The Global Burden of Lung Disease

Smoking, pollution major factors that could be controlled through a public health approach

Published on June 8, 2014by Elaine Meyer

In rural Kentucky, a middle-aged woman who used to smoke visits her doctor complaining of shortness of breath. In Beijing a young man walks to work in a haze of smog with a splitting headache. In Nairobi, Kenya, a young woman hunches over a stove, breathing in toxic fumes and coughing as she cooks her family’s dinner over charcoal.

These experiences represent the global scope of lung diseases, which are a heavy burden in low, middle, and high-income countries alike. They are among the leading causes of death in the world, according to a recently released report by the Forum of International Respiratory Societies. Yet because they often manifest in initially less dramatic symptoms like a cough or headache, and because they are associated with cigarettes, lung diseases often are ignored or written off as a smoker’s problem.

“Some of these things seem like background noise. I think that’s part of the problem,” says Dr. Neil Schluger, a professor of medicine, epidemiology, and environmental health sciences and chief of the pulmonary, allergy and critical care medicine division at Columbia University.

A new approach is required that goes beyond simply developing new treatments.

According to Dr. R. Graham Barr, a professor of medicine and epidemiology at Columbia, “The bottom line is that the amount we spend on research diagnosis and treatment in lung disease is miniscule compared to cardiovascular disease or nonsmoking related cancer.”

GRAPH cancer stats

The largest absolute increase in cancer-related costs is projected to occur with lung cancer, with a large proportion of the increase occurring due to medical costs and income losses.

Diseases of the lung have existed since Greek and Roman times, but they have increased dramatically with industrialization, the development and marketing of cigarettes, and the drop in deaths from other diseases.

A delicate and complex system, the lungs are the only internal organs that are constantly exposed to the environment. When people breathe in toxins, their lungs can experience inflammation, scarring, and infection. Yet, the damage accumulates gradually, over a long period of time, which is why people do not always make the connection between hazardous air exposures and diseases like lung cancer, chronic obstructive pulmonary illness or COPD, acute respiratory tract infection, and tuberculosis—four of the leading causes of death in the world.

Since becoming chief scientific officer of the World Lung Foundation, Dr. Schluger has been working to draw attention to lung diseases and the central role that is played by the air we breathe. “Although molecularly lung diseases are different from each other, they are all exacerbated by pollution and tobacco,” he says.

In March, he and Dr. Ram Koppaka, a ‎senior advisor at the Centers for Disease Control and Prevention published a think piece in the Annals of the American Thoracic Society, articulating the problem: “The lung diseases that account for the greatest global morbidity and mortality are preventable to a very significant degree.”

“A new approach is required that goes beyond simply developing new treatments for each of the major respiratory disorders.”

Outdoor air pollution

Last October, what was dubbed the “Airpocalypsehit Harbin, China, a city of 10 million in the northeastern part of the country. A thick, grey cloud of pollution rendered visibility so low that people walking side by side reported they could not see each other. Schools closed, highways shut down, and authorities urged people to stay home. The air quality score index went above 500—which is the highest possible number on that scale and 20 times the level of particulate matter considered safe by the World Health Organization (WHO).

Beijing Image: Chris Aston

Image: Chris Aston

Catastrophic levels of air pollution and other related consequences, such as heavy traffic, contaminated farmland, and ailments among factory workers, spotlight the Chinese government’s failure to check the pace of industrialization and development. Where that pace once evoked fear on the part of economic competitors like the U.S., China is increasingly becoming an exemplar of the problems wrought by unrestrained development seen in many middle-income countries, like India, Egypt, and Pakistan. “There’s such a rush to develop economically that government regulations on things like air pollution or sale of cigarettes sometimes become secondary,” says Dr. Schluger.

According to WHO, one in eight of total global deaths in 2012—7 million people—were linked to air pollution. With the global trend toward urbanization, the problem will likely get worse.

In their paper, Drs. Schluger and Koppaka say that “Governments must be held accountable…for protecting the lives of their citizens at least as much as they protect the commercial interests of large industries.” They cite ways that high-income countries have reduced pollution at its source, such as mandating lead-free gasoline, encouraging fuel-efficient vehicles, traffic planning, and air filtering methods at factories.

Government air quality standards have made a difference, as the U.S. has shown with the Clean Air Act passed in 1963. By the 1990s, air pollution in most American cities had declined or plateaued. “Those of us who live in high income cities, we breathe much cleaner air than our grandparents and our parents did,” says Dr. Darby Jack, assistant professor of environmental health sciences at Columbia’s Mailman School of Public Health.

