An astonishing number of people have developed diabetes over the last 20 years. By the age of 70, almost 1 in 3 Indian Asians and African Caribbeans and 1 in 6 Europeans will have diabetes. There is a steady rise in the numbers of people with diabetes even into older age. This is hugely important. We know that diabetes affects every system in the body and that it can shorten people’s lives, particularly because it can cause heart disease and stroke. Not only does diabetes shorten peoples’ lives, it can harm the quality of their lives too.
Our findings leads us to ask why Indian Asians and African Caribbeans have more diabetes than Europeans?
Type 2 diabetes is usually thought to be a disorder caused by overweight, particularly when fat accumulates around the waist. When we set out on the 20 year follow-up study we had proposed that it would be the patterns of where fat is deposited that would explain the ethnic differences in the amount of diabetes. Was this true? Yes and no!
As we expected, extra fat around the waist measured 20 years ago (both inside the abdomen and under the skin) is an important predictor of later development of diabetes in everyone and it mostly explains why Indian Asian and African Caribbean women are more at risk than European women. However, extra fat and extra resistance to the effects of insulin in middle age are only part of the reason why Indian Asian and African Caribbean men are more at risk and none of the risk factors that we measured 20 years ago was able to explain all of the extra risk of diabetes in these ethnic groups.
For more information about diabetes, visit Diabetes UK
As expected, numbers of strokes increase as people get older in all ethnic groups. Interestingly, in study participants who were free of diabetes in 1988-91, there were no ethnic differences in the proportions of people who developed strokes during follow-up. However, when we looked at people who had diabetes at the time of the baseline studies in 1988-91, we found that both Indian Asians and African Caribbeans with diabetes were twice as likely to develop strokes as Europeans with diabetes.
We also found that the MRI brain scans showed that African Caribbeans had more early signs of blood vessel problems in the brain than Europeans and that this was particularly related to having diabetes. These findings suggests that diabetes is especially harmful to people in our ethnic minorities, and although we don’t yet know why this is, it may be because the blood vessels in the brain are more affected by diabetes and pre-diabetes making them less able to cope with day to day changes in blood pressure – more research is needed to confirm this.
For more information about stroke, visit The Stroke Association.
The heart is a pump which makes sure that all the tissues of the body receive a blood supply containing oxygen and nutrients. Like all pumps, the heart may become less efficient as it gets older and eventually it may not be able to keep up with the demands of the body- this is called heart failure, and although there are treatments available for heart failure, it is a serious and unpleasant disorder. Heart failure is more likely to happen when people have already had a heart attack and it may also be related to high blood pressure and diabetes.
The 3 dimensional echo scans that participants underwent at the SABRE follow-up are new and tell us about early signs of heart failure. We found that African Caribbeans and Europeans were very similar with regard to the size of the left ventricle (this is the part of the heart which pumps blood around the whole body and if it becomes enlarged it may be an early sign that the heart is under strain (picture of heart here)). On the other hand, in Indian Asians the left ventricle was on average a little smaller in relation to body size than in Europeans, but at the same time their heart muscles needed more oxygen to work efficiently.
Very few SABRE participants had actual heart failure at the 2008-2011 follow-up. However, as participants are moving towards older age, they are more at risk of this disorder.
For more information about heart failure, visit the British Heart Foundation.