Older people may too often be diagnosed with an underactive thyroid and prescribed thyroid hormones, which can cause new troubles and expenses without improving their lives, researchers say.

A recent case study provides a snapshot of the larger problem, the authors write in JAMA Internal Medicine.

Just 1 percent to 2 percent of people have hypothyroidism, in which their thyroid gland is underactive and requires treatment, coauthor Dr. Juan P. Brito of the Mayo Clinic in Rochester, Minnesota, told Reuters Health. But about 15 percent of people have “subclinical hypothyroidism” – hormone levels that are between the healthy range and the diagnostic cutoff for hypothyroidism and that cause few or no symptoms.

Clinical hypothyroidism can cause constipation, depression, fatigue, dry skin, unexplained weight gain and greater sensitivity to cold.

The authors present the story of a 72-year-old obese man with type 2 diabetes, high blood pressure and heart disease who complained to his doctor of fatigue. The doctor ordered a hormone panel and found a blood thyroid-stimulating hormone (TSH) level of 7.2 microunits per milliliter (mlU/L).

TSH triggers the thyroid to make hormones that control metabolism, so elevated TSH is considered a sign the thyroid might be making too little thyroid hormone. The healthy TSH reference range for adults is usually 0.3 to 5.0 microunits per milliliter.