Patterns of hormone therapy use in the Norwegian Women and Cancer study (NOWAC) 1996-2005.
OBJECTIVE
To examine patterns of use of hormone therapy (HT), including duration of use, in North Norway in 1996, 2002 and 2005.


METHODS
Within the NOWAC cohort we conducted a cross-sectional comparison of questionnaire data among women aged 48-62 years in 1996 (N=8822), 2002 (N=6262) and 2005 (N=4830). Response rates for first time respondents: 58% in 1996 and 66% in 2005. The 2002 participants were second time respondents including 4814 of the 1996 participants. The partial dependence was managed statistically using generalized estimating equations (GEE) and linear mixed models.


RESULTS
Use of HT increased from 1996 (30.5% current, 43.3% ever) to 2002 (38.2% current, 59.3% ever), and decreased toward 2005 (14.7% current, 35.8% ever). High-dose combinations were still the most used HT products in 2005, although low-dose estrogen products and tibolone had gained market shares. Current use of HT among pre-/perimenopausal women was 9.4% in 1996, 13.2% in 2002 and 0.6% in 2005. Mean duration of current HT use was 3.7 years in 1996, 5.8 years in 2002 and 6.3 years in 2005 (p<0.05). In 2005 current HT use was not associated with formerly known predictors, except age and menopausal status.


CONCLUSIONS
Succeeding high levels of HT use in 2002, the prevalence in 2005 is below that in 1996, in accordance with national policies. In 2005 climacteric complaints seems to be the only predictor of HT use. Extensive long-term use in 2005 raises questions regarding compliance with treatment recommendations.
Waaseth
Marit
M
Institute of Community Medicine, University of Tromsø, N-9037 Tromsø, Norway. marit.waaseth@uit.no
Bakken
Kjersti
K
Lund
Eiliv
E
D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D015914:Estrogen Replacement Therapy / Q000706:statistics & numerical data*; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D008875:Middle Aged; D009652:Norpregnenes / Q000008:administration & dosage; D009664:Norway; D047648:Perimenopause; D017697:Premenopause; D011795:Surveys and Questionnaires; D013997:Time Factors
D004967:Estrogens; D009652:Norpregnenes; C027385:tibolone