Asia-Pacific faces diabetes challenge
2010; Elsevier BV; Volume: 375; Issue: 9733 Linguagem: Inglês
10.1016/s0140-6736(10)61014-8
ISSN1474-547X
Autores Tópico(s)Global Public Health Policies and Epidemiology
ResumoHealth systems in the Asia Pacific region are battling an epidemic of obesity and diabetes that many are poorly equipped to deal with. Margaret Harris Cheng reports from Hong Kong. Wilson Dick presides over paradise. Rolling green hills, warm tropical breezes, fresh air, flowers, warm welcomes, and delightful children characterise Vanuatu's Tanna Island health district that Dick has served as the district nurse at Greenhill Health Centre for the past 20 years. Look a little closer and you begin to wonder why the people are smiling. The children's legs show the classic ulcers of yaws and Dick's casebook records a slow but steady trickle of malaria. But it is not the infectious diseases that bother Dick—he has medication and technical support for managing the infectious diseases his populations have long been burdened with. What is troubling Dick is a rise in new diseases he has no means to manage: diabetes and heart disease. “The new one [disease] is diabetes, and…there's more each year”, he says. Over at the White Sands Mini-Hospital, health staff told a similar story as Mount Yasur, an active volcano that lures tourists to this tiny island at the bottom of the Vanuatu archipelago, grumbled ominously and rained ash on our heads. “We haven't got enough health staff”, says Lui Naling, manager for provincial health services, Tafea—a province covering Tanna and Vanuatu's outlying islands. “We don't have the medical staff to deal with the diabetes and heart disease. We had training here last year to raise community awareness about diet and teach them their health is their responsibility.” Dick and his Tanna Island colleagues are not alone in feeling overwhelmed by the epidemic of diabetes and its complications. The Pacific Island nations have health systems geared to dealing with infectious diseases but their economies, dependent on imported food and urban-based activity, encourage obesity and its consequences: type 2 diabetes. “In 1948, the US navy did a health survey and found no diabetes in Pohnpei [the Federated States of Micronesia]. Now one in three have that problem”, said Lois Engelberger from Let's Go Local—a group researching and promoting a return to traditional Pacific Island diets (panel).PanelPacific solutions to the diabetes epidemicLet's Go Local is a non-governmental organisation working in Pohnpei, the Federated States of Micronesia—an island group in the Northern Pacific Ocean, known to have a wide range of Indigenous food sources, including 55 varieties of bananas, 171 types of yam, and 133 different forms of breadfruit—the food that originally brought Captain Cook to the Pacific.In less than 50 years, the population of Pohnpei has gone from having no diabetes (according to a US Navy survey done in 1948) to a prevalence of 43%, according to their most recent WHO survey. Vitamin A deficiency is common in children and obesity widespread in adults.In 2006, Let's Go Local analysed food content—both imported and locally grown—in Pohnpei and found the population had a very high intake of nutrient poor imported food. At the same time they found a high intake of nutrient rich varieties of banana (particularly a type known locally as karat) and taro.Using a range of strategies—including an awareness campaign using posters with messages promoting yellow-fleshed fruit and vegetables as a good source of vitamin A and other health benefits; proclamation of karat as the Pohnpei State Banana; national karat postal stamps; a Going Yellow video and Go Local billboards and email network; conservation of rare carotenoid-rich plants in gene bank collections; support for small-scale local food processing; and research they were able to persuade people to eat more local food.But, Lois Engelberger from Let's Go Local, told the Pacific Food Summit, that there is still a long way to go. “By 2007, we were able to raise the content of banana and taro in the diet…but Pohnpei still imports US$17 million worth of processed food.” Let's Go Local is a non-governmental organisation working in Pohnpei, the Federated States of Micronesia—an island group in the Northern Pacific Ocean, known to have a wide range of Indigenous food sources, including 55 varieties of bananas, 171 types of yam, and 133 different forms of breadfruit—the food that originally brought Captain Cook to the Pacific. In less than 50 years, the population of Pohnpei has gone from having no diabetes (according to a US Navy survey done in 1948) to a prevalence of 43%, according to their most recent WHO survey. Vitamin A deficiency is common in children and obesity widespread in adults. In 2006, Let's Go Local analysed food content—both imported and locally grown—in Pohnpei and found the population had a very high intake of nutrient poor imported food. At the same time they found a high intake of nutrient rich varieties of banana (particularly a type known locally as karat) and taro. Using a range of strategies—including an awareness campaign using posters with messages promoting yellow-fleshed fruit and vegetables as a good source of vitamin A and other health benefits; proclamation of karat as the Pohnpei State Banana; national karat postal stamps; a Going Yellow video and Go Local billboards and email network; conservation of rare carotenoid-rich plants in gene bank collections; support for small-scale local food