Thyroid stimulating hormone (TSH) concentrations and menopausal status in women at the mid-life: SWAN.

OBJECTIVE

We evaluated menopausal symptoms, menstrual cycle bleeding characteristics and reproductive hormones for their associations with thyroid stimulating hormone (TSH) concentrations in women at the mid-life from five ethnic groups.

METHODS

This report is from the baseline evaluation of the Study of Women's Health Across the Nation (SWAN), a community-based multiethnic study of the natural history of the menopausal transition. Enrollees were 42-52 years old (pre- and early perimenopausal) African American, Caucasian, Chinese, Hispanic and Japanese women (n = 3242). Enrollees were interviewed about self-reported diagnosed hypo- and hyperthyroidism or thyroid treatment, menopausal symptoms and menstrual cycle bleeding characteristics. Serum was assayed for TSH, oestradiol, testosterone, FSH and SHBG.

RESULTS

There were 6.2% of women with TSH > 5.0 mIU/ml and 3.2% with TSH < 0.5 IU/ml, cutpoints that have been used to encompass clinical and subclinical hypo- and hyperthyroidism, respectively. African American women had significantly lower mean TSH concentrations than Caucasian, Hispanic and Chinese women. Of the more than 15 menopause symptoms evaluated, only fearfulness was associated with having a TSH value > 5.0 mIU/ml (P < 0.008) or < 0.5 mIU/ml (P < 0.02). Women with TSH values outside the range of 0.5-5.0 mIU/ml were more likely to report shorter or longer menstrual periods (P = 0.004 for both) than women within that range. FSH, SHBG, dehydroepiandrosterone sulphate (DHEA-S), testosterone, and oestradiol concentrations were not associated with TSH concentrations.

CONCLUSION

In mid-aged women, there was a 9.6% prevalence of TSH values outside the euthyroid range of 0.5-5.0 mIU/ml. Although TSH was associated with bleeding length and self-reported fearfulness, it was not associated with indicators of the menopausal transition, including menopausal stage defined by bleeding regularity, menopausal symptoms or reproductive hormone concentrations.