Operational definitions of sarcopenia and their associations with 5-year changes in falls risk in community-dwelling middle-aged and older adults

Summary: Sarcopenia may be diagnosed in the clinic using operational definitions based on low muscle mass or function. This prospective, population-based study revealed that sex-specific associations may exist between operational definitions of sarcopenia and falls in community-dwelling middle-aged and older adults.

Introduction:

The objective of this study is to verify associations between sarcopenia and falls risk and to determine changes in sarcopenia prevalence over 5 years in middle-aged and older men and women according to different anthropometric and performance-based operational definitions.

Methods: N = 681 volunteers (48 % female; mean ± SD age 61.4 ± 7.0 years) participated in baseline and follow-up assessments (mean 5.1 ± 0.5 years later). Appendicular lean mass (ALM) was assessed by dual-energy X-ray absorptiometry, hand grip (HGS) and lower-limb (LLS) strength were assessed by dynamometry, and falls risk was determined using the physiological profile assessment. Anthropometric definitions (ALM/height squared [ALM-H], ALM/weight × 100 and a residuals method [ALM-R]) and performance-based definitions (HGS, LLS and upper- and lower-limb muscle quality [LMQ]) of sarcopenia were examined. The lowest 20 % of the sex-specific distribution for each definition at baseline was classified as sarcopenia.

Results: Sarcopenia prevalence increased after 5 years for all operational definitions except ALM-H (men: -4.0 %; women: -5.5 %). Men classified with sarcopenia according to anthropometric definitions, and women classified with sarcopenia according to performance-based definitions, had significant increases in falls risk over 5 years (all P < 0.05) compared to individuals without sarcopenia. Significant sex interactions were observed for ALM-R, LLS and LMQ (all P < 0.05) definitions.

Conclusions:

Sarcopenia prevalence generally increases at a higher rate when assessed using performance-based definitions. Sarcopenia is associated with increases in falls risk over 5 years in community-dwelling middle-aged and older adults, but sex-specific differences may exist according to different anthropometric or performance-based definitions.