysis, Indians have a 3-fold risk of developing premature AMI when compared to other ethnic groups.

CONCLUSION

Young AMI patients in Singapore are characterized by male predominance, high incidence of smoking and obesity. Overall in-hospital clinical outcomes are favourable. Among the 3 ethnic groups, Indians have the highest risk of developing premature AMI.

Diabetes screening among immigrants: a population-based urban cohort study

OBJECTIVE

To examine diabetes screening, predictors of screening, and the burden of undiagnosed diabetes in the immigrant population and whether these estimates differ by ethnicity.

RESEARCH DESIGN AND METHODS

A population-based retrospective cohort linking administrative health data to immigration files was used to follow the entire diabetes-free population aged 40 years and up in Ontario, Canada (N = 3,484,222) for 3 years (2004-2007) to determine whether individuals were screened for diabetes. Multivariate regression was used to determine predictors of having a diabetes test.

RESULTS

Screening rates were slightly higher in the immigrant versus the general population (76.0 and 74.4%, respectively; P < 0.001), with the highest rates in people born in South Asia, Mexico, Latin America, and the Caribbean. Immigrant seniors (age ≥65 years) were screened less than nonimmigrant seniors. Percent yield of new diabetes subjects among those screened was high for certain countries of birth (South Asia, 13.0%; Mexico and Latin America, 12.1%; Caribbean, 9.5%) and low among others (Europe, Central Asia, U.S., 5.1-5.2%). The number of physician visits was the single most important predictor of screening, and many high-risk ethnic groups required numerous visits before a test was administered. The proportion of diabetes that remained undiagnosed was estimated to be 9.7% in the general population and 9.0% in immigrants.

CONCLUSIONS

Overall diabetes-screening rates are high in Canada's universal health care setting, including among high-risk ethnic groups. Despite this finding, disparities in screening rates between immigrant subgroups persist and multiple physician visits are often required to achieve recommended screening levels.

The Birmingham Registry for Twin and Heritability Studies (BiRTHS)

In this article we present the protocol of the Birmingham Registry for Twin Heritability Studies (BiRTHS), which aims to establish a long-term prospective twin registry with twins identified from the antenatal period and subjected to detailed follow-up. We plan to investigate the concordance in anthropo-metrics and early childhood phenotypes between 66 monozygotic and 154 dizygotic twin pairs in the first 2 years of recruitment. In this project we plan to determine the relative contributions of heritability and environment to fetal growth, birth size, growth in infancy and development up to 2 years of age in an ethnically mixed population. Twins will be assessed with the Griffitth's Mental Development Scales, which will enable us to obtain detailed information on development. As maternal depression may have an effect on the twins' neurodevelopment, the Edinburgh Postnatal Depression Scale will be used at various stages during pregnancy and after delivery to assess maternal depressive symptoms. The increasing prevalence of obesity in both adults and children has raised concerns about the effect of maternal obesity in pregnancy on fetal growth. The prospective study design gives us the opportunity to obtain data on maternal nutrition (reflected by body mass index) and ante- and postnatal growth and development of twins.

Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes-related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. 'Westernization', acculturation, socio-economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic-specific cut-off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries.

Migrating husbands and changing cardiovascular risk factors in the wife: a cross sectional study in Asian Indian women

OBJECTIVE

The authors studied the influence of migration of husband on cardiovascular risk factors in Asian Indian women.

METHODS

Population-based studies in women aged 35-70 years were performed in four urban and five rural locations. 4608 (rural 2604 and urban 2004) of the targeted 8000 (57%) were enrolled. Demographic details, lifestyle factors, anthropometry, fasting glucose and cholesterol were measured. Multivariate logistic and quadratic regression was performed to compare influence of migration and its duration on prevalence of risk factors.

