Christopher J.L. Murray, a Professor of Global Health at the University of Washington, is at the forefront of the effort to quantify disparities in health around the world. As the Institute Director of the Institute for Health Metrics and Evaluation (IHME), he led 500 researchers from 50 countries to create the Global Burden of Diseases, Injuries, and Risk Factors Study 2010. The study, which is updated yearly, provides estimates of health outcomes for populations in dozens of countries. As he continues his work at the Institute, his goal is “to create the most complete and up-to-date roadmap to help policymakers and donors determine which avenues to pursue to help people live longer, healthier lives.”
Why is life expectancy in the United States growing more slowly than other countries?
There are a lot of factors that could be slowing down life expectancy in the United States. Tobacco, obesity, and dietary risk factors are all part of the story. After the mid-1990s, obesity rates quickly increased in the United States, while countries like Canada and Germany saw a more gradual rise in obesity. By 2013, the US had much higher rates of obesity than Germany. In terms of tobacco, Canada has made faster progress in reducing the number of people who smoke than we have in the United States. The U.S. also has less of a primary health care strategy than in other high-income countries, such as Australia. Australia used to have lower life expectancy than the U.S. The country has really invested in primary care, and it has improved so significantly in life expectancy that Australia has surpassed the U.S. in longevity. We also have to remember that the United States is a very big country with some very large disparities in economic opportunity, education, access to health care, and other dynamics. People in places like Marin County in California have a life expectancy of 85 years, among the highest in the world. But then across the country, men living in McDowell, West Virginia can expect to live to 64 years, which is the same as Pakistan. As long as you have that kind of discrepancy in survival within the same country, it’s going to be challenging to see faster progress.
How great is the discrepancy in life expectancy between different parts of the country?
This discrepancy is fairly substantial, especially when you look at what’s happening for American women. Between 1985 and 2010, hundreds of counties saw no significant change or actual declines in female life expectancy. This finding was most evident in the South and Midwest, with a number of counties in Georgia, Kentucky, and Oklahoma registering shorter life expectancies for women in 2010 than in 1985. During this time period, 95% of U.S. counties saw improvements for male expectancy; only 55% of counties experienced the same for women.
What are some of the possible reasons for the slowing of longevity in certain parts of in the United States?
When you’re looking at risk factors for disease and injury in the U.S., dietary risks, such as eating too little fruit, nuts, and seeds and too much salt, are the number one cause. That’s followed by smoking, high body mass index, high blood pressure, high blood sugar, insufficient exercise, and alcohol use. Hypertension is a big missed opportunity in the U.S. If we had a primary health care system that was able to better identify hypertension, recommend appropriate treatments, and control the risks, we would make a huge dent in death and disability from high blood pressure. Longevity is likely to vary a lot based on where you are in the U.S. In some places, such as a number of counties in Montana and Idaho, rates of daily smoking haven’t changed much since the 1990s – which is the complete opposite of what you see nationwide. The proportion of women who are overweight or obese has increased much faster than the national average for many counties in Oklahoma, Louisiana, and Missouri. These kinds of health disparities, coupled with large inequalities in education, rates of poverty, and access to quality healthcare, can make it very challenging to improve life expectancy.
In areas where life expectancy has increased at pace with the rest of the world over the last two decades, like New York City, what are the causes?
Since most of the United States’ health problems stem from things we can change (poor diet, lack of exercise, smoking, alcohol and drug consumption), large gains in life expectancy are at least due in part to improved health behaviors. That means eating healthier, being more physically active, quitting smoking or not smoking at all, and so on. In New York City, there have been tremendous reductions in the percentage of people who smoke since 1980. It’s likely that the city’s efforts to curb smoking and to reduce exposure to second-hand smoke have contributed to these health gains. The city has also been a leader in encouraging healthier diets. Given that dietary risk factors contribute more to the burden of disease in the United States than any other factor, those types of efforts are certain to have an impact. There’s also a question about how much of this is due to healthy people moving in, because New York had a lot of people move to the city during that time period. That may have played a role here.
