Human evolution. Diabetes running wild

From Hong Kong Diabetes Register to JADE Program to RAMP-DM for Data-Driven Actions

In 1995, the Hong Kong Diabetes Register (HKDR) was established by a doctor-nurse team at a university-affiliated, publicly funded, hospital-based diabetes center using a structured protocol for gathering data to stratify risk, triage care, empower patients, and individualize treatment. This research-driven quality improvement program has motivated the introduction of a territory-wide diabetes risk assessment and management program provided by 18 hospital-based diabetes centers since 2000. By linking the data-rich HKDR to the territory-wide electronic medical record, risk equations were developed and validated to predict clinical outcomes. In 2007, the HKDR protocol was digitalized to establish the web-based Joint Asia Diabetes Evaluation (JADE) Program complete with risk levels and algorithms for issuance of personalized reports to reduce clinical inertia and empower self-management. Through this technologically assisted, integrated diabetes care program, we have generated big data to track secular trends, identify unmet needs, and verify interventions in a naturalistic environment. In 2009, the JADE Program was adapted to form the Risk Assessment and Management Program for Diabetes Mellitus (RAMP-DM) in the publicly funded primary care clinics, which reduced all major events by 30-60% in patients without complications. Meanwhile, a JADE-assisted assessment and empowerment program provided by a university-affiliated, self-funded, nurse-coordinated diabetes center, aimed at complementing medical care in the community, also reduced all major events by 30-50% in patients with different risk levels. By combining universal health coverage, public-private partnerships, and data-driven integrated care, the Hong Kong experience provides a possible solution than can be adapted elsewhere to make quality diabetes care accessible, affordable, and sustainable.

Leptin and the endocrine control of energy balance

The discovery of leptin changed the view of adipose tissue from that of a passive vessel that stores fat to that of a dynamic endocrine organ that actively regulates behaviour and metabolism. Secreted by adipose tissue, leptin functions as an afferent signal in a negative feedback loop, acting primarily on neurons in the hypothalamus and regulating feeding and many other functions. The leptin endocrine system serves a critical evolutionary function by maintaining the relative constancy of adipose tissue mass, thereby protecting individuals from the risks associated with being too thin (starvation and infertility) or too obese (predation). In this Review, the biology of leptin is summarized, and a conceptual framework is established for studying the pathogenesis of obesity, which, analogously to diabetes, can result from either leptin hyposecretion or leptin resistance. Herein, these two states are distinguished with the terms 'type 1 obesity' and 'type 2 obesity': type 1 obesity describes a subset of obese individuals with low endogenous plasma leptin levels who respond to leptin therapy, whereas type 2 obesity describes most obese individuals, who are leptin resistant but might respond to leptin therapy in combination with other drugs, such as leptin sensitizers.

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.

Transmission of energy-saving efficiency from obese parents to their offspring: the Korean National Health and Nutrition Examination Survey 2007-2011

BACKGROUND/OBJECTIVES

Concerns of a growing obesity epidemic have increased since the association between obesity in parents and that in offspring was reported. However, the evidence regarding whether the energy-saving efficiency of obese parents is conveyed to their offspring and the duration of the expression of such transmitted efficiency is limited.

SUBJECTS/METHODS

We included 7647 matching sets of parent-offspring trios from South Korea. Multiple linear regression models were performed to estimate the energy-saving efficiency, as assessed by the associations between energy intake and obesity-related indices (waist-to-height ratio, waist circumference and body mass index z-score), and to compare the energy-saving efficiency of offspring of obese and non-obese parents. All analyses were based on a complex sample design and were stratified by gender and age.

RESULTS

We identified a parental influence on obesity, that is, the more obese the parent, the higher the obesity-related indices of their offspring, in both genders and all age groups. The energy-saving efficiency of child offspring was highest when both parents were obese and lowest when both were non-obese; this difference was significant (P<0.05) with regard to the energy-saving efficiency of all types of intake studied, except fat. However, the energy-saving efficiency of obese and non-obese parents did not differ when their offspring were adolescents and adults.

CONCLUSIONS

The critical window for transmission of energy-saving efficiency is limited to childhood. These findings suggest that children of obese parents should be more emphatically advised to maintain a balanced diet and to engage in regular physical activity.

