Sweden is apparently the place to be if you are a twin. This country boasts the world’s largest Twin Registry, following over 70,000 pairs of twins born before 1985, with ongoing new studies of younger twins starting when they reach the age of nine.
Right now, over 30 ongoing research projects based on the Twin Registry cover a wide range of topics like aging, dementia, allergy, cancer, and cardiovascular disease. Researchers are also looking at the effects of gender differences on health and life situations.
And the Swedish Twin Registry was recently part of a groundbreaking study to determine whether the risk for hip fracture is increased in people who have cardiovascular disease.
The study, published in the Journal of the American Medical Association this month, included 15,968 twin pairs who were 50 years old when the study began, and were followed until the date of a hip fracture, death, or study conclusion in December 2005.
What Dr. Ulf Sennerby of Uppsala University and his fellow researchers found was disturbing: a diagnosis of cardiovascular disease (CVD) significantly increased the risk of subsequent hip fracture in both women and men. Of the twins participating in this research, hip fracture was diagnosed in 1,442 patients during the course of the study, 70% of whom were women.
Having a stroke or heart failure has already been widely recognized as a risk factor for future hip fracture, partly because of resulting immobility. In relative terms, this means that if you studied 1,000 person-years among those who do not have CVD, you’d expect to find 1.2 with hip fracture. But you’d find 12.6 per 1,000 person-years among patients diagnosed with heart failure or stroke, and even for patients diagnosed with cardiovascular disease, that number jumps to 5.2.
But it now looks like an underlying genetic predisposition may exist for other forms of heart disease and osteoporosis.
For example, researchers looked at fracture risk in identical twins, and found that in identical pairs where only one sibling had heart failure, the other also had a fourfold increased risk of hip fracture. When only one had a stroke, the other had a doubled risk of hip fracture.
Read more about the Swedish twin study from MedPage Today.
What do you think?