How might the longevity gap in the U.S. shrink in the future?
To narrow the gap between the people who live the longest and shortest lives in the U.S., there needs to be a focus on aligning health policies and programs with local health needs. In the State of the US Health policy report we published last year, we provide three main recommendations. First, focus public health initiatives on modifiable risks and behaviors, such as poor diet and smoking tobacco. Use policy tools to incentivize healthy behaviors and discourage unhealthy decision-making. Second, improved access to and delivery of high quality primary care services are needed to treat chronic conditions such as diabetes and hypertension. Third, accelerated research on and development of products for leading causes of illness and unhealthy behaviors is needed to improve treatment and prevention efforts. It’s possible for this longevity gap to shrink, but a strong political commitment to addressing America’s epidemic of unhealthy behaviors and lifestyles will be necessary.
Is the United States unique in its longevity gap?
We know that the United States isn’t completely unique in its longevity gap. In the United Kingdom, for instance, a study found that men living in East Dorset averaged 10 more years of life than men living Glasgow City. We did an analysis that looked at Canada, Japan, and the U.K., and we found that the longevity gaps in the U.S. are greater than those countries. It’s also the case that the disparities are widening in the U.S. At IHME, we’re now working on estimating more localized life expectancies for China, Indonesia, Norway, and Mexico.
How much is life expectancy tied to economics?
It’s not surprising that some of the poorest countries in the world have life expectancies less than 50 years, such as Haiti and Central African Republic, and that richer countries have some of the highest -- 86 years in Japan, for example. But having a strong economy or spending the most on healthcare doesn’t guarantee having the highest life expectancy. The United States is a prime example of this. A better economy can support the things that can affect life expectancy, such as a strong health system, but we also have seen that higher-income countries tend to have more problems with obesity and high blood pressure, two of the biggest risk factors for poor health. It’s similar for individuals – having more money can definitely help with having a longer life, especially since having a higher income is associated with other factors that can increase life expectancy: education, good health insurance, lower rates of obesity and smoking, living in a safer neighborhood, and so on. But having more money doesn’t guarantee a long life, particularly if you live in a place that doesn’t have high quality healthcare or a responsive health system.
What are some other factors, worldwide, that cause some countries to have lower life expectancies than others?
Countries hit the hardest with AIDS, especially in southern Sub-Saharan Africa, have seen their average life expectancies fall by at least 10 years between 1990 and 2010. Violence and political unrest can negatively affect life expectancy. In fact, we’ve seen mortality rates increase for men in many Latin American countries since the 1970s, largely because of violence. Any kind of abrupt event, whether it’s an earthquake or famine or economic collapse, can make it very difficult for people to access health services, have enough food, and live in relative safety – all factors that are associated with lower life expectancy. There are also a whole range of infectious diseases that kill children at very young ages, including pneumonia, diarrhea, and malaria. Despite great progress in reducing deaths from diarrhea globally, more than half a million children under the age of 5 still die from diarrhea globally every year. If children aren’t making it past their 5th birthday in your country, you are going to have low life expectancy overall.
Is there reason to believe that the longevity gap worldwide will narrow? How can we make it so that people in countries the world over can expect to live equally long lives?
On the current trajectory, we have to expect that the health disparities in the U.S. are going to widen, but there is the potential to change that course. We have made incredible advances in medicine, prevention efforts, and educational attainment, among other things. But the best science and technology in the world can’t offset persistent disparities in access to health services, inadequate funding of public health programs, or lax policies related to health risks. The belief that everyone deserves to live a long, healthy life underlies all the work I do. In my lifetime, I’d love to see people in Haiti live as long as someone in Japan. Achieving greater equality in global life expectancy would be extremely challenging and it would take a lot of money, political will, and time. But if the financial and political commitment to do so can intersect with medical advances and public health initiatives, we might just see a world with better health and longer lives.
Interview by Jordan G. Teicher.