processing; and research they were able to persuade people to eat more local food. But, Lois Engelberger from Let's Go Local, told the Pacific Food Summit, that there is still a long way to go. “By 2007, we were able to raise the content of banana and taro in the diet…but Pohnpei still imports US$17 million worth of processed food.” Engelberger was speaking at the Pacific Food Summit, a meeting held in Port Vila, Vanuatu's capital, in April this year. The summit brought Pacific Island health ministers, academics and representatives from the food industry, development agencies, and non-governmental organisations together for the first time in an attempt to curb the epidemic of food-related ill health in the region. The Pacific region tops the world obesity and diabetes charts. WHO STEPS (Step-wise approach to surveillance) reports have found obesity rates—defined as a body-mass index (BMI) greater than 30 kg/m2—of 75% in American Samoa, Nauru, and Tokelau; 51% in Kiribati; 45% in the Marshall Islands; 43% in the Federated States of Micronesia (Pohnpei); 33% in the Solomon Islands; and 30% in Fiji. Diabetes rates are just as astonishing. Population surveys in different islands have recorded rates of 47% in American Samoa; 44% in Tokelau; 32% in the Federated States of Micronesia (Pohnpei); 28% in the Marshall Islands and Kiribati; 23% in Nauru; and 14% in the Solomon Islands. As a comparison, in nearby Australia, the diabetes rate is 3·6%, whereas in 2007, the USA's overall population rate of diabetes was 7·8%. The Pacific Island diet has shifted from one based on traditional root crops and seafood to one relying on energy dense and nutritionally poor imported products such as highly refined cereals (instant noodle and white rice) and fatty meats, sold cheaply by their developed neighbours—turkey tails from the USA and lamb flaps from Australia and New Zealand. Although the Pacific nations form a tiny group in terms of world population they cover a third of the earth's surface area, so a problem like an epidemic of non-communicable diseases is magnified many times over by the distance between these nations. According to a World Bank study done in three Pacific countries in 2000, the cost of treating non-communicable diseases used up between 39% and 58% of health expenditure. For many Pacific nations, providing advanced management such as dialysis for people with diabetes and renal disease is beyond their economic and human resource capabilities. The wealthy fly to their more developed neighbours such as Australia or the USA for dialysis or renal transplants. The poor simply die. Throughout the Pacific the story is the same. “Fiji is being used as a dump for Asian products…Fiji is focusing on exporting food but there is no safeguard on imports. Why aren't we protecting our consumers?” says Premila Kumar, chief executive officer of the Fiji Consumer Council—the only body of its kind among Pacific Island nations. Hong Kong is also a small group of islands, but there the resemblance between it and its Pacific Island nation neighbours ends. Where Hong Kong is a sleepless, time-poor island that pursues change relentlessly, in the Pacific there is an abundance of time, so much so that locals tend to ignore it. Yet, just like the Pacific, Hong Kong has had an epidemic of type 2 diabetes in the past 20 years, and, at least superficially, for some of the same reasons. Rapid socioeconomic development, including a shift from industries utilising largely physical labour to those requiring mental, or at least sedentary, activity, has led to a drop in daily calorific requirements. At the same time, higher incomes and greater availability of snack foods—both eastern (instant noodles and roast pork) and western (burgers and fries)—has resulted in a rise in consumption and an expansion of waistlines. In the early 1990s, warning signs were seen when school surveys showed a troubling rise in obesity rates in primary school children—especially in boys. There were few endocrinologists, and no mass-screening programmes for diabetes, but the number of people coming into casualty with end-stage complications, renal failure, gangrene, and stroke was increasing. A 1993 survey of employees aged 30–64 years showed a diabetes prevalence of 7·7% in Hong Kong. 3 years later, a general survey of adults aged 25–74 years put the prevalence at close to 10%. By the mid-1990s, diabetes rates were tracking Asian economic growth rates. Taiwan reported a prevalence of 9·2% in 1996, Korea reported a prevalence of 6·9% in 1997, and India reported an overall prevalence of 4·3% (5·6% urban, 3·1% rural) in 2002. In Singapore, diabetes prevalence rose from 2% when first measured in 1975, to 4·7% in 1984, 8·6% in 1992, and 9% of adults aged 18–69 years in 1998. The results of that study showed that some ethnic groups were at greater risk than others: Malay and Indian women (rates of 14·3% and 14·9%, respectively) and Indian men (16·7%) had a much higher prevalence. Singaporeans linked their rising prevalence of diabetes to rapidly rising obesity rates, particularly childhood obesity (in 1998, 12% of Singaporean school children were reported to be obese). Firmly pointing the finger at westernised diets and inactivity, they gave their school children fat grades, weighing them regularly and sending those who failed off to fitness camp. What happens in Hong Kong happens in China (only a little bit later), is a mantra widely repeated by Hong Kong academics. And so it was with diabetes. In 1980, a 14-province study showed a diabetes prevalence