The epidemiology and natural history of NIDDM--lessons from the South Pacific

The Impact of Westernization on the Insulin/IGF-I Signaling Pathway and the Metabolic Syndrome: It Is Time for Change

The metabolic syndrome is a cluster of overlapping conditions resulting in an increased incidence of type 2 diabetes, cardiovascular disease, and cancer. In the last few decades, prevalence of the metabolic syndrome in the Western world has reached epidemic proportions and this is likely due to alterations in diet and the environment as well as decreased physical activity. This review discusses how the Western diet and lifestyle (Westernization) has played an important etiological role in the pathogenesis of the metabolic syndrome and its consequences by exerting negative effects on activity of the insulin-insulin-like growth factor-I (insulin-IGF-I) system. It is further proposed that interventions that normalize/reduce activity of the insulin-IGF-I system may play a key role in the prevention and treatment of the metabolic syndrome. For successful prevention, limitation, and treatment of the metabolic syndrome, the focus should be primarily on changing our diets and lifestyle in accordance with our genetic make-up, formed in adaptation to Paleolithic diets and lifestyles during a period of several million years of human evolution. Translating this insight into clinical practice, however, requires not only individual changes in our food and lifestyle, starting in pediatric populations at a very young age, but also requires fundamental changes in our current health systems and food industry. Change is needed: primary prevention of the metabolic syndrome should be made a political priority. New strategies and policies should be developed to stimulate and implement behaviors encouraging the sustainable use of healthy diets and lifestyles to prevent the metabolic syndrome before it develops.

A multi-level, multi-component obesity intervention (Obesity Prevention and Evaluation of InterVention Effectiveness in NaTive North Americans) decreases soda intake in Native American adults

OBJECTIVE

To evaluate the impact of a multi-level, multi-component (MLMC) adult obesity intervention on beverage intake in Native American adults living in five geographically and culturally diverse tribal communities.

DESIGN

A 14-month, community-randomised, MLMC design was utilised, with three communities randomised to Intervention and two communities randomised to Comparison. FFQ were administered pre- and post-interventions, and difference-in-differences (DiD) analysis was used to assess intervention impact on beverage intake.

SETTING

The intervention took place within food stores, worksites, schools and selected media outlets located in the five communities. Key activities included working with store owners to stock healthy beverages, display and dispersal of educational materials, support of policies that discouraged unhealthy beverage consumption at worksites and schools and taste tests.

PARTICIPANTS

Data were collected from 422 respondents between the ages of 18 and 75 living in the five communities pre-intervention; of those, 299 completed post-intervention surveys. Only respondents completing both pre- and post-intervention surveys were included in the current analysis.

RESULTS

The DiD for daily servings of regular, sugar-sweetened soda from pre- to post-intervention was significant, indicating a significant decrease in Intervention communities (P < 0·05). No other changes to beverage intake were observed.

CONCLUSIONS

Large, MLMC obesity interventions can successfully reduce the intake of regular, sugar-sweetened soda in Native American adults. This is important within modern food environments where sugar-sweetened beverages are a primary source of added sugars in Native American diets.

Anti-hyperglycaemic activity of H. rosa-sinensis leaves is partly mediated by inhibition of carbohydrate digestion and absorption, and enhancement of insulin secretion

ETHNOPHARMACOLOGICAL RELEVANCE

Hibiscus rosa-sinensis (HRS) is a tropical flowery plant, widely distributed in Asian region and an important traditional medicine used in many diseases including cough, diarrhoea and diabetes.

AIM OF THIS STUDY

Hibiscus rosa-sinensis (HRS) leaves have been reported to possess anti-hyperglycaemic activity, but little is known concerning the underlying mechanism. This study investigated effects of ethanol extract of HRS on insulin release and glucose homeostasis in a type 2 diabetic rat model.

MATERIALS & METHODS

Effects of ethanol extract of grinded H. rosa-sinensis (HRS) leaves on insulin release, membrane potential and intracellular calcium were determined using rat clonal β-cells (BRIN-BD11 cells) and isolated mouse pancreatic islets. Effects on DPP-IV enzyme activity were investigated in vitro. Acute effects of HRS on glucose tolerance, gut perfusion in situ, sucrose content, intestinal disaccharidase activity and gut motility were measured. Streptozotocin induced type 2 diabetic rats treated for 28 days with ethanol extract of HRS leaf (250 and 500 mg/kg) were used to assess glucose homeostasis.

RESULTS

HRS, significantly increased insulin release from clonal rat BRIN-BD11 cells and this action was confirmed using isolated mouse pancreas islets with stimulatory effects equivalent to GLP-1. HRS induced membrane depolarization and increased intracellular Ca²⁺ in BRIN BD11 cells and significantly inhibited DPP-IV enzyme activity in vitro. HRS administration in vivo improved glucose tolerance in type 2 diabetic rats, inhibited both glucose absorption during gut perfusion and postprandial hyperglycaemia and it reversibly increased unabsorbed sucrose passage through the gut following sucrose ingestion. HRS decreased intestinal disaccharidase activity and increased gastrointestinal motility in non-diabetic rats. In a chronic 28-day study with type 2 diabetic rats, HRS, at 250 or 500 mg/kg, significantly decreased serum glucose, cholesterol, triglycerides and increased circulating insulin, HDL cholesterol and hepatic glycogen without increasing body weight.

CONCLUSION

These data suggest the antihyperglycaemic activity of HRS is mediated by inhibiting carbohydrate digestion and absorption, while significantly enhancing insulin secretion in a dose dependent manner. This suggests that HRS has potential as a novel antidiabetic therapy or a dietary supplement for the treatment of type 2 diabetes.

Nigella sativa stimulates insulin secretion from isolated rat islets and inhibits the digestion and absorption of (CH2O)n in the gut

Nigella sativa seeds are traditionally reputed as possessing anti-diabetic properties. As a result, we aim to explore the mechanism of its anti-hyperglycemic activity. The present study uses various experimental designs including gastrointestinal (GI) motility, intestinal disaccharidase activity and inhibition of carbohydrate digestion and absorption in the gut. The animals used as type 2 diabetic models were induced with streptozotocin to make them as such. Oral glucose tolerance test was performed to confirm that the animals were indeed diabetic. The extract reduced postprandial glucose, suggesting it interfered with glucose absorption in the gut. It also improved glucose (2.5g/kg, b/w) tolerance in rats. Furthermore, treatment with N. sativa produced a significant improvement in GI motility, while reduced disaccharidase enzyme activity in fasted rats. The extract produced a similar effect within an acute oral sucrose (2.5g/kg, b/w) load assay. Following sucrose administration, a substantial amount of unabsorbed sucrose was found in six different parts of the GI tract. This indicates that N. sativa has the potentiality to liberate GI content and reduce or delay glucose absorption. A potential hypoglycemic activity of the extract found in insulin release assay, where the extract significantly improved insulin secretion from isolated rat islets. These concluded present findings give rise to the implication that N. sativa seeds are generating postprandial anti-hyperglycemic activity within type 2 diabetic animal models via reducing or delaying carbohydrate digestion and absorption in the gut as well as improving insulin secretion in response to the plasma glucose.

