Data di Pubblicazione:
2019
Citazione:
Sarcopenia and gynecological cancer patients / S. Damanti, M. Cesari. ((Intervento presentato al convegno La chimica degli alimenti e I giovani ricercatori: nuovi approcci in tema di qualità, sicurezza e aspetti funzionali d’ingredienti alimentari tenutosi a Milano nel 2019.
Abstract:
Muscle mass progressively augments with growth reaching a variable peak during young adulthood (at approximately 25 years) and then it progressively declines. The age at which muscle loss begins is generally 40 years but may starts earlier or later according to different circumstances. Birth weight, nutrition, lifestyle and diseases influence muscle mass development and preservation.
The phenomenon of age related muscle loss was firstly given the name of sarcopenia by Rosenberg. The term derives from the Ancient Greek σάρξ (sárx, “flesh”) + πενῐ́ᾱ (peníā, “poverty”).
The original definition referred only to the reduction in muscle mass over time. Initially it was thought that the loss of muscle mass was the cause of the reduction of muscle strength which untimely lead to functional impairment and adverse outcomes. This link was beard by cross-sectional studies, which demonstrated that about one third of the variability in muscle strength in young adults was predicted by muscle mass.
However, more recent longitudinal studies have shown that there was a disassociation between age-related changes in muscle mass and strength. Indeed, in prospective studies less than 5% of variations of muscle strength over time were attributable to the corresponding reduction in muscle mass. Moreover, strength (1.5-5% year) declines more rapidly than muscle mass (1-2% year) and is strongly associated with physical performance, development of disability and other adverse outcomes. These associations are instead weak or not found when considering muscle mass alone.
Although the term “sarcopenia” has become widespread, the criteria for an operational definition vary among studies and experts. Initial work on defining sarcopenia was based on measures
of muscle mass alone
Baumgartner and colleagues defined sarcopenia a reduction in relative muscle mass measured Appendicular skeletal muscle mass through DXA and adjusting it for body size by dividing for height squared. A cut-off of ASM/height2 < 2 SDs the young normal mean value was arbitrarily chosen to define sarcopenia.
The positive correlation of this index of relative muscle mass (ASM/height2) with BMI, cause an underestimation of sarcopenia in overweight and obese subjects.
Newman et al. proposed alternative definitions of sarcopenia. They used a linear regression to model the relationship of ALM, measured by DXA on fat mass (kg) and height (m). Residuals from linear regression were calculated. The 20th percentile of the distribution of residuals was used as the cut-point for sarcopenia. This definition was compared to the one of Baumgartener by using a different cut-point the sex-specific lowest 20% of the distribution of the index (with results superimposable to the ones found by Baumgartner).
There was a good correlation between the two definition of sarcopenia (r=0.88 in men and r=0.71 in women), but each method classified a different subset of people as sarcopenic. The method of Baumgartner tended to identify the presence of sarcopenia mainly in thin people, but few overweight and no obese persons were classified as sarcopenic. Instead, by taking into account both fat and height more overweight and obese people were considered sarcopenic.
In 2009 the European Working Group on Sarcopenia in Older People proposed a definition of sarcopenia which represented a major change from the past since it added muscle function to former definitions based only on the evaluation of muscle mass. The presence of both low muscle mass and low muscle function (strength or performance) was necessary for the diagnosis of sarcopenia.
The 2009 EWGSOP consensus was based on expert opinions and lacked access to large data sets to validate recommendations. Ther
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
S. Damanti, M. Cesari
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