Selenium for Musculoskeletal Health

This is a double-blind, randomised, placebo controlled trial. We will evaluate two doses of selenium (50 and 200mcg) vs placebo over six months.

Participants are postmenopausal women with osteopenia or osteoporosis (T-score -1.0 to -3.0).

The investigators will include participants with any baseline serum selenium concentration for generalisability, but the primary endpoint efficacy analysis will only include women with baseline serum selenium below 120 mcg/l.

Primary endpoint: Urinary N-telopeptide of type I collagen (NTX/Cr). Secondary endpoints: other bone turnover markers, BMD, muscle function, thyroid function, blood glucose, anti-oxidant activity, inflammatory markers The investigators will make the primary analysis based on women with baseline serum selenium below 120 mcg/l. To ensure adequate power for this analysis we will plan to recruit 120 women (we expect that 100 of the 120 will have serum selenium below 120 mcg/l based on our previous cross-sectional study). The investigators will review the baseline serum selenium results when 40 women have been recruited to confirm the expected distribution of baseline levels, and we will adjust the total recruitment number accordingly to ensure at least 99 women with serum selenium below 120mcg/l have been randomised for the final primary endpoint intention-to-treat analysis.

Participants will be randomised according to a schedule produced by Sheffield Teaching Hospitals pharmacy according to their standard operating procedure. Randomisation will be carried out independently of the study investigators using block randomisation. The blind will only be broken if judged by the PI as clinically necessary for the wellbeing of a participant.

The study may be stopped early if the investigators, sponsor or DMEC identify a safety concern.

Trial management will be done by the Academic Unit of Bone Metabolism CTIMP group (who meet monthly), and progress reported to the AUBM management group and Lay Panel. We will establish a TSC and DMEC.

Inclusion criteria

women age over 55y at least 5y postemenopausal willing and able to give informed consent lumbar spine or total hip BMD T-score between -1.0 and -3.0 not clinically requiring treatment for osteoporosis

Exclusion criteria

diabetes mellitus, thyroid dysfunction, any conditions known to affect bone metabolism (such as inflammatory disease, parathyroid disease, malabsorption ), medications known to affect bone metabolism (such as osteoporosis treatment, aromatase inhibitors, anti-epileptics), alcohol intake >21 units per week, prolonged immobility (>3 months), fracture in the last year, taken selenium supplements in the last year