Effect of diet composition on insulin sensitivity in humans

Diet composition has a marked impact on the risk of developing type 2 diabetes and cardiovascular disease. Prospective studies show that dietary patterns with elevated amount of animal products and low quantity of vegetable food items raise the risk of these diseases. In healthy subjects, animal protein intake intensifies insulin resistance whereas plant-based foods enhance insulin sensitivity. Similar effects have been documented in patients with diabetes. Accordingly, pre-pregnancy intake of meat (processed and unprocessed) has been strongly associated with a higher risk of gestational diabetes whereas greater pre-pregnancy vegetable protein consumption is associated with a lower risk of gestational diabetes. Population groups that modify their traditional dietary habit increasing the amount of animal products while reducing plant-based foods experience a remarkable rise in the frequency of type 2 diabetes. The association of animal protein intake with insulin resistance is independent of body mass index. In obese individuals that consume high animal protein diets, insulin sensitivity does not improve following weight loss. Diets aimed to lose weight that encourage restriction of carbohydrates and elevated consumption of animal protein intensify insulin resistance increasing the risk of developing type 2 diabetes and cardiovascular disease. The effect of dietary components on insulin sensitivity may contribute to explain the striking impact of eating habits on the risk of type 2 diabetes and cardiovascular disease. Insulin resistance predisposes to type 2 diabetes in healthy subjects and deteriorates metabolic control in patients with diabetes. In nondiabetic and diabetic individuals, insulin resistance is a major cardiovascular risk factor.

Samoan migrants' perspectives on diabetes: A qualitative study

ISSUE ADDRESSED

The Samoan community in Australia has one of the highest rates of diabetes in Australia. We explored the experiences and perceptions of Samoan patients living with diabetes and their family members.

METHODS

Semi-structured interviews were conducted with adults from a Samoan background living in Australia who had diabetes and their family members. Participants were recruited from a single general practice with a high proportion of Pacific Islander patients, through self-response to waiting room flyers. Inductive thematic analysis was conducted using a constructivist-grounded theory approach. This qualitative project was part of the developmental phase of a larger project aiming to promote healthy lifestyles and decrease diabetes in the Samoan community in Sydney, Australia.

RESULTS

Twenty participants, aged 36-67 years, were interviewed. The majority was men (n = 13) and all were migrants to Australia. Participants reported a range of barriers to early detection and self-management of diabetes, including dietary practices common within their culture and the role of church and religion. They identified that pride in their heritage and role within families could be a barrier to care but also provided an opportunity for health promotion.

CONCLUSIONS

The cultural factors which influence the risk and management of diabetes in the Samoan community in Australia can be the barriers to health change but also provide opportunities for culturally targeted diabetes education and health promotion. SO WHAT?: These findings will inform the development of approaches for the prevention and management of diabetes within the Samoan-Australian community. These include health-promotion initiatives which take into account the role of cultural dietary practices, diabetes stigma, cultural pride and working with churches.

Walking backwards into the future: the need for a holistic evolutionary approach in Pacific health research

CONTEXT

The Pacific region has had a complex human history. It has been subject to multiple major human dispersal and colonisation events, including some of the earliest Out-of-Africa migrations, the so-called Austronesian expansion of people out of Island Southeast Asia, and the more recent arrival of Europeans. Despite models of island isolation, evidence suggests significant levels of interconnectedness that vary in direction and frequency over time. The Pacific Ocean covers a vast area and its islands provide an array of different physical environments with variable pathogen loads and subsistence opportunities. These diverse environments likely caused Pacific peoples to adapt (both genetically and culturally) in unique ways. Differences in genetic background, in combination with adaptation, likely affect their susceptibility to non-communicable diseases.

OBJECTIVES

Here we provide an overview of some of the key issues in the natural and human history of the Pacific region which are likely to impact human health. We argue that understanding the evolutionary and cultural history of Pacific peoples is essential for the generation of testable hypotheses surrounding potential causes of elevated disease susceptibility among Pacific peoples.

Association of serum 25-hydroxyvitamin D and diabetes-related factors in Korean adults without diabetes: The Fifth Korea National Health and Nutrition Examination Survey 2010-2012

AIMS

Vitamin D is associated with diabetes mellitus (DM) occurrence by affecting insulin secretion and resistance. However, variations exist due to differences in vitamin D sensitivity among individuals. We investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] status and various indices of DM in a Korean population without DM.

METHODS

Large-scaled population-based analysis was conducted from the Korea National Health and Nutrition Examination Survey data (2010-2012) were analyzed. Adult survey participants >20years without diabetes (n=15,169) were included.

RESULTS

The mean 25(OH)D levels were lower in females, subjects aged 20-39 years, and subjects with body mass index <21.1kg/m² and less physical activity (p<0.001). Further, the mean 25(OH)D levels tended to be lower in subjects with FBG >126mg/dL. After adjustment for potential confounders, 25(OH)D was not correlated with FBG (p=0.925) or HbA1c (p=0.336); however, fasting insulin (β=-0.072, p=0.011) and homeostasis model assessment of β-cell function (β=-0.007, p<0.001) showed significant negative correlations with 25(OH)D levels.

CONCLUSION

Although 25(OH)D status was not significantly associated with FBG or HbA1c, low 25(OH)D levels were associated with compensative insulin increase and ongoing increase in insulin resistance. Thus, vitamin D deficiency is assumed to influence DM occurrence.

Diabetes Mellitus Type 2 and Yoga: Electro Photonic Imaging Perspective

Background:

Yoga is the most popular form of alternative medicine for the management of diabetes mellitus type 2. The electro-photonic imaging (EPI) is another contribution from alternative medicine in health monitoring.

Aim:

To evaluate diabetes from EPI perspective.

Objectives:

(1) Compare various EPI parameters in normal, prediabetic and diabetic patients. (2) Find difference in controlled and uncontrolled diabetes. (3) Study the effect of 7 days diabetes-specific yoga program.

Materials and Methods:

For the first objective, there were 102 patients (normal 29, prediabetic 13, diabetic 60). In the second study, there were 60 patients (controlled diabetes 27, uncontrolled diabetes 33). The third study comprised 37 patients. EPI parameters were related to general health as well to specific organs.