Diabetes in China: a societal solution for a personal challenge

China has a large burden of diabetes: in 2013, one in four people with diabetes worldwide were in China, where 11·6% of adults had diabetes and 50·1% had prediabetes. Many were undiagnosed, untreated, or uncontrolled. This epidemic is the result of rapid societal transition that has led to an obesogenic environment against a backdrop of traditional lifestyle and periods of famine, which together puts Chinese people at high risk of diabetes and multiple morbidities. Societal determinants including social disparity and psychosocial stress interact with factors such as low-grade infection, environmental pollution, care fragmentation, health illiteracy, suboptimal self-care, and insufficient community support to give rise to diverse subphenotypes and consequences, notably renal dysfunction and cancer. In the China National Plan for Non-Communicable Disease Prevention and Treatment (2012-15), the Chinese Government proposed use of public measures, multisectoral collaborations, and social mobilisation to create a health-enabling environment and to reform the health-care system. While awaiting results from these long-term strategies, we advocate the use of a targeted and proactive approach to identify people at high risk of diabetes for prevention, and of private-public-community partnerships that make integrated care more accessible and sustainable, focusing on registry, empowerment, and community support. The multifaceted nature of the societal and personal challenge of diabetes requires a multidimensional solution for prevention in order to reduce the growing disease burden.

Diabetes in the Western Pacific Region--past, present and future

In the 2013 issue of the International Diabetes Federation (IDF) Diabetes Atlas, the prevalence of diabetes in the Western Pacific (WP) Region was reported to be 8.6% in 2013, or 138 million adults, and estimated to rise to 11.1%, or 201 million adults, in 2035. The prevalence estimates of impaired glucose tolerance in 2013 and 2035 were 6.8% and 9.0%, respectively. Over 50% of people with diabetes were undiagnosed. In 2013, 187 million deaths were attributable to diabetes, 44% of which occurred in the under the age of 60. The WP Region is home to one quarter of the world's population, and includes China with the largest number of people with diabetes as well as Pacific Islands countries with the highest prevalence rates. There is a rapid increase in diabetes prevalence in the young-to-middle aged adults, possibly driven by high rates of childhood obesity and gestational diabetes as well as rapid demographic and sociocultural transitions. Differences in genetics, ethnicity, cultures and socioeconomic development have led to complex host-environment-lifestyle interactions with marked disease heterogeneity, further influenced by access to care and treatment. Despite these challenges, the WP Region has provided notable examples to prevent and control diabetes.

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.

Characteristics and Prevalence of Latent Autoimmune Diabetes in Adults (LADA)

Diabetes, one of the most commonly seen metabolic disorders, is affecting a major area of population in many developing as well as most of the developed countries and is becoming an alarming concern for the rising cost of the healthcare system. Latent Autoimmune Diabetes in Adults (LADA) is a form of diabetes which is less recognized and underdiagnosed type of diabetes which appears to have characteristics of both type 1 (autoimmune in nature) and type 2 diabetes (adult age at onset and initial response to oral hypoglycemic agents). An epidemiological study was carried out on 500 patients in the western region of India. Various parameters such as age at onset, duration of diabetes, gender, basal metabolic index (BMI), type of diabetes, family history, HbA1c levels, cholesterol levels, and current treatment regimen were evaluated and correlated with type 1 and type 2 diabetes. Moreover, diagnostic markers for LADA, namely, GAD autoantibodies and C-peptide levels, were determined for 80 patients selected from the epidemiological study. Some of the results obtained were found to be consistent with the literature whereas some results were found to be contradictory to the existing data.

Unconventional wisdom about the obesity epidemic

Diet and sedentary lifestyle, interacting with "thrifty" genes, are widely accepted as the principal cause of the current global obesity epidemic. However, a number of alternative etiologies for obesity have been proposed, including "drifty" genes, viruses, bacteria, environmental toxins, social network effects, maternal imprinting, sleep deprivation, and others. These Grand Rounds reviews the background of some of these unconventional ideas and evidence for or against their roles in the obesity epidemic.

Has human evolution stopped?

It has been argued that human evolution has stopped because humans now adapt to their environment via cultural evolution and not biological evolution. However, all organisms adapt to their environment, and humans are no exception. Culture defines much of the human environment, so cultural evolution has actually led to adaptive evolution in humans. Examples are given to illustrate the rapid pace of adaptive evolution in response to cultural innovations. These adaptive responses have important implications for infectious diseases, Mendelian genetic diseases, and systemic diseases in current human populations. Moreover, evolution proceeds by mechanisms other than natural selection. The recent growth in human population size has greatly increased the reservoir of mutational variants in the human gene pool, thereby enhancing the potential for human evolution. The increase in human population size coupled with our increased capacity to move across the globe has induced a rapid and ongoing evolutionary shift in how genetic variation is distributed within and among local human populations. In particular, genetic differences between human populations are rapidly diminishing and individual heterozygosity is increasing, with beneficial health effects. Finally, even when cultural evolution eliminates selection on a trait, the trait can still evolve due to natural selection on other traits. Our traits are not isolated, independent units, but rather are integrated into a functional whole, so selection on one trait can cause evolution to occur on another trait, sometimes with mildly maladaptive consequences.

