High blood pressure, a nationwide health threat, is taking an even bigger bite out of the Big Apple.

More than one in four adults in New York City — 1.8 million people — say they have hypertension, a citywide increase of 11 percent over the past decade, according to a pair of reports published Monday.

By comparison, the prevalence of high blood pressure nationwide has remained relatively unchanged in recent years, hovering around 30 percent for adults.

Often known as the silent killer, high blood pressure is a leading contributor to heart disease and stroke. In New York City, it’s killing one in five people under 65, according to the city’s Department of Health & Mental Hygiene. The city saw nearly 100,000 hospitalizations for hypertension, heart disease or stroke in 2014, totaling more than half a million days in the hospital.

The reports describe how many New Yorkers aren’t taking preventive steps with regular primary care visits and a focus on exercise and a healthy diet. The average New York City adult consumes nearly 40 percent more sodium than the daily recommended limit of 2,300 milligrams. Sodium-filled packaged and restaurant foods are often the culprit.

Diverse populations are hit the hardest, with high blood pressure more commonly reported among black and Latino adults compared with white adults, as well as those living in high-poverty neighborhoods compared to those living in low-poverty neighborhoods.

The city’s Health Department is launching a citywide response to help ensure New Yorkers have access to resources to prevent and control blood pressure as part of a wider health initiative by Mayor Bill de Blasio. The goal is to cut the city’s premature mortality by 25 percent by 2040, the Health Department said.

“Hypertension is a leading cause of heart disease and stroke. It’s a condition the majority of New Yorkers either have or are on track to develop, but it doesn’t have to be our destiny,” Health Commissioner Mary T. Bassett, M.D., said in a news release. “We have made significant gains in reducing smoking prevalence over the past decade and we want to see the same in hypertension.”

Mitchell Elkind, M.D., a neurologist and American Heart Association spokesperson, said the association applauds the city’s focus on hypertension.

“Diagnosing and treating high blood pressure with lifestyle counseling and with the right medications can prevent hospital admissions, heart attacks, strokes, heart failure and premature death,” he said.