Objectives. Women reaching menopause must make a controversial decision about whether to use hormone therapy (HT). The theory of planned behaviour (TPB) was the organizing framework. The objectives were to determine if (1) influence of different TPB constructs varied with stage of menopause and HT use, (2) women with diabetes were influenced in significantly different ways from women without, (3) the overall perceived behavioural control (PBC) and self-efficacy (SE) have independent effects on intention, and (4) physician influence was mediated by subjective norm (SN).
Design. Cross-sectional survey of women from a managed care organization.
Methods. Multiple regression analysis was used to analyse 765 responses (230 from women with diabetes) and separately four main subgroups: (1) early menopause stage and never used HT, (2) late menopause stage and never used HT, (3) late menopause stage and previously used HT, and (4) late menopause stage currently using HT.
Results. For the entire sample, the model explains 68% of variance in intention, where SE, physicians' influence, self-identification with menopause as a natural part of ageing, self-identification as someone who wants to delay menopause, HT status, menopause status, and diabetes were added to the TPB. For the entire sample, SE added 2% to the explained variance and the physician determinant added 7%.
Conclusions. An augmented TPB is useful for understanding women's HT use decisions. The theory explains more variance in intention before a behaviour is enacted than after, and decision structure changes over time. PBC and SE have independent effects on intention.