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.

'Hypertension' and 'microalbuminuria': the bell tolls for thee

Since the terms 'hypertension' and 'microalbuminuria' were first defined, data from numerous studies have documented the continuous, rather than dichotomous, relation between blood pressure, albumin excretion, and cardiovascular disease. Lower blood pressures, down to at least 115/75 mmHg, and lower albumin excretions, below an estimated 2 mg/day, are associated with less cardiovascular risk. We hypothesize that the abundances of modern civilization superimposed on the Paleolithic genotype of humans, which has not substantially changed in the last 10 000 years, have considerably shifted the 'normal' values for blood pressure and various biochemical indices such as albuminuria still found in today's stone-aged cultures to the 'neo-normal' values observed today in the rest of the modern world. Defining a large portion of the population as 'normal' based upon these dichotomous 'neo-normal' standards is not supported by the data, and therefore seems unjustifiable. We propose that the medical community consider abandoning the terms 'hypertension' and 'microalbuminuria' in favor of 'blood pressure-associated' and 'albuminuria-associated' disease.

Childhood obesity and the metabolic syndrome

The current epidemic of obesity reflects environmental changes that have an impact on a genetically susceptible population. The scope of obesity and its associated comorbidities warrants its position among the most crucial global public health problems faced today. Society has gained better appreciation for the significance of this problem yet still has much to learn regarding how best to address the obesity crisis. Although strategies for treating individuals who have weight problems successfully continue to evolve, the most profound impacts ultimately will arise from societal changes dictating that all individuals strive to adopt a healthy lifestyle.

Causes of blindness and the results of cataract surgical intervention in the Micronesian islands: a retrospective study

Since 1983, we have delivered eye care to inhabitants of the Micronesia islands a total of 18 times over an 18-year period. Approximately 14,000 islanders were examined. We diagnosed a total of 1226 blind eyes and 1231 eyes with low vision. Unoperated cataract (n = 765, 62.4%) was the leading cause of blindness in our data, and 611 cataract operations were performed. The preoperative visual acuity of the patients who underwent cataract surgery was less than 20/200. Visual acuity improved in 588 cases (96.2%) after the surgery. Sight-threatening complications occurred in 1.1% (7) of the eyes after the surgery, which is comparable to the rate in developed countries. Corneal opacity secondary to infection (11.2%) was the second leading cause of blindness in our data. Diabetic retinopathy (9.9%) was a cause of low vision in our data, and the number of eyes diagnosed with diabetic retinopathy in each district increased over the years. Glaucoma was the cause of blindness in 1.9% of the blind eyes, although the percentage may actually have been higher because visual loss was assessed only by reduced visual acuity. The demand for correcting refractive errors that caused a visual acuity of less than 20/60, was evident throughout the region. The majority of blind individuals in this study were suffering from operable cataract and good results were obtained with cataract surgery in this region. Further training of local medical staff would significantly improve eye care services in Micronesia.

Preparing nurses to face the pandemic of diabetes mellitus: a literature review

BACKGROUND

Diabetes constitutes a global public health problem. Today about 135 million people are affected and it is estimated that the number in 2025 will be 300 million.

AIMS

By reviewing existing literature the aim is to raise awareness among nurses, nurse educators and nursing students of the global epidemic of diabetes mellitus, its multiple underlying causes, especially social ones, and how to fight it. A further aim is to discuss the implications for future curriculum content in nurse education programmes.

FINDINGS

The main underlying causes of the disease are genetic and environmental factors, such as urbanization and industrialization, as well as increased longevity and changes in lifestyle from a traditional healthy and active life to a modern, sedentary, stressful life and over-consumption of energy-dense foods. This process, labelled 'coca-colonization', is evident all over the world, although more so in developing countries. The prevalence of diabetes mellitus varies among populations due to differences in genetic susceptibility and social risk factors such as change in diet, obesity, physical inactivity and, possibly, factors relating to intrauterine development. Migrants are especially affected. Diabetes mellitus needs to be treated by a holistic approach through dietary adjustment, exercise, medication (if needed), education and self-care measures. Type 2 diabetes mellitus is a preventable disease. The main implication for nurses and nursing curricula is to change the focus from the individual with diabetes mellitus and management to prevent deterioration of health (secondary prevention), to population-based community-intervention programmes. These need to focus on health promoting activities to raise awareness among healthy people of the risk factors for diabetes mellitus.

