With over one-third of East Asia’s 1.7 billion people overweight or obese, mounting demographic pressure and burgeoning healthcare costs are forcing public health officials to grapple with the rising morbidity and mortality associated with obesity. However, the presence of metabolically healthy obesity, in which the short-term disease risks of diabetes and heart disease are low, represents a possible buffer for healthcare planning in East Asia. This narrative review analyzes the health risks from obesity through representative Japan- and China-specific analyses that take into account unique cultural, genetic, and other factors that drive obesity; the potential impact of metabolically healthy obesity on public health; and suggested non-surgical/non-pharmacological interventions to relieve pressure on the nationalized healthcare systems prevalent in the region. Such an emphasis on interventions to both delay obesity as well as potentially reverse metabolic syndrome could save millions of lives and billions of USD equivalents in healthcare throughout East Asia.
Asian Obesity: A Focus on Metabolic Health
The Crisis Point: Expected Life and Public Costs for East Asia
Obesity-related risks mainly consist of cardiorespiratory, cerebrovascular, and metabolic diseases (such as heart failure, stroke, and diabetes)
[1]. Such obesity-related issues require both long-term intervention (e.g., insulin and monitoring for diabetes) as well as eventual invasive surgery for cardiorespiratory diseases or strokes
[1]. Furthermore, lost productivity from reduced functional capacity and medical recovery after procedures can drain thousands of USD equivalents per patient per year from an industrialized economy
[2].
Obesity will be a major drain on East Asian regional healthcare expenditures over the next 20 years since direct disease expenditures stemming from overweight/obese conditions already cost 0.78% of the GDP (or up to a pan-Asian average of 12% of healthcare costs annually) and as morbidity rates rise steadily throughout the region
[3]. Indirect costs, based on years of productive lifespan lost due to obesity-related illness, may reach as high as USD 32 billion in China, while countries with smaller populations, such as South Korea or Japan, may have costs in the range of USD 800 million to USD 2 billion
[3]. Yet another critical inflection point for Asia is the rapid aging of the current economic powerhouses of China, South Korea, and Japan, each with declining birthrates and increases in the percentage of population above age 65. In Japan, where 27% of the population is past retirement age, birthrates have not increased to compensate
[4]. China is also projected to double its older adult population from 7% to 14% within 23 years, while Korea was already reported at 14% and increasing in 2017
[5][6]. In all cases, the burden of care for these rapidly aging societies will be magnified by obesity-related illnesses and decreases in functional status within both the working and retired populations.
Obesity, Diabetes, the Heart, and the Brain: A Troublesome Tetrad
Obesity has been linked to the development of type 2 diabetes and hypertension that precedes cardiovascular problems such as hypertension, coronary heart disease, and cerebrovascular maladies (i.e., stroke)
[7]. The chance of developing these problems rises steadily as the obese person ages, with sarcopenia, non-alcoholic fatty liver disease (NAFLD), and metabolic slowdown contributing to the persistence of excess visceral body fat that maintains the increased risk
[8][9][10]. Prediabetes may also be present and persist over the development of obesity, as evidenced through higher homeostasis model of insulin resistance (HOMA-IR) scores without other metabolic syndrome elements
[11]. The effect of prediabetes as a chronically elevated glycemic state may cause inflammation and vascular damage that increases heart failure risk even if type 2 diabetes does not fully manifest
[12].
Chronic cardiovascular and cerebrovascular conditions are thought to be caused by the synergistic effect of diabetes or prediabetes with hypertension on forming calcified arterial plaques, especially in the coronary and cerebral arteries
[12][13]. This metabolism–disease relationship is proven by reports that mortality risks decrease observably upon loss of fat from the central trunk
[14][15][16][17]. Furthermore, studies of glucose-controlling drugs that result in smaller waistline circumference and large population studies have observed decreased odds ratios of diabetic and cardiovascular risks after moderate weight loss
[14][18]. These decreases are due to improvements in insulin sensitivity and resolution of NAFLD
[19]. Reductions in renin-angiotensin activation, increased sympathetic tone, lower inflammation, and less oxidative stress also accompany fat loss and greatly reduce the risks of hypertension and pathologic cardiac remodeling in the previously obese
[20].
General Interventions Available against Obesity
Clinical interventions such as medication to restore glucose sensitivity and bariatric surgery to limit caloric intake have met with some long-term success, but physiological/psychological side effects from medication and the invasiveness of surgery could be suboptimal for a significant portion of the younger obese population
[21]. Furthermore, public health costs to provide medication and surgery plus long-term follow-up for tens of millions of patients may be unfeasible for East Asian healthcare systems already under strain from demographic pressure. For these reasons, exercise and diet remain a mainstay treatment that could save money by precluding millions of new prescriptions or surgeries.
As most East Asian countries have some kind of nationalized healthcare, supervised diet and exercise interventions may be the most financially suitable, but disparities in coverage, diet quality, and exercise feasibility (due to pollution) as well as cultural differences make general recommendations difficult. In this review, customized, non-pharmacological, and non-surgical intervention plans are suggested based on analyses of two representative countries, China and Japan.