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Stroke Is Making a Comeback as an American Killer
For at least the past 50 years, the rate at which Americans died from stroke has declined. But that remarkable progress has stalled of late, according to a new federal report, and may even be reversing.
While stroke has dropped from the third-leading cause of death a decade ago to the fifth in 2013, that good-news story obscures a grimmer prospect: Years of deteriorating health among Americans may be manifesting in more people falling victim to stroke.
“The risk profile in the U.S. has changed, and changed significantly,” says Quanhe Yang, senior scientist at the Centers for Disease Control and lead author of the new report. “This is a wake-up call.”
Strokes are the result of blood clots or hemorrhages that lead to brain damage within minutes. Almost 800,000 Americans suffer a stroke each year, and about one-sixth of stroke victims die. Many survive only with serious disability. Risk factors for stroke include high blood pressure, smoking, obesity, and diabetes.
While the rate of high blood pressure, also called hypertension, has recently stabilized, more than half of Americans with hypertension don’t have it under control. Obesity and diabetes have increased significantly since the 1980s, with more than one-third of U.S. adults classified as obese. As people develop these conditions at younger ages and live with them for longer periods, the risk that they will have strokes increases.
A big chunk of the southeastern U.S. has long been considered the “stroke belt,” with rates of stroke deaths far higher than the rest of the country. The CDC’s latest analysis shows that troubling trends are spreading through a far wider area, to the nest and northeastern U.S. In 16 states, stroke mortality improvement has slowed down—meaning improvements haven’t kept up with historical trends. In another 21 states and the District of Columbia, the improvements have stalled entirely or reversed in some cases.
Yang and his colleagues at the CDC analyzed death certificate data with statistical software to discern recent patterns in stroke trends. The big picture looks positive: Among Americans 35 and older, the death rate from stroke declined to 73 per 100,000 residents in 2015, from 118 at the start of the century. (The rates are age-adjusted, meaning they account for the changing age distribution of the population.)
But, like overall mortality rates, long-term reductions in stroke deaths have flattened out. Rates actually increased 2.5 percent annually from 2013 to 2015, although the change wasn’t statistically significant, the CDC reports. There were significant increases in the south and among Hispanics nationally.
Some researchers worried that the history of improvement in stroke deaths would be overwhelmed by other worsening health trends. The authors of a 2011 article in the journal Stroke celebrating mortality declines warned that “the recent lows in stroke mortality may be short-lived. The obesity epidemic and the aging of the population in the U.S. threaten the improvements in stroke mortality achieved by better control of blood pressure, cholesterol, and tobacco use over the past 4 decades.”
Stroke deaths wouldn’t be expected to decline forever, of course. But Wang notes that 80 percent of strokes are preventable with modifications to lifestyle or other risk factors. The CDC encourages people to stop smoking, eat less sugar and salt, eat more fruits and vegetables, be physically active, and get treatment for such chronic conditions as high blood pressure, cholesterol, and diabetes. To improve survival for stroke patients, people should learn to recognize the signs quickly—numbness, confusion, difficulty seeing or walking, or sudden severe headaches—and call 911 immediately if they suspect a stroke might be happening.
There are some limitations to the CDC study. Because researchers relied on death certificate data, if causes of death are systematically misreported, that would affect the conclusions. There’s also some evidence that flu can influence cardiovascular disease, and severe flu seasons in recent years might have affected stroke mortality. Yang said his analysis found no statistically meaningful impact due to the flu, however.
Moreover, Yang says the distribution of stroke deaths broadly correlates with the distribution of risk factors such as uncontrolled hypertension. Stroke is a lagging indicator that may follow years of other chronic illness, and any inflection point in nationwide stroke death rates is a troubling sign.
“If we don’t get the control of those risk factors,” Yang says, “more people will die from stroke unnecessarily.”