Conclusion This is the first study to demonstrate that a higher predictive IL-6 cut-off level should be determined for aging sarcopenia in men than in women
Background Aging sarcopenia characterized by low muscle mass with low muscle strength affects men and women differently .
The contribution of interleukin-6 ( IL-6 ) to sarcopenia has been suggested based on a negative correlation between plasma IL-6 and muscle function described by some studies .
However , no consensus regarding clinical ly relevant cut-off criteria has been reached .
Another question arises whether pooling male and female data is an accurate way to determine the predictive value of IL-6 in sarcopenia .
The present meta- analysis was design ed to assess : ( 1 ) whether plasma IL-6 in aged population s in fact correlates negatively to muscle strength ; ( 2 ) whether such a correlation exists both in men and in women ; and ( 3 ) whether plasma IL-6 shows a gender difference in old age .
Inflammatory markers and physical performance in older persons: the InCHIANTI study.
BACKGROUND Some studies have proposed chronic inflammation as an underlying biological mechanism responsible for physical function decline in elderly people . The aim of this study is to evaluate the relationship between several inflammatory markers and physical performance in an older population . METHODS This study is part of the " Invecchiare in Chianti " ( InCHIANTI ) study , a prospect i ve population -based study of older people , aim ed at identifying risk factors for late-life disability . The study sample consisted of 1020 participants aged 65 years and older living in the Chianti area of Italy .  Physical performance  was assessed using walking speed , the chair-st and test , and the st and ing balance test . H and -grip strength  was assessed using a h and -held dynamometer .  Serum levels of C-reactive protein ( CRP ) , interleukin (IL)-6 , tumor necrosis factor-alpha ( TNF-alpha ) , IL-10 , IL-1beta , IL-6sR , and IL-1RA were determined . Linear regression analyses were used to assess the multivariate relationship of inflammatory marker levels with physical performance , scored as a continuous variable from 0 to 3 , and h and -grip strength after adjustment for demographics , chronic conditions , medication use , and other biological variables . RESULTS CRP , IL-6 , and IL1RA were significantly correlated with physical performance ( r=-0.162 , r=-0.251 , and r=-0.127 , respectively ) . Significant correlations with h and -grip strength were found for CRP and IL-6 ( r=-0.081 and r=-0.089 , respectively ) . After adjustment for covariates , high levels of IL-6 and IL-1RA continued to be strongly associated with worse physical performance ( p<.001 and p=0.004 , respectively ) . High levels of CRP ( p<.001 ) and IL-6 ( p<.001 ) were associated with low h and -grip strength . Mean adjusted physical performance scores ranged from 2.21 in the CRP<0.59 mg/dl group to 2.07 in the CRP>0.60 mg/dl group ( p for trend=.004 ) , and from 2.25 in the lowest IL-6 quartile to 2.08 in the highest IL-6 quartile ( p for trend<.001 ) . This trend was also reflected in mean adjusted h and -grip strength , with a range from 28.8 kg for the CRP<0.59 mg/dl group to 26.0 kg for the CRP>0.60 mg/dl group ( p for trend=.001 ) , and from 27.4 kg for the lowest IL-6 quartile to 25.1 kg for the highest IL-6 quartile ( p for trend=.001 ) . CONCLUSIONS Inflammation , measured as high levels of IL-6 , CRP , and IL-1RA , is significantly associated with poor physical performance and muscle strength in older persons . These data also support the biological face validity of physical performance measures . The assessment of inflammatory markers may represent a useful screening test and perhaps a potential target of intervention
Conclusion This is the first study to demonstrate that a higher predictive IL-6 cut-off level should be determined for aging sarcopenia in men than in women
Background Aging sarcopenia characterized by low muscle mass with low muscle strength affects men and women differently .
The contribution of interleukin-6 ( IL-6 ) to sarcopenia has been suggested based on a negative correlation between plasma IL-6 and muscle function described by some studies .
However , no consensus regarding clinical ly relevant cut-off criteria has been reached .
Another question arises whether pooling male and female data is an accurate way to determine the predictive value of IL-6 in sarcopenia .
The present meta- analysis was design ed to assess : ( 1 ) whether plasma IL-6 in aged population s in fact correlates negatively to muscle strength ; ( 2 ) whether such a correlation exists both in men and in women ; and ( 3 ) whether plasma IL-6 shows a gender difference in old age .