CONCLUSION

Nurses all over the world have an important role in fighting the diabetic pandemic by health promotion aimed to keep people healthy as long as possible.

A war on obesity, not the obese

In their efforts to lose weight, obese individuals may be fighting a powerful set of evolutionary forces honed in an environment drastically different from that of today.

Antioxidant activity in medicinal plants associated with the symptoms of diabetes mellitus used by the indigenous peoples of the North American boreal forest

Thirty-five plant species were selected from the published literature as traditionally used by the Indigenous Peoples of the boreal forest in Canada for three or more symptoms of diabetes or its complications. Antioxidant activities in methanolic extracts support the contribution of these traditional medicines in a lifestyle historically low in the incidence of diabetes. In a DPPH assay of free radical scavenging activity 89% of the methanol extracts had activity significantly greater than common modern dietary components, 14% were statistically equal to ascorbic acid and 23% had activities similar to green tea and a Trolox positive control. Superoxides produced with an NBT/xanthine oxidase assay found scavenging was significantly higher in 29% of the species as compared with the modern dietary components and Trolox. The methanol extracts of Rhus hirta, Quercus alba and Cornus stolonifera performed similarly to green tea's in this assay. Assessment of peroxyl radical scavenging using a DCF/AAPH assay showed 60% of the plant extracts statistically similar to Trolox while R. hirta and Solidago canadensis extracts were greater than green tea, ascorbic acid and Trolox. The majority of the species (63 and 97%, respectively) had scavenging activities similar to ascorbic acid in the superoxide and peroxyl radical scavenging assays.

Prevalence of latent autoimmune diabetes of adults (LADA) in Southern Spain

OBJECTIVE

To study the prevalence of diabetes mellitus and islet autoantibodies in an adult population from Southern Spain.

RESEARCH AND METHODS

A cross-sectional study in Southern Spain of 1226 people, age 18-65 years. Clinical data were obtained and a blood sample taken to measure autoantibodies (glutamic acid decarboxylase antibodies (GADAb), tyrosine phosphatase antibodies (IA2Ab), and insulin antibodies (IAA)). An oral glucose tolerance test (OGTT) was also given to 982 of the subjects.

RESULTS

The overall prevalence of diabetes mellitus according to the WHO 1979 criteria was 10.9% and according to the ADA 1997 criteria it was 14.7% (8.8% were unaware of their diabetes). The prevalence of impaired fasting glucose (IFG) was 12.4% and of impaired glucose tolerance (IGT) 11.5%. The prevalence of GADAb+ in the general population was 0.9% and in the diabetic population 3.7%. There were no significant differences between groups in the prevalence of IA2Ab or IAA (both were 0.8% in the general population). Of the three autoantibodies studied, only GADAb were significantly different in the diabetic population (P=0.0006).

CONCLUSIONS

The prevalence of Type 2 diabetes and LADA are high in the south of Spain.

A reconsideration of the origins of the type 2 diabetes epidemic among Native Americans and the implications for intervention policy

Type 2 diabetes has reached epidemic proportions in many Native American communities in North America. The overwhelming majority of physicians, biomedical researchers, and medical ecologists continue to explain the astoundingly high prevalence rates of diabetes among Native Americans and other high prevalence populations in terms of yet-to-be-identified genetic factors. Recent experimental and epidemiological research, however, has brought to light an etiological alternative to the genetic-predisposition model. This body of research suggests that type 2 diabetes may result initially from fetal malnutrition and, in subsequent generations, be propagated via perturbations in the intrauterine environment. Native American populations at greatest risk for diabetes today are the ones most likely to have endured severe nutritional stress in their recent histories, thus experiencing the conditions that are most conducive to the diabetic developmental sequence. If further substantiated, the implications of the fetal-origin model of diabetes for diabetes intervention programs are profound.

