Updated

U.S. life expectancy has hit another all-time high — 77.6 years — and deaths from heart disease, cancer and stroke continue to drop, the government reported Thursday.

Still, the march of medical progress has taken a worrisome turn: Half of Americans in the 55-to-64 age group — including the oldest of the baby boomers — have high blood pressure, and two in five are obese. That means they are in worse shape in some respects than Americans born a decade earlier were when they were that age.

The health of this large group of the near-elderly is of major concern to American taxpayers, because they are now becoming eligible for Medicare and Social Security.

"What happens to this group is very important because it's going to affect every other group," said Amy Bernstein of the National Center for Health Statistics, which put out the new report.

The report presents the latest data collected by the National Center for Health Statistics and dozens of other health agencies and organizations.

Among the new data: Deaths from heart disease, cancer and stroke, the nation's three leading killers, all dropped in 2003. They were down between 2 percent and 5 percent.

Also, Americans' life expectancy increased again in 2003. By comparison, it was 75.4 in 1990.

Life expectancy in the U.S. has been rising almost without interruption since 1900, thanks to several factors, including extraordinary advances in medicine and sanitation, and declines in some types of unhealthy behavior, such as smoking.

Those trends may allow life expectancy to continue to inch up despite the increases in obesity and high blood pressure, said Bernstein, the study's director.

Still, health officials are trying to draw attention to unhealthy behavior, and this year chose to break out data on people 55 to 64.

"The late 50s and early 60s are a crucial time to focus on disease prevention," said Dr. Julie Gerberding, director of the Centers for Disease Control and Prevention in Atlanta. "It's never too late to adopt a healthy lifestyle to enjoy a longer, healthier life."

The 55-to-64 age group is expected to rise from 29 million Americans in 2004 to 40 million in 2014. That is because of the baby boom, the explosion of births during the prosperous postwar period between 1946 and 1964.

The report looked back at data on people who were in the 55-to-64 bracket around the early 1990s, which basically means people born in the 1930s. Researchers compared them to people in that age range today, which essentially is people born in the 1940s.

They found that rates of hypertension and obesity were higher for the current group of 55-to-64-year-olds.

When the 1930s group was tested around 1990, 42 percent had high blood pressure. That compares with 50 percent for the 1940s group. The older group's rate of obesity was 31 percent back then, compared with 39 percent for the 1940s babies now. Because of the advent of cholesterol-lowering drugs, the prevalence of high cholesterol actually went down, from 35 percent for the 1930s group to 23 percent among the 1940s babies.

Also noted in the report:

--Infant mortality in 2003 dropped slightly to 6.9 deaths per 1,000 live births. Infant mortality has been on a general decline since 1958.

--Spending on health care rose 7.7 percent in 2003, to $1.7 trillion. Health expenditures as a percentage of gross domestic product rose to 15.3 percent in 2003, up from 14.9 percent in 2002.

--Prescription drugs were the fastest-growing expenditure. Spending on prescriptions rose 11 percent in 2003.

--Twenty-eight percent of all adults reported recent low back pain.