of 1%. By 1995, results of the next major study (sample of 19 provinces) reported a prevalence of 2·5%. That study also found that people with diabetes had slightly higher BMI's (around 25·2 kg/m2) than those with impaired glucose tolerance. By 2001, diabetes prevalence in China had risen to 5·5% and, with its population, it was expected to overtake India and achieve the dubious honour of becoming home to more people with diabetes than any other country, sometime in the next decade. As with everything else, China has already exceeded the world's expectation. In March this year, Yang and colleagues published a large study, in which glucose tolerance tests were done on 46 239 people from 14 different provinces of China. Their results were staggering. Yang and his team reported an age-standardised prevalence of diabetes of 9·7% (10·6% in men and 8·8% in women) and prevalence of prediabetes as 15·5% (16·1% in men and 14·9% in women). They extrapolated this to 92·4 million adults with diabetes (50·2 million men and 42·2 million women) and 148·2 million adults with prediabetes (76·1 million men and 72·1 million women). “For every person in the world with HIV there are three people in China with diabetes”, David Whiting, an epidemiologist with the International Diabetes Federation, pointed out when Yang's study was released. The size of the problem was not the only disturbing feature of this study. Although the prevalence increased with age, it was already very high in young people—3·2% in people aged 20–39 years. At age 60 years and above, one in five of those tested were found to be diabetic. The throwaway figure for Asia's diabetes epidemic is 100 million. But if Yang's findings truly indicate what is going on in China—93 million people with diabetes, many of them young to middle-aged—then the real extent of diabetes in Asia and the effect on human health, even human history, is far greater than anyone realised. It is not simply a rise in obesity that has led to the Asian diabetes epidemic, says Juliana Chan, of the Hong Kong Institute of Diabetes and Obesity at the Chinese University of Hong Kong. “This group—those who developed diabetes biologically—they are not ready for this energy dense nutrition…There is a window in this disease evolution, here in Hong Kong and we can learn from it.” This idea is supported by Yang's study, which found a diabetes prevalence of 4·5% in Chinese people with a BMI of less than 18 kg/m2, and 7·6% in people with a BMI of 18·5–24·9 kg/m2. Although it has been argued that the cutoff points for BMI should be lowered in Asians, this still gives a very high prevalence among people judged to be normal or underweight. Although the two core factors—obesity and inactivity—causing so much concern in the Pacific, are just as relevant to their Asian neighbours, those charting the epidemic point to other factors peculiar to the high-stress and crowded lives Asians are now living in their ever-burgeoning cities. “Psychosocial stress, depression, and short sleeping hours, which have become increasingly common in developing countries undergoing rapid economic developments, have been associated with higher risk of metabolic syndrome in Asian populations”, Chan and colleagues indicated in a 2009 article. Chan says that there are strong genetic and anthropological factors that need to be considered rather than just lumping it all in the diet and exercise basket. Although diabetes prevalence did indeed rise as waistlines expanded, not all those who developed diabetes were overweight. Several Hong Kong groups have been investigating this trend: the surge in diabetes in non-obese Asians, aiming to find improved means of predicting and preventing metabolic syndrome, and ultimately, curbing the diabetes epidemic. “The most accepted explanation is that for a given BMI, Chinese have a greater percentage of body fat and a higher cardiovascular risk. This has led to the WHO proposal of Asian criteria for overweight as greater than 23 and obesity as greater than 27·5 [in East Asians]”, says Karen Lam Siu Ling, professor of endocrinology and medicine at the University of Hong Kong. Lam's team used those criteria to assess a cohort of men and women they followed for 12 years for their Hong Kong Cardiovascular Risk Factors Prevalence Study. “Using those criteria, 15% and 15·5% respectively of our men and women, aged 37–74 years, would be considered as obese.” But, says Lam, weights are not changing as quickly as the physical distribution of fat. The instrument that defines the problem in Hong Kong (and therefore China) is not the scales but the measuring tape. She says that “central obesity, defined by the Asian criteria of [waistline] great than 90 cm for men and greater than 80 cm for women, was found in 33·5% of men and 44·7% in women”. “These data would suggest that, as in South Asians, Hong Kong Chinese appear to have more problems with central obesity than general obesity. This is bad news, because in our 6-year follow-up, central obesity confers a hazard ratio of 3·3 (CI 2·2–4·8) for the development of diabetes over 6 years.” “If we assume that the above Hong Kong data also apply to the rest of China, then the most important strategy to reverse or curb the rise in glucose intolerance in China would be to prevent or reduce obesity, especially central obesity.” Although China, with its diverse populations and landscapes and complex mix of impoverished traditional rural communities and excessively wealthy, westernised urban communities seems to share little beyond ethnic origin