Expression of monosaccharide transporters in intestine of diabetic humans

Noninsulin-dependent diabetes mellitus (NIDDM) is an increasingly common disease, which brings a number of life-threatening complications. In rats with experimentally induced diabetes, there is an increase in the capacity of the intestine to absorb monosaccharides. We have examined the activity and the expression of monosaccharide transporters in the intestine of patients suffering from NIDDM. Na(+)-dependent D-glucose transport was 3.3-fold higher in brush-border membrane (BBM) vesicles isolated from duodenal biopsies of NIDDM patients compared with healthy controls. Western analysis indicated that SGLT1 and GLUT5 protein levels were also 4.3- and 4.1-fold higher in diabetic patients. This was associated with threefold increases in SGLT1 and GLUT5 mRNA measured by Northern blotting. GLUT2 mRNA levels were also increased threefold in the intestine of diabetic patients. Analysis of other BBM proteins indicated that the activity and abundance of sucrase and lactase were increased by 1.5- to 2-fold and the level of the structural proteins villin and beta-actin was enhanced 2-fold in diabetic patients compared with controls. The increase in the capacity of the intestine to absorb monosaccharides in human NIDDM is due to a combination of intestinal structural change with a specific increase in the expression of the monosaccharide transporters SGLT1, GLUT5, and GLUT2.

An obligation for primary care physicians to prescribe physical activity to sedentary patients to reduce the risk of chronic health conditions

Physical inactivity increases the risk of many chronic disorders. Numerous studies have convincingly demonstrated that undertaking and maintaining moderate levels of physical activity (eg, brisk walking 3 hours a week) greatly reduces the incidence of developing many chronic health conditions, most notably type 2 diabetes mellitus, obesity, cardiovascular disease, and many types of cancers. However, the underlying mechanistic details of how physical activity confers such protective effects are not well understood and consequently constitute an active area of research. Although changing an individual's ingrained behavior is commonly perceived to be difficult, encouraging evidence suggests that intensive and repeated counseling by health care professionals can cause patients to become more physically active. Therefore, counseling patients to undertake physical activity to prevent chronic health conditions becomes a primary prevention modality. This article summarizes the vast epidemiologic and biochemical evidence supporting the many beneficial health implications of undertaking moderate physical activity and provides a rationale for incorporating physical activity counseling as part of routine practice in the primary care setting.

Nutritional origins of insulin resistance: a rat model for diabetes-prone human populations

While there has been little success identifying the genetic bases of noninsulin-dependent (type-2) diabetes, current epidemiological data and animal models implicate fetal undernutrition in the development of type-2 diabetes. We examined the effects of fetal undernutrition on insulin responses and glucose tolerance in adulthood in genetically normal rats. Control rats were adequately nourished in utero and consumed nutritionally adequate (N) diets throughout life. Experimental rats (F1 generation) were undernourished in utero and consumed either N or high-energy, high-fat (HF) diets postweaning. The offspring of the experimental rats (F2 generation) received the respective diets of their parent. Body weights of experimental F1 rats at d 4 were 40% less than that of control pups, and they remained significantly smaller than controls throughout adulthood. The experimental F1 rats consuming N diets postweaning had a reduced insulin response (-30%) at 30-min postglucose challenge in adulthood (P > 0.05). However, their offspring (F2 generation) displayed a markedly elevated insulin response [+80% at 30 min (P < 0.05) and + 230% at 120 min (P < 0.001) postglucose challenge]. The insulin response of the F2 generation rats fed the high-energy, HF diet was even more pronounced [+130% at 30 min (P < 0.003) and + 250% at 120 min (P < 0.001) postglucose challenge]. Thus, undernourishment in utero produces striking insulin resistance in genetically normal, well-nourished second-generation rats.

Globalization, coca-colonization and the chronic disease epidemic: can the Doomsday scenario be averted?

There are at present approximately 110 million people with diabetes in the world but this number will reach over 220 million by the year 2010, the majority of them with type 2 diabetes. Thus there is an urgent need for strategies to prevent the emerging global epidemic of type 2 diabetes to be implemented. Tackling diabetes must be part of an integrated program that addresses lifestyle related disorders. The prevention and control of type 2 diabetes and the other major noncommunicable diseases (NCDs) can be cost- and health-effective through an integrated (i.e. horizontal) approach to noncommunicable diseases disease prevention and control. With the re-emergence of devastating communicable diseases including AIDS, the Ebola virus and tuberculosis, the pressure is on international and regional agencies to see that the noncommunicable disease epidemic is addressed. The international diabetes and public health communities need to adopt a more pragmatic view of the epidemic of type 2 diabetes and other noncommunicable diseases. The current situation is a symptom of globalization with respect to its social, cultural, economic and political significance. Type 2 diabetes will not be prevented by traditional medical approaches; what is required are major and dramatic changes in the socio-economic and cultural status of people in developing countries and the disadvantaged, minority groups in developed nations. The international diabetes and public health communities must lobby and mobilize politicians, other international agencies such as UNDP, UNICEF, and the World Bank as well as other international nongovernmental agencies dealing with the noncommunicable diseases to address the socio-economic, behavioural, nutritional and public health issues that have led to the type 2 diabetes and noncommunicable diseases epidemic. A multidisciplinary Task Force representing all parties which can contribute to a reversal of the underlying socio-economic causes of the problem is an urgent priority.

