Yesterday, at Cancer and Your Genes, I mentioned an interesting study assessing the degree to which survival in prostate cancer seems to run within families (and therefore may be genetic). Some of the same authors, including Kari Hemminki, the lead author, also have a paper in the May 2008 issue of the Journal of Epidemiology and Community Health that assesses familial risks for chronic obstructive pulmonary disease (COPD) amongst siblings in Sweden.
The results basically showed that siblings of individuals with COPD had much higher risks of COPD themselves (Standardized Incidence Ratio [SIR] = ~4.6) as compared to spouses of individuals with COPD (SIR = ~1.6). The fact that the SIR was much higher for sibling pairs than for spouses is consistent with genetics underlying at least some familial susceptibility to this disabling lung disease.
Although there is a rare familial cause of COPD (alpha-antitrypsin deficiency), it seems unlikely that this would account for a significant fraction of the familial effect. It will be interesting to see what we learn in the future about other genes underlying COPD risk--and also the extent to which they interact with a known environmental risk factor for this disease, smoking, which itself has a heritable component. Very complicated!
