The unstoppable Australian obesity and diabetes juggernaut. what should politicians do?
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Biomedical subjects
Publications and source records attributed to W Philip T James.
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Excess bodyweight is the sixth most important risk factor contributing to the overall burden of disease worldwide. 1.1 billion adults and 10% of children are now classified as overweight or obese. Average life expectancy is already diminished; the main adverse consequences are cardiovascular disease, type 2 diabetes, and several cancers. The complex pathological processes reflect environmental and genetic interactions, and individuals from disadvantaged communities seem to have greater risks than more affluent individuals partly because of fetal and postnatal imprinting. Obesity, with its array of comorbidities, necessitates careful clinical assessment to identify underlying factors and to allow coherent management. The epidemic reflects progressive secular and age-related decreases in physical activity, together with substantial dietary changes with passive over-consumption of energy despite the neurobiological processes controlling food intake. Effective long-term weight loss depends on permanent changes in dietary quality, energy intake, and activity. Neither the medical management nor the societal preventive challenges are currently being met.
BACKGROUND: Cardiovascular diseases and their nutritional risk factors--including overweight and obesity, elevated blood pressure, and cholesterol--are among the leading causes of global mortality and morbidity, and have been predicted to rise with economic development. METHODS AND FINDINGS: We examined age-standardized mean population levels of body mass index (BMI), systolic blood pressure, and total cholesterol in relation to national income, food share of household expenditure, and urbanization in a cross-country analysis. Data were from a total of over 100 countries and were obtained from systematic reviews of published literature, and from national and international health agencies. BMI and cholesterol increased rapidly in relation to national income, then flattened, and eventually declined. BMI increased most rapidly until an income of about ID 5,000 (international dollars) and peaked at about ID 12,500 for females and ID 17,000 for males. Cholesterol's point of inflection and peak were at higher income levels than those of BMI (about ID 8,000 and ID 18,000, respectively). There was an inverse relationship between BMI/cholesterol and the food share of household expenditure, and a positive relationship with proportion of population in urban areas. Mean population blood pressure was not correlated or only weakly correlated with the economic factors considered, or with cholesterol and BMI. CONCLUSIONS: When considered together with evidence on shifts in income-risk relationships within developed countries, the results indicate that cardiovascular disease risks are expected to systematically shift to low-income and middle-income countries and, together with the persistent burden of infectious diseases, further increase global health inequalities. Preventing obesity should be a priority from early stages of economic development, accompanied by population-level and personal interventions for blood pressure and cholesterol.
OBJECTIVES: To determine the prevalences of overweight, obesity, type 2 diabetes mellitus (DM) and hypertension (HT) in the Mexican population and compare them with those of a previous Mexican urban survey and an American survey. DESIGN: A structured, randomised, nationally representative Mexican sample was compared with a 1993 Mexican urban survey and the US Third National Health and Nutrition Examination Survey (NHANES III) of non-Hispanic Whites. SETTING: The Mexican National Health Survey 2000. SUBJECTS: SUBJECTS were 12,856 men and 28,332 women, aged 20-69 years, who had their body weight, height, waist circumference (WC), blood pressure and fasting capillary blood glucose measured. RESULTS: Mexican adult men and women had a high prevalence of overweight (41.3 and 36.3%, respectively) and obesity (19.4 and 29.0%, respectively), similar to those in the USA in 1988-1992 and exceeding those of the 1993 Mexican survey. The prevalence of HT was 33.3% in men and 25.6% in women, with inferred DM rates of 5.6 and 9.7%, respectively. Abdominal obesity affected 46.3% of men (WC>or=94 cm) and 81.4% of women (WC>or=80 cm). There was a high prevalence of abdominal obesity in normal-weight women, with co-morbidities relating better to WC than to body mass index (BMI) in both sexes. Rates of DM and HT exceeded US rates on a comparable BMI or WC basis in adults aged <50 years. CONCLUSION: The high prevalence of obesity and abdominal obesity in Mexicans is associated with markedly increased prevalences of DM and HT to levels comparable with, or even higher than, those in NHANES III of non-Hispanic Whites.
