Epidemiology of Sarcopenia: Determinants Throughout the Lifecourse

Abstract

Sarcopenia is an age-related syndrome characterised by progressive and generalised loss of skeletal muscle mass and strength; it is a major contributor to the risk of physical frailty, functional impairment in older people, poor health-related quality of life and premature death. Many different definitions have been used to describe sarcopenia and have resulted in varying estimates of prevalence of the condition. The most recent attempts of definitions have tried to integrate information on muscle mass, strength and physical function and provide a definition that is useful in both research and clinical settings. This review focuses on the epidemiology of the three distinct physiological components of sarcopenia, and highlights the similarities and differences between their patterns of variation with age, gender, geography and time and the individual risk factors that cluster selectively with muscle mass, strength and physical function. Methods used to measure muscle mass, strength and physical functioning and how differences in these approaches can contribute to the varying prevalence rates will also be described. The evidence for this review was gathered by undertaking a systematic search of the literature. The descriptive characteristics of muscle mass, strength and function described in this review point to the urgent need for a consensual definition of sarcopenia incorporating these parameters.

Keywords: Epidemiology; Muscle mass; Muscle strength; Physical functioning; Risk factors; Sarcopenia.

Fig. 1

Cross-cohort centile curves for grip strength. Centiles shown 10th, 25th, 50th, 75th and 90th. ADNFS Allied Dunbar National Fitness Survey, ALSPAC Avon Longitudinal Study of Parents and Children, ELSA English Longitudinal Study of Ageing, HAS Hertfordshire Ageing Study, HCS Hertfordshire Cohort Study, LBC1921 and LBC1936 Lothian Birth Cohorts of 1921 and 1936, N85 Newcastle 85 + Study, NSHD Medical Research Council National Survey of Health and Development, SWS Southampton Women’s Survey, SWSmp mothers and their partners from the SWS, T-07 West of Scotland Twenty-07 Study, UKHLS Understanding Society: the UK Household Panel Study [25]

Fig. 2

Grip strength mean values from included samples, by UN region. Each point represents the mean value of grip strength for each item of normative data, plotted against the mid-point of the age range it relates to. Values from the same sample are connected. Data from developing and developed regions are shown with triangles and circles, respectively. For comparison, the grey curve shows the mean values from our normative data for 12 British studies [36]

Fig. 3

Age-adjusted incidence (per 100,000 person-years) of first-ever hip fracture among women and men residing in Rochester (1928–2006) or rural Olmsted County (1980–2006), Minnesota, by calendar year [41]

Fig. 4

Cumulative effect of unhealthy behaviours (1991–1993 to 2002–2004) on physical functioning in 2007–2009 before and after mutual adjustment for health behaviours, and additionally adjusted for body mass index (BMI). β represents mean difference in standardised score of physical functioning. Models are adjusted for age, sex, educational level, marital status and height (and mutually adjusted for health behaviour scores for bold square results). Estimates are for a 1-point increment in cumulative score of the unhealthy behaviour under consideration assuming a linear association between the number of times a person was classified as having the unhealthy behaviour in the three assessments (1991–1993, 1997–1999 and 2002–2004) and physical functioning. Filled diamond each health behaviour separately, filled square health behaviours mutually adjusted, filled triangle additionally adjusted for BMI [131]

Fig. 5

Forest plot of studies assessing the association between birth weight (kg) and later muscle strength (kg), after adjustment for age and height. Studies ordered by mean age at time of strength measurement. B both males and females, M males only, F females only included in study [139]