A comment before today’s Dean’s Note. President Obama proclaimed this last week to be Prescription Opioid and Heroin Epidemic Awareness Week; a welcome and much-needed focus on a key public health challenge. During the week, the administration spotlighted a range of efforts to tackle the opioid crisis, including expanded treatment for people with addiction, investment in Distance Learning and Telemedicine (DLT) to support the health needs of rural communities, a competition to develop a Naloxone smartphone app to prevent overdoses, and bilateral measures aimed at disrupting the flow of fentanyl from China. This strategy, with its emphasis on innovation, marginalized populations, and the broader political and economic policies that shape health, strikes me as just the right approach, and is consistent with our own focus on social context and the upstream determinants of health. Going forward, we must continue to advocate for the centrality of these factors, and for a health policy that is founded on the same creativity and comprehensiveness that we are beginning to see applied to the opioid epidemic.
On to today’s Note.
Sometimes, the next public health challenge can be a product of the last public health success. The beginnings of public health, for example, were rooted in preventing infectious disease and promoting sanitation. Now that we have largely eradicated many of these infectious conditions in the United States and in other high-resource countries, humans are living long enough to die from non-communicable diseases, or NCDs. Although the definition can be debated, broadly speaking NCDs are illnesses that are not physically transmissible from person to person; they are typically chronic and usually occur later in the lifecourse. They also now cause more than 75 percent of deaths worldwide. In 2014, the World Health Organization (WHO) Director-General Margaret Chan said of NCDs, “The challenges presented by these diseases are enormous. They demand some fundamental changes in the way social progress is measured, the way governments work, the way responsibilities are assigned, and the way the boundaries of different government sectors are defined.” A Note, then, mindful of this week’s World Heart Day, on the rise of NCDs, and how public health can confront the ever-evolving future of human illness.
To begin, a few words about the scope of the problem. Cardiovascular diseases cause the highest proportion of NCD deaths under the age of 70, accounting for 39 percent of NCD mortality worldwide. Cancers are next, at 27 percent, followed by digestive and chronic respiratory diseases, which, taken together with other NCDs, are responsible for 30 percent of global NCD mortality (Figure 1).
What is arresting is not so much the diseases themselves, familiar as they are, but the rate at which their prevalence is growing, even as the prevalence of infectious diseases declines. This is in keeping with global trends. The top three causes of death across the world in 2012 were Ischemic heart disease, stroke and chronic obstructive pulmonary (lung) disease—all NCDs. The WHO has predicted that cancer and ischaemic heart disease, as well as cerebrovascular disease, will rise steadily through 2030, while infectious diseases like malaria, tuberculosis, and HIV/AIDS largely decelerate (Figure 2).
As shown below in Figure 3, deaths due to stroke and heart disease have increased since 2000. Six years ago the WHO projected that, between 2010 and 2020, NCD deaths would increase by 15 percent globally, which translates to roughly 44 million lives lost. The WHO regions of Africa, South-East Asia and the Eastern Mediterranean will bear the brunt of this burden, seeing NCD increases of over 20 percent. In the African Region, NCDs are predicted to cause approximately 3.9 million deaths; this figure is dwarfed by the WHO projection for South-East Asia (10.4 million deaths) and the Western Pacific (12.3 million deaths).
Even in lower-resource countries, where the majority of deaths are still caused by infectious disease, NCDs are on the rise. For example, more people die from cancers in low-resource countries than from many infectious diseases combined. And while it is true that, in 2010, the WHO reported more deaths from infectious disease than from NCDs in the Africa Region, NCDs are fast gaining ground in that part of the world. By 2020, NCDs are projected to outstrip nutritional, perinatal, maternal, and communicable diseases, causing nearly three-quarters as many deaths as these other conditions.
The rise in NCDs not only challenges us to mobilize against a growing public health threat, it also necessitates a shift in how we quantify morbidity, and how we measure progress. NCDs are often chronic conditions that undermine wellbeing throughout the lifecourse. Chronic diseases by definition tend to have long durations, so another way of quantifying burden—in addition to death—is decrease in quality of life over time. The disability-adjusted life-year, or DALY, combines years of healthy life lost due to both mortality and morbidity, or living with poor health in general. Figure 4 shows a recent ranking from the Global Burden of Disease project of the top diseases contributing to the most DALYs, by region of the world. All of the top 10 conditions in high-income countries are non-communicable. Success in the fight against NCDs therefore means success in promoting quality of life throughout the lifecourse. Chronic disease management is key to healthy aging; coming to grips with NCDs is thus an opportunity to spotlight the wellness needs of older adults, and work towards improving health at every stage of the aging process.
The problem of NCDs also necessitates a shift in how we think of the etiology of disease. If there ever was any doubt about the complexity of pathogenesis, NCDs extinguish it. Social determinants of health, including economic inequality, education, and housing, are an ineluctable part of the production of NCDs, and shape how they emerge and flourish. Consider obesity, associated as it is with the onset of many NCDs, including cancer. The interaction between obesity and a range of factors—from smoking, to physical activity, to other NCDs like diabetes—can determine the incidence of cancer in populations. To tackle the problem of cancer, we must therefore look at the structural drivers that lead to obesity—factors like income, the availability of healthy food, and cultural norms—and the interplay of these factors.
The rise of NCDs, while worrying, represents a unique opportunity for public health. It is core to the work of public health over the coming decade to raise awareness of these diseases; of both their ubiquity and their preventability. This mission is, I think, consistent with where we are headed as a school. When we discuss the social context of disease, or examine how our living space affects our health; when we take a hard look at global poverty, or facilitate conversations around healthy aging, we are highlighting the steps we must take to prevent and mitigate the consequences of the diseases that will preoccupy the world over the coming decades. This puts our work squarely at the leading edge of the promotion of health and the prevention of disease, towards the production of healthier populations.
I hope everyone has a terrific week. Until next week.
Sandro Galea, MD, DrPH
Dean and Robert A. Knox Professor
Boston University School of Public Health
Acknowledgement: I am grateful to Laura Sampson and to Eric DelGizzo, for their contributions to this Dean’s Note
Previous Dean’s Notes are archived at: https://www.bu.edu/sph/tag/deans-note/