title: Sex differences in the limit to deficit accumulation in late middle-aged and older Chinese people: results from the Beijing Longitudinal Study of Aging.
abstract: BACKGROUND
  On average, as people age, they accumulate more health deficits and have an increased risk of death. The deficit accumulation-based frailty index (FI) can quantify health and its outcomes in aging. Previous studies have suggested that women show higher FI values than men and that the highest FI score (the "limit to frailty") occurs at a value of FI ~ 0.7. Even so, gender differences in the limit to frailty have not been reported.
  
  
  METHODS
  Data for this analysis were obtained from the Beijing Longitudinal Study of Aging that involved 3,257 community-dwelling Chinese people, aged 55+ years at baseline. The main outcome measure was 5-year mortality. An FI consisting of 35 health-related variables was constructed. The absolute and 99% FI limits were calculated for different age groups and analyzed by sex.
  
  
  RESULTS
  The mean level of the FI increased with age and was lower in men than in women (F = 67.87, p < .001). The 99% FI limit leveled off slightly earlier with a relatively lower value in men (60 years; 0.44 ± 0.02) compared with that in women (65 years; 0.52 ± 0.04). The highest absolute FI value was 0.61 in men and 0.69 in women. In both groups, people with an FI greater than or equal to the 99% limit showed close to 100% mortality by 5 years.
  
  
  CONCLUSIONS
  Compared with men, women appeared to better tolerate deficits in health, yielding both relatively lower mortality and higher limit values to the FI. Even so, the FI did not exceed 0.7 in any individual.
authors.affiliation: Beijing Institute of Geriatrics, Beijing Hospital, Ministry of Health, China. Geriatric Medicine Research Unit, Centre for Health Care of the Elderly, QEII Health Sciences Centre, Capital District Health Authority, Halifax, Nova Scotia, Canada.
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
authors.affiliation: Geriatric Medicine Research Unit, Centre for Health Care of the Elderly, QEII Health Sciences Centre, Capital District Health Authority, Halifax, Nova Scotia, Canada. Department of Biology, Crandall University, Moncton, New Brunswick, Canada.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Geriatric Medicine Research Unit, Centre for Health Care of the Elderly, QEII Health Sciences Centre, Capital District Health Authority, Halifax, Nova Scotia, Canada. Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Song
authors.affiliation: Beijing Institute of Geriatrics, Beijing Hospital, Ministry of Health, China.
authors.forename: Pulin
authors.initials: P
authors.lastname: Yu
authors.affiliation: Department of Evidence-Based Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Fang
authors.affiliation: Department of Evidence-Based Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Beijing Institute of Geriatrics, Beijing Hospital, Ministry of Health, China.
authors.forename: Dantao
authors.initials: D
authors.lastname: Peng
authors.affiliation: Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada. Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Arnold
authors.initials: A
authors.lastname: Mitnitski
authors.affiliation: Geriatric Medicine Research Unit, Centre for Health Care of the Elderly, QEII Health Sciences Centre, Capital District Health Authority, Halifax, Nova Scotia, Canada. Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada. kenneth.rockwood@dal.ca.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Rockwood
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging; D044466:Asian People; D002681:China / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D016330:Frail Elderly / Q000706:statistics & numerical data*; D015577:Geriatric Assessment / Q000379:methods*; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017678:Sex Distribution; D012737:Sex Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors
keywords: Aging; Deficit accumulation; Frailty limit; Gender difference; Mortality.