Familial clustering of pleural mesothelioma was reported previously, but none of the reports quantified the familial risk of mesothelioma or the association with other cancers. The contributions of shared environmental or genetic factors to the aggregation of mesothelioma were unknown.
We used a number of Swedish registers, including the Swedish Multigeneration Register and the Swedish Cancer Register, to examine the familial risk of mesothelioma in offspring. Standardised incidence ratios (SIRs) were used to calculate the risk. Age standardised incidence rates of mesothelioma were calculated from the Swedish Cancer Registry.
The incidence of mesothelioma reached its peak rate in 2000 and decreased thereafter. Risk of mesothelioma was significantly increased when parents or siblings were diagnosed with mesothelioma, with SIRs of 3.88 (95% CI 1.01–10.04) and 12.37 (95% CI 5.89–22.84), respectively. Mesothelioma was associated with kidney (SIR 2.13, 95% CI 1.16–3.59) and bladder cancers (SIR 2.09, 95% CI 1.32–3.14) in siblings. No association was found between spouses.
Family history of mesothelioma, including both parental and sibling history, is an important risk factor for mesothelioma. Shared genetic factors may contribute to the observed familial clustering of mesothelioma, but the contribution of shared environmental factors could not be neglected. The association with kidney and bladder cancers calls for further study to explore the underlying mechanisms.
Mesothelioma in Sweden began to decrease after 2000; family history is a risk factor for mesothelioma http://ow.ly/4mJemg
Support statement: This work was supported by grants to K. Sundquist from the Swedish Research Council (K2009-70X-15428-05-3; K2012-70X-15428-08-3), as well as ALF funding from Region Skåne awarded to J. Sundquist, K. Sundquist and J. Ji. Funding information for this article has been deposited with FundRef.
Conflict of interest: None declared.
- Received January 13, 2016.
- Accepted April 5, 2016.
- Copyright ©ERS 2016