Not smoking and being socially active keys to longevity

Associate Professor Yoram Barak, a consultant psychogeriatrician, says the results show people can have some control over the ageing process.

"Electing not to smoke and committing to maintain social networking will be the best investment one can make towards successful ageing," he says.

Being socially active means physically going out of your home and away from families and interacting with people whether that is visiting friends, volunteering or participating in activities such as attending a concert or playing golf, Professor Barak says.

Together with his colleague Professor Paul Glue, from the Department of Psychological Medicine, and Dr Sharon Leitch from the Department of General Practice and Rural Health, Associate Professor Barak set out to investigate the variables associated with exceptionally healthy extreme old age.

"This is so we can make some recommendations to try and help people age well."

The researchers examined data relating to 292 centenarians who were free of common chronic diseases such as diabetes, depression, dementia and hypertension. They also included information relating to a further 103,377 older people aged over 60. All of these people were living in private accommodation in the community and not in aged residential care.

Results showed social engagement of participants, whereby they are participating in social activities of long-standing interest was similar across all age groups.

Rates of depression and diabetes declined steadily with increasing age and rates of dementia declined after the age of 80. Hypertension rates increased by nearly 30 per cent from age 60 to 100 years.

There is evidence that exercise improves health and length of life but in this study most participants had a similar profile of physical activity and there was not sufficient spread of duration or intensity of physical activities to test the effects on ageing.

However, among those surveyed the highest physical activity groups were at the lowest risk of dementia.

As of 2011, there are estimated to be between 400 to 500 centenarians living in New Zealand. Of these, fewer than 40 would be aged over 105. The mean age of those interviewed in the study was 101.

The centenarians were more likely to be female (75 per cent) and in any age group, women were more likely to be free of the common chronic diseases outlined above.

"Women have a longer life expectancy and are therefore more likely to be represented in centenarian studies. However, after correcting for this advantage, men who do make it to 100 years of age are more likely to be free of common illnesses," Associate Professor Barak says.

This study found higher rates of centenarians free of common chronic diseases in New Zealand than reported in other countries.

However, one explanation is that this survey considered only centenarians living in the community, who were likely to be in better health compared with those living in residential care or hospital settings.

Professor Barak explains the biopsychosocial foundations of remarkable health and longevity among centenarians is unclear. Genetic factors, certain geographical locations and life-style characteristics have all been studied in an effort to identify potential predisposing factors of exceptional longevity.