Uses of Evolutionary Theory in the Human Genome Project

▪ Abstract  The Human Genome Project (HGP) originally sought to sequence the human genome but excluded studies on genetic diversity. Now genetic diversity is a major focus, and evolutionary theory provides needed analytical tools. One type of diversity research focuses on complex traits. This is often done by screening genetic variation at candidate loci functionally related to a trait followed by gene/phenotype association tests. Linkage disequilibrium creates difficulties for association tests, but evolutionary analyses using haplotype trees can circumvent these problems and result in greater statistical power, better disease risk prediction, the elimination of some polymorphisms as causative, and physical localization of causative variation when combined with an analysis of recombination. The HGP also now proposes to map over 100,000 single nucleotide polymorphisms to test for gene/phenotype associations through linkage disequilibrium in isolated human populations affected by past founder or bottleneck events. This strategy requires prior knowledge of recent human evolutionary history and current population structure, but other evolutionary considerations dealing with disequilibrium and nonrandom mutation pose difficulties for this approach. Studies on population structure also focus upon traits of medical relevance, and an understanding of the evolutionary ultimate cause for the predisposition of some populations to certain diseases is a useful predictor for shaping public health policies. Studies on the genetic architecture of common traits reveal much epistasis and variation in norms of reaction, including drug response. Because of these interactions, context dependency and sampling bias exist in disease association studies that require population information for effective use. Overall, the population thinking of evolutionary biology is an important counterweight to naive genetic determinism in applying the results of the HGP to issues of human health and well-being.

Saponins and phenolic content in plant dietary additives of a traditional subsistence community, the Batemi of Ngorongoro District, Tanzania

Reports of plants added to milk and meat-based soups by the Maasai and Batemi in East Africa support a role for phenolic antioxidants and hypocholesterolemic agents in the diet, and provide explanation of the low incidence of cardiovascular disease of populations that traditionally consume high levels of dietary fat and cholesterol. Plant food additives used by the Batemi of Ngorongoro District, Tanzania, were tabulated, based on interviews with 22 informants, while 17 specimens were collected in the field and analyzed for saponin and phenolic content. A total of 81% of the Batemi additives and 82% of those known to be used by the Maasai contain potentially hypocholesterolemic saponins and/or phenolics.

Renal disease and hypertension in non-insulin-dependent diabetes mellitus

Recent epidemiologic data demonstrate a dramatic increase in the incidence of end-stage renal disease (ESRD) in patients with non-insulin-dependent diabetes mellitus (NIDDM), thus dispelling the mistaken belief that renal prognosis is benign in NIDDM. Currently, the leading cause of ESRD in the United States, Japan, and in most industrialized Europe is NIDDM, accounting for nearly 90% of all cases of diabetes. In addition to profound economic costs, patients with NIDDM and diabetic nephropathy have a dramatically increased morbidity and premature mortality. NIDDM-related nephropathy varies widely among racial and ethnic groups, genders and lifestyles; and gender may interact with race to affect the disease progression. While the course of insulin-dependent diabetes mellitus (IDDM) progresses through well-defined stages, the natural history of NIDDM is less well characterized. NIDDM patients with coronary heart disease have a higher urinary albumin excretion rate at the time of diagnosis and follow-up. This greater risk may also be associated with hypertension and hyperlipidemia, and genes involved in blood pressure are obvious candidate genes for diabetic nephropathy. Hyperglycemia appears to be an important factor in the development of proteinuria in NIDDM, but its role and the influence of diet are not yet clear. Tobacco smoking can also be deleterious to the diabetic patient, and is also associated with disease progression. Maintaining euglycemia, stopping smoking and controlling blood pressure may prevent or slow the progression of NIDDM-related nephropathy and reduce extrarenal injury. Treatment recommendations include early screening for hyperlipidemia, appropriate exercise and a healthy diet. Cornerstones of management should also include: (1) educating the medical community and more widely disseminating data supporting the value of early treatment of microalbuminuria; (2) developing a comprehensive, multidisciplinary team approach that involves physicians, nurses, diabetes educators and behavioral therapists; and (3) intensifying research in this field.

Diabetes epidemic in newly westernized populations: is it due to thrifty genes or to genetically unknown foods?

