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 .
Serum IL-6 level and the development of disability in older persons.
BACKGROUND The serum concentration of interleukin 6 ( IL-6 ) , a cytokine that plays a central role in inflammation , increases with age . Because inflammation is a component of many age-associated chronic diseases , which often cause disability , high circulating levels of IL-6 may contribute to functional decline in old age . We tested the hypothesis that high levels of IL-6 predict future disability in older persons who are not disabled . METHODS Participants at the sixth annual follow-up of the Iowa site of the Established Population s for Epidemiologic Studies of the Elderly aged 71 years or older were considered eligible for this study if they had no disability in regard to mobility or in selected activities of daily living ( ADL ) , and they were re-interviewed 4 years later . Incident cases of mobility-disability and of ADL-disability were identified based on responses at the follow-up interview . Measures of IL-6 were obtained from specimens collected at baseline from the 283 participants who developed any disability and from 350 participants selected r and omly ( 46.9 % ) from those who continued to be non-disabled . FINDINGS Participants in the highest IL-6 tertile were 1.76 ( 95 % CI , 1.17 - 2.64 ) times more likely to develop at least mobility-disability and 1.62 ( 95 % CI , 1.02 - 2.60 ) times more likely to develop mobility plus ADL-disability compared with to the lowest IL-6 tertile . The strength of this association was almost unchanged after adjusting for multiple confounders . The increased risk of mobility-disability over the full spectrum of IL-6 concentration was nonlinear , with the risk rising rapidly beyond plasma levels of 2.5 pg/mL. INTERPRETATION Higher circulating levels of IL-6 predict disability onset in older persons . This may be attributable to a direct effect of IL-6 on muscle atrophy and /or to the pathophysiologic role played by IL-6 in specific diseases
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 .