Dr Anna Davies-Barrett
If you turn over to a news channel or website today, it probably won’t take long before you see a report about air pollution and its related health problems. It’s here that you’ll likely learn that particulates (small inhalable particles) produced by growing urban landscapes, industry, and exhaust fumes have been proven to increase respiratory inflammation and the risk of developing diseases.
But this isn’t a new problem. Sadly, societies throughout time across the globe have encountered the same issues. After facing a global pandemic, now more than ever, understanding the risk factors that led to respiratory diseases in the past can help us to comprehend today’s health challenges. But to understand ancient diseases, we have to look at what remains of past people: their skeletons.
Ever had a blocked nose and aching in your cheeks or forehead? You might have been suffering from sinusitis. This is a common inflammation of the lining of your upper respiratory tract, affecting the air-filled spaces – known as sinuses – located in the bones of your cheeks, forehead, and behind your eyes. If this inflammation becomes severe and prolonged, it can actually trigger new bone to form inside the sinuses. It is this reaction that I look for in human skulls from the past to decipher if they suffered from sinusitis.
I also look for evidence of inflammation of the lower respiratory tract, including the lungs. There is a thin pocket of fluid that surrounds the lungs and lies directly beneath the ribs, known as the pleural cavity. If lung inflammation or infection spreads to this cavity, it’s thought to trigger bone formation on the inner surfaces of the ribs. Infectious diseases like tuberculosis and pneumonia have been linked to this type of bone change.
Why is this useful? Well, by looking at the frequency of such bone formation in skeletons across time periods and regions, I can start to build a picture of how often people from different environments and backgrounds suffered from respiratory diseases.
The results have certainly been interesting. My research has shown that respiratory diseases in the past were likely to have been common; people from a range of backgrounds could have developed ailments. Unsurprisingly, what myself and other researchers have found is that the type of conditions people lived in were likely to have had an impact on whether a person developed a respiratory disease. People living in poorly ventilated and smoky houses or in crowded cities with industrial pollution show higher frequencies of respiratory disease.
My own research on past people from Sudan (Ancient Nubia) has shown that the climate also has an important impact on respiratory health. Although mostly arid today, Sudan’s landscape was filled with swamplands several thousand years ago. It’s only from around 5000 BC that it started to slowly transform into the desert environment seen today. This transformation likely introduced greater levels of inhalable dust and sand in the air, including the massive dust storms that are still common in Sudan today.
During the more humid Neolithic period (5000–3100 BC), hunter-gatherers had much lower rates of respiratory disease than Nubian people living in the later, drier periods. As well as less dust in the air, the nomadic and active lifestyle of hunter-gatherers may also have been beneficial to their health.
However, in later periods (2500 BC–1500 AD), a number of factors led to higher rates of respiratory disease. The encroaching desert forced people to live closer to the river and produced high volumes of dust, particularly when people tried to farm the dry land. Permanent settlements became more crowded, lowering levels of sanitation and encouraging infectious disease. People also relied on cooking in ovens placed inside mud brick buildings that may not have been well ventilated.
Interestingly, I found the highest frequencies of respiratory disease in people from the Medieval city of Soba East, located near modern-day Khartoum, at its peak a rich hub of produce and trade. The urban landscape likely produced industrial pollution and poor sanitation, but would have also attracted people – and the infectious diseases they carried – from afar.
It’s easy to think that the respiratory problems of the ancient Nubians are a thing of the past. But as we have seen in the current pandemic, many of these factors are prevalent today. Travel and trade are at a global scale, with urban and arid environments predicted to increase dramatically in the years ahead. By understanding how respiratory disease affected people in the past, we can better prepare ourselves for this future.