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Parathyroidectomy Improved Cognition but Not Sleep in PHPT

Researchers published the study covered in this summary on Research Square as a preprint that has not yet been peer reviewed.

Key Takeaways

  • Sleep disturbance and sleep latency appeared to partially mediate the link between parathyroid hormone (PTH) level and cognitive impairment in people with primary hyperparathyroidism (PHPT) before they underwent parathyroidectomy surgery (PTX).

  • Following PTX, PTH levels fell and cognitive scores improved, but surgery did not appear to improve sleep quality in people with PHPT.

Why This Matters

  • Cognitive impairment and decreased quality of life are common in people with typical or asymptomatic PHPT. This raises a need to identify factors that affect cognition in these people and explore potential mechanisms that might help people with PHPT improve their cognitive performance.

  • The findings suggest that people with PHPT should regularly undergo testing before surgery for PTH levels and cognition. They should also receive testing for sleep quality issues such as sleep latency and sleep disturbance that may be alleviated by exercise and other interventions because improved sleep quality may potentially postpone cognitive impairment.

  • Cognitive function is influenced by multiple factors, and hence, it is worth further investigating whether interventions for elevated PTH levels and sleep disturbances are useful for enhancing cognitive preservation in people with PHPT.

Study Design

  • Researchers performed a retrospective review of medical-record data from 146 people diagnosed with PHPT and treated with PTX from June 2019 to August 2022 at a single medical center in Beijing, China.

  • As controls, samples were used from 24 patients who underwent surgery for benign thyroid diseases and were comparable to the people with PHPT in the study by age and sex.

  • Researchers assessed sleep quality and cognition preoperatively and 2 months postoperatively using the Pittsburgh Sleep Quality Index and Mini-Mental State Examination.

Key Results

  • Higher presurgical PTH levels were significantly linked with poorer sleep quality and lower cognition scores.

  • After controlling for sex variables, worse cognitive function weresignificantly linked with higher PTH level and poorer sleep quality, particularly sleep disturbance and sleep latency, in patients who underwent PHPT.

  • Higher presurgical levels of PTH were significantly linked with greater sleep latency in people with PHPT, and higher presurgical levels of both PTH and sleep latency significantly predicted lower cognition scores.

  • Sleep latency partially mediated the effect of PTH on cognitive function, accounting for 15% of the total PTH effect in people with PHPT.

  • The link between higher PTH levels and lower cognition was also partially mediated by sleep disturbance, accounting for 13% of the total effect in people with PHPT.

  • Neither sleep latency nor sleep disturbance showed significant relationships with cognition among controls.

  • Among people with PHPT, surgery resulted in a significant decline in PTH levels and a significant improvement in cognitive function, but they also showed no significant change in sleep quality.


  • The study relied on self-reported assessments of sleep quality, which may be biased.

  • The authors said they were unable to propose a mechanism that links sleep quality, PTH level, and cognition.


  • The study received no commercial funding.

  • None of the authors had disclosures.

This is a summary of a preprint research study, “PTH levels, sleep quality, and cognitive function in primary hyperparathyroidism,” written primarily by researchers at Beijing Chaoyang Hospital and colleagues on Research Square and provided to you by Medscape. It has not yet been peer reviewed. The full text of the study can be found on

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