Results:

In the first study, significant difference was observed between (1) Diabetics and normal: average intensity 5.978, form coefficient 3.590, immune organs 0.281 all P < 0.001; (2) Diabetics and prediabetics: average intensity 6.676, form coefficient 4.158, immune organs 5.890 P < 0.032; (3) Normal and prediabetes: immune organs (−6.171 P = 000). In the second study, remarkable difference was in the immune organs (0.201, P = 0.031). In the pre- and post-study, the mean difference was: area 630.37, form coefficient 1.78, entropy 0.03, liver 0.24, pancreas 0.17, coronary vessels 0.11, and left kidney 29, with all P < 0.02.

Conclusion:

There is a significant difference in EPI parameters between normal, prediabetics and diabetics, the prominent being average intensity, form coefficient, and immune organs. Between controlled and uncontrolled diabetes, immune organs show significant change. Intervention of yoga results in change in most parameters.

A thrifty variant in CREBRF strongly influences body mass index in Samoans

Samoans are a unique founder population with a high prevalence of obesity, making them well suited for identifying new genetic contributors to obesity. We conducted a genome-wide association study (GWAS) in 3,072 Samoans, discovered a variant, rs12513649, strongly associated with body mass index (BMI) (P = 5.3 × 10(-14)), and replicated the association in 2,102 additional Samoans (P = 1.2 × 10(-9)). Targeted sequencing identified a strongly associated missense variant, rs373863828 (p.Arg457Gln), in CREBRF (meta P = 1.4 × 10(-20)). Although this variant is extremely rare in other populations, it is common in Samoans (frequency of 0.259), with an effect size much larger than that of any other known common BMI risk variant (1.36-1.45 kg/m(2) per copy of the risk-associated allele). In comparison to wild-type CREBRF, the Arg457Gln variant when overexpressed selectively decreased energy use and increased fat storage in an adipocyte cell model. These data, in combination with evidence of positive selection of the allele encoding p.Arg457Gln, support a 'thrifty' variant hypothesis as a factor in human obesity.

Epidemiology of Diabetes-Status of a Pandemic and Issues Around Metabolic Surgery

The number of people with diabetes worldwide has more than doubled during the past 20 years. One of the most worrying features of this rapid increase is the emergence of type 2 diabetes in children, adolescents, and young adults. Although the role of traditional risk factors for type 2 diabetes, such as genetic, lifestyle, and behavioral risk factors, has been given attention, recent research has focused on identifying the contributions of epigenetic mechanisms and the effect of the intrauterine environment. Epidemiological data predict an inexorable and unsustainable increase in global health expenditure attributable to diabetes, so disease prevention should be given high priority. An integrated approach is needed to prevent type 2 diabetes and must recognize its heterogeneity. Future research needs to be directed at improved understanding of the potential role of determinants, such as the maternal environment and other early life factors, as well as changing trends in global demography, to help shape disease prevention programs. Equally important is a better understanding of the role of metabolic surgery in helping to address the management both of persons with type 2 diabetes and of those persons in the community who are at higher risk for type 2 diabetes, particularly in emerging nations where the diabetes epidemic is in full flight.

Investigation on hypoglycemic effects of ethanol extract of Alpinia nigra (Gaertn.) in animal model

Background:

Our study aims at exploring the hypoglycemic effect, efficacy, and possible mode of action of ethanol extract of Alpinia nigra (EEAN) as an antidiabetic agent in an animal model.

Methods:

Oral glucose tolerance test (OGTT) was used to identify primary hypoglycemic effect in mice. Three tests (glucose absorption, sucrose absorption, and disaccharidase activity) were carried out by gut perfusion and six segments studies to assess carbohydrate absorption and glucose utilization.

Results:

In OGTT, at 400 mg/kg and 800 mg/kg dose of EEAN extract significantly improved oral glucose tolerance among normal mice at 60 min and 90 min with compared to control. Both doses of extract significantly (P < 0.01) reduced blood glucose level and showed the hypoglycemic effect by retarding 11.43% and 20.82% of blood glucose level after 2 h of administration in glucose-induced mice, respectively. In situ perfused rat intestinal model demonstrated reduced glucose absorption at a 500 mg/kg dose. Inhibition of intestinal disaccharidase was also found by the extract. This was confirmed, yet again, via the six segment study. Throughout the length of the gastrointestinal tract, sucrose digestion was found to be inhibited which is also evident in the six segment study.

Conclusions:

This study suggests that the EEAN has hypoglycemic effects in a dose-dependent manner by inhibiting intestinal glucose absorption, and these may be effective in the treatment of diabetes. Further study is required to explicate the effect this extract or the active compounds have on the individual glucose transporters and the precise mechanism.

Diabetes in Asia and the Pacific: Implications for the Global Epidemic

The last three decades have witnessed an epidemic rise in the number of people with diabetes, especially type 2 diabetes, and particularly in developing countries, where more than 80% of the people with diabetes live. The rise of type 2 diabetes in South Asia is estimated to be more than 150% between 2000 and 2035. Although aging, urbanization, and associated lifestyle changes are the major determinants for the rapid increase, an adverse intrauterine environment and the resulting epigenetic changes could also contribute in many developing countries. The International Diabetes Federation estimated that there were 382 million people with diabetes in 2013, a number surpassing its earlier predictions. More than 60% of the people with diabetes live in Asia, with almost one-half in China and India combined. The Western Pacific, the world's most populous region, has more than 138.2 million people with diabetes, and the number may rise to 201.8 million by 2035. The scenario poses huge social and economic problems to most nations in the region and could impede national and, indeed, global development. More action is required to understand the drivers of the epidemic to provide a rationale for prevention strategies to address the rising global public health "tsunami." Unless drastic steps are taken through national prevention programs to curb the escalating trends in all of the countries, the social, economic, and health care challenges are likely to be insurmountable.

Pacific Populations, Metabolic Disease and 'Just-So Stories': A Critique of the 'Thrifty Genotype' Hypothesis in Oceania

Pacific populations have long been observed to suffer a high burden of metabolic disease, including obesity, type 2 diabetes and gout. The 'Thrifty Genotype' hypothesis has frequently been used to explain this high prevalence of disease. Here, the 'Thrifty Genotype' hypothesis and the evolutionary background of Pacific populations are examined. We question its relevance not only in the Pacific region but more generally. Not only has the hypothesis not been explicitly tested, but most archaeological and anthropological data from the Pacific fundamentally do not support its application.

Diabetes: a 21st century challenge

The number of people with diabetes worldwide has more than doubled during the past 20 years. One of the most worrying features of this rapid increase is the emergence of type 2 diabetes in children, adolescents, and young adults. Although the role of traditional risk factors for type 2 diabetes (eg, genetic, lifestyle, and behavioural risk factors) has been given attention, recent research has focused on identifying the contributions of epigenetic mechanisms and the effect of the intrauterine environment. Epidemiological data predict an inexorable and unsustainable increase in global health expenditure attributable to diabetes, so disease prevention should be given high priority. An integrated approach is needed to prevent type 2 diabetes, taking into account its many origins and heterogeneity. Thus, research needs to be directed at improved understanding of the potential role of determinants such as the maternal environment and other early life factors, as well as changing trends in global demography, to help shape disease prevention programmes.

