A population-based study from Sweden found that a family history of mesothelioma, specifically in parents and siblings, is a risk factor for mesothelioma in a person. The study, “Incidence and familial risk of pleural mesothelioma in Sweden: a national cohort study,” was published in the European Respiratory Journal.
Previous studies have reported familial clustering of pleural mesothelioma. The underlying causes may be shared environmental factors within a family, or familial clustering may have a genetic etiology through shared genes. Until now, no study has quantified the familial risk of mesothelioma or the association with other cancers.
Researchers investigated the familial risk of mesothelioma in offspring using a number of Swedish registers, including the Swedish Multigeneration Register and the Swedish Cancer Register. To calculate the risk, researchers used standardized incidence ratios (SIRs).
In this population-based nationwide cohort, researchers found that 2000 was the peak year for mesothelioma incidence, decreasing in the following years. The risk for mesothelioma in a person increased when either their siblings or parents were diagnosed with mesothelioma, and if siblings had kidney and bladder cancers. No association was observed between spouses. Overall, researchers observed an increase in mesothelioma incidence of about four times (SIRs of 3.88) in those with affected parents, and an increase of 12 times (SIRs of 12.37) in those with affected siblings.
These results support that a family history of mesothelioma, including both parental and sibling history, is an important risk factor for mesothelioma. While shared genetic factors poses a strong predictor for the observed familial clustering of mesothelioma, the contribution of environmental factors is still important to consider. In fact, the authors noted that one limitation to this study was the lack of information relative to asbestos exposure. But the results’ stratification suggested it was likely to be a small contributor to the observed familial aggregation of mesothelioma.
Finally, authors noted that the association of mesothelioma risk with kidney and bladder cancers is a link worth pursuing in future studies, to identify potential underlying mechanisms.