Is climacterium by the mid-40s associated with thyroid dysfunction or autoimmunity? A population-based study.

OBJECTIVE

We investigated whether more advanced climacteric stage in the mid-40s is associated with thyroid autoimmunity and dysfunction.

METHODS

This cross-sectional cohort study included 2,569 46-year-old women. Thyroid hormone, thyroid peroxidase antibodies, and follicle-stimulating hormone levels were determined. Using menstrual history and follicle-stimulating hormone levels, the participants were divided into climacteric (n = 340) and preclimacteric (n = 2,229) groups. Women diagnosed with premature ovarian insufficiency (menopause by 40 y of age) were excluded. The use of thyroid medication was evaluated from the medication reimbursement register. The prevalence of thyroid medication use, laboratory-based thyroid dysfunction, and thyroid peroxidase antibody positivity was compared between the two groups. The association between climacteric status and thyroid disorders was investigated using a logistic regression model including smoking and thyroid antibody status.

RESULTS

At 46 years old, climacteric women used thyroid medication more often than preclimacteric women (9.1% vs 6.1%; P = 0.04). There was no difference in the prevalence of subclinical or clinical hypothyroidism and hyperthyroidism in nonmedicated participants (5.5% vs 5.0%; P = 0.7) or thyroid peroxidase antibody positivity (14.0% vs 15.0%, P = 0.7). In the regression model, being climacteric (OR = 1.6; 95% CI 1.1-2.3; P = 0.02) and antibody positivity (OR 4.9; 95% CI 3.6-6.6; P < 0.001) were associated with a higher prevalence of thyroid dysfunction.

CONCLUSIONS

More advanced climacteric stage in the mid-40s was slightly associated with thyroid dysfunction but not thyroid autoimmunity.