Phytochemicals and their impact on adipose tissue inflammation and diabetes

Type 2 diabetes mellitus is an inflammatory disease and the mechanisms that underlie this disease, although still incompletely understood, take place in the adipose tissue of obese subjects. Concurrently, the prevalence of obesity caused by Western diet's excessive energy intake and the lack of exercise escalates, and is believed to be causative for the chronic inflammatory state in adipose tissue. Overnutrition itself as an overload of energy may induce the adipocytes to secrete chemokines activating and attracting immune cells to adipose tissue. But also inflammation-mediating food ingredients like saturated fatty acids are believed to directly initiate the inflammatory cascade. In addition, hypoxia in adipose tissue as a direct consequence of obesity, and its effect on gene expression in adipocytes and surrounding cells in fat tissue of obese subjects appears to play a central role in this inflammatory response too. In contrast, revisiting diet all over the world, there are also some natural food products and beverages which are associated with curative effects on human health. Several natural compounds known as spices such as curcumin, capsaicin, and gingerol, or secondary plant metabolites catechin, resveratrol, genistein, and quercetin have been reported to provide an improved health status to their consumers, especially with regard to diabetes, and therefore have been investigated for their anti-inflammatory effect. In this review, we will give an overview about these phytochemicals and their role to interfere with inflammatory cascades in adipose tissue and their potential for fighting against inflammatory diseases like diabetes as investigated in vivo.

Exercise intervention in New Zealand Polynesian peoples with type 2 diabetes: Cultural considerations and clinical trial recommendations

The Maori and Pacific Islands peoples of New Zealand suffer a greater burden of type 2 diabetes mellitus (T2DM) and associated comorbidities than their European counterparts. Empirical evidence supports the clinical application of aerobic and resistance training for effective diabetes management and potential remission, but few studies have investigated the effectiveness of these interventions in specific ethnic cohorts. We recently conducted the first trial to investigate the effect of prescribed exercise training in Polynesian people with T2DM. This article presents the cultural considerations undertaken to successfully implement the study. The research procedures were accepted and approved by cultural liaisons and potential participants. The approved methodology involved a trial evaluating and comparing the effects of two, 16-week exercise regimens (i.e. aerobic training and resistance training) on glycosylated haemoglobin (HbA1c), related diabetes markers (i.e. insulin resistance, blood lipids, relevant cytokines and anthropometric and hemodynamic indices) and health-related quality of life. Future exercise-related research or implementation strategies in this cohort should focus on cultural awareness and techniques to enhance participation and compliance. Our approach to cultural consultation could be considered by researchers undertaking trials in this and other ethnic populations suffering an extreme burden of T2DM, including indigenous Australians and Americans.

Complete mitochondrial genome sequencing reveals novel haplotypes in a Polynesian population

The high risk of metabolic disease traits in Polynesians may be partly explained by elevated prevalence of genetic variants involved in energy metabolism. The genetics of Polynesian populations has been shaped by island hoping migration events which have possibly favoured thrifty genes. The aim of this study was to sequence the mitochondrial genome in a group of Maoris in an effort to characterise genome variation in this Polynesian population for use in future disease association studies. We sequenced the complete mitochondrial genomes of 20 non-admixed Maori subjects using Affymetrix technology. DNA diversity analyses showed the Maori group exhibited reduced mitochondrial genome diversity compared to other worldwide populations, which is consistent with historical bottleneck and founder effects. Global phylogenetic analysis positioned these Maori subjects specifically within mitochondrial haplogroup - B4a1a1. Interestingly, we identified several novel variants that collectively form new and unique Maori motifs – B4a1a1c, B4a1a1a3 and B4a1a1a5. Compared to ancestral populations we observed an increased frequency of non-synonymous coding variants of several mitochondrial genes in the Maori group, which may be a result of positive selection and/or genetic drift effects. In conclusion, this study reports the first complete mitochondrial genome sequence data for a Maori population. Overall, these new data reveal novel mitochondrial genome signatures in this Polynesian population and enhance the phylogenetic picture of maternal ancestry in Oceania. The increased frequency of several mitochondrial coding variants makes them good candidates for future studies aimed at assessment of metabolic disease risk in Polynesian populations.

Diet, physical activity, and obesity in school-aged indigenous youths in northern australia

Purpose. To examine the relationship between diet, physical activity, and obesity in Indigenous youths from northern Australia. Methods. In a cross-sectional study, physical activity and dietary intake ("short nutrition questionnaire") were assessed among all youths during a face-to-face interview. For 92 high school youths, additional dietary information was assessed using a food-frequency questionnaire. Height and weight were measured and BMI was calculated. Multiple logistic regression was used to assess associations. Results. Of the 277 youths included, 52% had ≤2 servings of fruit and 84% had <4 servings of vegetables per day; 65% ate fish and 27%, take-away food ("fast food") at least twice a week. One in four ate local traditional sea food including turtle and dugong (a local sea mammal) at least twice a week. Overweight/obese youths engaged in fewer days of physical activity in the previous week than normal weight youths (OR = 2.52, 95% CI 1.43-4.40), though patterns of physical activity differed by sex and age (P < 0.001). Overweight/obese youths were 1.89 times (95% CI 1.07-3.35) more likely to eat dugong regularly than nonobese youths. Analysis of food-frequency data showed no difference by weight assessment among high-school students. Conclusions. Low fruit and vegetable intake were identified in these Indigenous youths. Regular consumption of fried dugong and low frequency of physical activity were associated with overweight/obesity reinforcing the need to devise culturally appropriate health promotion strategies and interventions for Indigenous youths aimed at improving their diet and increasing their physical activity.

Antidiabetic effect of a black mangrove species Aegiceras corniculatum in alloxan-induced diabetic rats

Earlier ethnopharmacological records divulged the traditional usages of mangrove Aegiceras corniculatum (Linn.) Blanco distributed in coastal and estuarine areas of Southeast India. Excluding scientific knowledge of A. corniculatum against diabetes an upgrowing endocrinal disorder, our present study evaluated the effect on alloxan-induced diabetic rats. Diabetes was induced in adult rats of the Wistar strain by intraperitoneal injection of alloxan monohydrate. The experimental rats were administered with leaf suspension of A. corniculatum post orally using an intragastric tube. On completion of the 60-day treatment, a range of biochemical parameters were tested including liver hexokinase, glucose-6phosphatase and fructose 1, 6 bisphosphatase in the liver of control and allaxon-diabetic rats. As a result, A. corniculatum leaf suspension showed moderate reduction in blood glucose (from 382 ± 34 to 105 ± 35), glycosylated hemoglobin, a decrease in the activities of glucose-6 phosphatase and fructose 1, 6-bisphosphatase, and an increase activity of liver hexokinase achieved through the oral administration of extract on 100 mg/kg. The present findings support promising results in terms of antidiabetic activities establishing its candidacy for further purification of individual compound in order to understand their mechanism of action.

