Hyperprolactinaemia associated with increased thyroid volume and autoimmune thyroiditis in patients with prolactinoma

Authors

  • Muyesser Sayki Arslan,

    Corresponding author
    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
    • Correspondence: Müyesser Sayki Arslan, Department of Endocrinology and Metabolism Ankara Diskapi Training and Research Hospital, 12 Irfan Bastuğ Street, 06110 Altindağ, Ankara, Turkey. Tel.: +90 530 551 13 80; Fax: +90 312 317 05 13; E-mail: muyessersaykib@yahoo.com.tr

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  • Mustafa Sahin,

    1. Department of Endocrinology and Metabolic Diseases, Ankara University, School of Medicine, Ankara, Turkey
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  • Oya Topaloglu,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Esra Tutal,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Melia Karakose,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Askin Gungunes,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Erman Cakal,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Mustafa Ozbek,

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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  • Tuncay Delibasi

    1. Department of Endocrinology and Metabolic Diseases, Diskapi Yıldırım Beyazid Training and Research Hospital, Ankara, Turkey
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Summary

Objective

The aim of this investigation was to evaluate the effects of hyperprolactinaemia on thyroid function, volume and nodularity in patients with prolactinoma.

Context

Hyperprolactinaemia has been associated with various autoimmune diseases; however, the data on the correlation between the level of prolactin (PRL) and thyroid disorders have not been adequately clarified.

Design

Case–control study.

Patients

Forty-eight subjects with new diagnosis of hyperprolactinaemia (group 1) and 39 subjects undergoing treatment for prolactinoma (group 2) were recruited from our outpatient clinic. Fifty-two healthy subjects were included as a control group (group 3).

Measurements

The serum PRL, thyroid-stimulating hormone (TSH), thyroxine (free T4), thyroidal microsome (anti-TPO) and antithyroglobulin antibodies (TgAb) levels were evaluated, and ultrasonographic thyroid volume was calculated.

Results

The frequencies of positive anti-TPO and TgAb were significantly higher in group 1 than in groups 2 and 3 (P = 0·008). Also, the percentage of patients with thyroid heterogeneity were significantly higher in groups 1 and 2 than in group 3 (P < 0·05). The percentage of patients with thyroid nodules were higher in group 1 than in groups 2 and 3 (p1–2 = 0·03, p1–3 = 0·05 and p2–3 = 0·637). The mean thyroid volume was significantly higher in group 1 (P = 0·001), and a positive correlation was found between thyroid volume and the level of PRL (r = 0·616; P = 0·0001). Prolactin had a significant effect on the total volume according to stepwise multiple linear regression analysis (adjusted R2 is 0·268; P < 0·0001).

Conclusions

Patients with hyperprolactinaemia have significantly increased thyroid volume, thyroid autoimmunity and nodule prevalence.

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