RESULTS

Details of migration were available in 4573 women (rural 2267, rural-urban migrants 455, urban 1552 and urban-rural migrants 299). Majority were married, and illiteracy was high. Median (interquartile) duration of residence in urban locations among rural-urban migrants was 9 (4-18) years and in rural areas for urban-rural migrants 23 (18-30) years. In rural, rural-urban migrants, urban and urban-rural migrants, age-adjusted prevalence (%) of risk factors was tobacco use 41.9, 22.7, 18.8 and 38.1; sedentary lifestyle 69.7, 82.0, 79.9 and 74.6; high-fat diet 33.3, 54.2, 66.1 and 61.1; overweight 21.3, 42.7, 46.3 and 29.7; large waist 8.5, 38.5, 29.2 and 29.2; hypertension 30.4, 49.4, 47.7 and 38.4; hypercholesterolaemia 14.4, 31.3, 26.6 and 9.1 and diabetes 3.9, 15.8, 14.9 and 8.4, respectively (p<0.001). In rural-urban migrants, there was a significant correlation of duration of migration with waist size, waist-to-hip ratio and systolic blood pressure (quadratic regression, p<0.001). Association of risk factors with migration remained significant, though attenuated, after adjustment for socioeconomic, lifestyle and obesity variables (logistic regression, p<0.01).

CONCLUSIONS

Compared with rural women, rural-urban migrants and urban have significantly greater cardiometabolic risk factors. Prevalence is lower in urban-rural migrants. There is significant correlation of duration of migration with obesity and blood pressure. Differences are attenuated after adjusting for social and lifestyle variables.

A registry-based follow-up study, comparing the incidence of cardiovascular disease in native Danes and immigrants born in Turkey, Pakistan and the former Yugoslavia: do social inequalities play a role?

Background

This study compared the incidence of cardiovascular disease (CVD) and acute myocardial infarction (AMI) between native Danes and immigrants born in Turkey, Pakistan and the former Yugoslavia. Furthermore, we examined whether different indicators of socioeconomic status (SES), such as employment, income and housing conditions influenced potential differences.

Methods

In this registry-based follow-up study individuals were identified in a large database that included individuals from two major regions in Denmark, corresponding to about 60% of the Danish population. Incident cases of CVD and AMI included fatal and non-fatal events and were taken from registries. Using Cox regression models, we estimated incidence rates at 5-year follow-up.

Results

Immigrant men and women from Turkey and Pakistan had an increased incidence of CVD, compared with native Danish men. In the case of AMI, a similar pattern was observed; however, differences were more pronounced. Pakistanis and Turks with a shorter duration of residence had a lower incidence, compared with those of a longer residence. Generally, no notable differences were observed between former Yugoslavians and native Danes. In men, differences in CVD and AMI were reduced after adjustment for SES, in particular, among Turks regarding CVD. In women, effects were particularly reduced among Yugoslavians in the case of CVD and in Turks in the case of CVD and AMI after adjustment for SES.

Conclusions

In conclusion, country of birth-related differences in the incidence of CVD and AMI were observed. At least some of the differences that we uncovered were results of a socioeconomic effect. Duration of residence also played a certain role. Future studies should collect and test different indicators of SES in studies of CVD among immigrants.

An FTO variant is associated with Type 2 diabetes in South Asian populations after accounting for body mass index and waist circumference

AIMS

A common variant, rs9939609, in the FTO (fat mass and obesity) gene is associated with adiposity in Europeans, explaining its relationship with diabetes. However, data are inconsistent in South Asians. Our aim was to investigate the association of the FTO rs9939609 variant with obesity, obesity-related traits and Type 2 diabetes in South Asian individuals, and to use meta-analyses to attempt to clarify to what extent BMI influences the association of FTO variants with diabetes in South Asians.

METHODS

We analysed rs9939609 in two studies of Pakistani individuals: 1666 adults aged ≥40 years from the Karachi population-based Control of Blood Pressure and Risk Attenuation (COBRA) study and 2745 individuals of Punjabi ancestry who were part of a Type 2 diabetes case-control study (UK Asian Diabetes Study/Diabetes Genetics in Pakistan; UKADS/DGP). The main outcomes were BMI, waist circumference and diabetes. Regression analyses were performed to determine associations between FTO alleles and outcomes. Summary estimates were combined in a meta-analysis of 8091 South Asian individuals (3919 patients with Type 2 diabetes and 4172 control subjects), including those from two previous studies.

RESULTS

In the 4411 Pakistani individuals from this study, the age-, sex- and diabetes-adjusted association of FTO variant rs9939609 with BMI was 0.45 (95%CI 0.24-0.67) kg/m(2) per A-allele (P=3.0 × 10(-5) ) and with waist circumference was 0.88 (95% CI 0.36-1.41) cm per A-allele (P=0.001). The A-allele (30% frequency) was also significantly associated with Type 2 diabetes [per A-allele odds ratio (95%CI) 1.18 (1.07-1.30); P=0.0009]. A meta-analysis of four South Asian studies with 8091 subjects showed that the FTO A-allele predisposes to Type 2 diabetes [1.22 (95%CI 1.14-1.31); P=1.07 × 10(-8) ] even after adjusting for BMI [1.18 (95%CI 1.10-1.27); P=1.02 × 10(-5) ] or waist circumference [1.18 (95%CI 1.10-1.27); P=3.97 × 10(-5) ].