Prevalence and risk factors of diabetes and impaired fasting glucose in Nauru

BACKGROUND

No comprehensive assessment of diabetes prevalence in Nauru has been conducted since an extreme prevalence was documented more than two decades ago. This study aims to determine the prevalence and risk factors of diabetes and impaired fasting glucose.

METHODS

A nationwide survey in 2004 of people aged 15- 64 years (n = 1592). Fasting plasma glucose levels were used to defined diabetes (≥ 7.0 mmol/l or 126 mg/dl) and prediabetes (6.1-6.9 mmol/l or 110-125 mg/dl).

RESULTS

The sex-standardized prevalence of diabetes was 13.0% (95% CI: 10.6, 15.4) in men, 14.4% (11.9, 16.9) in women, and 13.7% (12.0, 15.4) combined. The sex-standardized prevalence of prediabetes was 6.4% (4.6, 8.2) for men, 5.5% (3.9, 7.2) for women, and 6.0% (4.8, 7.3) combined. The prevalence of diabetes for individuals 15-24, 25-34, 35-44, 45-54 and 55-64 years was 4.5%, 7.6%, 24.1%, 32.9%, and 42.7%, respectively. The prevalence of prediabetes for the same age categories was 4.2%, 8.8%, 5.9%, 6.6%, 7.1%, respectively. Multivariable, multinomial logit modeling found risk factors for prediabetes were high cholesterol levels (OR: 2.02, 95% CI: 1.66, 2.47) and elevated waist circumference (OR: 1.04, 95% CI: 1.00, 1.08), and for diabetes were age in years (OR: 1.06; 95% CI: 1.04, 1.07), cholesterol levels (OR: 1.84, 95% CI: 1.58, 2.14) and waist circumference (OR: 1.04, 95% CI: 1.02, 1.07).

CONCLUSIONS

Diabetes remains a major public health problem in Nauru, affecting one out of every ten people. While the prevalence of diabetes has declined, its burden has persisted among the old but also extended towards the younger age groups.

Worldwide spatial genetic structure of angiotensin-converting enzyme gene: a new evolutionary ecological evidence for the thrifty genotype hypothesis

As JV Neel put forward the 'thrifty genotype' hypothesis, many researches tend to support this hypothesis involved in the regulation of energy balance. However, the phrase could equally well encapsulate broader traits and the forms of thrift should be multiple. In particular, genes involved in the regulation of water and sodium balance may also be excellent candidates as thrifty genes. In the present study, we selected the ancestral D allele of angiotensin-converting enzyme (ACE) gene, a key gene involved in water and sodium balance regulation, as a candidate to confirm the 'thrifty genotype' hypothesis in the framework of evolutionary ecology. On the basis of our compiled worldwide spatial genetics database of I/D frequency of ACE gene and spatial climate database, using techniques of spatial statistics, we found (1) an obvious decreasing geographic genetic cline following the route of out-of-Africa expansion from East Africa, (2) a positive association between D allele and synthetic temperature factor, (3) and a negative relationship between D allele and synthetic humidity factor that covered most regions of the world, and obvious spatial dependence between D allele and these two climate factors followed the route of out-of-Africa expansion from Africa. This suggested that D allele of ACE gene is not only plastic in response to its environmental circumstance but also presents a striking geographic distribution showing the evidence of 'signatures of selection' by climate factors. Thus, it can be identified as a thrifty allele and could provide a new evolutionary ecological evidence for the 'thrifty genotype' hypothesis.

Testing the thrifty gene hypothesis: the Gly482Ser variant in PPARGC1A is associated with BMI in Tongans

Background

The thrifty gene hypothesis posits that, in populations that experienced periods of feast and famine, natural selection favoured individuals carrying thrifty alleles that promote the storage of fat and energy. Polynesians likely experienced long periods of cold stress and starvation during their settlement of the Pacific and today have high rates of obesity and type 2 diabetes (T2DM), possibly due to past positive selection for thrifty alleles. Alternatively, T2DM risk alleles may simply have drifted to high frequency in Polynesians. To identify thrifty alleles in Polynesians, we previously examined evidence of positive selection on T2DM-associated SNPs and identified a T2DM risk allele at unusually high frequency in Polynesians. We suggested that the risk allele of the Gly482Ser variant in the PPARGC1A gene was driven to high frequency in Polynesians by positive selection and therefore possibly represented a thrifty allele in the Pacific.

Methods

Here we examine whether PPARGC1A is a thrifty gene in Pacific populations by testing for an association between Gly482Ser genotypes and BMI in two Pacific populations (Maori and Tongans) and by evaluating the frequency of the risk allele of the Gly482Ser variant in a sample of worldwide populations.

Results

We find that the Gly482Ser variant is associated with BMI in Tongans but not in Maori. In a sample of 58 populations worldwide, we also show that the 482Ser risk allele reaches its highest frequency in the Pacific.

Conclusion

The association between Gly482Ser genotypes and BMI in Tongans together with the worldwide frequency distribution of the Gly482Ser risk allele suggests that PPARGC1A remains a candidate thrifty gene in Pacific populations.

Pharmacogenetics of Anti-Diabetes Drugs

A variety of treatment modalities exist for individuals with type 2 diabetes mellitus (T2D). In addition to dietary and physical activity interventions, T2D is also treated pharmacologically with nine major classes of approved drugs. These medications include insulin and its analogues, sulfonylureas, biguanides, thiazolidinediones (TZDs), meglitinides, α-glucosidase inhibitors, amylin analogues, incretin hormone mimetics, and dipeptidyl peptidase 4 (DPP4) inhibitors. Pharmacological treatment strategies for T2D are typically based on efficacy, yet favorable responses to such therapeutics are oftentimes variable and difficult to predict. Characterization of drug response is expected to substantially enhance our ability to provide patients with the most effective treatment strategy given their individual backgrounds, yet pharmacogenetic study of diabetes medications is still in its infancy. To date, major pharmacogenetic studies have focused on response to sulfonylureas, biguanides, and TZDs. Here, we provide a comprehensive review of pharmacogenetics investigations of these specific anti-diabetes medications. We focus not only on the results of these studies, but also on how experimental design, study sample issues, and definition of 'response' can significantly impact our interpretation of findings. Understanding the pharmacogenetics of anti-diabetes medications will provide critical baseline information for the development and implementation of genetic screening into therapeutic decision making, and lay the foundation for "individualized medicine" for patients with T2D.

