title: Body composition and all-cause mortality in subjects older than 65 y.
abstract: BACKGROUND
  A low or high body mass index (BMI) has been associated with increased mortality risk in older subjects without taking fat mass index (FMI) and fat-free mass index (FFMI) into account. This information is essential because FMI is modulated through different healthcare strategies than is FFMI.
  
  
  OBJECTIVE
  We aimed to determine the relation between body composition and mortality in older subjects.
  
  
  METHODS
  We included all adults ≥65 y old who were living in Switzerland and had a body-composition measurement by bioelectrical impedance analysis at the Geneva University Hospitals between 1990 and 2011. FMI and FFMI were divided into sex-specific quartiles. Quartile 1 (i.e., the reference category) corresponded to the lowest FMI or FFMI quartile. Mortality data were retrieved from the hospital database, the Geneva death register, and the Swiss National Cohort until December 2012. Comorbidities were assessed by using the Cumulative Illness Rating Scale.
  
  
  RESULTS
  Of 3181 subjects included, 766 women and 1007 men died at a mean age of 82.8 and 78.5 y, respectively. Sex-specific Cox regression models, which were used to adjust for age, BMI, smoking, ambulatory or hospitalized state, and calendar time, showed that body composition did not predict mortality in women irrespective of whether comorbidities were taken into account. In men, risk of mortality was lower with FFMI in quartiles 3 and 4 [HR: 0.78 (95% CI: 0.62, 0.98) and 0.64 (95% CI: 0.49, 0.85), respectively] but was not affected by FMI. When comorbidities were adjusted for, FFMI in quartile 4 (>19.5 kg/m(2)) still predicted a lower risk of mortality (HR: 0.72; 95% CI: 0.54, 0.96).
  
  
  CONCLUSIONS
  Low FFMI is a stronger predictor of mortality than is BMI in older men but not older women. FMI had no impact on mortality. These results suggest potential benefits of preventive interventions with the aim of maintaining muscle mass in older men. This trial was registered at clinicaltrials.gov as NCT01472679.
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Christophe E
authors.initials: CE
authors.lastname: Graf
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Véronique L
authors.initials: VL
authors.lastname: Karsegard
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Adrian
authors.initials: A
authors.lastname: Spoerri
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Makhlouf
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Sylvain
authors.initials: S
authors.lastname: Ho
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: François R
authors.initials: FR
authors.lastname: Herrmann
authors.affiliation: From the Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland (CEG and FRH); Clinical Nutrition, Geneva University Hospitals, Geneva, Switzerland (VLK, A-MM, SH, and LG); and the Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland (AS).
authors.forename: Laurence
authors.initials: L
authors.lastname: Genton
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D009026:Mortality; D018482:Muscle, Skeletal / Q000737:chemistry; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012189:Retrospective Studies; D013557:Switzerland
keywords: body composition; body mass index; co-morbidities; cumulative illness rating scale; fat mass index; fat-free mass index; mortality; weight