CONCLUSIONS

The strong association between FTO genotype and BMI and waist circumference in South Asians is similar to that observed in Europeans. In contrast, the strong association of FTO genotype with diabetes is only partly accounted for by BMI.

Consensus dietary guidelines for healthy living and prevention of obesity, the metabolic syndrome, diabetes, and related disorders in Asian Indians

India is undergoing rapid nutritional transition, resulting in excess consumption of calories, saturated fats, trans fatty acids, simple sugars, salt and low intake of fiber. Such dietary transition and a sedentary lifestyle have led to an increase in obesity and diet-related non-communicable diseases (type 2 diabetes mellitus [T2DM], cardiovascular disease [CVD], etc.) predominantly in urban, but also in rural areas. In comparison with the previous guidelines, these consensus dietary guidelines include reduction in the intake of carbohydrates, preferential intake of complex carbohydrates and low glycemic index foods, higher intake of fiber, lower intake of saturated fats, optimal ratio of essential fatty acids, reduction in trans fatty acids, slightly higher protein intake, lower intake of salt, and restricted intake of sugar. While these guidelines are applicable to Asian Indians in any geographical setting, they are particularly applicable to those residing in urban and in semi-urban areas. Proper application of these guidelines will help curb the rising "epidemics" of obesity, the metabolic syndrome, hypertension, T2DM, and CVD in Asian Indians.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Acute effect of a single high-fat meal on forearm blood flow, blood pressure and heart rate in healthy male Asians and Caucasians: a pilot study

Research has shown that ingestion of a single high-fat (HF) meal causes postprandial lipemia and produces a reduced brachial artery blood flow response to vascular occlusion in Caucasians. However, the forearm BF response to occlusion in Caucasian and Asian populations after a single HF meal has not been compared. Eleven healthy male Asians, mean age 26.4 (+/- 4.2) years, height 174.2 (+/- 7.4) cm, and weight 73.8 (+/- 5.7) kg and eight Caucasians, mean age 26.8 (+/- 4.6) years, height 182.9 (+/- 5.9) cm, and weight 82.8 (+/- 4.8) kg were studied. A randomized cross-over study design was used with a HF (50.1 g total fat) or low-fat (LF) (5.1 g total fat) test meal 1 week apart. Forearm blood flow was measured over a 2-minute period following a 4-minute occlusion (FBFO) at 2 and 4 hours following ingestion of a test meal. This study found that FBFO was significantly attenuated in Asians (19.3%; p = 0.09) compared to Caucasians after the ingestion of a HF meal. When comparing LF vs. HF meals in Asians, the FBFO were 336.9 ml/100 ml tissue/ minute and 240.8 ml/100 ml tissue/minute, respectively (p = 0.02), whereas in Caucasians, the FBFO were 344.8 ml/100 ml tissue/minute and 287.4 ml/100 ml tissue/minute, respectively. It appears Asians have a more sensitive response to a single HF meal which may be explained, in part, by genotypic variation. These findings suggest that a single HF meal may contribute to the detrimental effects on vascular health in Asian males and raises speculation regarding the cumulative impact of a chronic HF diet in this population.

Ethnic differences in body composition and the associated metabolic profile: a comparative study between Asians and Caucasians

It is estimated that Asia will be the home of more than 100 million people with type 2 diabetes by the year of 2025. This region combines a high proportion of the world's population with rapidly rising diabetes prevalence rates. The increase in diabetes in Asia differs from that reported in other parts of the world: it has developed in a shorter time, in a younger age group, and in people with lower body-mass index (BMI). Studies reported that for the same BMI, Asians have a higher body fat percentage, a prominent abdominal obesity, a higher intramyocellular lipid and/or a higher liver fat content compared to Caucasians. These characteristics may contribute to a higher predisposition to insulin resistance at a lesser degree of obesity than Caucasians. The differences in body composition are more pronounced depending on the region. For the same BMI, among three major ethnic groups in Asia, Asian Indians have the highest body fat, followed by Malay and Chinese. Lower insulin sensitivity is already observed in Asian Indian adolescents with a higher body fat and abdominal obesity compared to Caucasian adolescents. In general, Asian adolescents share the same feature of body composition such as higher body subcutaneous fat, lower appendicular skeletal muscle and lower gynoid fat compared to Caucasian adolescents. This unfavourable body composition may predispose to the development of insulin resistance at later age. Genetics may play a role and the interaction with environmental factors (changes in lifestyle) could increase the risk of developing the metabolic syndrome.