Until a few decades ago, certain 'new-world' populations that kept to traditional dietary habits were virtually free from diabetes; then, after they began eating some foods that are common in Europe, the disease reached epidemic proportions. Europeans, by contrast, have a low rate of diabetes. To account for this paradox, it has been suggested that those new-world populations have a thrifty genotype, which would have conferred a selective advantage during the frequent famines of the past, while today it would be detrimental because the recently adopted foods are constantly available. Here it is proposed that thrifty genes are unlikely to exist. Both the diabetes epidemics that occur in newly westernized populations and the low rate of diabetes in Europeans can be explained by the hypothesis that Europeans, through millenary natural selection, have become adapted, albeit incompletely, to some diabetogenic foods for which humankind is genetically unequipped.

Diabetic nephropathy in type II diabetes

The incidence of end-stage renal failure in patients with type II diabetes has dramatically increased in recent years, both in the United States and, with some delay, in some European countries. These epidemiologic observations have thoroughly dispelled the mistaken belief that renal prognosis was benign in type II diabetes. Recent interest has focused on the early stages of nephropathy in type II diabetes. With respect to renal hemodynamics, renal morphology, and progression of established diabetic nephropathy, there are no substantial differences between types I and type II diabetes. There is good evidence that preventive measures are effective, ie, glycemic control, blood pressure control, protein restriction, and discontinuation of smoking. The high prevalence of the disease (which in principle is preventable) calls for intense efforts to (1) educate the medical community, (2) substantially improve patient education and medical care, and (3) intensify research in this field.

New World syndrome in Western Australian aborigines

1. It has become clear over the past 25 years that Aborigines in Western Australia (WA) now experience very high rates of type 2 diabetes mellitus and its complications as well as hypertension and cardiovascular disease; these disorders are often associated with obesity and abnormalities of plasma lipids. 2. This experience is similar to that of Aboriginal people in other parts of Australia and to other previously traditional societies now in transition to an urbanized, Westernized existence; this is widely attributed to lifestyle factors and genetic susceptibility. 3. This so-called 'New World Syndrome' is responsible for disproportionately high levels of morbidity and mortality in the Aboriginal population of WA; prevention and improved methods of screening, detection and management are needed to reduce this problem.

Comparative hospitalisation and mortality rates of aboriginal and non-aboriginal Western Australians in their sixth and seventh decades

BACKGROUND

Aboriginals have higher hospitalisation and mortality rates and die, on average, about 15 years earlier than non-Aboriginals in Western Australia (WA).

AIMS

To investigate Aboriginal morbidity and mortality rates in WA in comparison with the rest of the population, with particular reference to the ages of 50 to 65 years.

METHODS

Mortality rates from 1983-1989 inclusive for Aboriginals and non-Aboriginals in WA were compared. Major causes of Aboriginal mortality in males and females were matched to the ages at which similar rates from the same causes occurred in non-Aboriginals. Rate ratios (Aboriginal:non-Aboriginal) for causes of death at ages 60-64 years were determined. Hospitalisation rates for Aboriginal and non-Aboriginal people aged 50-64 years in WA in 1988 were used to estimate hospitalisation rate ratios.

RESULTS

Hospitalisation rates in WA were much higher among 50 to 64 year old Aboriginals than non-Aboriginals for most diseases, particularly for infectious and parasitic diseases, and injury and poisoning. Admissions for circulatory diseases were double to four times as frequent among Aboriginals. The main causes of deaths in Aboriginal males were circulatory diseases, injury and poisoning, respiratory diseases, neoplasms, and digestive diseases; in Aboriginal females the main causes of deaths were circulatory diseases, neoplasms, diabetes, respiratory diseases, and injury and poisoning. Except for neoplasms, deaths from these causes occurred among 50-54 year old Aboriginals at rates that were experienced by non-Aboriginal people ten to 30 years later in life. These results underline special needs of the Aboriginal population that have not been adequately met by appropriate services.

Genetic determinants of myocardial infarction

There is a strong familial and genetic nature of CAD and predisposing metabolic disorders. This should encourage health care workers to focus additional attention on the younger members of affected families, particularly the families of patients with MI prior to age 55. This should take the form of genetic counseling as well as patient education and follow-up with respect to hygienic measures of proven efficacy, and aggressive treatment of metabolic disorders that prove resistant to changes in lifestyle. In certain cases, as discussed in this review, genetic testing may prove helpful.