with Hong Kong, the two share strong cultural traits. And one of the strongest is a veneration of male children. In Asian towns and countries, where Chinese are the dominant ethnic group, childhood obesity rates are much higher in boys than in girls. In Singapore, they blamed doting grandmothers for this distribution and tried to persuade proud grandmothers not to show their love by feeding up their number one grandsons. In China, where the one-child policy has led to grandmothers, mothers, aunts, and neighbours all competing for the affection of a few little boys, it is no wonder that childhood obesity rates are skyrocketing—especially among boys. In 2000, a survey of children aged 7–18 years, found that 17% of the boys and 10% of the girls were overweight or obese. “Whether the one-child policy has contributed to this [trend], on top of the dramatic surge in prosperity in recent years, remains speculative”, says Lam. “Vigorous efforts to promote regular exercise and healthy diet, targeting at our young, should be urgently implemented.” Although the sheer magnitude of the Chinese epidemic has only recently been confirmed, the Chinese medical establishment has long been aware they have a serious problem and looked for ways to reverse it. Early in the 1990s, a group in Da Qing showed that modification of diet and use of exercise could reduce the risk of developing diabetes by more than 30% in people with impaired glucose tolerance. Even so, applying such work in a vast country with severe infrastructure, income, and health service mismatches is no easy task. Reaching medical help is physically difficult for many, and, too often, economically impossible for most. Enter Hong Kong, China's window on the problem. One approach that might enable doctors to focus on who needs most care, and where and when they might need it, is being trialled in Hong Kong. The Joint Asia Diabetes Evaluation programme is a web-based programme developed by a team from the Hong Kong Institute of Diabetes and Obesity at the Chinese University of Hong Kong that uses an interactive risk engine to stratify patients into risk levels. However, the programme relies on each patient first undergoing a comprehensive assessment of their complications and risk factors, a luxury still beyond the reach of many people with diabetes in mainland China. In Singapore, researchers are trying to find out whether the problem starts in the womb, and if so what can best be done to prevent it. Chong Yap Seng at Singapore's National University Health System, is recruiting more than 1000 pregnant women and following up their infants during the pregnancy, then 3 years after birth, and possibly even further into adolescence and young adulthood. Although their neighbours are pursuing answers to the diabetes question, for Pacific Islanders any solutions that might be found, might be found too late. Like the seas, steadily rising and eating away at their land, the diabetes epidemic is eating away at their populations. And just as western development is seen as the cause of the rising sea waters, so too are western food and western marketing methods seen as the causes of the relentless rise in diabetes. Fiji's consumer advocate, Kumar, said her group surveyed schools and found that “schools were teaching about healthy food but had unhealthy food in the canteens. Coca-Cola was giving special school prizes—free fizzy drinks. So this is where it starts.” When her group asked Fijian school children to pick foods to put in their lunchboxes—ranging from healthy foods such as fruit and vegetables, to unhealthy snack foods—20% chose one or two healthy items, but 80% filled the entire lunchbox with unhealthy foods. Susana Tuisawau, executive director of the Pacific Foundation for the Advancement of Women, says that there is no point in just telling people to eat more fruit and vegetables when these are much more expensive than the imported processed foods. “If people do not have a place to grow their own vegetables and fruit, they are unlikely to return to traditional diets because such a diet is priced beyond what most can afford”, says Tuisawau. Her group asked politicians gathered at the Pacific Food Summit in April to consider “encouraging Pacific Island Governments to re-look at new low-cost housing and building policies so that in the Pacific these must make provisions for home gardening”. But be they sedate Pacific Islanders or driven Hong Kong traders, the inhabitants of the Asia-Pacific region are all facing the same problem, a disease that their health systems have yet to tackle effectively, and one that poses more and more difficult questions daily. However, the fact there are questions, is a positive sign, says Juliana Chan. “This is a very complex disease. If we don't understand the epidemiology, the evolution, and the anthropology, we won't understand diabetes.” Juliana Chan—helping patients live with diabetesAt some point, the wiser members of the medical profession accept an unfashionable truth: doctors can't do everything. For Juliana Chan the moment came during a workshop on peer empowerment. The presenter, Edward Fisher, calculated the number of hours people live with diabetes in a year, then subtracted the tiny fraction they get to spend with physicians. “8765 hours a year patients live with diabetes. For 1 of those hours, we doctors have contact with them. If we think in that 1 hour we can change things—how a patient eats, lives, we are really kidding ourselves. Full-Text PDF
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