Thursday, December 08, 2016 Researchers Find 'Unsettling' Uptick in Stroke Rates in Adults Under 55 A recent study of stroke rates has found that while rates have declined in patients older than age 55, there has been an uptick among younger populations—and the potential underlying factors are “unsettling.” Authors of the study, published in the Journal of the American Heart Association, write that over the past 20 years, the incidence of stroke has decreased in many countries, but that trend may now be reversing itself. Researchers applied an “age-period-cohort” analysis to data from the Myocardial Infarction Data Acquisition System in New Jersey in an attempt to “unravel the separate effects due to aging, secular changes, and life course experience” on incidence of ischemic stroke and ST-elevated myocardial infarction (STEMI). The time periods considered were 1995-1999 (period 1), 2000-2004 (period 2), 2005-2009 (period 3), and 2010-2014 (period 4). Researchers found that overall, the stroke rate for individuals aged 35 to 84 decreased from 314.1 strokes per 100,000 “person-years” (PY) in period 1 to 271 in period 4. The overall rate for STEMI decreased by 60% in the same time period. However, the stroke rate among patients 35-39 more than doubled over that same 20-year period, from 9.5 to 23.6 per 100,000 PY. The rate also doubled for those in the age 40-44 cohort, from 22.9 to 46.0 strokes per 100,000 PY between periods 1 and 4. There also were smaller yet still significant increases for individuals aged 45-49 and 50-54. For groups older than 55, rates declined. These findings echo results of similar studies in the United States, as well as Taiwan, France, and Denmark, authors noted, writing that, in their study, “the downward trend in the oldest age groups, the flattening trend in the middle age groups, and the upward trend in the youngest groups suggest a birth cohort effect.” Authors suspect that higher prevalence of obesity and diabetes among younger cohorts, in addition to lack of treatment for high blood pressure and lower likelihood of having health insurance, may be contributing to this disturbing trend in the US. The rise in obesity among younger populations has also led to an increase in atrial fibrillation, a risk factor for stroke. Interestingly, the STEMI rate decreased for all groups. Authors suggest this could be due to the fact that STEMI is more closely associated with lipid levels than with high blood pressure, and “the increasing prevalence of atrial fibrillation in the young would have a greater impact on rates of stroke than those of STEMI.” Taken together, researchers assert, “these trends may have significant implications for health outcomes and the overall healthcare burden in the future.” Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.