In vivo Studies on Antidiabetic Plants Used in South African Herbal Medicine

Diabetes is one of the most common metabolic disorders worldwide. It is a major health problem with its frequency increasing every day in most countries. The disease is generally believed to be incurable; and the few orthodox drugs available to manage the disease are not readily affordable to the poor. Based on the historical success of natural products as antidiabetic agents and the ever increasing need for new antidiabetics, a number of South African medicinal plants have been evaluated for their antidiabetic properties. In this article, we review the major studies conducted based on ethnobotanical surveys carried out between 2005 and 2008 in South Africa on plants that are traditionally used for the treatment of diabetes. Overall, the results of the studies conducted confirmed the potential of South African medicinal plants in antidiabetic drug discovery and identified a number of promising taxa for further in vivo investigation as plant-based antidiabetic agents.

Usefulness of vegetarian and vegan diets for treating type 2 diabetes

Significant benefits for diabetes prevention and management have been observed with vegetarian and especially vegan diets. This article reviews observational studies and intervention trials on such diets, and discusses their efficacy, nutritional adequacy, acceptability, and sustainability. Research to date has demonstrated that a low-fat, plant-based nutritional approach improves control of weight, glycemia, and cardiovascular risk. These studies have also shown that carefully planned vegan diets can be more nutritious than diets based on more conventional diet guidelines, with an acceptability that is comparable with that of other therapeutic regimens. Current intervention guidelines from professional organizations offer support for this approach. Vegetarian and vegan diets present potential advantages in managing type 2 diabetes that merit the attention of individuals with diabetes and their caregivers.

Island health: hope and challenges for public health

The Asia-Pacific region is a region of small islands, perhaps 100 000 of them. The health, communication, and development problems of islands present difficult challenges for the delivery of health care. The discussions at the Okinawa Symposium centred on how health can be provided to all in the region, not only those in metropolitan areas, but also the poor in rural areas and those on living on far-flung island archipelagos. It is important to apply principles of "public health" and "primary health care" so that all island residents may have a reasonable expectation of health care. Schools of public health have a special responsibility to educate those who are responsible for the delivery and management of health care in these remote locations. The development of telehealth systems will be important to support health workers in remote locations and to deliver continuing education programs.

Investigation of the locus near MC4R with childhood obesity in Americans of European and African ancestry

Recently a modest, but consistently, replicated association was demonstrated between obesity and the single-nucleotide polymorphism (SNP), rs17782313, 3' of the MC4R locus as a consequence of a meta-analysis of genome-wide association (GWA) studies of the disease in white populations. We investigated the association in the context of the childhood form of the disease utilizing data from our ongoing GWA study in a cohort of 728 European-American (EA) obese children (BMI > or =95th percentile) and 3,960 EA controls (BMI <95th percentile), as well as 1,008 African-American (AA) obese children and 2,715 AA controls. rs571312, rs10871777, and rs476828 (perfect surrogates for rs17782313) yielded odds ratios in the EA cohort of 1.142 (P = 0.045), 1.137 (P = 0.054), and 1.145 (P = 0.042); however, there was no significant association with these SNPs in the AA cohort. When investigating all 30 SNPs present on the Illumina BeadChip at this locus, again there was no evidence for association in AA cases when correcting for the number of tests employed. As such, variants 3' to the MC4R locus present on the genotyping platform utilized confer a similar magnitude of risk of obesity in white children as to their adult white counterparts but this observation did not extend to AAs.

Host genetics and infectious disease

Recent work on the inheritance of susceptibility to malaria suggests that, over what may have been a relatively short evolutionary period, a remarkably diverse series of gene families have been modified in response to the selective drive of this single infection. The phenotype consequences are not confined to the red cell, but involve the immune system, cytokines and many other systems. It seems likely that the mechanisms of variation in genetic susceptibility to other infective agents will reflect at least a similar degree of complexity and, if the selective pressures have been present for longer periods of our evolutionary history, may be even more diverse. This may have important implications for work directed at trying to define susceptibility loci for current infectious and non-infectious diseases.

Association analysis of the FTO gene with obesity in children of Caucasian and African ancestry reveals a common tagging SNP

Recently an association was demonstrated between the single nucleotide polymorphism (SNP), rs9939609, within the FTO locus and obesity as a consequence of a genome wide association (GWA) study of type 2 diabetes in adults. We examined the effects of two perfect surrogates for this SNP plus 11 other SNPs at this locus with respect to our childhood obesity cohort, consisting of both Caucasians and African Americans (AA). Utilizing data from our ongoing GWA study in our cohort of 418 Caucasian obese children (BMI>or=95th percentile), 2,270 Caucasian controls (BMI<95th percentile), 578 AA obese children and 1,424 AA controls, we investigated the association of the previously reported variation at the FTO locus with the childhood form of this disease in both ethnicities. The minor allele frequencies (MAF) of rs8050136 and rs3751812 (perfect surrogates for rs9939609 i.e. both r(2) = 1) in the Caucasian cases were 0.448 and 0.443 respectively while they were 0.391 and 0.386 in Caucasian controls respectively, yielding for both an odds ratio (OR) of 1.27 (95% CI 1.08-1.47; P = 0.0022). Furthermore, the MAFs of rs8050136 and rs3751812 in the AA cases were 0.449 and 0.115 respectively while they were 0.436 and 0.090 in AA controls respectively, yielding an OR of 1.05 (95% CI 0.91-1.21; P = 0.49) and of 1.31 (95% CI 1.050-1.643; P = 0.017) respectively. Investigating all 13 SNPs present on the Illumina HumanHap550 BeadChip in this region of linkage disequilibrium, rs3751812 was the only SNP conferring significant risk in AA. We have therefore replicated and refined the association in an AA cohort and distilled a tag-SNP, rs3751812, which captures the ancestral origin of the actual mutation. As such, variants in the FTO gene confer a similar magnitude of risk of obesity to children as to their adult counterparts and appear to have a global impact.

An epidemiological overview of diabetes across the world

Once the Cinderella of chronic diseases, diabetes mellitus is now fast emerging as one of the biggest health catastrophes the world has ever witnessed. Almost 6% of the world's adult population now live with diabetes (Sicree et al, 2003; International Federation of Diabetes, 2006). It has been predicted that the total number of people with diabetes will rise to 366 million in less than 30 years if preventative action is not taken (Wild et al, 2004). Diabetes is no longer a concern of an individual country. It has huge global and societal implications, particularly in developing countries where the development of diabetes at an early age can lead to untoward human suffering, disability and socioeconomic cost. An internationally coordinated effort is required to improve human behaviour and lifestyle to halt the global diabetes epidemic and the development of such complications as retinopathy, nephropathy, neuropathy, cardiovascular diseases, peripheral vascular diseases and stroke. For such a formula to be successful, it is important for nurses to be proactive in their political role in ensuring that people with diabetes become expert in their condition. In so doing, healthcare systems and resources could be used more effectively to reduce real human and economic costs.

