(CNN) As the number of American adults dying of cancer continues to decline, the number who are dying of heart disease is on the rise, according to a new report.
Researchers at the US Centers for Disease Control and Prevention's National Center for Health Statistics examined death certificates filed across the country from 1999 to 2017 for adults 45 to 64, documenting the number of deaths attributed to cancer and heart disease.
Cancer deaths dropped 19% from 1999 to 2017 for those adults. Deaths due to heart disease dropped 22% between 1999 and 2011 but then increased a total of 4% by 2017, according to the report, published Wednesday in National Vital Statistics Reports.
Cancer death rates were higher than heart disease death rates during the study period, with both men and women seeing a similar pattern of overall decline in cancer deaths and recent increases for heart disease deaths.
White women saw the greatest rise in the rates of death from heart disease, a 12% increase; Hispanic women saw a general decline. Black women had the highest rates among women, and black men had the largest increase among men.
Cancer and heart disease are the leading causes of death for middle-aged Americans, accounting for approximately half of all deaths in this age group, according to the CDC.
The past several decades had come with a downward trend in mortality from cardiovascular disease and stroke, but those trends are now being reversed, said Dr. Mariell Jessup, chief science and medical officer at the American Heart Association, who was not involved in the study.
"It has to do with obesity, a lack of a healthy lifestyle and really the increasing incidence and prevalence of hypertension," she said, adding that combating obesity and hypertension is a war that the country is losing.
"The good news about cardiovascular disease and stroke is that 90% of cardiovascular disease is preventable." Although it's not always easy to keep up, Jessup says the answers to prevention are simple: exercise more, don't smoke, keep your blood pressure under control and maintain an ideal weight.
As for cancer, she explains that some of the same factors known to increase the risk of cardiovascular disease -- such as a lack of exercise and obesity -- are known to increase the risk of cancer.
"Our understanding about risk factors and how you can prevent them have really made it possible for people not to be sort of fatalistic but to fight against both of these diseases," Jessup said.