Noncommunicable Diseases and How They Are Measured
How to track and understand the world’s leading causes of death.
The health problems that attract the world’s attention tend to be infectious diseases, like the respiratory illness COVID-19, which has infected more than 755 million people around the world as of February 2023. But some of the deadliest killers are no longer those that pass from person to person. Over 70 percent of the world’s deaths result from diseases such as cancer or diabetes that aren’t transmitted between people. These are called noncommunicable diseases (NCDs).
NCDs are a growing problem. In 2000, just four out of the top ten causes of death worldwide were noncommunicable. By 2019, that number had grown to seven out of ten.
When you look at graphs showing all NCDs lumped together, the trend becomes apparent: rates of NCDs are on the rise. But when you begin to parse the data, other trends emerge that emerge how differently those diseases affect various communities.
To better understand the effects, let’s isolate the data on three of the deadliest NCDs: heart disease, dementia, and lung cancer. Each disease's effects can demonstrate a different aspect of measuring, preventing, and treating NCDs.
Access to Health Care Matters
The most common type of heart disease is ischemic heart disease, also known as coronary artery disease, related to problems with the arteries that bring blood to the heart. Heart disease is the number one cause of death around the world, claiming almost eighteen million lives a year. It is often caused by other conditions such as high blood pressure, high cholesterol, diabetes, and obesity. The disease can also result from lifestyle characteristics such as smoking or a lack of physical activity. It’s also shaped by something called the social determinants of health—factors like where people live, what they do for work, and how much they make. In the United States, systemic racism has influenced many of these factors, resulting in lower-quality health care for many people of color.
Health researchers use a measure called the Socio-Demographic Index (SDI) to evaluate a country’s level of development. Countries are given a grade that shows their development level based on factors such as overall income and education. High SDI countries include the United States, the Czech Republic, and South Korea; low SDI countries include Chad, Nepal, and Papua New Guinea. The SDI is unique in that it doesn’t use overall health as a factor in its analysis. That exclusion makes it a useful tool for health researchers because with health taken out of the picture, they can compare different countries and find out which factors help good health outcomes and which ones hinder them.
Such data is important to understand, for example, when looking at the mortality rates for heart disease. Separating the countries by their SDI rankings makes it clear that heart disease mortality rates are mostly decreasing in high SDI countries but have increased in the lower SDI countries.
So what does that mean? People in wealthy countries tend to have better access to health care, which makes dealing with chronic diseases easier, so deaths from chronic diseases are decreasing in those places. People in wealthy countries are more likelier to have access to preventive health care and thus be aware of risk factors such as high blood pressure or cholesterol, which can be managed before they cause heart disease.
Middle SDI countries, such as Brazil, and low-middle SDI countries, such as Myanmar, aren’t there yet. As those countries develop, their citizens become exposed to unhealthy lifestyle changes—think more sedentary office jobs or access to cheap fast-food options—that often accompany a country’s advancement. Such lifestyle changes amplify the conditions that help increase the risk of heart disease. And because access to health care tends to be more limited in those countries, the risk is magnified.
Age as a Challenge
Dementia is the loss of or reduction in brain functions such as memory, decision-making, and even language. It occurs when healthy nerve cells in the brain deteriorate, lose connections with other brain cells, and die.
Globally, more than fifty-five million people live with dementia—over 60 percent of them in in low- and middle-income-level countries. Although dementia causes an estimated two million deaths each year, mortality isn’t the most useful method of measuring dementia’s effects. A more interesting way to understand the consequences of conditions like dementia is to look at years lived with disability (YLDs).
As life expectancies increase around the world, the number of YLDs is also rising for dementia in all countries.
Simply put, that means people with dementia are receiving care for longer periods of time than they used to.
Longer lifespans are generally beneficial. However, they also mean more people with dementia who need extended care, which is harder to access in low SDI countries that tend to have less-developed health infrastructure.
Additionally, one study estimates that more than 60 percent of global dementia cases go undetected, meaning dementia rates could be much higher than estimates reveal—and that those living with undiagnosed dementia aren’t getting the care they need.
The Effect of Gender
Lung cancer is the growth of malignant tumors in the lungs. It is the deadliest cancer, and it caused 1.8 million deaths in 2020. Although nonsmokers also get lung cancer, over 60 percent of lung cancer deaths are associated with tobacco uses.
Lung cancer death rates are much higher for men than for women due to higher smoking rates. Globally, around 37 percent of all men smoke, compared to about 8 percent of women.
As trends such as vaping emerge, new cases of lung cancer and other lung injuries could arise. Although some of those cases have already been documented, others could take longer to appear.
What Can Be Done
NCDs create new challenges—not only for people they affect but also for the web of organizations and governments dedicated to tackling global health problems. For example, most people ultimately die due to an NCD, but most global health funding doesn’t target NCDs. Because NCDs are a relatively new challenge often correlated with lifestyle factors—including rising income—and require prolonged care and treatment, funding to combat them hasn’t caught up with the need. Moreover, infectious diseases are often a more attractive intervention area for donors: a specific, quantifiable problem that can be targeted more straightforwardly, such as with vaccines or mosquito nets.
From Data to Day-to-Day Life
As lifespans extend, noncommunicable diseases pose a larger setback to the progress made in global health. Although NCDs are on the rise globally, data shows that not every disease affects everyone in the same way. People’s level of risk of heart disease, dementia, and lung cancer depends on who they are, where they live, and the choices they make.