Correlation between Muscle Mass and Physical Activity Level in Older Adults at Risk of Falling: The FITNESS Study.

Background: The study investigates the correlation between muscle mass and physical activity level measured objectively and subjectively in older adults who fall or are at high risk of falling.

Methods: FITNESS (Fall Interest to Target Newly Sarcopenic Society) is a multi-center (French university hospitals of Angers, Lille, Limoges and Orléans), cross-sectional, observational study of routine care within a French multidisciplinary hospital consultation. Inclusion criteria were ≥ 75 years old, living at home and consulting for fall or gait disorder. A standardized geriatric assessment, muscle mass evaluation by impedancemetry, physical activity by continuous actimetry (5 days) and Incidental and Planned Exercise Questionnaire (IPEQ) were performed at patient inclusion.

Results: 170 people aged 75 and over were included in the FITNESS study (mean age 82.9 ±4.7 years, women 72.9%). Muscle mass (whole body and lower limbs) correlated with active energy expenditure (AEE, ρ whole body = 0.32, p-value < 0.001; ρ lower limbs = 0.25, p-value = 0.003), but not with number of daily steps, nor with IPEQ score. Multivariate analysis of whole-body muscle mass showed a positive and significant association with AEE and albumin levels and for lower limb muscle mass, a positive association with AEE and Charlson.

Conclusion: This study suggests that in the particular population of older adults who fall and/or are at high risk of falling, loss of muscle mass correlates with reduced physical activity. So subjects who fall or at high risk of falling constitute a special group for whom the fight against sedentary lifestyles and the maintenance of physical activity should be a dual priority.