title: Assessment of muscle mass and its association with protein intake in a multi-ethnic Asian population: relevance in chronic kidney disease.
abstract: BACKGROUND
  Clinical practice guidelines recommend objective nutritional assessments in managing chronic kidney disease (CKD) patients but were developed while referencing to a North-American population. Specific recommendations for assessing muscle mass were suggested (mid-arm circumference, MAC; corrected mid-arm muscle area, cAMA; mid-arm muscle circumference, MAMC). This study aimed to assess correlation and association of these assessments with dietary protein intake in a multi-ethnic Asian population of healthy and CKD patients.
  
  
  METHODS
  We analyzed 24-hour urine collections of selected participants to estimate total protein intake (TPI; g/day). Ideal body weight (IDW; kg) was calculated and muscle assessments conducted. Analyses involved correlation and linear regression, taking significance at p<0.05.
  
  
  RESULTS
  There were 232 stable CKD patients and 103 healthy participants comprising of 51.0% male, 38.5% Chinese, 29.6% Malay, 23.6% Indian, and 8.4% others. The mean TPI was 58.9 ± 18.4 g/day in healthy participants and 53.6 ± 19.4 g/day in CKD patients. When normalized to ideal body weight, TPI-IDW (g/kg/day) was similar in healthy and CKD participants. Overall, TPI was associated with MAC (r=0.372, p<0.001), cAMA (r=0.337, p<0.001), and MAMC (r=0.351, p<0.001). TPI-IDW was also associated with MAC (r=0.304, p<0.001), cAMA (r=0.202, p<0.001), and MAMC (r=0.200, p<0.001) but not for TPI normalized to actual body weight. When examined separately, TPI was associated with MAC, cAMA, and MAMC in both CKD and healthy participants, but was associated with TPI-IDW only in CKD patients.
  
  
  CONCLUSIONS
  Total protein intake was associated with muscle assessments in all participants. TPI normalized to IDW should only be used in CKD patients.
authors.affiliation: Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Level 10 NUHS Tower Block, Singapore 119074, Singapore. mdctbw@nus.edu.sg.
authors.forename: Boon Wee
authors.initials: BW
authors.lastname: Teo
authors.forename: Qi Chun
authors.initials: QC
authors.lastname: Toh
authors.forename: Xue Wei
authors.initials: XW
authors.lastname: Chan
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Jia Liang
authors.initials: JL
authors.lastname: Li
authors.forename: Evan Jc
authors.initials: EJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D001132:Arm; D015992:Body Mass Index; D001835:Body Weight; D002681:China / Q000208:ethnology; D004044:Dietary Proteins / Q000008:administration & dosage*; D005006:Ethnicity; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000473:pathology*; D015596:Nutrition Assessment; D051436:Renal Insufficiency, Chronic
chemical_list: D004044:Dietary Proteins