Reduced postprandial energy expenditure in women predisposed to type 2 diabetes

Type 2 (non-insulin dependent) diabetes is so common that it has been hypothesized that in the course of evolution the predisposition to it may have conferred some advantage, before or during the reproductive years. It is frequently preceded by gestational diabetes. In order to test the basis for the hypothetical advantage, energy expenditure was investigated in 10 women with documented transient diabetes in a previous pregnancy. They were studied early in a subsequent pregnancy while glucose tolerance wa still normal and 9 were re-studied after pregnancy. Their results were compared with normal matched controls. During pregnancy, resting energy expenditure was similar in the study group and controls (6.58 (5.77-7.55) median (range) vs 6.91 (6.56-7.36) MJ day-1, respectively). However, the energy response to a mixed meal (42 kJ, kg-1 lean body mass) was decreased in the study group (45 (33-68) vs 76 (50-89) kJ, p < 0.05). After pregnancy resting energy expenditure was again similar in the two groups, but the decrease in postprandial thermogenesis persisted (78 (59-84) vs 92 (79-105) kJ, p < 0.05). The patients were resistant to exogenous insulin, 0.05 U kg-1 intravenously (slope of the plasma glucose decline in the 15 min after insulin; during pregnancy patients 52 (37-92) vs controls 111 (104-121) mumol l-1 min-1, p < 0.01; after pregnancy 130 (88-156) vs controls 186 (152-221) mumol l-1 min-1, p < 0.01). The postprandial energy saving in these women could constitute an evolutionary advantage. Insulin resistance may be the mechanism for limiting postprandial thermogenesis.

The prevalence of diabetes mellitus and impaired glucose tolerance among Hong Kong Chinese adults of working age

We studied 1513 employees (910 men and 603 women) from a public utility company and a regional hospital to document the prevalence of diabetes mellitus (DM) and impaired glucose tolerance (IGT) in the Chinese working population of Hong Kong using a 75-g oral glucose tolerance test and World Health Organisation (1985) criteria. The overall prevalence of DM was 4.5 (95% confidence interval: 3.5-5.7%) and that of IGT 7.3 (6.0-8.6%). The prevalence of DM was 5.1 (3.7-6.5%) in men and 3.6 (2.1-5.1%) in women, while that of IGT was 7.4 (5.7-6.5%) in men and 7.1 (5.1-9.1%) in women. The truncated age-adjusted rate of DM for age 30-64 is 7.7% which is comparable to the age-adjusted prevalence rates among Chinese living in Singapore and Mauritius but in marked contrast to the low prevalence rate in Chinese living in Mainland China. Among the diabetic subjects, 38.2% had been previously diagnosed and 32% gave a family history affecting at least one first degree relative. Using polychotomous logistic regression analysis, the independent predictive factors for the development of DM include age (t = 7.31, P < 0.001), family history (t = 5.1, P < 0.001), waist hip ratio (t = 4.05, P < 0.001) and body mass index (t = 4.62, P < 0.001). Our data further confirm that Hong Kong Chinese have a moderate to high susceptibility to non-insulin-dependent diabetes (NIDDM) when exposed to sufficient environmental and lifestyle factors. The high prevalence of IGT indicates a potential for the prevalence of DM to continue to rise unless effective preventive measures are implemented.

Genetic influences on glucose neurotoxicity, aging, and diabetes: a possible role for glucose hysteresis

Glucose may drive some age-correlated impairments and may mediate some effects of dietary restriction on senescence. The hypothesis that cumulative deleterious effects of glucose may impair hypothalamic neurons during aging, leading to hyperinsulinemia and other age-correlated pathologies, is examined in the context of genetic influences. Susceptibility to toxic effects of gold-thio-glucose (GTG) is correlated with longevity across several mouse strains. GTG and chronic hyperglycemia induce specific impairments in the ventromedial hypothalamus similar to impairments which occur during aging. GTG and a high-calorie diet both induce chronic hyperinsulinemia, leading initially to hypoglycemia, followed by the development of insulin resistance and hyperglycemia. Aging in humans and rodents appears to entail a similar pattern of hyperinsulinemia followed by insulin resistance. In humans, genetic susceptibility to high-calorie diet-induced impairments in glucose metabolism is extremely common in many indigenous populations, possibly due to the selection of the 'thrifty genotype'. It is suggested that the 'thrifty genotype' may entail enhanced sensitivity to the neurotoxic effects of glucose, and may represent an example of antagonistic pleiotropy in human evolution. These data are consistent with the hypothesis that genetic susceptibility of hypothalamic neurons to the cumulative toxic effects of glucose (glucose neurohumoral hysteresis) may correlate with genetic influences on longevity.