When I get older

The ageing space invaders machine in the lounge still gets a work-out. Participants in the Dunedin longitudinal study have gathered around it every time they have been called back for a new round of tests.  

"We got it when they were 11 and we keep thinking we'll throw it away," says Prof Temi Moffitt, associate director of the groundbreaking health and development study.

"But when we call them and ask if they'll come in this year, they always ask, 'Will there be space invaders?'."

In between shooting at aliens, the 38-year-olds will test their fitness on an exercycle, open their mouths to a dentist, give blood, have their lung function measured and answer questions about their sex lives, finances and friendships.

Like the Video Village machine in the corner, they are also advancing in years. The oldest were born in 1972 - the year that Norman Kirk became prime minister, the Watergate scandal broke and Mark Spitz won seven Olympic gold medals - so the project they are part of is repositioning itself at the forefront of study into the ageing process.

Researchers have introduced new tests in a bid to find out why some people age faster than others, fully expecting that even though all the study members are 38, some will have the bodies of 25-year-olds while others will be more like 60.

The Dunedin Multidisciplinary Health and Development Study has tracked the lives of more than 1000 people since birth, in a project that has attracted international interest not only for its high participation rate but for its discoveries.

"There are much larger longitudinal studies," says the director, Prof Richie Poulton.

"But they have not measured people as frequently as we have or in the depth that we have or in the breadth that we have ..."

One of the study's great advantages is that it was founded as a multidisciplinary research project at a time when that was not in vogue, Prof Poulton says. Back in the early 1970s, people did not understand the interractions between various bodily systems, let alone between the body and the mind. Now those are exactly the type of projects that funding agencies want to invest in.

Not only does the Dunedin study have world-class data in areas such as mental, oral, respiratory and sexual health, but it can marry themes together and ask questions others cannot - looking, for example, at a possible link between gum disease and cardiovascular health or how poor mental health might "get under the skin" to cause physical problems.

The Dunedin study is also one of the lengthiest, says Prof Moffitt, an American who is in the city during assessments and spends the rest of her time at Duke University in North Carolina and King's College in London.