I've posted about this study before, but as there are a fair number of new people on the board, it's worth repeating because it's one of the few studies that attempts to look at what happens in familial hypercholesterolemia without selection for early cardiovascular disease.
To explain this simply - most of the statistics you hear about FH are about people that are on registers of people with 'diagnosed' FH. The problem is that to be diagnosed with FH, one of the criteria is that you have a high cholesterol level. Another is that you have a close relative with early heart disease.
What this leads to is that registers of people with supposed FH are in fact only basically registers of people with relatives with early heart disease. So there are two reasons why this may give a false picture of the risks of FH. One is that some factor OTHER than cholesterol is causing the early heart disease, such as another genetic mutation that those people share because they're relatives.
The second factor is that there could be huge amounts of people with FH mutations and high cholesterol who are never put on FH registers because they don't have relatives with early heart disease. We know 85% of people with FH are supposedly undiagnosed. What if that's because there's nothing wrong with them?
Anyway to the study, it's from the BMJ, so we know it's a legitimate study and it gets referenced all over the place.
Some key quotes:
Risk of death varies significantly among patients with familial hypercholesterolaemia. This large variability over time and between branches of the pedigree points to a strong interaction with environmental factors. Future research is required to identify patients with familial hypercholesterolaemia who are at extreme risk and need early and vigorous preventive measures.
What is already known on this topic Familial hypercholesterolaemia is associated with excess mortality in families of patients who present with cardiovascular disease
Population data are lacking
What this study adds: Many untreated patients with familial hypercholesterolaemia (about 40%) reach a normal life span
Standardised mortality ratio was normal in the 19th century and rose to a peak in the 1930s to 1960s
The variation in mortality suggests an interaction between genetic and environmental factors
Harlan et al described normal survival in a large pedigree with familial hypercholesterolaemia in 1966. They suggested that “the precocious onset of cardiovascular disease and the bad prognosis of familial hypercholesterolemia have been overemphasized because many of the early studies were of the relatives of patients who had sought medical attention.”These findings were largely ignored, and since then many studies have been done in probands (and relatives) who presented with symptoms of cardiovascular disease in lipid clinics. We found many affected people who had normal lifespans.