Americans are dying from heart disease at a faster rate, stalling four decades of gains against the nation’s leading killer and driving up the U.S. mortality rate overall.

The death rate from heart disease rose 0.9% last year, according to U.S. mortality data released Thursday by the Centers for Disease Control and Prevention. The death rate also rose 3% for stroke, the fifth-leading cause of death in the U.S.

Both changes, which researchers tie in large part to the rise in obesity and diabetes, helped push life expectancy down by one-tenth of a percentage point, to 78.8 years, according to the CDC.

Cardiovascular disease has been the biggest killer in the U.S. for more than a century. But death rates from heart disease in the U.S. have declined nearly 70% since 1969, brought about by antismoking and other public-health campaigns, the advent of medications to control blood pressure and cholesterol, and new techniques for saving peoples’ lives from heart attacks.

The decline in heart-related deaths has been so precipitous, in fact, that until 2011 heart disease was poised to drop below cancer as the leading cause of death in the U.S., researchers say. But then the downward trajectory suddenly slowed at that point and remained slow until the heart disease death rate rose in 2015.

“It’s a definite milestone in the wrong direction, and the concern a lot of us have is that it reflects largely the approximately three-decade-long epidemic of obesity,” said Stephen Sidney, senior research scientist with the Kaiser Permanente Northern California division of research, who led a study published earlier this year that pinpointed the halt in progress against heart disease.

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