A comparison of perceived uselessness between centenarians and non-centenarians in China

Table 3 Relative risk ratios of high and moderate frequencies relative to low frequency of self-perceived uselessness for those lived to age 100 and above in comparison with those lived to age 91 yet died before age 100 among those born in 1906–1913, CLHLS 2005–2014

Age at death	Model I	Model II	Model III	Model IV	Model V	Model VI
High frequency relative to low frequency
Survived to age 100 vs. died at ages 91–94	0.62^* (0.41–0.91)	0.64^* (0.42–0.97)	0.62^* (0.41–0.84)	0.74 (0.48–1.12)	0.80 (0.52–1.22)	0.85 (0.55–1.32)
Survived to age 100 vs. died at ages 95–99	0.98 (0.77–1.24)	1.02 (0.80–1.29)	0.98 (0.78–1.24)	1.11 (0.88–1.43)	1.16 (0.91–1.47)	1.25 (0.97–1.60)
Moderate frequency relative to low frequency
Survived to age 100 vs. died at ages 91–94	0.61^* (0.41–0.91)	0.62^* (0.42–0.93)	0.61^* (0.41–0.91)	0.64^* (0.43–0.97)	0.69+ (0.47–1.04)	0.71+ (0.48–1.06)
Survived to age 100 vs. died at ages 95–99	0.93 (0.75–1.17)	0.95 (0.76–1.19)	0.94 (0.75–1.17)	0.98 (0.78–1.23)	1.02 (0.81–1.28)	1.04 (0.82–1.31)

Note: (1) Figures in the table were relative risk ratios based on unweighted multinomial logistic regression models from 2921 respondents who were born between January 1, 1906 and December 31, 1913. (2) The high frequency of feelings of useless referred to always/often; the moderate frequency referred to sometimes; and the low frequency referred to seldom/never. The category of “unable to answer” of the self-perceived uselessness was included in the analyses, but their results were not presented because they are not our focuses. (3) Model I controlled for demographic attributes (sex, urban-rural residence, ethnicity), and the years of survey; Model II added resource factors (educational attainment, primary life occupation, economic independence, family economic condition, and adequate access to healthcare services when in need) in Model I; Model III controlled for social environmental factors (marital status, coresidence with children, primary caregivers) in addition to covariates in Model I; Model IV controlled for behavioral factors (leisure activities) in addition to covariates in Model I; Model V controlled for health-related factors (disability in activities of daily living and cognitive impairment) in addition to covariates in Model I; and Model VI controlled for all covariates in Models I to V. (4) + p < 0.1, ^*p < 0.05, ^**p < 0.01, ^***p < 0.001