We usually think of strokes being associated with old age. But studies of stroke trends have indicated that there have been sharp increases among younger people. For example, there were 30,000 more hospitalizations for acute ischemic stroke in people under 65 in 2012 as compared to 2003. Among men ages 18-34, the rates have almost doubled. The increase in stroke prevalence in younger adults seems to mirror an increase in hypertension and hyperlipidemia in this population. Other factors that are related to strokes, such as diabetes and obesity, also increased in that group.

These increases have led stroke specialists to emphasize the importance of focusing on prevention in younger adults. But others question whether the increase is more a function of diagnostic classification systems and coding. Some observers think that similar diagnostic and coding factors may be involved in calculations of both stroke incidence and risk factor prevalence.

It has been noted that other factors that may account for the increases, including greater use of MRI imaging and changes in the definitions of TIA (temporary ischemic attack) and ischemic strokes. Some events diagnosed as TIA in 2003 would likely be diagnosed as ischemic stroke in 2012.

The difficulties in deciding whether there has been an actual increase, as opposed to changes in classification and coding factors, are frustrating for those who study stroke trends. According to James Burke, MD and Lesli Skolarus, MD, of the University of Michigan, “it is startling that in a country that spends almost 20% of [GDP] on healthcare, we cannot say with confidence whether the fifth leading cause of death in the United States is increasing or decreasing in the young.”