Body size, body composition and fat distribution: comparative analysis of European, Maori, Pacific Island and Asian Indian adults

Although there is evidence that Asian Indians, Polynesians and Europeans differ in their body fat (BF)-BMI relationships, detailed comparative analysis of their underlying body composition and build characteristics is lacking. We investigated differences in the relationships between body fatness and BMI, fat distribution, muscularity, bone mineral mass, leg length and age-related changes in body composition between these ethnic groups. Cross-sectional analysis of 933 European, Maori, Pacific Island and Asian Indian adult volunteers was performed for total and percentage of BF, abdominal fat, thigh fat, appendicular muscle mass, bone mineral content and leg length measured by dual-energy X-ray absorptiometry. Asian Indian men and women (BMI of 24 and 26 kg/m2, respectively) had the same percentage of BF as Europeans with a BMI of 30 kg/m2 or Pacific men and women with BMI of 34 and 35 kg/m2, respectively. Asian Indians had more fat, both total and in the abdominal region, with less lean mass, skeletal muscle and bone mineral than all other ethnic groups. Leg length was relatively longer in Pacific men and Asian and Pacific women than in other ethnic groups. In Asian Indians, abdominal fat increased with increasing age, while the percentage of BF showed little change. In the other ethnic groups, both abdominal and total BF increased with age. In conclusion, ethnic differences in fat distribution, muscularity, bone mass and leg length may contribute to ethnic-specific relationships between body fatness and BMI. The use of universal BMI cut-off points may not be appropriate for the comparison of obesity prevalence between ethnic groups.

Insulin resistance phenotypes and coronary artery disease in a native Pakistani cohort

OBJECTIVE

To determine the relationship between insulin resistance (IR) and atheroma burden in Pakistanis.

METHODS

A prospective case-control study of 400 patients selected for the presence/absence of angiographic disease. Coronary atheroma burden was quantified and IR and cardiovascular risk factors were measured.

RESULTS

The patients were divided into two groups by QuickI score. Waist circumference (90 +/- 10 vs. 90 +/- 9 cm; p = 0.7) was similar but the groups differed in body mass index (26.5 +/- 3.7 vs. 24.2 +/- 3.5 kg/m(2); p < 0.001) and waist:hip ratio (0.94 +/- 0.09 vs. 0.90 +/- 0.06; p < 0.001). Lipid parameters showed similar high-density lipoprotein cholesterol (HDL-C) (0.77 +/- 0.23 vs. 0.82 +/- 0.22 mmol/l; p = 0.1) differences in triglycerides [1.32 (0.08-3.98) vs. 1.12 (0.37-3.61) mmol/l; p = 0.01], but no difference in low-density lipoprotein cholesterol (LDL-C) (2.75 +/- 1.00 vs. 2.90 +/- 0.94 mmol/l; p = 0.14). In insulin-resistant patients C-reactive protein (CRP) [6.8 (0.3-175.1) vs. 3.9 (0.2-57.9) mg/l: p < 0.001], sialic acid (82 +/- 14 vs. 77 +/- 15 mg/l; p < 0.001) aspartate transaminase [24 (7-171) vs. 21 (7-83) IU/l; p < 0.001] and gamma-glutamyl transferase [27 (8-482) vs. 21 (7-168) IU/l; p = 0.005] levels were increased. In insulin-resistant patients (n = 187), coronary artery disease (CAD) burden correlated (r = 0.55) with age (beta = 1.62; p < 0.001), HDL-C (beta = -53.2; p < 0.001), lipoprotein (a) (beta = 11.4; p = 0.007), smoking (beta = 7.98; p = 0.004), CRP (beta = 6.06; p = 0.03) and QuickI index (beta = -146; p = 0.04). In contrast in insulin-sensitive patients (n = 178) CAD burden (r = 0.46) correlated with LDL-C (beta = 10.0; p = 0.02), CRP (beta = 7.13; p = 0.03), HDL-C (beta = -38.1; p = 0.03), and weakly with age (beta = 0.73; p = 0.07) and smoking (beta = 5.52; p = 0.09).

