The thyroid, a small butterfly-shaped gland in the neck, regulates nearly all metabolic processes by producing thyroid hormones. Thyroid disease arises when the gland overproduces (hyperthyroidism) or underproduces (hypothyroidism) these hormones, ranging from harmless goiters to life-threatening cancer. Globally, the World Health Organization (WHO) reports over 2 billion people face iodine deficiency - a leading risk factor and 750 million live with undiagnosed cases. Untreated hypothyroidism may trigger myxedema coma (a rare fatal condition), while hyperthyroidism damages the heart; infants with hypothyroidism may develop intellectual disability without early intervention.

Thyroid disease has diverse causes. Hyperthyroidism often stems from Graves’ disease (autoimmune overstimulation) or toxic nodules, causing weight loss, irregular heartbeats, sweating and nervousness. Hypothyroidism is linked to Hashimoto’s thyroiditis (autoimmune attack on the thyroid), iodine deficiency, thyroid removal or certain drugs like lithium. Its symptoms include fatigue, weight gain, cold sensitivity and depression. Early red flags for both types include changes in weight, energy or temperature tolerance.

Key biomarkers for diagnosis are thyroid-stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4), measured via blood tests - the gold standard. Additional tests include neck ultrasound (to detect nodules) and physical exams (feeling for gland enlargement). Prevention involves adequate iodine intake (via fortified salt), regular screenings for high-risk groups (women, those with family history) and avoiding excessive iodine from medications or supplements.

In summary, the thyroid is vital for bodily balance. While thyroid disease is common, most cases are manageable with early diagnosis and targeted treatment (e.g., hormone replacement for hypothyroidism). Prioritizing awareness, screening and healthy iodine intake is critical to reducing its global impact.