Cigarette smoking linked to thyroid hormone changes

  • Gruppen EG & al.
  • Endocrine
  • 9 Nov 2019

  • International Clinical Digest
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Takeaway

  • Cigarette smoking is associated with increased levels of free triiodothyronine (FT3) and free thyroxine (FT4) and reduced levels of thyroid-stimulating hormone (TSH), according to a cross-sectional study.

Why this matters

  • The relationship between cigarette smoking and thyroid function is poorly understood, especially when adjusting for other lifestyle factors such as alcohol consumption.

Key results

  • Smoking ≤20 cigarettes/day or >20 cigarettes/day were both associated with increased FT3 (P<.001 for both and decreased tsh in multivariate analysis. style="list-style-type:circle;">
  • Smoking ≤20 cigarettes/day was significantly associated with increased FT4 (P=.018), whereas smoking >20 cigarettes/day was not (P=.076).
  • Urinary cotinine levels were correlated with FT3 (P<.001 and ft4 inversely correlated with tsh>
  • Alcohol consumption >30 g/day was associated with increased TSH (P=.015) and reduced FT3 (P=.009).
  • Study design

    • 5766 subjects with euthyroid status were analysed for smoking patterns and associations with thyroid hormone levels.
    • Funding: EU Joint Programme Initiative: A Healthy Diet for a Healthy Life, the Food Biomarker Alliance.

    Limitations

    • Cross-sectional study design.