CONCLUSIONS

Indian Asians show a dichotomous insulin-resistance phenotype. Atheroma is associated with low HDL-C and inflammation associated in all but LDL-C is a factor in the insulin sensitive in contrast to age and extent of IR in the insulin resistant.

Risk factors for acute ischaemic stroke in young adults in South India

BACKGROUND

Stroke is a leading cause of death and disability in developing countries, afflicting individuals at a young age. The contribution of established vascular risk factors to ischaemic stroke in young adults has not been evaluated systematically in Indians.

METHODS

We conducted a case control study in 214 South Indian patients with first acute ischaemic stroke that occurred between the ages of 15 and 45 years, 99 age and sex matched hospital controls and 96 community controls. We compared the prevalence of the following risk factors: smoking, elevated blood pressure, high fasting blood glucose and abnormal lipids.

RESULTS

Compared with community controls, stroke patients had a higher prevalence of smoking (multivariable adjusted odds ratio (OR) 7.77, 95% CI 1.93 to 31.27), higher systolic blood pressure (OR per SD increment of 1.88, 95% CI 1.01 to 3.49) and fasting blood glucose (OR per SD increment of 4.55, 95% CI 1.63 to 12.67), but lower high density lipoprotein (HDL) cholesterol (OR per SD increment of 0.17, 95% CI 0.09 to 0.30). Compared with hospital controls, stroke patients had a higher prevalence of smoking (OR 3.95, 95% CI 1.61 to 9.71) and lower HDL cholesterol (OR per SD increment 0.27, 95% CI 0.17 to 0.44). The presence of > or = 3 metabolic syndrome components was associated strongly with stroke (OR 4.76, 95% CI 1.93 to 11.76; OR 2.09, 95% CI 1.06 to 4.13) compared with community and hospital controls.

CONCLUSIONS

Key components of the metabolic syndrome and smoking are associated with ischaemic stroke in young South Indian adults. Our observations underscore the importance of targeting adolescents and young adults for screening and prevention to reduce the burden of ischaemic stroke in young adults.

Ethnic differences in cardiovascular risk factors in healthy Caucasian and South Asian individuals with the metabolic syndrome

BACKGROUND

The metabolic syndrome is a cluster of atherothrombotic risk factors that are commonly associated with insulin resistance.

OBJECTIVES

The aim of this study was to investigate ethnic differences in insulin resistance and non-traditional cardiovascular risk factors in relation to the International Diabetes Federation (IDF) definition of the metabolic syndrome.

PATIENTS AND METHODS

A total of 245 healthy South Asians and 245 age- and sex-matched Caucasians were studied. C-reactive protein (CRP), complement C3, plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA) were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated from fasting plasma glucose and insulin levels.

RESULTS

Fifty Caucasian (20%) and 95 (39%) South Asian subjects had the metabolic syndrome as defined by the IDF. In South Asian subjects, HOMA-IR, CRP, C3, PAI-1 and t-PA were significantly higher in subjects with the metabolic syndrome. In contrast, in Caucasian individuals there was no difference in HOMA-IR or C3 levels and only CRP, PAI-1 and t-PA were higher in subjects with the metabolic syndrome. In a logistic regression model, plasma levels of CRP and PAI-1 were independent predictors of the metabolic syndrome in Caucasians, whereas plasma levels of C3 and t-PA as well as HOMA-IR were independent predictors of the metabolic syndrome in South Asian subjects.

CONCLUSIONS

In the cohort of individuals studied, the IDF definition of the metabolic syndrome was associated with insulin resistance in the South Asian but not the Caucasian population. This work also showed ethnic differences in non-traditional cardiovascular risk factors in the presence of the metabolic syndrome.

Ethnic diversity: South Asian ethnicity is associated with increased coronary artery bypass grafting mortality

OBJECTIVE

South Asian ethnicity might result in a higher atherosclerotic vascular risk compared with white ethnicity. However, the effect of South Asian ethnicity on clinical outcomes after cardiac surgery is unknown. Thus, we determined whether South Asian ethnicity is a predictor of a poorer outcome after coronary artery bypass grafting.

