Objective: To describe the social and behavioural influences on the uptake of hormone replacement therapy before the age of 50.
Design: Nationally representative birth cohort study with detailed hormone replacement therapy histories and prospective data on health, social and behavioural factors collected throughout life.
Setting: England, Scotland and Wales.
Population: General population sample of 1,572 women followed to the age of 50 years.
Main outcome measure: Age at first hormone replacement therapy use
Results: By the age of 50 years, 45% of women had tried hormone replacement therapy and one third were current users. Over two-fifths of users had tried more than one preparation and over one quarter had episodic use. For the vast majority, prescribing conformed to current guidelines. More educated women took hormone replacement therapy for long term prevention compared with their less educated peers. Hysterectomy increased the chances of taking hormone replacement therapy, particularly where an oophorectomy had also been performed, and was associated with longer and more continuous use. Results of a Cox's proportional hazards model showed that the age at which first hormone replacement therapy is used by women who have not had a hysterectomy was influenced by previous contact with health services for menstrual disorders, previous use of oral contraception and cigarettes, past reporting of health problems and low social class. The relation between smoking and low social class with early use of hormone replacement therapy may be due to their association with early menopause.
Conclusions: The trend over the last two decades towards greater use of hormone replacement therapy has continued unabated for younger women. So far, hormone replacement therapy users in this generation have had less healthy lifestyles and social advantages than nonusers, in contrast to many older mainly American studies based on earlier generations. This may have long term implications for health and health care as the postwar baby boom generation ages.