Examining ageing over time

Much of what we know about ageing and its effects on individual wellbeing comes from cross-sectional research – taking a “snap-shot” of a particular group at a particular moment. But ageing is a process that takes time and if we are to understand it we need to follow people as they age and document the changes in their lives and characteristics. This is what a longitudinal study can do. The researchers go back to the same group of people at periodic intervals (called “waves” of research) to update information about their lives, feelings and activities.

Around the world there are several longitudinal studies of ageing. Here are a few examples:

• Health and Retirement Study http://hrsonline.isr.umich.edu/

HRS started in 1992 and is based at the University of Michigan. It surveys more than 22,000 Americans over the age of 50 every two years, covering physical and mental health, financial status, family support systems, labour market status and retirement planning.

• English Longitudinal Study of Ageing http://www.ifs.org.uk/ELSA

ELSA collects data on health, economic position and quality of life as people age. It is a study of English people’s quality of life as they age beyond 50 and of the factors associated with it. A report using data from the fifth wave of ELSA was published in October 2012.

• Canadian Longitudinal Study on Aging http://www.clsa-elcv.ca/

CLSA is a national, long-term study that will follow 50,000 men and women between the ages of 45 and 85 for at least 20 years. The study will collect information on the changing biological, medical, psychological, social, lifestyle and economic aspects of people’s lives.

• Melbourne Longitudinal Studies on Healthy Ageing
http://www.med.monash.edu.au/sphc/haru/melsha/

MELSHA is an ongoing study of 1000 people aged 65 and over living in Melbourne. Participants have been followed up every 2 years since 1994. It began at a time when concepts such as healthy and active ageing were rarely seen on policy agendas for older people.

The New Zealand Longitudinal Study of Ageing http://nzlsa.massey.ac.nz/

Now New Zealand has its own longitudinal study of ageing. Work on NZLSA started in 2007, bringing together researchers from two projects:
 The Health, Work, & Retirement Study (HWR) based at Massey University
 Enhancing Wellbeing in an Ageing Society (EWAS), a research collaboration between the Family Centre and Waikato University

NZLSA aims to follow 4,000 New Zealanders over the coming years to understand the factors that promote successful ageing. It will examine what contributes to people’s quality of life in four broad areas as they age:
1. Economic participation (e.g. work, employment, retirement)
2. Social participation (e.g. family support, community and civic participation)
3. Intergenerational transfers (e.g. family care, income, wealth and knowledge)
4. Resilience and health (e.g. control, coping, physical, emotional, cognitive condition)

All participants in the study were randomly selected from the New Zealand electoral roll. There are two main components to this study – postal surveys repeated every 2 years and face-to-face interviews to look at specific topics in more depth.

The first wave of NZLSA took place in 2010 and surveyed 3,317 people aged between 50 and 84. A second wave was in the field in mid 2012. Some of the results from 2010 were presented at a seminar in Wellington in June 2012, hosted by the Institute of Policy Studies, Victoria University of Wellington. Here are a few glimpses from each presentation.

Peter King talked about how measures of wellbeing and quality of life change with age. He found that while monetary wealth and physical health declined with age; mental health, happiness and satisfaction with life actually increased. Perhaps feeling better about ourselves as we grow older can balance out reduced functional capacity.

Fiona Alpass’s presentation focussed on how health and workforce participation were related. People who retired before 65 tended to have poorer physical health but better mental health. Retirees older than 65 tended to have poorer health than workers in that age group. Further research might tell us whether they retired because of poor health or whether retirement brings on poorer health.

Charles Waldegrave looked at income, poverty and housing among older people. He showed that the attributes of having a low income and few assets and renting were associated with low levels of wellbeing, of poor physical and mental health and higher levels of depression. An ability to save and create assets, even on a low income, was strongly associated with good health and wellbeing.

Christine Stephens’ results support other research, which shows that having wide social networks contributes positively to mental and physical health. These findings suggest the need to maintain social networks as people age and for housing types which facilitate this.

The final presentation, by Mary Breheny, described how measures of living standards for older people could be framed. Rather than focusing on material conditions, the measure should encompass older people’s ability to choose what they value. People with high living standards have many choices whereas those with low living standards have few.

As of now, we have results from only one wave of NZLSA, so there are no longitudinal comparisons. Numerous questions arose from the presentations which we cannot yet answer. The real value of the research will be clear when we can track changes between 2010 and 2012 and into the future. Let us hope that the potential usefulness of the study will be recognised by those who hold the purse-strings for research funding.