METHODS

We examined data from 6177 South Asian and white patients who underwent coronary artery bypass grafting at the Toronto General Hospital from January 1994 through June 2003 and used propensity score matching techniques to analyze 917 patients from each group in more detail. Patients were matched for age, sex, body surface area, left ventricular ejection fraction, New York Heart Association class, previous cardiac surgery, number of diseased vessels, and other factors. Independent predictors of operative morbidity and mortality were determined by means of multivariate logistic regression.

RESULTS

Overall operative mortality was 1.8%. Mortality was higher in South Asian patients than in white patients (2.5% vs 1.1%, P = .02). Postoperative morbidity (eg, myocardial infarction, sepsis, sternal wound infection, postoperative hospital stay, and use of inotropes) also was higher in the South Asian group. In addition to the standard independent predictors of mortality, South Asian ethnicity was an independent predictor of mortality (odds ratio, 3.1; 95% confidence interval, 1.4-6.8).

CONCLUSIONS

These data indicate that South Asian ethnicity per se is an independent predictor of a poorer outcome after coronary artery bypass grafting and suggest that ethnicity is a cardiovascular risk factor that should be considered when assessing clinical outcomes preoperatively before coronary artery bypass grafting or other interventional revascularization procedures.

Metabolic syndrome components in Indian migrants with type 2 diabetes. A matched comparative study

OBJECTIVE

To study the metabolic syndrome (MS) in Indian subjects with type 2 diabetes (T2D) in comparing them with controls from the Indian community and from the general population.

METHOD

An adapted definition of MS by the Third report of the National Cholesterol Education Program's Adult Treatment Panel III was used. We defined three groups matched for sex and age (+/-5 years). Non parametric tests for comparison of matched samples and conditional logistic regression were used.

RESULTS

We selected 71 Indians with T2D (group 1) and two control groups with fasting blood glucose<6.1 mmol/L: 71 Indians (group 2) and 213 subjects from the general population (group 3). Patients were 24 to 76 years-old and each group contained 56% men. Globally, MS was identified in 77% of the group 1 when diabetes was taken into account. When diabetes was excluded there were 47% of MS in group 1, 18% in group 2 and 16% in group 3. The clusters of four factors (hypertension, large waist circumference, hypertriglyceridemia and Low HDL-C) were more common in Indians. The most frequent factors were hypertriglyceridemia and large waist circumference in Indians. Indians with T2D had a 5-fold higher risk of MS than the general population group, OR (95% CI): 4.93 (2.71 - 8.97); P<0.001.

CONCLUSION

The high frequency of MS and of hypertriglyceridemia in Indians with T2D highlights the need for screening and management of MS in this population facing a high cardiovascular risk.

Do known risk factors explain the higher coronary heart disease mortality in South Asian compared with European men? Prospective follow-up of the Southall and Brent studies, UK

AIMS/HYPOTHESIS

We examined prospectively whether measured risk factors can explain the higher CHD mortality in South Asians compared with Europeans.

MATERIALS AND METHODS

Conventional CHD risk factors and those associated with insulin resistance were measured in 1,787 European and 1,420 South Asian men aged 40 to 69 years at baseline in the population-based Southall and Brent studies (London) between 1988 and 1990. Participants were followed up for mortality.

RESULTS

By February 2006, there were 202 CHD deaths (108 Asian, 94 European). South Asian men had double the CHD mortality of European men in Cox regression analyses adjusted for age, smoking, and cholesterol (hazard ratio [HR] 2.14, 95% CI 1.56-2.94, p<0.001). Nearly half of all South Asian CHD deaths versus 13% of deaths among Europeans were among persons with diabetes. Asian men had greater CHD mortality than Europeans, both in the with- and the without-diabetes categories at baseline. CHD mortality remained significantly higher in South Asian men in multivariable models that adjusted for conventional risk factors and diabetes and/or impaired glucose regulation, features of insulin resistance, or the metabolic syndrome (HR 1.6-1.9). Accounting for co-morbidity and socio-economic status did not materially alter the findings.

CONCLUSIONS/INTERPRETATION

These data confirm that South Asian men have significantly higher CHD mortality than their European counterparts, while indicating that neither conventional risk factors, nor insulin resistance parameters or metabolic syndrome criteria as currently defined can account for this excess risk. The contribution of unmeasured factors to the elevated vascular risk in South Asians should be addressed in future studies.

