Researchers from Britain and the United States said their study suggested that crowded living and working conditions, dust in mines, and the spread of HIV mean Africa’s mining industry may figure in up to 760,000 new cases of TB each year.
Men travelling from afar to work in mines, such as from Botswana to South Africa, are at the greatest risk of getting TB, the researchers wrote in a study published in the American Journal of Public Health.
But their wives, children and friends are also at high risk of catching the disease when miners travel back and forth to work, often many times a year.
“Improving living and healthcare conditions for miners may be necessary not only for the miners, but for controlling tuberculosis epidemics throughout sub-Saharan Africa,” said Dr David Stuckler from the Department of Sociology at Oxford University, who led the study.
Tuberculosis killed 1.8 million people worldwide in 2008, or nearly 5,000 people a day.
The disease can be cured with antibiotics, but they must be taken daily for months to be effective, and scarce health funds in some countries mean fewer drugs are available.
TB has been on the rise in sub-Saharan Africa over the past 20 years, with a doubling of the annual incidence from 173 to 351 per 100,000 population between 1990 and 2007.
These rises are largely the result of a growing epidemic of the human immunodeficiency virus (HIV) that causes AIDS. But Stuckler and colleagues said data shows that HIV is only one of several factors involved in TB’s spread in the region.
HIV increases the risk of TB because it weakens the body’s immune system.
Miners are also known to spread tuberculosis to their families and communities, the researchers said, since nearly half of workers in large mining countries like South Africa are foreign and routinely travel across large distances.
The scientists took data on mining between 2001 and 2005 and compared them with TB incidence and death rates for 44 countries in sub-Saharan Africa.
They found evidence that mining had a significant impact on the spread of TB, and that the risk appeared to be worst in countries with high levels of HIV.
The risks were associated with the living conditions around mines, they said, and with mining for gold, which is believed to expose miners to more potentially harmful silica dust than any other mineral.
The study also found that when countries reduced their mining activity, TB rates fell more quickly, or rose less, than in neighbouring nations where mining rates were stable or increased. Reuters