- 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.
- 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).
- 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.
- Cross-sectional study design.