MSFinals-2447

MSFinals-2447

A 67-year-old man presents to secondary care for a routine follow-up. He is asymptomatic. Routine blood tests reveal the following:
Calcium 3.1 mmol/L (2.1-2.6)
Phosphate 0.3 mmol/L (0.8-1.4)
Parathyroid hormone (PTH) 11.8 pmol/L (1.6 – 6.9)
Magnesium 0.9 mmol/L (0.7-1.0)
Thyroid stimulating hormone (TSH) 3.2 mU/L (0.5-5.5)
Free thyroxine (T4) 17 pmol/L (9.0 – 18)
What is the patient’s most likely risk factor for developing a condition?