Effect of selenium supplementation on musculoskeletal health in older women: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Observational and preclinical studies show associations between selenium status, bone health, and physical function. Most adults in Europe have serum selenium below the optimum range. We hypothesised that selenium supplementation could reduce pro-resorptive actions of reactive oxygen species on osteoclasts and improve physical function. METHODS: We completed a 6-month randomised, double-blind, placebo-controlled trial. We recruited postmenopausal women older than 55 years with osteopenia or osteoporosis at the Northern General Hospital, Sheffield, UK. Participants were randomly assigned 1:1:1 to receive selenite 200 µg, 50 µg, or placebo orally once per day. Medication was supplied to the site blinded and numbered by a block randomisation sequence with a block size of 18, and participants were allocated medication in numerical order. All participants and study team were masked to treatment allocation. The primary endpoint was urine N-terminal cross-linking telopeptide of type I collagen (NTx, expressed as ratio to creatinine) at 26 weeks. Analysis included all randomly assigned participants who completed follow-up. Groups were compared with analysis of covariance with Hochberg testing. Secondary endpoints were other biochemical markers of bone turnover, bone mineral density, short physical performance battery, and grip strength. Mechanistic endpoints were glutathione peroxidase, highly sensitive C-reactive protein, and interleukin-6. This trial is registered with EU clinical trials, EudraCT 2016-002964-15, and ClinicalTrials.gov, NCT02832648, and is complete. FINDINGS: 120 participants were recruited between Jan 23, 2017, and April 11, 2018, and randomly assigned to selenite 200 µg, 50 µg, or placebo (n=40 per group). 115 (96%) of 120 participants completed follow-up and were included in the primary analysis (200 µg [n=39], 50 µg [n=39], placebo [n=37]). Median follow-up was 25·0 weeks (IQR 24·7-26·0). In the 200 µg group, mean serum selenium increased from 78·8 (95% CI 73·5-84·2) to 105·7 µg/L (99·5-111·9). Urine NTx to creatinine ratio (nmol bone collagen equivalent:mmol creatinine) did not differ significantly between treatment groups at 26 weeks: 40·5 (95% CI 34·9-47·0) for placebo, 43·4 (37·4-50·5) for 50 µg, and 42·2 (37·5-47·6) for 200 µg. None of the secondary or mechanistic endpoint measurements differed between treatment groups at 26 weeks. Seven (6%) of 120 participants were withdrawn from treatment at week 13 due to abnormal thyroid-stimulating hormone concentrations (one in the 200 µg group, three in the 50 µg group, and three in the placebo group) and abnormal blood glucose (one in the 50 µg group). There were three serious adverse events: a non-ST elevation myocardial infarction at week 18 (in the 50 µg group), a diagnosis of bowel cancer after routine population screening at week 2 (in the placebo group), and a pulmonary embolus due to metastatic bowel cancer at week 4 (in the 200 µg group). All severe adverse events were judged by the principal investigator as unrelated to trial medication. INTERPRETATION: Selenium supplementation at these doses does not affect musculoskeletal health in postmenopausal women. FUNDING: UK National Institute for Health Research Efficacy and Mechanism Evaluation programme.

Kcnn4 is a regulator of macrophage multinucleation in bone homeostasis and inflammatory disease.

Macrophages can fuse to form osteoclasts in bone or multinucleate giant cells (MGCs) as part of the immune response. We use a systems genetics approach in rat macrophages to unravel their genetic determinants of multinucleation and investigate their role in both bone homeostasis and inflammatory disease. We identify a trans-regulated gene network associated with macrophage multinucleation and Kcnn4 as being the most significantly trans-regulated gene in the network and induced at the onset of fusion. Kcnn4 is required for osteoclast and MGC formation in rodents and humans. Genetic deletion of Kcnn4 reduces macrophage multinucleation through modulation of Ca(2+) signaling, increases bone mass, and improves clinical outcome in arthritis. Pharmacological blockade of Kcnn4 reduces experimental glomerulonephritis. Our data implicate Kcnn4 in macrophage multinucleation, identifying it as a potential therapeutic target for inhibition of bone resorption and chronic inflammation.

