Vitamin D status, physical performance and body mass in patients surgically cured for primary hyperparathyroidism compared with healthy controls - a cross-sectional study

Interactions between PTH and adiposity: appetizing possibilities

Although parathyroid hormone (PTH) is best known for its role as a regulator of skeletal remodelling and calcium homeostasis, more recent evidence supports a role for it in energy metabolism and other non-classical targets. In this report, we summarize evidence for an effect of PTH on adipocytes. This review is based upon all peer-reviewed papers, published in the English language with PubMed as the primary search engine. Recent preclinical studies have documented an effect of PTH to stimulate lipolysis in both adipocytes and liver cells and to cause browning of adipocytes. PTH also reduces bone marrow adiposity and hepatic steatosis. Although clinical studies are limited, disease models of PTH excess and PTH deficiency lend support to these preclinical findings. This review supports the concept of PTH as a polyfunctional hormone that influences energy metabolism as well as bone metabolism.

Impaired physical function and evaluation of quality of life in normocalcemic and hypercalcemic primary hyperparathyroidism

INTRODUCTION

Severe primary hyperparathyroidism may be associated with muscle weakness and fatigue, but little is known about this effect in milder forms of the disease. This study aimed to evaluate physical function and quality of life in patients with normocalcemic (NPHPT) and hypercalcemic (HPHPT) primary hyperparathyroidism.

METHODS

This was a case-control study on 40 postmenopausal women. Thirteen patients with NPHPT, 7 patients with HPHPT, and their controls were studied. Mean serum PTH in the control group was 49.10 ± 12.38 pg/mL. All of the participants answered the Medical Outcomes Short-Form Health Survey (SF36) and were submitted to 2 strength tests (Hand Grip strength and Chair stand test) and 2 performance tests for physical function (Short physical performance battery and Gait speed). Body composition analysis was performed by dual-energy X-ray absorptiometry (DXA) and multifrequency bioimpedance (BIA).

RESULTS

Patients with NPHPT had lower grip strength (p = 0.005), a higher mean time of the chair stand test (p = 0.012), a lower mean gait speed (p < 0.001) and a lower score for the Short Physical Performance Battery (SPPB) (p = 0.010) than the control group. Patients with HPHPT had lower handgrip strength (p = 0.027), a higher mean time of the chair stand test (p = 0.017), and a lower score for the SPPB (p = 0.049) than the control group. Patients with NPHPT showed a higher gait speed when compared to HPHPT (p = 0.048). There was no difference between BIA and DXA body composition indices between the PHPT groups and their controls. The evaluation of the SF-36 showed significantly less quality of life in the general health domain among the NPHPT group and in the mental health domain among the HPHPT than in the controls.

CONCLUSION

Patients with NPHPT and HPHPT have decreased physical performance and strength.

Non classical complications of primary hyperparathyroidism

Several studies suggested that the condition of primary hyperparathyroidism (PHPT) may be associated not only with the classical bone, kidney and gastrointestinal consequences, but also with cardiovascular, neuromuscular and articular complications, impaired quality of life and increased cancer risk. However, the only cardiovascular complications associated with PHPT, which seems to improve after parathyroidectomy, is left ventricular hypertrophy, while, data regarding the reversibility of hypertension, valve calcifications and increased vascular stiffness are inconsistent. Parathyroidectomy seems to ameliorate neuropsychological, cognitive disturbances and quality of life in moderate-severe PHPT, while data in mild PHPT are less clear. At variance, the effect of parathyroidectomy on neuromuscular and articular complications is still unknown, and no studies demonstrated a reduction of cancer risk after recovery from PHPT. Overall, to date, cardiovascular and neuropsychological evaluation are not recommended solely because of PHPT, nor cardiovascular disease, muscle weakness, and neuropsychological complications are indication for parathyroidectomy.

The surgical management of primary hyperparathyroidism: an updated review

Patients with primary hyperparathyroidism often present clinically asymptomatic with various biochemical compositions of serum calcium, parathyroid hormone, vitamin D and urinary calcium. Understanding the subtle differences in clinical and biochemical presentations is key for timely diagnosis and referral to an experienced parathyroid surgeon. Surgery remains the only option for cure of primary hyperparathyroidism, which now favors a directed parathyroidectomy with intra-operative adjuncts. However it is important to understand and revise the surgical approach for patients with hereditary conditions or nonlocalizing studies. Revised guidelines from the Fourth International Workshop on the Management of Asymptomatic Primary Hyperparathyroidism in 2013 and the American Association of Endocrine Surgeons in 2016 are reviewed in this paper for an updated review of this condition.

Muscle function and quality of life are not impaired in familial hypocalciuric hypercalcemia: a cross-sectional study on physiological effects of inactivating variants in the calcium-sensing receptor gene (CASR)

BACKGROUND

Familial hypocalciuric hypercalcemia (FHH) is often due to inactivating variants in the calcium-sensing receptor (CASR) gene causing chronically elevated plasma calcium levels with inappropriately normal or elevated parathyroid hormone levels. In patients with primary hyperparathyroidism, the state of hyperparathyroid hypercalcemia is associated with reduced muscle strength and impaired quality of life (QoL).

OBJECTIVE

To study whether FHH affects muscle function, postural stability, and QoL.

