Older people with money not only have the means to buy expensive cuts of steak and good bottles of Beaujolais, they also have an easier time walking through the store shopping for their purchases and then carrying them home.

A new study, co-authored by University of Toronto social work professor Esme Fuller-Thomson, has found it's not just greater purchasing power that older people with more money enjoy, it's also greater physical prowess.

And each increase or decrease in level of household income, from poverty to wealth, correlates to a similar change in physical functioning.

"The discrepancy between poorest and richest is huge," says Fuller-Thomson, "but even very high up the spectrum, the richer are doing better than the people just one step down.

"Why would the top 75th percentile be worse off than the 85th percentile?" she wonders. "If it was just health, housing and nutrition, one wouldn't expect any difference between them."

The research, published in the current New England Journal of Medicine, found that Americans ages 55 to 84 who are wealthier have an easier time walking, carrying, reaching, lifting objects and climbing stairs than those with less money.

For example, people ages 55 to 64 who are living below the poverty level are six times more likely than the wealthiest groups to say they have functional limitations, reports the U.S. National Institute on Aging, in collaboration with the University of Toronto and the University of California, Berkeley.

The large set of data from the U.S. census "allowed us to explore something that hadn't been explored before," explains Fuller-Thomson, who says the research backs Canadian work on different physical health outcomes depending on income, but with more fine-tuning.

Why should money make a difference in climbing stairs?

"We've known for a long time that people at the low end of the socio-economic spectrum do much more poorly health-wise than people at the higher end," explains senior author Dr. Jack Guralnik, chief of the NIA Laboratory of Epidemiology, Demography and Biometry.

"And many chronic conditions — heart disease, arthritis — can have an impact on functioning, strength and balance."

He was surprised to find, however, that differences in functioning were reported even at the uppermost incremental levels of income. The highest income category used in the analysis — 700 per cent or more of the U.S. poverty line — began at $57,813 for an older adult living alone and $124,327 for a four-person household.

But York University professor and health policy researcher Dennis Raphael explains, "It reflects a lifetime of lived experience. And each step in income represents a difference in lived experience.

"These effects are independent of health care and they are evident in Canada as well."

What surprises Raphael most about the U.S. study is the analysis by income.

"Income is consistently downplayed or ignored," he says. "Americans would agree that nobody should be at a disadvantage because of colour or cultural origins. But if you talk about inequalities related to income, then it opens up questions about how great are income differences and should it be a cause for concern."

Observes Fuller-Thomson, "Almost every disease, you see higher rates in the poor. If it is causal, as we're anticipating, the war on poverty was the right solution. Making sure there are no people in absolute poverty makes a huge difference, with a huge payback."