Hormone replacement therapy use over a decade in an Australian population

To describe the prevalence of hormone replacement therapy (HRT) during the 1990s in an Australian population and the length of time this therapy has been used. Design Data were obtained from five biennial representative population face-to-face interview surveys of the South Australian population from 1991 to 2000, and an additional telephone survey in 2001. The main surveys used consistent methods and quality control procedures.

Over 3000 South Australian adults were interviewed in their own homes by trained health interviewers in each of the biennial surveys.

In 2000, 28% of women aged over 50 were currently using HRT, and ever-use of HRT was 43%. Highest use of HRT was in the 55-59-year age group, where current use was 47% and ever-use was 70%. Among women 55 years and older there was a statistically significant increase in the prevalence of HRT use between 1991 and 2000. Mean length of use in women aged over 55 years increased from 5.4 years in 1991 to 9.6 years in 2000.

Consistent surveillance of the population has shown that HRT use has not increased before age 55, but has greatly increased thereafter. Long-term effects may now be occurring, and further results of current long-term randomized trials are awaited to confirm the overall risk/benefit ratio suggested by observational studies and early results from long-term trials.