Bone turnover and bone mineral density are independently related to selenium status in healthy euthyroid postmenopausal women.

CONTEXT: Selenium status may have direct effects on bone and indirect effects through changes in thyroid hormone sensitivity. OBJECTIVE: We hypothesized that variation in selenium status in healthy euthyroid postmenopausal women is associated with differences in bone turnover, bone mineral density (BMD) and fracture susceptibility. DESIGN: The Osteoporosis and Ultrasound Study (OPUS) is a 6-yr prospective study of fracture-related factors. SETTING: The study was comprised of a population-based cohort from five European cities. PARTICIPANTS: A total of 2374 postmenopausal women participated. Subjects with thyroid disease and nonthyroidal illness and those receiving drugs affecting thyroid status or bone metabolism were excluded, leaving a study population of 1144. INTERVENTIONS: There were no interventions. MAIN OUTCOME MEASURES: We measured selenium (micrograms per liter); selenoprotein P (milligrams per liter); free T(4) (picomoles per liter); free T(3) (picomoles per liter); TSH (milliunits per liter); bone turnover markers; BMD; and vertebral, hip, and nonvertebral fractures. RESULTS: Higher selenium levels were associated with higher hip BMD at study entry (ß = 0.072, P = 0.004) and lower levels of bone formation (osteocalcin: ß = -0.101, P < 0.001; procollagen type 1 N-terminal propeptide: ß = -0.074, P = 0.013) and resorption markers (C-telopeptide of type 1 collagen: ß = -0.058, P = 0.050; N-telopeptide of type 1 collagen: ß = -0.095, P = 0.002). Higher selenoprotein P was associated with higher hip (ß = 0.113, P < 0.001) and lumbar spine BMD (ß = 0.088, P = 0.003) at study entry, higher hip BMD after the 6-yr follow-up (ß = 0.106, P = 0.001) and lower osteocalcin (ß = -0.077, P = 0.009), C-telopeptide of type 1 collagen (ß = -0.075, P = 0.012), and N-telopeptide of type 1 collagen (ß = -0.110, P < 0.001). CONCLUSION: Selenium status is inversely related to bone turnover and positively correlated with BMD in healthy euthyroid postmenopausal women independent of thyroid status.

Radioiodine treatment for benign thyroid disorders: results of a nationwide survey of UK endocrinologists.

BACKGROUND: A survey of physicians' practice relating to radioiodine administration for hyperthyroidism was carried out in the UK over 15 years ago and showed wide variations in patient management. This led to the development of national guidelines for the use of radioiodine in hyperthyroidism. As there have been significant advances in the field since that survey, we carried out another survey to study the prevalent practices relating to radioiodine therapy for benign thyroid disorders across the UK. SUBJECTS AND METHODS: We mailed 698 UK consultant endocrinologists a questionnaire on radioiodine treatment based on three patient scenarios: hyperthyroid Graves' disease, subclinical hyperthyroidism and nontoxic goitre. RESULTS: The response rate was 40%. For the scenario of an initial presentation of Graves' disease, 80%, 19% and 0.4% of respondents preferred thionamide, radioiodine or thyroidectomy, respectively. There were inconsistencies in respondents' recommendations on radioiodine dose, the use of pre- and post-radioiodine supplementary treatments, timing of a repeat dose, and the use of radioiodine in thyroid eye disease. For the case of subclinical hyperthyroidism, one-third of respondents would generally initiate treatment. The majority were more likely to treat subclinical hyperthyroidism in the presence of paroxysmal atrial fibrillation or osteoporosis. If a decision were made to treat subclinical hyperthyroidism, 63%, 35%, 1% and 0.4% would recommend radioiodine, thionamide, beta-blocker and thyroidectomy, respectively. For the scenario of nontoxic goitre, 62%, 21%, 13% and 5% favoured observation, thyroidectomy, radioiodine and thyroxine, respectively. CONCLUSIONS: There remain significant differences in several aspects of clinical practice relating to the use of radioiodine treatment for benign thyroid disorders in the UK.