Recent development in pharmacogenomics: from candidate genes to genome-wide association studies

Genetic diversity, most notably through single nucleotide polymorphisms and copy-number variation, together with specific environmental exposures, contributes to both disease susceptibility and drug response variability. It has proved difficult to isolate disease genes that confer susceptibility to complex disorders, and as a consequence, even fewer genetic variants that influence clinical drug responsiveness have been uncovered. As such, the candidate gene approach has largely failed to deliver and, although the family-based linkage approach has certain theoretical advantages in dealing with common/complex disorders, progress has been slower than was hoped. More recently, genome-wide association studies have gained increasing popularity, as they enable scientists to robustly associate specific variants with the predisposition for complex disease, such as age-related macular degeneration, Type 2 diabetes, inflammatory bowel disease, obesity, autism and leukemia. This relatively new methodology has stirred new hope for the mapping of genes that regulate drug response related to these conditions. Collectively, these studies support the notion that modern high-throughput single nucleotide polymorphism genotyping technologies, when applied to large and comprehensively phenotyped patient cohorts, will readily reveal the most clinically relevant disease-modifying and drug response genes. This review addresses both recent advances in the genotyping field and highlights from genome-wide association studies, which have conclusively uncovered variants that underlie disease susceptibility and/or variability in drug response in common disorders.

The genetics of common diseases: the implications of population variability

The results of recent work on the inheritance of susceptibility to malaria suggest that, over what may have been a relatively short evolutionary period, a remarkably diverse series of gene families have been modified in response to the selective drive of this infectious disease. The phenotypic consequences are not confined to the erythrocyte, they also involve the immune system, cytokines and many other systems. It seems likely that the mechanisms of genetic susceptibility to current environmental agents will reflect at least a similar degree of complexity and, if the selective pressures have been present for longer periods of our evolutionary history, may be even more diverse. These issues are discussed in the light of current efforts to identify some of the major genes involved in variation in susceptibility to the common non-infectious diseases of the developed world.

Clinical characteristics of Korean type 2 diabetic patients in 2005

Korean type 2 diabetics differ from Western diabetics in showing non-obese but centrally obese anthropometry and relatively more insulin secretory defects than insulin resistance. We assessed insulin secretion based on fasting serum C-peptide level and insulin resistance using the short insulin tolerance test (Kitt; rate constant for plasma glucose disappearance) in 1601 type 2 diabetic Korean patients (831 men and 770 women). Insulin secretory defects were catergorized as severe (C-peptide<1.10 ng/ml), moderate (C-peptide 1.10-1.69 ng/ml), and mild to non-secretory defect (C-peptide> or=1.70 ng/ml). Groups with a Kitt value of less than 2.5%/min were considered insulin-resistant, while those with a Kitt value > or =2.5%/min were considered insulin-sensitive. Overall, 42.5% of patients had a BMI>or =25.0 kg/m(2), and 70.2% had a BMI> or =23.0 kg/m(2); 45.2% (41.7% of men and 58.3% of women) were abdominally obese (waist> or =90 cm in men and 80 cm in women); mean fasting serum C-peptide level was 1.93+/-0.90 ng/ml, and the mean Kitt value was 2.03+/-0.96%/min. Accordingly, 13, 33, and 54% of patients showed a severe, moderate, and mild to non-secretory defect, respectively; 70.6% were insulin-resistant; and 29.4% were insulin-sensitive. Obese type 2 diabetes is recently increasing in Korea, indicating a shift from insulin secretory defects to insulin resistance.

Familial aggregation and excess maternal transmission of type 2 diabetes in Tunisia

AIM

To evaluate the degree of familial aggregation of type 2 diabetes mellitus in Tunisia and to investigate transmission patterns of the disease and their relationships with patients' clinical profiles.

METHODS

Family history of diabetes and clinical data were collected for 132 unrelated type 2 diabetic Tunisian patients. Diabetes status was recorded for first degree relatives (parents, siblings) and second degree relatives (aunts and uncles from both maternal and paternal sides). Information about family history of diabetes was gathered for a total of 1767 individuals.

RESULTS

Familial aggregation of type 2 diabetes was prominent and more important among first degree relatives than among second degree relatives (p = 0.01). Among studied subjects, 70% reported at least one relative with diabetes and 34% had at least one parent with diabetes. Diabetes was more frequent among mothers than fathers of probands (p = 0.03). This maternal effect extends to second degree relatives as diabetes was more common among maternal than paternal aunts and uncles (p = 0.01). There is no significant difference in clinical and metabolic profiles between patients according to transmission patterns of the disease.

CONCLUSION

These results suggest familial aggregation and excess maternal transmission of type 2 diabetes in the Tunisian studied population.

Evolutionary origins of insulin resistance: a behavioral switch hypothesis

BACKGROUND

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

PRESENTATION OF THE HYPOTHESIS

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

TESTING THE HYPOTHESIS

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

IMPLICATIONS OF THE HYPOTHESIS

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

Identification of a candidate genetic variant for the high prevalence of type II diabetes in Polynesians

The prevalence of non-insulin-dependent diabetes mellitus (type II diabetes) in Polynesia is among the highest recorded worldwide and is substantially higher than in neighboring human populations. Such large differences in the frequency of a phenotype between populations may be explained by large allele frequency differences between populations in genes associated with the phenotype. To identify genes that may explain the high between-population variation in type II diabetes prevalence in the Pacific, we determined the frequency of 10 type II diabetes-associated alleles in 23 Polynesians, 23 highland New Guineans and 19 Han Chinese, calculated population-pairwise Fst values for each allele and compared these values to the distribution of Fst values from approximately 100,000 SNPs from the same populations. The susceptibility allele in the PPARGC1A gene is at a frequency of 0.717 in Polynesians, 0.368 in Chinese but is absent in the New Guineans. The striking frequency difference between Polynesians and New Guineans is highly unusual (Fst=0.703, P=0.007) and we therefore suggest that this allele may play a role in the large difference in type II diabetes prevalence between Polynesians and neighboring populations.

