Dose adjustment of oral thyroxine in patients consuming dairy products: A cohort retrospective study

Aim: Hypothyroidism management with levothyroxine might be affected by a range of factors, including diet. Dairy sources are rich in calcium and proteins which may interfere with the absorption of thyroxine so dose adaptability might be required. This study assesses the effect of dairy intake on levothyroxine dose and clinical outcomes.

Materials and Methods: Retrospective cohort study over 14 months in an endocrinology center in Najaf, included 150 adult patients with primary hypothyroidism on stable oral levothyroxine therapy. We classified individuals into high, medium and low dairy consumers. A comparative approach was performed between these groups on terms of the dose, time to stabilization, dose response, clinical outcome, and economic outcome.

Results: After multivariable analysis, we found that participants who consumed one or more servings of dairy products per day were 6.8 times more likely to report taking their medications at least once with inadequate preparation p<0.001. These findings suggest that dietary interventions targeting dairy intake could stabilize treatment and reduce healthcare costs.

Conclusions: Dietary intake of dairy has a major impact on both the absorption and dosing of levothyroxine in hypothyroid patients. Given the healthcare burden arising from dose adjustments, clinicians should consider dietary counselling and timing strategies to improve therapy.