Age-old issues

The multidisciplinary CHALICE study is investigating how New Zealand's increasing elderly population can age healthily.

New Zealand stands on the cusp of a demographic milestone. For the first time in recorded history the number of people aged 65 years and over will soon outnumber children aged under five years.

This "grey tsunami" brings with it huge financial implications for taxpayers, especially in regard to health care. The big question remains how to minimise these costs by promoting "healthy ageing" and a better understanding of factors impacting on costly chronic conditions such as diabetes, heart disease and dementia, common in the elderly.

Professor Peter Joyce and colleagues from the University of Otago, Christchurch have designed a study to address these concerns.

The Canterbury Health, Ageing and Life Course (CHALICE) study is a longitudinal study of people aged over 50 that will track their health and well-being over time.

"CHALICE has two aims – looking at determinants of healthy ageing and understanding predictors of what are risk factors for conditions such as dementia, stroke, heart disease and depression in old age," Joyce says.

"We want to understand why some people age well and others don't."

One of the strengths of CHALICE is that the team comprises experts in myriad areas relevant to ageing, he says. Researchers include psychiatrists, geneticists, infectious disease specialists, biostatisticians, Māori health experts, gastroenterologists, gerontologists, cardiologists and a nutritionist.

"One thing which may set us apart is that, early on, we decided to put emphasis on nutrition because it's a modifiable factor. We are collecting data on whether healthy eating leads to healthy ageing.

"If you can encourage people to eat better it's a pretty straightforward way of helping people to stay healthier. For a country focused on producing food it's something that definitely should be modifiable," Joyce says.

"We want to understand why some people age well and others don't.

"What role does diet and physical exercise play, for example, and what role do genetics play?"

A central component of CHALICE is the development of an extensive repository of biological samples – a biobank – for each participant. This biobank will allow researchers to do wide-ranging tests relating to participants" immune systems, genetics and biochemistry.

Genetics is an increasingly important aspect of medical research.

"Over the past few years genome-wide association studies have yielded over 2,000 common genetic variants that influence risk of complex diseases. CHALICE will be able to investigate in a large group of study participants what the impact of these genetic changes are in relation to age-related disease."

Joyce says health inequalities between Māori and non-Māori are an area of ongoing concern so the study has been designed specifically to address this by oversampling Māori.

"Māori die earlier, but are at risk of being excluded from health gains created by non-Māori because of inadequate representation in many studies."

Joyce says the study will inform policy development and provide much-needed information for those trying to maximise the potential of older people within broader New Zealand society.