A call for focus on stroke prevention in women

Stroke disproportionately affects women. The risk for stroke among women in the United States is high. Stroke is the third leading cause of death in women, and 3.8 million women are living after having a stroke. In contrast, stroke is the fifth leading cause of death in men, and 3 million men are living after having a stroke. Certainly, diabetes is a risk factor for both heart disease and stroke, but we often focus on its cardiac effects and may not recognize its impact on stroke.

A recent epidemiological study by Zhao et al looked at all patients with type 2 diabetes in the Louisiana State University Hospital-Based Longitudinal Study to investigate the risk for developing a stroke. This included 10,876 men and 19,278 women. Interestingly, for women, there was a significant graded relationship between HbA1c and risk for stroke, with this risk more pronounced in women aged older than 55 years. In women, for each increase in 1% of HbA1c, there was a 5% increase in stroke. For women aged younger than 55 years, the risk for stroke increased by 2% for each unit increase in HbA1c; however, this risk increased by 5% for those aged 55 years and older. This relationship with HbA1c level and risk of stroke was not seen in men.

These sex differences are important to try to understand. Women may have more comorbidities and CV risk factors, as we have seen previously in women with ischemic heart disease and HF and was seen in this study group (aside from a lower rate of smoking in women compared with men).

We could also hypothesize that there is a difference in preventive treatment strategies between the sexes. It is important to note that the use of lipid-lowering agents and antihypertensive medications were used more frequently in women in this cohort, compared with men. We have no information about aspirin use in either sex. We also do not know who was taking ACE inhibitors. We also have no information about control of risk factors during the follow-up period, aside from HbA1c. There was a statistical difference in use of glucose-lowering medication between sexes at baseline, with women on fewer medications, particularly insulin and sulfonylureas.

When a woman has diabetes, the lower cardiac risk usually attributed to a menstruating woman (whether this be due to estrogen or other factors) appears to be erased by the presence of diabetes. Although the risk for stroke is high in all women, it appears that the risk is significantly higher in women aged 55 years and older. It may be that poor glucose control affects older women greater than younger women, and heightens the risk for stroke. It could also indicate that in older women more aggressive control of diabetes is needed to lower the risk for stroke. Certainly, this association is noted, but this was just an observational study and more information is still needed.

Nonetheless, this is an important study that highlights some observational sex differences in stroke that need to be studied further. This study had a good representation of women — in fact, more women than men, which given the prevalence of diabetes seems representative of the population from where it was taken. In addition, blacks were well represented in this study. The majority of participants were uninsured, but this does not take away from the importance of the findings to this population.

This study also raises many important questions about control of diabetes and its overall CV effects, particularly the effect on stroke. But what is needed is to see how aggressively we treat all CV risk factors, including diabetes in this very high-risk population and its ultimate effect on lowering the risk for both heart disease and stroke.

With the recent Guidelines for the Prevention of Stroke in Women, a statement from the American Heart Association and American Stroke Association, more focus needs to be given to women and control of their diabetes, in addition to control of all CV risk factors. Appropriate preventive strategies need to be part of the management of women with diabetes to lower the risk for stroke and heart disease. This remains one of the highest risk groups for CVD, and as diabetes continues to become epidemic worldwide its impact on global health remains a focus of our preventive strategies.