XXXX reassessed: a geographically-based population study.

@entity2835 @entity1 @entity41292 @entity792
BACKGROUND/AIMS: Development of @entity2835 in the close relatives of @entity1 with the disease has been reported in several series, suggesting a genetic component to disease susceptibility. In this study we set out to calculate, as accurately as possible, the prevalence of @entity41292 in a geographically-based population. Using local population prevalence data, we have also calculated the first-degree relative, sibling and offspring relative risks of overt @entity2835 development. METHODS: All @entity1 with definite or probable @entity2835 in the city of Newcastle-upon-Tyne, England, were identified by an exhaustive case-finding search and were prospectively interviewed by a single investigator. Full details of family pedigree and @entity41292 history were obtained. RESULTS: One hundred and seventy-three @entity1 were identified, with 160 participating in the study. Thirteen reported a family history of @entity2835 . In three cases, both relative pairs were within the study group. The prevalence of a positive family history of @entity2835 was therefore 10/157 (6.4% [95% Confidence Interval 2.6-10.2%]), 8/10 cases occurring in first-degree relatives. The @entity1 had a total of 1118 first-degree relatives (live or dead) and 468 siblings. The first-degree relative prevalence of @entity2835 was 0.72% [0.2-1.2%] (siblings 0.41% [-0.2-1.0%]). The offspring prevalence was 1.2% [0.04-2.4%], (2.3% [0.1-4.5%] for daughters). The sibling relative risk (lambda(s)) was 10.5. CONCLUSIONS: The overall prevalence of definite or probable @entity2835 in the first-degree relatives of existing @entity1 is <1%. The risk of disease is not, however, uniform, the highest prevalence being seen in the daughters of @entity1 . Suspicion of disease should therefore be highest in this relative group. The calculated lambda(s) for @entity2835 in this geographically-based study is significantly lower than previous estimates from case-note-derived case series, but similar to values seen in other @entity792 .
