The etiology of chronic Inflammatory Bowel Diseases (IBD) remains unknown, with both genetic and environmental risk factors having been implicated. A recent collaborative study of IBD provides clinical data from families with three or more affected first-degree relatives. The scientific question is whether specific clinical characteristics aggregate among affected individuals within families. G...

BACKGROUND Although they were once considered separate nosologic entities, there is current interest in the etiologic overlap between bipolar disorder (BD) and schizophrenia. A critical issue concerns the familial basis of the overlap, specifically, the possibility of a distinct familial subtype of BD with psychotic features. METHODS We recruited individuals with BD from the community and com...

BACKGROUND Familial clustering of incident prostate cancer and some cancers at other discordant sites has been reported. Less is known about familial clustering of fatal prostate cancer with any fatal discordant cancers. Estimates on familial aggregation based on mortality are free from bias of overdiagnosis. PATIENTS AND METHODS We used the nationwide Swedish Family-Cancer Database to calcul...

OBJECTIVE To estimate familial aggregation of rheumatoid arthritis (RA) in 3 large population-representative samples and to test if familial aggregation is affected by rheumatoid factor (RF)/anti-citrullinated protein antibody (ACPA) status, type of relative, sex, and age at onset of RA. METHODS A register-based nested case-control study was performed in the Swedish total population. Data on ...

BACKGROUND An elevated risk of developing non-Hodgkin's lymphoma (NHL) has been associated with a family history of NHL and several other malignancies, but the magnitude of risks and mechanisms are uncertain. METHODS We used self-reported family history data from a recent multicenter U.S.-based case-control studies of NHL to evaluate familial aggregation of NHL with various hematolymphoprolif...