New results from a decade-long epidemiological study have shown that overweight older men are less likely to develop dementia.
The results, published in this month's PLoS ONE Journal, indicate that men with a body mass index (BMI)* in the overweight category and with high measurements of fat deposits around the waist were less likely to develop dementia compared to their normal weighted peers.
The study surveyed 12,047 community-dwelling men aged between 65 and 84 years over a 10- year period.
"We found that older men who have more body fat around their waist are less likely to develop dementia," said Winthrop Professor Osvaldo Almeida, Chair of Old Age Psychiatry at The University of Western Australia and Research Director Western Australian Centre for Health and Ageing, based at the Western Australian Institute for Medical Research.
"There is some controversy over whether obesity guidelines that have been developed for adults should be applied to the elderly.
"It is well established that obesity is a contributing factor for many lifestyle diseases such as cardiovascular disease, and diabetes, which in turn increases the risk of death in middle age. However, the same may not true for older men.
"Recent research has shown that being classified as overweight in old age reduces your chance of dying from cancer, heart attack, stroke and other diseases that are associated with old age. Our findings add further weight to the argument for the need to review the BMI for the elderly.
"These findings have relevance to the ongoing debate about developing suitable BMI guidelines for later life: older men who have a slight increase in adiposity markers are not at greater risk of dementia, and current guidelines for ‘healthy' adiposity values for BMI, waist circumference and waist/hip ratio might require recalibration in older age."
Professor Almeida said the prevalence of obesity in older Australians had tripled between 1985 and 2004, affecting 22 per cent of men aged 65-74 and 14 per cent of those older than 75 years.
"The strength of our study is that, to our knowledge, it is the largest, longest epidemiological survey of old men and dementia," he said.
"Many other studies have looked at far fewer men. We cannot comment on whether the findings would apply to older women, without doing further research with women."
This study was part of a 10-year, Perth-based epidemiological survey: The Health In Men Study, involving men originally recruited for a trial of screening for abdominal aortic aneurysm. Participants were randomly selected from the electoral roll. Between 1996 and 1999, men aged 65 and older (mostly Caucasian) attended a clinic and completed a questionnaire, providing a range of demographic and risk factor data. Five years later, surviving men were invited to a follow-up study. Between 2001 and 2004, the men completed a second questionnaire, and attended a clinic.
*A statistical measurement which utilises a person's height and weight, the BMI has long been used as a formula by the World Health Organization to enable health professionals to discuss weight problems objectively with their patients.
The Western Australian Centre for Health & Ageing (WACHA) is dedicated to researching issues associated with ageing in order to extend healthy life. To date, the Centre has achieved notable success in cognitive impairment, mental health and Indigenous ageing. WACHA is one of Australia's most productive research centres.
WACHA is partnered with the WA Institute for Medical Research and The University of Western Australia and is a hospital based research centre.