Clearing the air: UChicago scholar’s cross-cultural research on household air pollution could improve the health of half the global population

December 3, 2020

  • Christopher "Sola" Olopade

    Sometimes the biggest problems have relatively simple solutions that can emerge in unexpected places.

    Christopher Sola Olopade can attest to that. Recently named Dean for Academic Affairs in the Biological Sciences Division, Olopade is also Professor of Family Medicine and Medicine in the Section of Pulmonary, Critical Care, and Sleep Medicine at UChicago Medicine, where his research focuses on reducing global disparities in asthma outcomes. Olopade’s most noteworthy research identified multiple potential health risks of exposure to household air pollution (HAP), along with possible solutions. This breakthrough research didn’t originate at the University of Chicago or anywhere in the United States, but rather in Nigeria, a middle-income West African country with limited resources and a high poverty rate.

    Olopade completed medical school at Nigeria’s University of Ibadan. After relocating to the United States, he returned periodically to his alma mater to share information and exchange ideas about his clinical training and research.

    “I had an opportunity to attend medical school in Nigeria for free on a full scholarship, and I always felt it was important to find a way to give back,” Olopade said. “For years at my former university seeing patients on the South Side of Chicago, I wondered a lot about what could be driving differences in the expression of asthma, and the diverging trend in the prevalence of allergies between low-income versus high-income countries. I wanted to learn more about what caused the differences, and I wondered what we might be able to learn from Nigeria that could apply to the United States.”

    Exploring the root causes of respiratory issues

    In general, Nigerians with asthma experience milder symptoms and allergies than Americans. Olopade wondered if the “hygiene hypothesis,” which suggests that exposure to dirt early in life might be a driver of how the immune system is primed to function in later life, might explain the observed differences between low- and high-income countries. He implemented a research study that eventually collected biological samples including blood, stool, indoor dust samples, and allergy skin tests from Nigerian children and adults. 

    While collecting dust samples, Olopade noted that in nearly 70% of homes he visited, kitchen walls were covered in black soot—from traditional cooking techniques. This observation raised the likelihood that regular exposure to and inhalation of large amounts of pollutants from cooking smoke at an early age may lead to chronic lung diseases like asthma. Olopade observed that allergies may not be the root cause of the breathing problem in Nigerian children, and that household air pollution (HAP) associated oxidative stress may be the key factor. He later found out that exposure to HAP accounted for more than three million premature and preventable deaths globally each year, especially in women and children. 

    With the support of a grant from the American College of Chest Physicians, Olopade soon returned to Nigeria to conduct a study confirming that indoor levels of particulate matter were 100 times World Health Organization (WHO) standard levels, and that indoor levels of carbon monoxide were also dangerously high. Replacing traditional firewood stoves with an improved firewood stove improved indoor air quality by reducing particulate matter levels to about five times WHO standards, which would still cause significant lung damage over the long term. 

    With funding from the United Nations Foundation and the Susie and Richard Kiphart Foundation, Olopade conducted a randomized controlled study exploring the effects of transitioning pregnant women from using polluting fuels for cooking, such as firewood and kerosene, to clean-burning ethanol. The study showed that residences that switched to ethanol stoves experienced much improved indoor air quality. Women using ethanol were more likely to carry their pregnancies to term than women using polluting fuels. Additionally, women using ethanol had lower rates of miscarriage, stillbirth, and neonatal deaths; a reduced risk of developing hypertension during pregnancy; and had healthier babies. 

    Nigerians, along with roughly half of the world’s population, suffer from severe exposure to HAP due to lack of access to clean energy. Olopade’s research illustrated how millions of people could instantly benefit from switching to clean cooking fuel such as ethanol, which can be easily fermented from agricultural waste. He used some of his grant funds to purchase the stoves used in the experiment, which cost $60 apiece, for women in the control group. Many of the women continue to cook with ethanol stoves today. Once the research was published, Olopade turned his attention to working with international governments and agencies to make ethanol stoves more widely available.

    “We demonstrated that cooking with kerosene and firewood is bad, but so what? People need access to the information and resources in order to change their habits,” Olopade said. “Look at the potential to help a lot of people around the world. It’s a huge opportunity to make a difference in public health and simultaneously reduce environmental degradation from cutting down trees for cooking.” 

    Applying lessons learned to the local Chicago community

    With funding from the National Institute of Health (NIH), Olopade is conducting longitudinal studies of the birth cohort of the completed Nigerian study to determine the impact of in-utero exposure to HAP on cognitive development in early childhood. He also applied his findings back in Chicago by examining the city’s South Side, which has some of the highest premature delivery and infant mortality rates in the country. Considering what he’d learned in Nigeria, Olopade set out to determine whether this issue could be related to environmental factors.

    After widely deploying low-cost monitors to determine HAP levels in homes in several census tracts on the South Side, Olopade was surprised to discover that the pollution rates in some homes were nearly as high as they’d been in Nigerian homes that used kerosene and firewood stoves for cooking. When talking with South Side residents, Olopade learned that generations of low-income families consistently turn on gas ranges to supplement heat in drafty homes during the winter months, leading to high levels of HAP. With support from the NIH-funded ChicAgo Center for Health and Environment, a collaborative between the University of Chicago and the University of Illinois, Olopade and colleagues are continuing this research on the South Side by monitoring HAP levels in the homes of pregnant women to determine the impact of seasonal exposure to HAP on pregnancy outcomes.

    “If we can prove that this learned behavior is an action that causes a lot of self-harm to our people, and if we see a major difference in HAP levels and adverse birth outcomes between the warmer and cooler months, we can improve the health of many Chicagoans by just running some public service announcements to educate our neighbors,” Olopade said.

    Olopade, who also serves as Director of International Programs for the Pritzker School of Medicine, said his research demonstrates the importance of global health research and stresses that important findings can be discovered anywhere, even in low-resource settings. 

    “When I wake up every day and see the potential impact of this work, I feel really good about paying attention to soot-colored kitchen walls,” he said. “Everything one hopes their research will be about happened for me because I went back to Nigeria. As long as we continue to promote global health and work with students who we can help develop a global state of mind, I think the future’s going to be really good.”