Family history of heart disease can be beaten
The bad news is that heart disease is partly inherited. The good news is that those who inherit the gene most associated with heart disease – and suffer a heart attack – survive pretty well.
In fact, Kiwis with the dodgy inheritance survive as well as those without the dodgy inheritance, recently published international research shows.
‘‘We cannot change our DNA but we are not doomed by it either,’’ said Dr Anna Pilbrow, a senior research fellow at the Christchurch Heart Institute at the University of Otago’s Christchurch campus.
‘‘Even if we have a strong family history of heart disease, we can mitigate our heart disease risk by having a healthy lifestyle and taking our meds,’’ she said.
‘‘Our lifestyle choices influence our heart health, for better or worse.’’
Pilbrow, with Professor Vicky Cameron and colleagues, first reported this in April 2010, based on years of research with almost 1900 Kiwis with heart problems.
They were the first heart researchers to show ‘‘heart patients carrying the high-risk DNA variant survived equally well as those who carry the low risk DNA form’’.
That work has now been replicated in a meta-analysis that collated data from 57 studies from 18 countries that included nearly 200,000 people, including 3000 from New Zealand.
‘‘The findings of the much larger international study have convincingly replicated the earlier research done here in Christchurch,’’ said Cameron.
These sorts of rich findings about genetics and heart disease became possible starting in the 2000s, when the whole human genome was sequenced.
Early on, it was thought a slice of human DNA now labelled 9p21, was ‘‘junk’’ that played no current role in human health, Cameron said in an interview.
But from 2007, overseas studies showed the presence of 9p21 increased the chance of a carrier having heart problems, now estimated as 15 per cent to 35 per cent higher.
It was a good research question, then, to ask if 9p21 made matters worse for carriers after their first heart attack.
In 2010, Cameron and Pilbrow showed it didn’t.
But that New Zealand study was fairly small.
Getting an international meta-analysis to validate your findings is ‘‘always good’’, Cameron said.
There are caveats. One is that most research participants had European ancestry. The metaanalysis consortium is based in Britain and Holland and the institutes contributing their data were mostly in Europe and North America.
Similar research is under way with Asian and other populations.
Ma¯ ori and Pacific Islanders were not excluded from the New
Zealand cohorts, which were recruited from Christchurch and Auckland hospitals, Cameron said.
But relatively few people with Ma¯ ori and Polynesian ancestry walked through the researchers’ doors.
The research team are now ‘‘over-sampling’’ Ma¯ ori and Polynesian communities to give greater statistical power to their data, Cameron said.
The international research population was also strongly male – 73 per cent, although that may reflect that men suffer more heart attacks than women.
The orthodox advice on preventing heart disease has remained stable for a while – eat well, including lots of fruits and vegetables, don’t smoke, drink moderately and exercise, Cameron said.
This is true for everybody, but especially true for those with a family history of heart disease. ‘‘Never feel that family history is your fate,’’ she said.
The meta-analysis – a study of studies – was undertaken by the Genetics of Subsequent Coronary Heart Disease Consortium.