A systematic review and meta-analysis of some 850,000
people shows that women with diabetes are 44 per cent more likely to develop coronary heart disease (CHD) than men with diabetes independent of sex differences in the levels of other major cardiovascular risk factors.
The data used in the study stretches back almost 50 years, from 1966 to 2011, and includes 64 studies, 858,507 people and 28,203 incident CHD events.
Women with diabetes were almost 3 times more likely to develop CHD compared with women without diabetes, while men with diabetes were only twice as likely to develop CHD than men without diabetes, researchers found.
Combining the two sets of data showed that women with diabetes were 44 per cent more likely to develop CHD than men with diabetes even after consideration was made for sex differences in other CHD factors.
The authors say that this study, the largest ever of its kind backs up findings from a smaller analysis including fewer studies that showed a 46 per cent increased risk of dying from CHD in women with diabetes compared with men with diabetes.
In the new analysis by Professor Rachel Huxley, School of Population Health, University of Queensland, Australia and colleagues, the sex difference in diabetes-related risk for incident CHD was consistent across subgroups defined by age and region and remained unchanged after excluding non-fatal CHD events.
They note that in another previous study they authored, diabetes in women increased the risk of stroke by 25 per cent compared with diabetes in men.
"Taken together, these data provide convincing evidence that diabetes poses a greater relative risk for cardiovascular diseases in women than in men," researchers said. Several possible reasons for the difference are discussed by the research authors.
Women have, particularly in the past, been under-treated for risk factors for cardiovascular disease, researchers said. However, even in more contemporary populations, when diabetes is treated similar to men, women have generally been less likely to achieve treatment targets.
The research authors speculate that women may have to metabolically deteriorate further than men to become diabetic, so they are at a worse starting point even before treatment begins.
Furthermore, in the prediabetic state where glucose tolerance may already be impaired but does not meet all diagnostic criteria of diabetes, risk factor levels are more elevated in women than in men.
The study was published in the journal Diabetologia.