Population-based national incidence of thyroid dysfunction in Spain.

Area of Science:

• Endocrinology
• Epidemiology
• Public Health

Background:

• Thyroid dysfunction is a prevalent health issue with limited geographical incidence data.
• Understanding the incidence and risk factors is crucial for public health strategies.

Purpose of the Study:

• To determine the incidence of thyroid dysfunction in the adult Spanish population.
• To identify factors associated with the onset of thyroid dysfunction.

Main Methods:

• Nationwide observational population-based cohort study of 1,629 euthyroid adults.
• Baseline assessment (2008-2010) with follow-up evaluation (2016-2017).
• Multivariable logistic regression and ROC analysis for risk factor and predictive cut-off identification.

Main Results:

• Hypothyroidism incidence: 13.38/1,000 person-years (TSH ≥ 5 mIU/mL) and 6.78/1,000 person-years (TSH ≥ 10 mIU/mL).
• Hyperthyroidism incidence: 2.65/1,000 person-years.
• Independent predictors of hypothyroidism: female sex, age (30-40, >60 years), elevated TPOAb (>20 mIU/L), and TSH (>2.8 mIU/mL).

Conclusions:

• This study provides essential incidence data for thyroid dysfunction in Spain.
• Identified key risk factors including female sex, age, and specific TPOAb and TSH levels.
• Established predictive cut-offs for TPOAb (9.1 mIU/L) and TSH (2.03 mIU/mL) for incident hypothyroidism.