The original focus on energy and protein needs for combating malnutrition gave way to UNICEF promoted concerns for maternal care and complementary feeding in association with longer-term breast feeding. Nevertheless the World Food Summit's drive to halve malnutrition rates by 2015 was not accelerating the fall in malnutrition prevalences. The UN's Standing Committee on Nutrition's commission highlighted the crucial role of maternal nutrition and low birthweights, the need for a life cycle approach to prevention and the current global effects of maternal/fetal and childhood malnutrition in amplifying the impact of the new epidemic of obesity and chronic diseases. The emphasis on poverty reduction and free market solutions is too crude and national interventions geared to protecting the vulnerable, promoting equity with major community involvement in integrated multifaceted programmes are needed. The same principles apply to overnutrition and specifically to the avoidance of the current pandemic of the metabolic syndrome. An intergenerational amplification of diabesity is now emerging as overweight but poorly fed micronutrient deficient girls enter pregnancy and produce ever more susceptible children. So new strategies are now needed as recognized by economists but not by doctors and nutritionists! Economy, agriculture, food processing and marketing policy changes are crucial in determining patterns of food consumption because the costs of foods and their availability, rather than policies centred on individual responsibility for consumer choice, are the keys to making coherent public health advances.
OBJECTIVE: To establish the prevalence of overweight and obesity in Mexican children 10 to 17 years of age according to the percentiles from both the Centers of Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). RESEARCH METHODS AND PROCEDURES: Heights and weights were measured in children from nationally representative, randomly chosen households in the Mexican National Health Survey 2000. The study population consisted of 7862 boys and 8947 girls, 10 to 17 years of age. Measurements used were the percentage of children in the corresponding BMI categories for overweight and obesity specified by the CDC and the IOTF BMI percentiles. RESULTS: The children were short, with mean Z scores for height by age varying from - 0.62 +/- 1.26 to -1.12 +/- 1.06 in boys and from -0.45 +/- 1.25 to -1.19 +/- 1.12 in girls. CDC-based overweight prevalences varied by age from 10.8% to 16.1% in boys and 14.3% to 19.1% in girls, with obesity prevalences from 9.2% to 14.7% in boys and 6.8% to 10.6% in girls; these prevalences did not relate to stunting. IOTF-based excess weight prevalences were similar, with higher overweight rates (boys, 15.4% to 18.8%; girls, 18.4% to 22.3%) but lower obesity rates (boys, 6.1% to 9%; girls, 5.9% to 8.2%). DISCUSSION: Mexican children have one-half the overweight/obesity prevalences of U.S. Mexican-American children; however, there are higher rates in Northern Mexico, which is closer to the U.S. These escalating rates of excess weight demand new prevention, as well as management, policies.
The growth in the global epidemic of obesity is fundamentally linked to economic factors. The rising prevalence of overweight and obesity has occurred during a period when the real cost of the main components of many processed foods has declined significantly,partly due to state subsidies in the protected markets of Western economies. It is suggested that the vigorous promotion of foods high in fats and sugars, and intensive marketing to children, have aggravated the problems of obesity. The metabolic syndrome, a recent feature of the epidemic, now is a marker for the health impact of obesity both in the US and other countries. The IOTF suggests that global populations will continue to become progressively heavier if present consumption forecasts are sustained, with obesity imposing a burden of social and economic costs that no country, least of all developing countries with limited resources, can afford. Commitments to deliver effective action are needed from non-health sectors such as culture and education, commerce and trade, development,planning, and transport. Only a comprehensive and integrated international approach, based on an effective implementation of the WHO global strategy on diet, physical activity and health, offers any real hope of arresting the public health catastrophe unfolding throughout the world.
