Menopausal transition and thyroid function trajectories: a large-scale longitudinal study of healthy women
Authors' conclusion
Menopause was not associated with clinically meaningful changes in thyroid function beyond aging.
Study context
- Population
- Healthy Japanese midlife women with natural menopause and ≥1 health checkup before and after menopause, St. Luke's International Hospital, Tokyo; hormone therapy or surgical menopause excluded
- Participants
- 7,644 women86,967 visits
- Exposure
- Before vs after menopause
- Outcome
- Serum TSH and free thyroxine (fT4) levels
Methodological detailsinterrupted time-series analyses within mixed-effects linear models, annual health checkup data
- Interrupted time-series analyses within mixed-effects linear models
- Annual health checkup data
Main finding
As reported in the abstract
median 13.7-year follow-up
TSH change per year before menopause
0.014 mIU/L
95% CI 0.010 to 0.019
Additional TSH slope change at menopause, not significant
−0.006 mIU/L per year
CI, −0.012 to 0.000
Free thyroxine (fT4) change per year before menopause
−0.005 ng/dL
CI, −0.006 to −0.005
Additional fT4 slope change at menopause, stabilized thereafter
+0.005 ng/dL per year
CI, 0.004 to 0.005
Observational data: associations, not effects.
Secondary outcomes
Abnormal TSH categories (>4.5, >10.0, <0.4, <0.1 mIU/L) and self-reported thyroid disorders
- Prevalence of abnormal TSH and thyroid disorders increased with age, but no distinct changes at menopause
Original publication
Menopausal transition and thyroid function trajectories: a large-scale longitudinal study of healthy women. J Clin Endocrinol Metab. Published 19 August 2026. doi:10.
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