An estimated 4.3 million people die each year as a result of exposure to household air pollution, a big part of which comes from rudimentary cook stoves that burn dirty fuels like coal, animal dung, straw, and agricultural waste, according to WHO. Image: Ben Grey

An estimated 4.3 million people die each year as a result of exposure to household air pollution, a big part of which comes from rudimentary cook stoves that burn dirty fuels like coal, animal dung, straw, and agricultural waste, according to WHO.
Image: Ben Grey

Household air pollution

Around 3 billion people, especially in nations in sub-Saharan Africa, South and East Asia, the Middle East, and Latin America, heat their homes with open fires and cook using leaky stoves that burn dirty fuels like coal, animal dung, straw, and agricultural waste. Soot from these sources penetrates deeply into the lungs and can lead to pneumonia in children and COPD in adults. An estimated 4.3 million people die each year as a result of exposure to household air pollution, a big part of which is from cooking on these kinds of stoves, according to WHO.

This is the cost of living in a country where sources of clean fuel from electricity and natural gas are not often available, and stoves are not fuel-efficient.

Several initiatives have sprung up to promote the design of more efficient, cleaner burning stoves, but it has proven difficult because of the limited budgets. “We’ve seen a lot of effort in the past that has not resulted in improved health because the interventions weren’t that clean at the end of the day. Burning these fuels in a way that reduces exposure is a really hard problem,” says Dr. Jack.

He is currently conducting an intervention study in Ghana that compares giving people “the latest and greatest biomass stoves” with giving them liquefied petroleum gas, which is cleaner than the fuels they usually use. “Those are sort of the two options: clean fuels or clean combustion. Our study is designed to look at both of those side by side. Most of those studies have just looked at the clean cook stoves,” he says.

Based on disappointing results from previous studies of stoves, he believes the solution will likely come from clean fuels but acknowledges that money is a big obstacle. “It’s much more expensive.”


New York City residents are used to breathing smoke-free air in restaurants, bars, stores, and other public spaces, and are accustomed to cigarettes priced at upwards of 14 dollars. Here, smoking may no longer seem mainstream. But in other parts of the world, the number of smokers is climbing, a result of population growth and marketing efforts of tobacco companies. The total number has risen from 721 million to 967 million since 1980, although rates of smoking have declined worldwide over that period, according to a study in the Journal of the American Medical Association. Still, nearly six million deaths are linked to tobacco each year.


A cigarette billboard in India

While high-income countries began snuffing out cigarette advertising many decades ago, cigarette companies redirected their efforts toward nations with growing middle classes and fewer anti-tobacco regulations. In China, which has nearly one-third of the world’s smokers, the state-run tobacco company China National Tobacco Corporation has not set cigarette taxes at any meaningful level. As a result, smoking runs cheap—74 cents a pack—but costly in health—an estimated 1 million people die of tobacco-related causes of death each year, a number that is expected to triple by 2050.

In Africa, smoking rates are rising amidst dedicated marketing efforts by cigarette companies to target a continent that has been called “Big Tobacco’s last frontier.” Tobacco companies employ locals in their factories and deploy marketing strategies, such as selling individually-wrapped cigarettes to increase affordability for those who do not have much spending money—such as children.

Dr. Schluger says that tobacco companies, not individuals, should primarily be held responsible for smoking rate spikes: “By no means should we treat people who use tobacco and have lung disease as if it’s their fault. The tobacco industry says this all the time: ‘people choose to do it.’ Let’s face it: it’s not a fair fight. The tobacco industry is spending billions of dollars on advertising, which is extremely effective.”

In the U.S., New York City has been a leader, with a hefty increase on cigarette taxes and ban on smoking at indoor and outdoor public spaces. Since the ban was enacted in 2003, the percent of active smokers has decreased in New York City from 21 to 14, and the city now has the lowest rates of lung cancer deaths in the New York state, according to the American Cancer Society of New York and New Jersey.

“Mayor Bloomberg saved more lives from lung disease than any physician in New York or any hospital because of what he did to decrease tobacco use in the city,” says Dr. Schluger.  “Individuals can say, ‘I’m not going to smoke,’ but they need help from the government,” he adds.

That help is more forthcoming in some countries than others. In 2013, the WHO ratified the Framework Convention on Tobacco Control, which sets a universal standard for regulating tobacco production, sales, advertising, distribution, and taxes. “Almost every country in the world has signed it, almost no country has adopted all of its measures,” says Dr. Schluger. 

Despite the challenges implementing the tobacco treaty, Drs. Schluger and Koppaka urge WHO to pass a similar treaty to address air pollution and occupational exposure.


A man smokes on the streets in China

“We do not underestimate the difficulty in reducing the impact of the important drivers of lung disease in the world,” they say. “These drivers arise to a great degree because of poverty (e.g., due to a lack of access to clean burning fuels and efficient stoves for cooking) because of a lack of government oversight and regulation (regarding the sale of tobacco products or worker safety), or a combination of both.”

The centrality of public health interventions cannot be underestimated. Dr. Schluger says that the global epidemic of lung disease is not one that we can treat ourselves out of: “When I think of the global burden of lung disease, these public health and population approaches could be so much more effective than waiting for people to get sick and treating them.”

Featured image by Jon Kalish. Edited by Barbara Aaron