Physical activity, bone mineral density, and lean mass in patients with haemophilia

Introduction Prior investigations point towards the fact that patients with haemophilia are affected by reduced bone mineral density (BMD), which is directly linked to physical activity (PA). Based on prior literature, it is assumed that patients with severe haemophilia are physically less active compared to patients with moderate or mild haemophilia. This study aims to objectively evaluate the PA with regard to BMD and lean mass in dependance to severity phenotype.

Method This investigation was part of a large prospective cohort study examining the relation between osteoporosis and haemophilia (registered at clinicaltrials.gov (ID: NCT04524481)). 223 Patients underwent a dual X-ray screening to examine both bone mineral density (BMD) and lean mass of the four extremities. This assessment was conducted and analyzed using Horizon™ (Hologic, USA; Apex Software, V. 13.6.0.7). Supporting to the lean mass, circumferences of the extremities were examined via the haemophilia joint health score (HJHS). Further, step tracked electronically for 7 days consecutive after examination, augmented by a 7-day subjective activity diary.

Results Data of 197 patients with either mild (N=45), moderate (N=46), and severe (N=132) haemophilia A or B were analyzed. PwH had a mean age of 43.6±15.6 years. Step activity was similar between severity phenotypes (p=0.162). Subjective activity data revealed that the most frequent type of physical activity in all severities was walking (n=72), cycling (n=60), and strength training (n=60). Lean mass of the upper and lower (mean value of left and right) extremities differed significantly between severity phenotypes (legs: p=0.028; arms: p=0.017; Bonferroni corrected post-hoc: legs: p>0.005, arms p=0.022 between severe and moderate phenotype). The circumference of thighs and arms did not differ between severities, though the shanks are significantly smaller in patients with severe haemophilia compared to patients with moderate haemophlia (p=0.005; Bonferroni corrected post-hoc: left shank p=0.010, right shank: p=0.020). Both, lean mass and circumference of the extremities correlated positively with BMD (see [Fig. 1]), though not with step activity nor subjective activity data (p>0.05).

Fig. 1 Spearmans’s correlation coefficient of activity, lean mass, and circumference of extremity; Explanation: BMD=bone mineral density *indicates significant difference of p<0.05, **indicates significant difference of p<0.001

Conclusion The present study shows that step activity does not differ between the severity phenotypes, though lean mass of the extremities does. Higher lean mass seems to positively influence BMD. However, neither step activity nor the duration of subjective reported activity seems to affect BMD. It needs to be highlighted that only step activity is tracked electronically and most of the patients performed walking as PA. Though, it is assumed that the type of activity plays an important role on bone metabolism, as strength training is most efficient in increasing extremity circumference as well as lean mass and has been shown to oppose reduction of BMD. Hence, it is highly recommended to promote whole body strength training in PwH.

Conflict of Interest

This study was supported by Bayer Vital AG

Publication History

Article published online:
26 February 2024