Raina Kranz, C.P.T, Contributor
Raina discusses the dangers of smoking and how it affects your thyroid.
Cigarette Smoking (Nicotine) and Thyroid Function
Smoking cigarettes was never something that interested me. I knew the facts, dangers to my health and increased risk of disease with cigarette smoking, but I would never imagine that chronic intake of nicotine may actually prevent a disease from happening.
There actually is a fall in serum Thyroid Stimulating Hormone and is dose dependent with nicotine and this is without any intake of iodine. In area’s that there is iodine deficiency, smokers have slighter greater thyroid size (goiter) than in areas of with adequate iodine levels. This is caused by the competitive inhibition of thyroidal uptake by Thiocyanate (This is produced by the metabolism of cysteine and detoxification of cyanide, which is inhaled from cigarette smoking and excreted by urine) this inhibits the iodination of iodine in the thyroid. Not all smokers will be deficient in iodine, depending on where you live and the foods that are consumed.
Smokers do have an increased risk of non- toxic goiters and multi thyroid nodules. Although, current smokers do reduce their risk of thyroid cancer, they are more likely to acquire Papillary Cancer than the other types of thyroid cancer and former smokers decrease their risk even more to the level of those who never smoked at all.
Current smokers also lower their risk of developing Hashimotos Thyroiditis with no thyroid peroxidase, thyroglobulin antibodies, subclinical and overt autoimmune hypothyroidism. Once smokers quit smoking, they have a 6 fold increase risk of developing Hashimoto’s and overt hypothyroidism within a 3 year period.
It is also important to note, smoking is a dose dependent risk for Graves’ disease and Graves’s eye disease (ophthalmopathy) and that risk increases if smoking is continued after radioactive iodine 1311.
Another thing to consider, when it comes to smoking with those already diagnosed with Hashimotos Thyroiditis and hypothyroidism, is the possibility of being under medicated with thyroid hormone replacement therapy. Since the serum TSH will be lower in those with hypothyroid and the serum T4 and T3 will rise with dose dependent nicotine, Thyroid lab results may come back in normal range and even optimal range. This may leave the patient not feeling up to par since nicotine is not thyroid hormone and Hashimoto’s slowly destroys thyroid tissue and is hormone dependent for proper function. Doctors may tell a patient that their thyroid numbers are fine when it’s the nicotine masking what the thyroid levels would be without the dose dependent nicotine.
Once a smoker decides to stop smoking, altered thyroid hormone signaling may lead to a sub-clinical or overt hypothyroidism …which could then lead to cognitive function deficits.
There is a 9% reduction in thyroid hormone secretion upon withdrawal from nicotine, this indicates an increase in medication is going to be needed in patients already diagnosed with Hashimoto’s and hypothyroid.
Don’t Smoke – Stop Smoking – Check Your Thyroid
About the Author
Raina Kranz, C.P.T. attended and is certified from the American College of Sports Medicine. She studied Kinesiology/Biomechanics. Living in Hollywood, Florida she is a full time personal trainer and coach. Find her at her website, Personal Fitness Training Florida and wonderful online Facebook Group, Thyroid Discussion Group. Click to schedule an appointment or to learn more about Raina’s Customized Thyroid Exercise Training Program at Thyroid Trainer.