Low-Magnitude Mechanical Signals May Aid Bone Health in Anorexia Without Exercise Risks

A recent double-blind, sham-controlled, randomized clinical trial investigated the impact of low-magnitude mechanical signals (LMMS) on bone health in adolescents and young women with anorexia nervosa.

LMMS, which delivers high-frequency, low-intensity mechanical stimulation through a vibrating platform, has demonstrated potential in preventing bone loss in at-risk populations without requiring strenuous activity. Anorexia nervosa is associated with an increased risk of early-onset osteoporosis due to hormonal dysregulation, reduced lean body mass, and decreased weight-bearing activity.

“Effective therapies for preventing bone loss in [patients with] anorexia nervosa remain elusive,” the authors wrote. “Hormonal therapies have yielded disappointing results and are associated with poor patient acceptance. As adolescence is a critical period for bone acquisition, identifying strategies to preserve bone mineral density (BMD) in adolescents with anorexia nervosa is paramount.”

Conducted at a hospital-based specialty clinic, researchers enrolled 50 female participants (median age, 16.3 years; median body mass index (BMI), 87.2% of the age-matched median) to determine whether LMMS could preserve BMD over 6 months.

Participants were randomly assigned to receive either LMMS (0.3 g at 32-37 Hz) or sham treatment for 10 minutes daily. The primary outcome, trabecular volumetric BMD (vBMD) at the tibia, did not significantly differ between groups. However, secondary outcomes revealed that total cross-sectional area (CSA) at the 4% tibia site increased significantly in the LMMS group (median increase from 795.8 mm² to 827.5 mm²), while it remained unchanged in the placebo group (median decrease from 847.3 mm² to 843.3 mm²; P = .01). Similarly, trabecular CSA increased in the LMMS group but decreased in the placebo group (P = .02). Despite these findings, cortical vBMD, cortical section modulus, and muscle CSA did not differ significantly between groups.

Adherence to the intervention was moderate, with participants using the device for approximately 53% of the recommended duration. Weight gain was observed in both groups, but the placebo group exhibited greater increases in BMI, possibly due to greater fat mass accrual. No adverse events related to LMMS were reported.

Study limitations included a high dropout rate, which reduced statistical power, and suboptimal adherence to the intervention. Additionally, the 6-month duration may have been insufficient to detect changes in bone mass, as bone remodeling is a prolonged process. The cohort was predominantly White and female, limiting generalizability.

“Future studies should use a longer duration of intervention, explore strategies to optimize adherence, and potentially focus on a more malnourished and/or diverse patient population, including male patients and those with different racial and ethnic backgrounds,” the study authors wrote. “As restrictive eating disorders continue to increase in prevalence, identifying an intervention that slows bone loss and prevents ultimate osteoporosis could have important public health implications.”

Reference
DiVasta AD, Stamoulis C, Rubin CT, et al. Low-Magnitude Mechanical Signals to Preserve Skeletal Health in Female Adolescents With Anorexia Nervosa: A Randomized Clinical Trial. JAMA Netw Open. 2024;7(10):e2441779. Published 2024 Oct 1. doi:10.1001/jamanetworkopen.2024.41779