Women in Healthy Transition (KISO) Survey: a cohort of 153,800 women aged 45-59 years living in Denmark.

The nationwide Women in Healthy Transition (KISO) Survey Cohort is a population-based longitudinal prospective cohort study established to explore the significant data gap on women's symptoms through different stages of menopause in a Northern European context. The KISO Survey Cohort was set up to represent women aged 45-59 years living in Denmark. In total 575,863 women were invited to participate in the study at baseline. Data were collected through digital questionnaires from June to December 2024 and included self-reported information on stages of menopause, menopausal symptoms, quality of life, physical activity, and work productivity loss using validated scales as well as information on various health, social and lifestyle factors. The follow-up of the KISO Survey Cohort will be conducted through digital questionnaires every three years over a 15-year period, inviting baseline respondents and eligible women aged 45-59 at follow-up. A total of 153,800 women completed the baseline questionnaire, yielding a 27% response rate. Among the participants, 8% were in premenopause, 24% in perimenopause, and 45% in postmenopause. Moreover, 13% had induced menopause and 10% were undergoing menopausal hormone therapy. The KISO Survey Cohort is the first large-scale longitudinal study on menopausal symptoms among women in Denmark. Data are coupled with the personal identification numbers (CPR) enabling opportunities to link data to national administrative registers. This ongoing study, thus, offers unique and extensive data, enabling future research to advance our understanding of menopause, how it affects women, and its long-term effects on women.