DESIGN

In a cross-sectional study, we investigated muscle strength (handgrip, elbow flexion/extension, and knee flexion/extension), balance function, physical activity, and QoL in 50 patients with FHH and in a similar number of age- and gender-matched population-based healthy controls. All but one of the FHH cases had genetically verified inactivating variants in the CASR gene.

RESULTS

Studied subjects (n=100, 68% females) had a mean age of 56.0 years. Muscle strength as assessed by measuring maximum force and maximum force production did not differ between the groups. Neither did groups differ in terms of QoL, physical activity, or postural stability, as assessed during normal standing with eyes open, normal standing with eyes closed, semi-tandem standing, or tandem standing. Adjustment for vitamin D status (plasma 25-hydroxyvitamin D levels) and BMI did not change results.

CONCLUSION

Despite a state of chronic hypercalcemia, muscle strength, balance function, and QoL are not impaired in patients with FHH. Our findings are reassuring for patients with FHH as they should not be considered as having a severe disease.

The roles of vitamin D in skeletal muscle: form, function, and metabolism

Beyond its established role in bone and mineral homeostasis, there is emerging evidence that vitamin D exerts a range of effects in skeletal muscle. Reports of profound muscle weakness and changes in the muscle morphology of adults with vitamin D deficiency have long been described. These reports have been supplemented by numerous trials assessing the impact of vitamin D on muscle strength and mass and falls in predominantly elderly and deficient populations. At a basic level, animal models have confirmed that vitamin D deficiency and congenital aberrations in the vitamin D endocrine system may result in muscle weakness. To explain these effects, some molecular mechanisms by which vitamin D impacts on muscle cell differentiation, intracellular calcium handling, and genomic activity have been elucidated. There are also suggestions that vitamin D alters muscle metabolism, specifically its sensitivity to insulin, which is a pertinent feature in the pathophysiology of insulin resistance and type 2 diabetes. We will review the range of human clinical, animal, and cell studies that address the impact of vitamin D in skeletal muscle, and discuss the controversial issues. This is a vibrant field of research and one that continues to extend the frontiers of knowledge of vitamin D's broad functional repertoire.

Current evidence for recommendation of surgery, medical treatment and vitamin D repletion in mild primary hyperparathyroidism

Management of patients with mild primary hyperparathyroidism (PHPT) has been widely discussed because most patients today do not have specific symptoms. While surgery is always an option, the recommendations for treatment have shifted, which mostly reflects changes in clinical practice. In this study, we aimed to evaluate evidence for the current recommendations concerning operation vs observation, repletion with vitamin D (VitD) and alternative medical management. Surgery is followed by normalisation of calcium and parathyroid hormone (PTH) and a decrease in bone turnover followed by an increase in bone mass. It is not known what the consequences would be for the frequency of fractures. Randomised studies have indicated beneficial effects of operation on quality of life (QoL), but the effects have been minor and inconsistent. Operation seems not to be superior to observation for cardiovascular risk factors. Although PHPT patients in average have slightly decreased plasma 25OH VitD, severe symptomatic VitD deficiency seems not to be a characteristic of PHPT patients in Europe. However, if present, we recommend VitD substitution before final decision on surgical treatment. It is unknown whether routine VitD supplementation should be offered preoperatively to all patients with mild PHPT or as part of long-term medical treatment. Targeted medical management could be an option for patients with contraindications to surgery. Antiresorptive therapy might be appropriate for patients with a low bone mass to prevent further bone loss. Calcimimetics could be tried to control serum calcium levels although there is no evidence of an effect on the hypercalcaemic symptoms or the QoL. Combined therapy with calcimimetics and alendronate could be considered for patients with hypercalcaemia and overt bone disease.

Patients with surgically cured primary hyperparathyroidism have a reduced quality of life compared with population-based healthy sex-, age-, and season-matched controls

OBJECTIVE

Primary hyperparathyroidism (PHPT) is associated with feelings of fatigue and depression, as well as limitation to physical and mental functioning. These quality of life (QoL) characteristics improve after parathyroidectomy. However, whether former patients fully regain QoL compared with healthy controls is largely unknown.

DESIGN AND PATIENTS

Cross-sectional study. Fifty-one former PHPT patients, successfully treated by surgery (mean time since parathyroidectomy 7.4 (range 5-15) years), and 51 sex- and age-matched healthy controls.

METHODS

The 36-item Short-Form Health Survey version 2 and the WHO-Five Well-being Index. The surveys included questions on overall physical and mental health, functioning, and limitation in daily life activities.

RESULTS

Former patients scored significantly lower compared with controls in physical functioning (P=0.01), role limitation caused by emotional problems (P=0.01), vitality (P<0.001), and general health (P=0.01). Compared with the controls, cases had a lower median (interquartile range) score of physical component summary (PCS; 54.9 (47.9-58.7) vs 49.6 (45.2-55.9), P=0.03) and mental component summary (MCS; 55.4 (49.7-58.1) vs 52.5 (44.7-55.5), P=0.04). There was no association between time since operation and PCS or MCS. Compared with controls, cases had higher body mass index (BMI; 26.0±4.7 vs 28.8±6.0 kg/m(2), P<0.001) and a higher frequency of cardiovascular diseases (CVD; 41.2 vs 62.7%, P=0.03). After adjustment for differences in BMI and CVD, PCS did no longer differ between groups. However, adjustments did not change the finding of a lower MCS in cases compared with controls.

CONCLUSION

Even though QoL may improve substantially after surgery, former PHPT patients still have reduced QoL compared with healthy controls.