Metabolic and polycystic ovary syndromes in indigenous South Asian women with previous gestational diabetes mellitus

OBJECTIVE

To determine the risk of metabolic syndrome (MS) and polycystic ovary syndrome (PCOS) in a cohort of indigenous South Asian women with a recent history of gestational diabetes mellitus (GDM).

DESIGN

Case-control study.

SETTING

Department of Obstetrics & Gynaecology, University of Colombo, Sri Lanka.

SAMPLE

Two hundred and seventy-four indigenous Sri Lankan women with previous GDM and 168 ethnically matched controls. Of these, 147 with previous GDM and 67 controls not taking hormonal contraception participated in an in-depth endocrine study.

METHODS

Assessing the prevalence of MS and PCOS based on clinical features, biochemistry and ovarian ultrasound examination at 3 years postpartum.

MAIN OUTCOME MEASURES

Prevalence of MS and PCOS.

RESULTS

Women with previous GDM and controls were studied at a mean (range) of 34.6 (13.4-84.1) and 46.5 (17.5-78) months postpartum, respectively. Those with previous GDM had a larger mean +/- 95% confidence interval waist circumference (90.9 +/- 1.3 versus 81.2 +/- 2.8 cm, P = 0.0004) and were more likely to have hypertension (17.6 versus 7.4%, P = 0.001), glucose intolerance (51.7 versus 10.4%, P = 0.00001), hypertriglyceridaemia (16.3 versus 5.9%, P = 0.02) and a lower level of high-density lipoprotein (70 versus 56.7%, P = 0.04) than the controls. Of the women who had GDM, 72 (49%) had MS, 86 (58.5%) had polycystic ovaries and 59 (40%) had PCOS, significantly more than the control women-4 (6%), 9 (13%) and 2 (3%), respectively (P = 0.00001).

CONCLUSIONS

The prevalence of MS and PCOS in indigenous Sri Lankan women 3 years postpartum is significantly higher in those with previous GDM compared with ethnically matched controls. This confirms an association between GDM and subsequent PCOS and MS.

Nuclear Cardiology: Present and Future

Nuclear cardiology has made significant advances since the first reports of planar scintigraphy for the evaluation of left ventricular perfusion and function. While the current "state of the art" of gated myocardial perfusion single-photon emission computed tomographic (SPECT) imaging offers invaluable diagnostic and prognostic information for the evaluation of patients with suspected or known coronary artery disease (CAD), advances in the cellular and molecular biology of the cardiovascular system have helped to usher in a new modality in nuclear cardiology, namely, molecular imaging. In this review, we will discuss the current state of the art in nuclear cardiology, which includes SPECT and positron emission tomographic evaluation of myocardial perfusion, evaluation of left ventricular function by gated myocardial perfusion SPECT and gated blood pool SPECT, and the evaluation of myocardial viability with PET and SPECT methods. In addition, we will discuss the future of nuclear cardiology and the role that molecular imaging will play in the early detection of CAD at the level of the vulnerable plaque, the evaluation of cardiac remodeling, and monitoring of important new therapies including gene therapy and stem cell therapy.

Complement C3 and C-Reactive Protein Are Elevated in South Asians Independent of a Family History of Stroke

BACKGROUND AND PURPOSE

Complement components are emerging risk factors for cardiovascular disease. In this study, we examined the relation among C3, C-reactive protein (CRP), factor B, and features of the insulin resistance (IR) syndrome in 143 first-degree relatives of South Asian subjects with ischemic stroke, 141 South Asian controls, and 121 white controls.

METHODS

C3, CRP (high-sensitivity assay), and factor B levels were measured by ELISAs, and their relation to features of the IR syndrome were assessed. Data are presented as geometric mean (95% CI).

RESULTS

There was no significant difference in the levels of C3 between South Asian relatives (1.25 [1.21, 1.29] g/L) and South Asian controls (1.20 [1.15, 1.24] g/L, P=0.2). Levels in both South Asian groups were significantly higher than in white controls (0.95 [0.92, 0.98] g/L; P<0.001 for both comparisons). These differences remained significant after adjustment for covariates. Similarly, levels of CRP were not different between the 2 South Asian groups, but levels in both South Asian groups, after adjustment for covariates, were significantly higher than in white controls. There was no difference in the levels of factor B among the 3 groups. South Asian subjects with elevated C3 levels clustered risk factors associated with IR to a greater extent than those with high CRP.

CONCLUSIONS

These results suggest that South Asians have a greater level of chronic subclinical inflammation than do whites, independent of a family history of stroke. In addition, C3 is more likely to cluster with features of the IR syndrome compared with CRP in South Asians.

