method

METHODS

In April 1996, women in three age groups - 18-23 years (born 1973-78), 45-50 years (born 1946-51), and 70-75 years (born 1921-26) were selected from the Medicare database, which contains the name and address details of all Australian citizens and permanent residents. These women were sent an invitation to participate in the Australian Longitudinal Study on Women’s Health (ALSWH), and more than 40,000 responded and agreed to participate in the project for 20 years.

The three age groups were selected in order to follow women through life stages which are critical to women’s health and well-being. ALSWH began collecting information from the 1973-78 cohort when they were young women in the early stages of transition from late adolescence to full adulthood.  Over time most of this group have moved into the workforce, entered adult relationships, and many have become mothers. The mid-age women, born 1946-51, were selected to examine menopausal transitions and the social and personal changes of middle age. The older women (born 1921-26) were selected when they were aged in their early 70s, an age when many were generally still active, involved members of the community. These women have been followed to obtain information on predictors of continuing well-being and independence in older adult life.



Sampling from the population was random within each age group, except that women from rural and remote areas were sampled at twice the rate of women in urban areas. This was done so that the numbers of women living outside major urban areas were large enough to allow statistical comparisons of the circumstances and health of city and country women, an important issue for Australia now and in the future. The Australian Longitudinal Study on Women’s Health is the largest study of health issues in rural and remote parts of Australia.

The longitudinal study design, by which the same women are followed for 20 years, means that the study is able observe changes in women’s health, to clarify cause-and-effect relationships and to assess the effects of changes in policy and practice.  From 1996 to 2011, each age cohort was surveyed once every three years via surveys sent in the mail.

Schedule of Surveys for the Australian Longitudinal Study on Women's Health Age in years and number of participants in each cohort

In 2011, the older cohort began receiving a shortened survey every six months, and in 2012 ALSWH began annual surveys of a new cohort of young women, born 1989-95.

As well as the main surveys, women are occasionally invited to participate in a variety of substudies, targeting particular areas of health.  A wide range of topics have been covered including:

  • Sleeping difficulties and disturbances
  • Domestic violence
  • Menopausal problems
  • Urinary incontinence
  • Leisure and time use
  • Diabetes
  • Caring
  • Future plans of young women