Spatio-temporal distribution of hypothyroidism in Quebec

Area of Science:

• Endocrinology
• Public Health
• Epidemiology

Background:

• Hypothyroidism, a condition of insufficient thyroid hormone production, affects a significant portion of the population.
• Understanding the epidemiological trends of hypothyroidism is crucial for public health planning and resource allocation.
• Previous estimates of hypothyroidism incidence and prevalence in Quebec were limited.

Purpose of the Study:

• To estimate the incidence and prevalence of hypothyroidism in Quebec.
• To analyze age- and sex-specific trends in hypothyroidism.
• To investigate regional variations in hypothyroidism rates.

Main Methods:

• Utilized a large dataset on thyroid hormone use from the Régie de l'assurance maladie du Québec (RAMQ) public drug insurance plan.
• Analyzed data from 1992 to 2001, covering individuals insured under the provincial drug plan.
• Calculated prevalence and incidence rates based on thyroid hormone prescriptions.

Main Results:

• In 2001, hypothyroidism prevalence was 10.8% in women and 2.9% in men, increasing with age.
• Prevalence in those aged 65+ was 21.9% for women and 8.0% for men.
• Incidence was highest in women aged 45-64 and men aged 65+, with significant regional variations (up to 2.4x higher than provincial rates).

Conclusions:

• Hypothyroidism is a common condition in Quebec, particularly affecting older women.
• Age and sex are significant factors influencing hypothyroidism rates.
• Substantial regional disparities in hypothyroidism incidence warrant further investigation into local determinants.