Relationship of serum adiponectin and resistin to glucose intolerance and fat topography in South-Asians

OBJECTIVES

South-Asians have lower adiponectin levels compared to Caucasians. It was not clear however, if this intrinsic feature is related to aspects of glucose metabolism. This study aims to determine the relationship between body fat distribution and adipocytokine in South-Asian subjects by measuring serum adipocytokines, adiposity, insulinemia, and glucose tolerance levels.

METHODS

In this cross-sectional study, 150 South-Asians (80 males, 70 females) were included, 60 had NGT (Control group, Age 51.33 +/- 11.5, BMI 27 +/- 2.3), 60 had IGT (Age 57.7 +/- 12.5, BMI 27.2 +/- 2.7), 30 had type 2 DM (Age 49.5 +/- 10.9, BMI 28 +/- 1.7). Measures of adiposity, adipocytokines and other metabolic parameters were determined. Parameters were measured using the following: a) Plasma glucose by glucose oxidase method b) CRP by immunoturbidimetric method (Roche/Hitachi analyser) c) insulin by Medgenix INS-ELISA immunoenzymetric assay by Biosource (Belgium) d) Leptin, Adiponectin by radioimmunoassay kits by Linco Research (St. Charles MO) e) Resistin by immunoassay kits by Phoenix Pharmaceuticals INC (530 Harbor Boulevard, Belmont CA 94002, USA).

RESULTS

Adiponectin concentrations were highest in NGT, decreased in IGT and lowest in DMT2, (both p < 0.01). Leptin was significantly higher in DMT2 than IGT and NGT p = 0.02 and 0.04 respectively. There was a significant positive relationships between log adiponectin and 2-hr insulin values, p = 0.028 and history of hypertensions and a ischemic heart disease p = 0.008 with R = 0.65. There was a significant inverse correlation between log adiponectin and resistin, p < 0.01.

CONCLUSION

Resistin levels had an inverse correlation with adiponectin levels, indicating an inverse relationship between pro-inflammatory cytokines and adiponectin. Adiponectin levels were related to glucose tolerance.

Doxazosin versus bendrofluazide: a comparison of the metabolic effects in British South Asians with hypertension

BACKGROUND

People from British South Asian communities have an increased risk of mortality from coronary heart disease (CHD). Doxazosin, a selective alpha(1)-adrenergic blocker, in addition to lowering blood pressure, has been shown to have positive effects on glucose metabolism and lipid profiles in patients with hypertension.

AIM

We studied doxazosin (1-8 mg) and bendrofluazide (2.5 mg) in patients of British South Asian origin with existing mild to moderate hypertension (doxazosin n = 78; bendrofluazide n = 82), to compare their effects on glucose and lipid metabolism in this group.

DESIGN OF STUDY

A 34-week randomised, double-blind, parallel-group, multicentre study.

SETTING

Primary care in the UK.

METHOD

All doxazosin patients started with an initial dose of 1 mg once daily, titrated to a maximum 8 mg once daily if diastolic blood pressure was >90 mmHg or was not <5 mmHg of the baseline value. The primary efficacy variables were mean glucose and total cholesterol concentrations at week 21.

RESULT

Doxazosin reduced glucose, total cholesterol, low-density lipoprotein-cholesterol and triglycerides and increased high-density lipoprotein-cholesterol. There were significant differences between doxazosin and bendrofluazide for glucose concentrations at week 21 (P = 0.029) and week 34 (P = 0.015), total cholesterol at week 21 (P = 0.048) and triglycerides at week 21 (P = 0.047) and week 34 (P = 0.009). There was no significant difference in blood pressure lowering between the two treatments.

CONCLUSION

Doxazosin exhibits beneficial effects on glucose concentrations and lipid profile, in particular in lowering triglyceride concentrations in British South Asians. Whether these desirable characteristics translate to improved overall cardiovascular risk requires formal evaluation.

Specific health issues in ethnic minority groups

The study of disease patterns in ethnic minority groups offers insights into the causation of disease. Ethnic minorities have wide variations in health conditions and behaviors, and stereotyping can lead to spurious assumptions in caring for patients. This article presents basic information relating to major illnesses such as cardiovascular disease, diabetes, and cancer and common health disorders observed among ethnic groups primarily in the United Kingdom and United States.

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.