Psychological wellbeing and all-cause mortality in the oldest old in China: a longitudinal survey-based study

Abstract Background Although the relationship between psychological wellbeing and physical health has been the subject of many studies among middle-aged and older adults, little is known about whether psychological wellbeing is associated with mortality among the fastest growing population segment—the oldest old (aged ≥80 years). Methods This study included 18 676 adults aged 80–122 years from the Chinese Longitudinal Healthy Longevity Survey, conducted in 22 of 31 provinces in China in 1998 and followed up in 2000, 2002, 2005, 2008–2009, 2011–12, and 2014. Psychological wellbeing was measured by seven items covering positive (optimism, sense of personal control, conscientiousness, and positive feelings about ageing) and negative (loneliness, anxiety, and loss of self-worth) affects with a five-point Likert scale. A psychological wellbeing index was constructed from the sum of these seven items, and scores were divided by quartile (Q1 0–22, Q2=23–25, Q3 26–28, and Q4 28–35), with higher scores indicating better wellbeing. The association between psychological wellbeing and all-cause mortality was evaluated with multivariable Cox proportional hazards regressions. Duke University Health System's Institutional Review Board, the National Bureau of Statistics of China, and the Ethical Committee of the Social Science Division of Peking University reviewed and approved ethics for the Chinese Longitudinal Healthy Longevity Survey study. Written consent was obtained from all participants or their proxies. Findings The mean age of the study population (58·8% women, n=10977) at baseline was 92 years (SD 7·4). Most participants (89·2%, n=16 661) died during follow-up, which ranged from 0·1 to 16·5 years (median 2·8). Compared with participants with a Q1 wellbeing score, hazard ratios for death were 0·95 (0·91 −0·99) for those with a Q2 score, 0·90 (0·86–0·94) for Q3, and 0·84 (0·79 −0·88) for Q4 (all p values