Canadians live longer and in better health than their American counterparts, researchers said.

A 19-year-old Canadian can expect 2.7 more years of "perfect health" than an American of the same age, according to David Feeny of Kaiser Permanente Northwest's Center for Health Research in Portland, Ore., and colleagues.

The difference probably arises from a combination of two factors, Feeny and colleagues said online in the journal Population Health Metrics: Canada's cradle-to-grave health insurance and lower social and economic inequality, especially among the elderly.

The finding, from a joint United States-Canada survey of health, seems certain to add fuel to the still-current debate over how recent reforms will affect health care.

"There is very substantial relevance," Feeny told MedPage Today. "I think there are some very important potential policy implications, particularly in the U.S."

The researchers analyzed data from the 2002/2003 Joint Canada/United States Survey of Health, which was conducted by the National Center for Health Statistics and Statistics Canada.

The survey, which used random-digit telephone dialing to obtain data, was described by the researchers as the first to "provide fully comparable data of health status, lifestyle, health care utilization, and other determinants of health" between the two countries.

Using the data, the researchers computed life expectancy, health-related quality of life (using an instrument dubbed Health Utilities Index Mark 3, or HUI3), and health-adjusted life expectancy for the two countries.

The health utilities index is based on eight aspects of health status -- vision, hearing, speech, ambulation dexterity, emotion, cognition, and pain and discomfort -- and each attribute has five or six levels, ranging from normal to severely disabled.

HUI3 scores range from 0.0 to 1.0 -- from dead to "perfect health," Feeny and colleagues said.

The study results are similar to other examinations of health in the two countries, Feeny said, but most previous studies were only able to compare things like life expectancy and health-related quality of life, or morbidity. The new factor here, he said, is the health-adjusted life expectancy, a measure that combines both.

The researchers found:

 Response rates were slightly higher for Canada -- 65.5 percent versus 50.2 percent.

 At birth, Canadians had a slightly longer life expectancy -- 79.7 years versus 77.2 years.

 The infant mortality rate, in deaths per 1,000 live births, was lower in Canada -- at 5.4 compared with 7.0.

 The overall poverty rate - defined as the proportion with incomes 50 percent below the median -- was 12 percent in Canada, compared with 17 percent in the U.S.

 The poverty rate among the elderly was also lower -- 6.0 percent versus 23 percent.

When the researchers calculated the health-adjusted life expectancy for a 19-year-old in Canada -- the number of additional years he or she could expect to live in perfect health -- they found the Canadian teen would have 52 years more, with a 95 percent confidence interval from 51.5 to 52.5 years.

In comparison, an American 19-year-old would have 49.3 years more of perfect health, with a 95 percent confidence interval from 48.9 to 49.7 years. The difference was significant at P<0.0001.

The "legacies of slavery and racial discrimination" probably affect population health in the U.S. more than in Canada, the researchers said, but a comparison of white-only respondents had similar results.

Because the study is a snapshot, it's not possible to disentangle the cause of the differences, the researchers said. But it "seems to be associated with substantial differences in access to care as well as substantial differences in social and economic inequality," they said.

They cautioned that the different response rates might have affected the outcome. For instance, if those in poor health were less likely to respond, the study's findings could be an underestimate.

The limited sample size might also have contributed some imprecision in the estimates of health-adjusted life expectancy, they said, although not enough for the confidence intervals to overlap.

Feeny said the study suggests that the recent health care reforms -- if they succeed in expanding access to care -- will slowly improve matters. In addition, measures to reduce poverty, such as changes to the tax system or better access to good education for the poor, might also be beneficial, he said.