Rapidly increasing diabetes-related mortality with socio-environmental changes in South Korea during the last two decades

Diabetes mellitus is the result of complex interactions involving many genes and environmental factors, and rapid socio-environmental changes have been strongly associated with the development of diabetes. In this study, we examined the trends in diabetes mortality and associated socio-environmental changes that have occurred in South Korea over the last 20 years. Data from a national database and government reports for the years from 1983 to 2001 were analyzed. The data included mortality, socio-economic changes, physical activity and dietary pattern indicators. Deaths from diabetes per 100,000 people increased from 5.3 in 1983 to 18.4 in 2001. Along with increasing diabetes-related mortality, many socio-economic indices (gross domestic production, proportion of tertiary industry and urbanization rate), proxies for physical activity (numbers of cars and time spent watching television) and diet indices (animal protein intake and fat intake) showed remarkable changes. To counter increasing prevalence of diabetes and its related mortality in South Korea, multidirectional efforts including lifestyle modification should be mandatory features of future public health policy.

Melanesian and Asian Origins of Polynesians: mtDNA and Y Chromosome Gradients Across the Pacific

The human settlement of the Pacific Islands represents one of the most recent major migration events of mankind. Polynesians originated in Asia according to linguistic evidence or in Melanesia according to archaeological evidence. To shed light on the genetic origins of Polynesians, we investigated over 400 Polynesians from 8 island groups, in comparison with over 900 individuals from potential parental populations of Melanesia, Southeast and East Asia, and Australia, by means of Y chromosome (NRY) and mitochondrial DNA (mtDNA) markers. Overall, we classified 94.1% of Polynesian Y chromosomes and 99.8% of Polynesian mtDNAs as of either Melanesian (NRY-DNA: 65.8%, mtDNA: 6%) or Asian (NRY-DNA: 28.3%, mtDNA: 93.8%) origin, suggesting a dual genetic origin of Polynesians in agreement with the "Slow Boat" hypothesis. Our data suggest a pronounced admixture bias in Polynesians toward more Melanesian men than women, perhaps as a result of matrilocal residence in the ancestral Polynesian society. Although dating methods are consistent with somewhat similar entries of NRY/mtDNA haplogroups into Polynesia, haplotype sharing suggests an earlier appearance of Melanesian haplogroups than those from Asia. Surprisingly, we identified gradients in the frequency distribution of some NRY/mtDNA haplogroups across Polynesia and a gradual west-to-east decrease of overall NRY/mtDNA diversity, not only providing evidence for a west-to-east direction of Polynesian settlements but also suggesting that Pacific voyaging was regular rather than haphazard. We also demonstrate that Fiji played a pivotal role in the history of Polynesia: humans probably first migrated to Fiji, and subsequent settlement of Polynesia probably came from Fiji.

Effects of traditional and western environments on prevalence of type 2 diabetes in Pima Indians in Mexico and the U.S

OBJECTIVE

Type 2 diabetes and obesity have genetic and environmental determinants. We studied the effects of different environments on these diseases in Pima Indians in Mexico and the U.S.

RESEARCH DESIGN AND METHODS

Adult Pima-Indian and non-Pima populations in the Sierra Madre mountains of Mexico were examined using oral glucose tolerance tests and assessments for obesity, physical activity, and other risk factors. Results were compared with those from Pima Indians in Arizona. Both Pima populations were typed for DNA polymorphisms to establish their genetic similarity.

RESULTS

The age- and sex-adjusted prevalence of type 2 diabetes in the Mexican Pima Indians (6.9%) was less than one-fifth that in the U.S. Pima Indians (38%) and similar to that of non-Pima Mexicans (2.6%). The prevalence of obesity was similar in the Mexican Pima Indians (7% in men and 20% in women) and non-Pima Mexicans (9% in men and 27% in women) but was much lower than in the U.S. Pima Indians. Levels of physical activity were much higher in both Mexican groups than in the U.S. Pima Indians. The two Pima groups share considerable genetic similarity relative to other Native Americans.

CONCLUSIONS

The much lower prevalence of type 2 diabetes and obesity in the Pima Indians in Mexico than in the U.S. indicates that even in populations genetically prone to these conditions, their development is determined mostly by environmental circumstances, thereby suggesting that type 2 diabetes is largely preventable. This study provides compelling evidence that changes in lifestyle associated with Westernization play a major role in the global epidemic of type 2 diabetes.

Energy intake and physical activity in Pima Indians: comparison with energy expenditure measured by doubly-labeled water

To test the validity of survey techniques for measuring diet and activity patterns of Pima Indians, sequential 24-hour recalls, a food frequency questionnaire (FFQ), and an activity questionnaire were compared to free-living energy expenditure. Total energy expenditure (TEE) measured by doubly labeled water was 13.27 +/- 2.95 MJ/d for the 12 males (mean +/- SD: 35 +/- 14 yr; 97 +/- 35 kg; 32 +/- 9% body fat) and 11.67 +/- 1.85 MJ/d for the 9 females (31 +/- 13 yr; 106 +/- 32 kg; 49 +/- 6% body fat). Energy intake assessed by 24-hour recall was 13.59 +/- 7.81 MJ/d for men and 9.29 +/- 2.77 MJ/d for women, compared to 12.84 + 2.85 and 9.40 + 2.61 MJ/d for men and women, respectively, by FFQ. Both dietary methods indicated significant underreporting by women when compared to TEE. Energy intake assessed by FFQ was significantly correlated with TEE (r=0.48, p=0.03). This was true with 24-hour recall energy intake only when data from two extremely large alcohol consumers were eliminated (r=0.64, p=0.03, N=19). Although a low level of activity was apparent, the activity questionnaire produced significant correlations with measurements of energy expenditure and therefore represents an important tool for examining the relationship between physical activity and diseases.

Prevalence, predisposition and prevention of type II diabetes

In 2000, more than 151 million people in the world are diabetic. It is predicted that by 2010, 221 million people and by 2025, 324 million will be diabetic. In the U.S., for the population born in 2000, the estimated lifetime risk for diabetes is more than 1 in 3. The economic and human cost of this disease is devastating. The current cost of diabetes in the U.S. is estimated to be at $132 billion, which includes $92 billion of direct medical costs and $40 billion of indirect costs such as disability, work loss and premature mortality. The outbreak of the current diabetic epidemic has been accompanied by a similarly drastic increase in obesity. The relation between the two is a matter of debate but presumably both are caused by changes in dietary habits and an increasingly sedentary modern lifestyle. Compelling scientific evidence indicates that lifestyle modification effectively prevents or delays the occurrence of type 2 diabetes. Recent clinical trials also demonstrate that success in the treatment of obesity, either surgically or pharmacologically, leads to the prevention of type 2 diabetes among the obese. Clinical data have also revealed that the insulin sensitizing agent troglitazone is efficacious in both beta-cell preservation and delaying the onset of type 2 diabetes. Future safe and more effective anti-obesity medicines and insulin sensitizing agents that help to preserve beta-cell function, in addition to efforts of lifestyle modification, thus hold promise for the overweight population with potential for reduction in the development of diabetics.