***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Dietary protein requirements of elderly people were determined by short-term nitrogen-balance techniques and using calculations recommended by the 1985 Joint FAO/WHO/UNU Expert Consultation . Twelve men and women aged 56 - 80 y were r and omly assigned to groups that consumed either 0.80 + /- 0.01 or 1.62 + /- 0.02 g protein.kg-1.d-1 ( mean + /- SEM ) . Net nitrogen balance was negative for the lower-protein group ( -4.6 + /- 3.4 mg N.kg-1.d-1 ) and positive for the higher-protein group ( 13.6 + /- 1.0 mg N.kg-1.d-1 ) ; the intake required for nitrogen equilibrium was estimated to be 1.00 g.kg-1.d-1 . Nitrogen-balance data from three previous protein requirement studies in elderly people were recalculated by using the same balance formula and combined with the current study data to provide an overall weighted mean protein requirement estimate of 0.91 + /- 0.043 g.kg-1.d-1 . Together , the current and retrospective nitrogen-balance data suggest that the mean protein requirement in elderly adults is considerably greater than the 0.60 g.kg-1.d-1 established by the 1985 Joint FAO/WHO/UNU Expert Consultation . A safe protein intake for elderly adults would be 1.0 - 1.25 g.kg-1.d-1 of high- quality protein BACKGROUND Underst and ing the health , behavioral , and social factors that influence physical performance in midlife may provide clues to the origins of frailty in old age and the future health of elderly population s. The authors evaluated muscle strength , postural control , and chair rise performance in a large representative prospect i ve cohort of 53-year-old British men and women in relation to functional limitations , body size , health and activity , and socioeconomic conditions . METHODS Nurses interviewed 2984 men and women in their own homes in Engl and , Scotl and , and Wales and conducted physical examinations in 2956 of them . Objective measures were height , weight , and three physical performance tests : h and grip strength , one-legged st and ing balance time , and time to complete 10 chair rises . Functional limitations ( difficulties walking , stair climbing , gripping , and falls ) , health status , physical activity , and social class were obtained using a structured question naire . RESULTS Those with the worst scores on the physical performance tests had higher rates of functional limitations for both upper and lower limbs . Women had much weaker h and grip strength , somewhat poorer balance time , and only slightly poorer chair rise time compared with men . In women , health problems and low levels of physical activity contributed to poor physical performance on all three measures . In men , physical activity was the predominant influence . Heavier weight and poorer socioeconomic conditions contributed to poorer balance and chair rise times . CONCLUSIONS In this representative middle-aged group , physical performance levels varied widely , and women were seriously disadvantaged compared with men . In general , physical performance was worse for men and women living in poorer socioeconomic conditions with greater body weight , poorer health status , and inactive lifestyles . These findings support recommendations for controlling excess body weight , effective health interventions , and the maintenance of active lifestyles during aging OBJECTIVES To test whether accelerated sarcopenia in older persons with high interleukin (IL)-6 serum levels plays a role in the prospect i ve association between inflammation and disability found in many studies . DESIGN Cohort study of older women with moderate to severe disability . PARTICIPANTS Six hundred twenty older women from the Women 's Health and Aging Study in whom information on baseline IL-6 serum level was available . MEASUREMENTS Self-report of functional status , objective measures of walking performance , and knee extensor strength were assessed at baseline and over six semiannual follow-up visits . Potential confounders were baseline age , race , body mass index , smoking , depression , and medical conditions . RESULTS At baseline , women with high IL-6 were more often disabled and had lower walking speed . After adjusting for confounders , women in the highest IL-6 tertile ( IL-6>3.10 pg/mL ) were at higher risk of developing incident mobility disability ( risk ratio ( RR ) = 1.50 , 95 % confidence interval ( CI ) = 1.01 - 2.27 ) , disability in activities of daily living ( RR = 1.41 , 95 % CI = 1.01 - 1.98 ) , and severe limitation in walking ( RR = 1.61 , 95 % CI = 1.09 - 2.38 ) and experienced steeper declines in walking speed ( P < .001 ) than women in the lowest IL-6 tertile ( IL-6 < or = 1.78 pg/mL ) . Decline in knee extensor strength was also steeper , but differences across IL-6 tertiles were not significant . After adjusting for change over time in knee extensor strength , the association between high IL-6 and accelerated decline of physical function was no longer statistically significant . CONCLUSIONS Older women with high IL-6 serum levels have a higher risk of developing physical disability and experience a steeper decline in walking ability than those with lower levels , which are partially explained by a parallel decline in muscle strength BACKGROUND Inadequate dietary protein intake results in loss of skeletal muscle mass . Some shorter-term nitrogen balance studies suggest that the Recommended Dietary Allowance ( RDA ) of protein may not be adequate for older people . The aim of this study was to assess the adequacy of the RDA of protein for older people by examining longer-term responses in urinary nitrogen excretion , whole-body protein metabolism , whole-body composition , and mid-thigh muscle area . METHODS This was a 14-week precisely controlled diet study . Ten healthy , ambulatory men and women , aged 55 to 77 years , were provided eucaloric diets that contained 0.8 g protein.kg(-1).day(-1 ) . The study was conducted at a General Clinical Research Center using an outpatient setting for 11 weeks and an inpatient setting for 3 weeks . The main outcome measures included urinary nitrogen excretion , postabsorptive and postpr and ial whole-body leucine kinetics via infusion of L-[1-(13)C]-leucine , whole-body density via hydrostatic weighing , total body water via deuterium oxide dilution , and mid-thigh muscle area via computed tomography scans . RESULTS Mean urinary nitrogen excretion decreased over time from Weeks 2 to 8 to 14 ( p = .025 ) . At Week 14 , compared with Week 2 , there were no changes in postabsorptive or postpr and ial leucine kinetics ( turnover , oxidation , incorporation into protein via synthesis , release via breakdown , or balance ) . Whole-body composition ( % body fat , fat-free mass , and protein + mineral mass ) did not change over time in these weight-stable subjects . Mid-thigh muscle area was decreased by -1.7 + /- 0.6 cm(2 ) ( p = .019 ) at Week 14 compared with Week 2 . The loss of mid-thigh muscle area was associated with the decrease in urinary nitrogen excretion ( Spearman r = .83 , p = .010 ) . CONCLUSIONS The maintenance of whole-body leucine metabolism and whole-body composition is generally consistent with a successful adaptation to the RDA for protein . However , the decrease in mid-thigh muscle area and the association with decreased urinary nitrogen excretion are consistent with a metabolic accommodation . These results suggest that the RDA for protein may not be adequate to completely meet the metabolic and physiological needs of virtually all older people 
    Output:
    
The linear dose-response meta- analysis illustrated that the risk of sarcopenia did not change significantly nor for a 0.5-h increment neither for 1-h increment in sleep duration per day .