While stroke rates have been declining for some time in the western world, new research suggests that this trend may be set to reverse, with a worrying increase in stroke rates occurring in the younger age group.
A new study, published online November 23 in the Journal of the American Heart Association shows stroke rates continuing to decline in people aged 55 years and older, but in those aged under 55 years the incidence of stroke appears to be increasing.
"There appears to be a golden generation — the baby boomers born between 1945 and 1954, who have the lowest risk of stroke," lead author, Joel N. Swerdel, MS, MPH, Rutgers University School of Public Health, New Brunswick, New Jersey, commented to Medscape Medical News. "In people born from 1955 onwards, the stroke rate is rising again."
The study — which analyzed a database of all hospital discharges in New Jersey from 1994 to 2014 — found that between 1995–1999 and 2010–2014, the rate of strokes doubled in those aged 40 to 44 years and more than doubled in people 35 to 39 years.
Commenting on the findings for Medscape Medical News, Ralph L. Sacco, MD, professor and Olemberg Chair of Neurology, Miller School of Medicine, University of Miami, and president-elect, American Academy of Neurology, said, "This is an interesting set of data that suggests an alarming trend for rising stroke rates among younger adults."
The data confirm what has also been observed in other cohorts, he added. "Although stroke rates have been declining, the decline may be levelling off in older adults and actually increasing in younger adults."
The researchers suggest the trends are all to do with lifestyle factors.
"People born between 1945 and 1954 seem to have benefitted from better living standards and healthcare than those before them, and this would have been the first generation with the knowledge that smoking kills," Swerdel said. "But they have also escaped the sugar revolution and the obesity and diabetes epidemics which are affecting those born later. The influx of heavily sugar-laden food didn't really start until the mid-60s, so those born in the 40 and 50s were not brought up on sugar-coated cereals and the like. This likely explains the increase in obesity and diabetes that occurred in later years."
A 'Wake-Up Call' for the Younger Generation
He stressed that younger people need to take heed of these new data. "This is a wake-up call. People in their 30s and 40s have time and the opportunity to improve their lifestyle and take medications to control risk factors to head off these effects."
Dr Sacco agreed that lifestyle factors are the culprit. "We have definitely improved the control of smoking, blood pressure and cholesterol, but obesity, physical inactivity, poor diet, and diabetes are still on the rise. These conditions could be having a detrimental effect on stroke rates in younger adults."
He added: "The American Heart Association/American Stroke Association has made improving the cardiovascular health of all Americans across all age groups a major strategic priority for 2020. We need to get younger people more focused on healthy habits, such as regular exercise, following the AHA [American Heart Association] diet, and losing weight before it is too late. It is never too early to start thinking about improving heart and brain health."
For the study, the researchers obtained data on stroke and ST-segment elevation myocardial infarction (STEMI) for the years 1995–2014 from the Myocardial Infarction Data Acquisition System, a database of hospital discharges in New Jersey. Rates by age for the time periods 1994–1999, 2000–2004, 2005–2009, and 2010–2014 were obtained by using census estimates as denominators for each age group and period.
Results showed the rate of stroke more than doubled in patients aged 35 to 39 years from 1995–1999 to 2010–2014 (rate ratio [RR], 2.47; P < .0001). For the same time period, comparison stroke rates doubled in the age group 40 to 44 years (RR, 2.01; P < .0001) and showed a 23% increase in those aged 50 to 54 years (RR, 1.23; P = .001).
In contrast, strokes rates in those older than 55 years decreased during these time periods.
Those born from 1945 to 1954 had lower age-adjusted rates of stroke than those born both in the prior 20 years and in the following 20 years.
STEMI rates, however, showed a different pattern, decreasing in all age groups and in each successive birth cohort, although the reduction did appear to be flattening out.
"STEMI rates have dropped like a rock over last 20 years, but this fall is getting slower in the younger age groups," Swerdel commented. "This has also been seen in other US-wide data and has been attributed to the increase in diabetes we are seeing recently."
Dr Sacco said it was surprising that STEMI did not follow the same pattern as stroke, but he noted that the two conditions may be affected differently by different risk factors, with cholesterol control having a greater impact on for myocardial infarction than for stroke.
Study coauthor John B. Kostis, MD, professor of cardiology, medicine and pharmacology, Rutgers Robert Wood Johnson Medical School, New Brunswick, agreed. "Stroke may be more affected by blood pressure than STEMI, while STEMI is more affected by LDL [low-density lipoprotein] cholesterol. But we didn't have data on these risk factors in this study — just reasons for admissions to hospital."
Dr Kostis pointed out that while cardiovascular and cerebrovascular diseases have been declining in the West, they are growing in newly developed countries such as Russia, India, and Asia. "We had thought we had dealt with this in the US, but it appears that it might be coming back again."
He added: "The message is clear. We have to start taking care of ourselves early in life and continue this throughout life. Don't smoke, look after your weight, partake in exercise, take medicines for blood pressure and cholesterol if they are high. Start all these things early in life."
Quoting the Latin "Dum spiro spero — While I breathe, I hope," Dr Kostis said of their findings, "Yes, this is a red flag but we can do something about it."
The study was funded by The Robert Wood Johnson Foundation and the Shearing-Plough Foundation. The authors have disclosed no relevant financial relationships.
J Am Heart Assoc. Published online November 23, 2016. Abstract
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Cite this: Stroke Rates Increasing in Under 50s - Medscape - Nov 23, 2016.