Americans are living longer and leading healthier lives compared to 20 years ago, according to a new study published in the American Journal of Public Health.

Researchers from the University of Massachusetts Medical School (UMMS) analyzed data from multiple government-sponsored health surveys that had been conducted over the last 21 years.

The researchers say that for the first time, they were able to measure how the quality-adjusted life expectancy (QALE) of all Americans had changed over time.

“QALE tells us more than how long a person can expect to live. It tells us what the relative quality of those added years are in terms of physical, emotional and mental well-being,” says Dr. Allison Rosen, associate professor of Quantitive Health Sciences at UMMS.

She continues:

Though many studies have measured this in different ways, this is really the first time we’ve been able to capture this type of information across the whole US population over an extended period.”

Overall, the results of the data revealed that Americans are living longer, reporting fewer symptoms of disease, have more energy, and show fewer impairments in everyday tasks compared to one generation ago.

In detail, the study authors say that in terms of life-expectancy, a person who is 25-years-old today can expect to live 2.4 quality years longer, compared with a person who was 25-years-old in 1987, while a 65-year-old can expect to live 1.7 years longer.

The researchers say that these results are likely to be a result of improvements in health care and the fact that many more conditions are treatable today compared to 25 years ago.

Dr. Rosen adds:

Today, it is far less likely that a patient recovering from a heart attack will become institutionalized or need around-the-clock care the way they once might have.”

They note that today, Americans are much more likely to experience quality of life declines linked to chronic, degenerative disease such as dementia and Alzheimer’s, while younger Americans are likely to experience health problems linked to a “sedentary lifestyle.”

But the analysis was not all good news. The findings showed an increase in anxiety in young and middle-aged Americans from 2001, while elderly people have shown a significant increase in problems with walking over the last 10 years.

The researchers say that previous studies have shown inaccuracies in determining health trends, adding that it is difficult to bring so many variables together, such as physical well-being and mental health, to equal a single number.

Furthermore, they say surveys that measure quality of life are frequently inconsistent with each other, as they all pose different definitions.

However, because their findings for this study were uncovered from multiple national surveys that asked Americans about their health in various ways over a 21-year period, this allowed them to identify areas where the studies overlapped.

This meant they could build a “single, large data set” covering the entire US population over two decades.

“Comprehensive measures of the overall health of the nation are practically nonexistent,” adds Dr. Rosen. “This study shows how existing national data can be used to systematically measure whether the population is getting healthier – not just living longer.”

Dr. Rosen concludes that having a consistent measure of population health signifies a major advance in the ability to measure the impact of health care reform on the general health of all Americans.