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OBJECTIVE: To determine optimum anthropometric cutoffs for predicting the likelihood ratios of type 2 diabetes mellitus (DM) and hypertension (HT) in Mexicans. RESEARCH METHODS AND PROCEDURES: Data from a randomly selected, nationally representative health survey (2000) with 11,730 men [37.4 (+/- 12.9) years] and 26,647 women [37.3(+/- 12.9) years] were assessed for values of body mass index (BMI) and waist circumference (WC) for predicting DM or HT by receiver operating characteristic curve analyses. Likelihood ratios for DM and HT were calculated, and BMIs or WCs for public-health screening were developed. Subanalyses included regional data. RESULTS: Likelihood ratios of DM and HT increased from BMI values of 22 to 24 kg/m(2) in both sexes and with WC values of 75 to 80 cm in men and 70 to 80 cm in women. The best BMI cutoffs for predicting DM were 26.3 to 27.4 kg/m(2) in men and 27.7 to 28.9 kg/m(2) in women, with similar values for HT, i.e., 26.2 to 27.0 kg/m(2) and 27.7 to 28.5 kg/m(2), for men and women, respectively; WC cutoffs for DM were 93 to 98 cm in men and 94 to 99 cm in women, and cutoffs for HT were 92 to 96 cm and 93 to 96 cm for men and women, respectively. The WC cutoffs had higher sensitivity and specificity than those of BMI. DISCUSSION: The risk for DM and HT starts at lower levels of BMI and WC than those suggested by WHO. WC is a better discriminator than BMI measures for use in public health.
Evolutionary pressures have probably amplified the mechanisms for minimizing the impact of environmental factors through compensatory maternal mechanisms. Nevertheless, experimentally there are clear long-term programming effects of manipulations to the maternal diet on the likelihood of neural-tube defects associated with folate deficiency The fat/lean ratios of the newborn, and subsequent development, seem to be linked to amino acid or folate supply. An altered balance in the hypothalamic-pituitary-adrenal axis, which experimentally has profound effects on brain development, is induced by low-protein maternal diets. Such diets are linked to a reduced pancreatic capacity for insulin production and to an altered hepatic architecture, with a change in the control of glucose metabolism. Human studies suggest that what happens in pregnancy is modified by the child's diet in the first months of life. Low birthweight is linked to early stunting, and predisposes to abdominal obesity and metabolic syndrome in later life. Metabolic syndrome amplifies the risks of diabetes, hypertension, coronary heart disease and probably some cancers. Mothers with gestational diabetes are themselves prone to early type 2 diabetes and produce heavier babies prone to childhood obesity and adolescent type 2 diabetes. There is increasing evidence of an intergenerational effect, with big babies being prone to excess weight gain, which then, in girls, predisposes them to diabetes in pregnancy, which, in turn, promotes an accelerating cycle of early diabetes in subsequent generations. Essential fatty acids and fat soluble vitamins are important, but we need early interventions and monitoring systems to justify coherent policies.
Forty years ago carbohydrates (CHO) were regarded as a simple energy source whereas they are now recognized as important food components. The human diet contains a wide range of CHO, the vast majority of which are of plant origin. Modern techniques based on chemical classification of dietary CHO replaced the traditional "by difference" measurement. They provide a logical basis for grouping into categories of specific nutritional importance. The physiological effects of dietary CHO are highly dependent on the rate and extent of digestion and absorption in the small intestine and fermentation in the large intestine, interactions which promote human health. Current knowledge of the fate of dietary CHO means that the potentially undesirable properties of many modern foods could be altered by using processing techniques that yield foods with more intact plant cell wall structures. Such products would more closely resemble the foods in the pre-agriculture diet with respect to the rate of digestion and absorption of CHO in the small intestine. The potentially detrimental physiological consequences of eating sugars and starch that are rapidly digested and absorbed in the small intestine suggest that, as fibre, the form, as well as the amount of starch should be considered. Increasing consumer awareness of the relationship between diet and health has led to demands for more widespread nutrition labelling. The entry "carbohydrate" is required in most countries, and the value is usually obtained "by difference" and used in the calculation of energy content. However, the value provides no nutritional information per se. Food labels should provide values that aid consumers in selecting a healthy diet.