New York: “Sweetie”, “Dear” and “What can I do for you today, young lady?” are all phrases that raise the hackles of the otherwise easy-going 83-year-old New Yorker.

“That sort of rhetoric changes me from a “sweet”, “dear” little old lady into a fierce cranky virago,” declared the feisty 5-ft tall retired charity fundraiser, occasional actress and yoga enthusiast.

But the condescending terms that so exasperate Miss Kelly are not just insulting to many elderly people; they can also be bad for their health, according to two ground-breaking studies.

So-called “elderspeak” – defined by researchers as overly caring, controlling and infantilising communication – bears many similar traits to “baby talk”, including simplified grammar and vocabulary and overly intimate endearments.

And such verbal ageism can harm longevity by delivering a self-fulfilling message that older people are incompetent, frail and feeble, sending them into a negative downward spiral, researchers say.

“Elderspeak is indicative of general negative stereotypes of the elderly,” said Becca Levy, a Yale School of Public Health professor. “It is another example of how people are treated differently based on their age in health care, in the workforce and in everyday life. And we have found a clear connection between the how the elderly are treated and their health and functioning.”

In a study that first alerted the academic world to these dangers, she found that older people exposed to negative stereotypes associated with ageing, reinforced by belittling phrases and condescending attitudes, performed markedly worse in memory and balance tests than peers who were not.

Indeed, in one Ohio town, she and her fellow researchers concluded that people aged over 50 who held positive perceptions about ageing lived on average of 7.5 years longer than those who did not, even when other health factors were allowed for. Remarkably, those perceptions – fuelled by even apparently innocuous words and phrases – had a greater impact than exercise or not smoking.

The worst offenders in elderspeak are often health care workers, whether it is doctors telling older patients who question them “You don’t want to upset your family, do you?” or nursing staff who deal with the elderly every day.

Indeed, Kristine Williams, a trained nurse and associate professor at Kansas University, found that nursing home residents with Alzheimer’s who are addressed like children are more likely to resist medical care – with obvious detrimental effects for their health.

Dr Williams and her team filmed the relationship between 20 patients with dementia and nursing staff. When spoken to and treated like children, many pulled faces, yelled or refused to do what they were told or co-operate with care.

Even for older patients receiving medical care for conditions not related to mental health, being spoken to and treated like a child can have a marked impact on their welfare.

“I was in hospital for two months after a fall and the whole time was subjected to condescending treatment and phrases such as “sweetie”, “dear” and “good girl”,” said Elaine Smith, 78, a retired Chicago schoolteacher.

“I often didn’t feel strong enough to answer back. But even worse, I felt that this sort of attitude and message was grinding me down. It reduces your self-esteem and at times I felt it was just easiest to give in to the stereotype that I didn’t know what I wanted or needed.”

Concern about ageism in all its forms, including elderspeak, has grown as the US population greys. The 85-and-over age group is the country’s fastest-growing demographic while Americans turning 65 now will live on average to 83.

Yet, says Dr Robert Butler, president of the International Longevity Centre-USA, that seems to do little to challenge the growth of ageism – the term he first conjured nearly four decades ago. “Daily we are witness to, or even unwitting participants in, cruel imagery, jokes, languages and attitudes directed at older people,” he said.

The current US presidential contest, in which John McCain is hoping to become the oldest candidate to win the presidency for the first time at the age of 72, has also thrust attitudes towards the elderly into the public spotlight.

Late night comics have regularly lampooned him as an angry or doddery old man while the Democratic candidate Barack Obama came under fire from the McCain campaign for allegedly deploying barely-coded language when he remarked that his rival had “lost his bearings”.

As a principle, Miss Kelly now makes clear her objections to patronising forms of address. “I really am a little old lady but there is nothing wrong with my mind and I don’t like being talked down to,” she said.

“When I tell people they have offended me like that, they can be quite indignant and enunciate very slowly that they were just trying to be nice.

“But I believe that the people who heap these endearments upon us are reacting to their own fears of ageing in a youth-oriented culture. My advice, darlings – get over it.”