Age may play a factor in mesothelioma risk
Older workers exposed to asbestos are less likely to develop pleural mesothelioma, a rare and incurable cancer of the lining of the lungs.
In a study published online this week in the European Respiratory Journal, French researchers analyzed 2,466 cases selected from two groups — a French case-control study and the French National Mesothelioma Surveillance Program. After adjusting for intensity and length of exposure, they concluded that the risk of pleural mesothelioma was lower for workers first exposed to asbestos after the age of 20.
The researchers say the new data underscore the need for clinicians to consider the age of first exposure when assessing the risk of mesothelioma.
One explanation for the French findings may be that, compared to younger workers, older workers may not live long enough for the disease to develop. Mesothelioma has a 20-50 year latency period, with the majority of cases diagnosed at least 30 years after initial exposure. Many patients are in their 60s or 70s when they learn they have the disease.
Despite advances in chemotherapy and radiation techniques, the prognosis for pleural mesothelioma remains poor: length of survival after diagnosis is 8-18 months. Doctors and researchers say a better understanding of who is at risk and more accurate diagnostic tools are needed to improve outcomes.
About 125 million people around the world are exposed to asbestos on the job — including at least 1 million Americans, according to the U.S. Occupational Health and Safety Administration.
Although OSHA adopted tighter workplace exposure limits for asbestos in 1994, the standard does not guarantee the safety of workers in industries where asbestos is prevalent, like construction, manufacturing and mining.
According to the Environmental Working Group, the agency acknowledges that under the “legal worker exposure limits,” one in every 200 workers exposed at length will develop lung cancer, and one in 500 will develop asbestosis, a non-cancer lung disease that is often fatal.
France is one of more than 50 countries that have banned the use and importation of asbestos, which previous research suggests has caused a “leveling off” of lung cancer and mesothelioma cases since 2000.
Almost all countries in Asia, Eastern Europe, Latin America and Africa still use asbestos. Without a global ban, international health and environmental officials predict, asbestos-related disease will end up claiming 10 million lives.