When talking about type 2 diabetes, diet and exercises are usually the two main things recommended.
But there may actually be another factor that is even more important.
Scientists have found that those thinking in a specific way are 60% more likely to develop type 2 diabetes than those who don’t think this way.
Researchers have long known that people with type 2 diabetes are more likely to have depression than the general population or, seen from the other direction, that people with depression are more likely to have diabetes than their non-depressed peers. This is what scientists call a bidirectional association.
According to previous studies, people with type II diabetes are 15 percent more likely to develop depression, while people with depression are 60 percent more likely to develop type 2 diabetes.
The mechanisms through which the two conditions influence each other are currently unknown. Many scientists have speculated that poor dieting and lack of exercise, among other lifestyle factors, play a significant role in both conditions. As a result, one would expect that people with such lifestyles are more likely than those who enjoy healthy lifestyles to develop both conditions.
Scientists at Kings College London now think that this is far from the whole story. They think that genes may play an even larger role.
They collected information from 160,000 pairs of twins (320,000 people) in Denmark and Sweden. These two countries have kept a comprehensive record of all their twins going back to the 1870s, making them perfect subjects for this kind of study.
Through a process called genetic model fitting, they tried to calculate the contribution genetic factors make to the overlap of these two conditions.
In the Swedish sample, they found that genetic factors could explain 31 percent of the overlap between them in men, and 75 percent in women. In the Danish sample, 87 percent of the overlap in men were due to genetic factors, while 74 percent in women could be explained by their genes.
What does this teach us, other than that we can blame our parents for our co-occurring diabetes and depression (which is, honestly, not a useful thing to learn)?
The first thing to remember is that genetic model fitting is not quite as accurate as studies that are carefully controlled in a laboratory.
For example, it is reasonable to assume that twins growing up in the 1990s would have had a very different diet from those in the 1890s, that wealthier people have healthier diets, that people with heart disease exercised less, and so forth. But much of the detail of the lifestyles of these twins was never recorded and could, thus, not be used to help with the conclusion.
The more important lesson, however, is that there is a scientific consensus that genes are not set in stone. While genes may determine which diseases we develop, genes are alterable though, you guessed it, environmental factors like lifestyle.
For example, while you may have inherited a genetic vulnerability to obesity (which the authors of this study believe may contribute to both depression and diabetes), a healthy diet and exercise program can ensure that you are not overweight and can weaken the obesity genes that you pass on to your children.
The harder you fight both conditions, the better your chance of altering the problematic genes.