High-Intensity Laser Therapy and Physiotherapy for Bone Health in Postmenopausal Women: A Randomized Trial

Bone loss accelerates after menopause because of the decline in oestrogen, raising the risk of progression from osteopenia to osteoporosis and of fractures. Current medication options are largely preventive and have limitations. High-intensity laser therapy (HILT) combined with physiotherapy is a non-invasive physical treatment that may stimulate bone formation with a favourable safety profile, but robust evidence in postmenopausal bone health is limited. This is a randomised, double-blind, placebo (sham)-controlled, parallel-group interventional trial with two equal arms. A standardised physiotherapy programme is delivered identically in both arms as a background co-intervention, so the comparison isolates the added effect of active HILT versus sham. Randomisation uses permuted blocks of four with 1:1 allocation, concealed with sealed opaque envelopes. Participants, the physiotherapist, the outcome assessor and the statistician are all blinded to allocation. Intervention parameters: pulsed HILT in the near-infrared spectrum, 7 W, 5 J/cm², applied over the lumbar region (L1-L5) with a scanning handpiece for approximately 150 seconds per session, three sessions per week for four weeks. The sham arm follows an identical procedure with a device that delivers no therapeutic laser energy. The bone-formation marker P1NP is measured in peripheral blood by ELISA (ng/mL). To avoid the confounding effect of acute exercise on bone turnover markers, the post-treatment sample is collected 72 hours (minimum 48 hours) after the last physiotherapy session, before any further physical activity, and all samples are analysed in a single batch. Analyses follow the intention-to-treat principle on all randomised participants, with a per-protocol analysis as a supportive check. For each measure, the change from baseline is compared between arms using parametric or non-parametric tests as appropriate, with results reported as effect sizes and 95% confidence intervals. Safety is monitored throughout the treatment sessions.