[Use of hormone replacement therapy by Icelandic women in the years 1996-2001.]

Since the late seventies the use of hormone replacement therapy by peri- and postmenopausal women has been steadily increasing. This was shown in a former study of hormonal use among Icelandic women who had responded to a questionnaire when attending cancer screening at the Cancer Detection Clinic (CDC) of the Icelandic Cancer Society in the years 1979-1996. This current study is an independent extension of the former study with the goal of investigating menopausal hormone use among Icelandic women during the period of 1996-2001 and comparing the results with the former study period of 1979-1995.

We used data from the CDC for the period of 1996-2001 and reviewed the responses from Icelandic women aged 40-69 years to questions regarding hormonal use. We investigated changes in the proportion of women using hormones, the proportion of women using combined hormone replacement therapy, the proportion using long-time hormone replacement therapy, and also the relationship between hormonal use and smoking. We also compared our results to the former study results.

During the period 1996-2001, 16.649 women aged 40-69 years responded to the questionnaire on hormonal use. There was an increase in use during that period, and also an increase compared to the period 1979-1995. Women born 1941-1945 were more likely to have ever used hormones (68%) than women born 1931-35 (42%). Present use of hormones was most prevalent among 52-57 year old women (57%). The proportion of women aged 50-55 years reporting present use did not change over the period ( approximately 50%). Long term use increased steadily during the period. During 1996-98 the proportion of women who had used hormones for more than 5 years was 49%, compared to 67% of women 1999-2001. This is also a considerable increase compared to the former study period. In the years 1996-2001, 19% of the women reported hormone use for 14 years or more. Smoking was more common among ever users of hormone replacement therapy (63%) than among never users of hormone replacement therapy (53%).

The proportion of women who had used hormones and the duration of hormone use increased steadily during the period of 1996-2001. There was also a considerable increase compared to the former study period.