Clinically relevant weakness in diverse populations of older adults participating in the International Mobility in Aging Study

The aims of this study were to compare cut points for weakness proposed by Foundation for the National Institutes of Health (FNIH) Sarcopenia Project with cut points estimated with our own data; to assess the prevalence of clinically relevant handgrip strength (HGS) weakness according to published criteria across distinct populations of older adults; to estimate the ability of HGS weakness to identify slowness. This is a cross-sectional analysis of International Mobility in Aging Study (IMIAS) involving 1935 community-dwelling older adults, between 65 and 74 years, who completed HGS and gait speed assessment. We used baseline data from Tirana (Albania), Natal (Brazil), Manizales (Colombia), Kingston (Ontario, Canada), and Saint-Hyacinthe (Quebec, Canada). Weakness was defined according to sex-specific HGS cut points associated with slowness proposed by FNIH Sarcopenia Project. Slowness was defined as gait speed <0.8 m/s. IMIAS cut points for clinical weakness had good agreement with those proposed by FNIH. Weakness prevalence across the research sites ranged from 1.1 % (Saint-Hyacinthe) to 19.2 % (Manizales) among men. Women from Manizales (13.5 %) and Natal (19.3 %) had higher prevalence of weakness than their counterparts. FNIH cut points had a strong association with slowness, for both sexes. The IMIAS population generated cut points which were close to those proposed by FNIH. There was large variability in prevalence of weakness across our research sites. The HGS cut points for weakness proposed by FNIH performed well in IMIAS populations, providing a useful tool for screening older adults at risk for functional problems.