Chinese Longitudinal Healthy Longevity Study

The Chinese Longitudinal Healthy Longevity Study (CLHLS) is a large-scale population-based study on health status and quality of life of the elderly in 23 provinces (out of 31 provinces) of China since 1998 with 8 waves so far. The study covers approximately 85% of the total population of China and was conducted to shed light on the determinants of human healthy longevity. The CLHLS tried to interview all consenting centenarians in the sampled counties and cities. For each centenarian interviewee, compatible nearby un-related elderly and younger participants were interviewed, including about one nonagenarian aged 90-99, one octogenarian aged 80-89, 1.5 young-old adult aged 65-79 and 0.7 middle-aged adult aged 40-64. Detailed longitudinal data on physical and mental health, cognitive function, social participation, etc. at old ages were collected from a total of 96,805 face-to-face interviews with 16,557 centenarians, 23,081 nonagenarians, 25,842 octogenarians, 19,650 younger elders aged 65-79, and 11,675 aged 35-64 in the completed 7 waves from 1998 to 2014. For the 26,701 participants who died between these seven waves, data on mortality and quality of life before death (i.e., degree/length of disability and suffering before death) were collected in interviews with a close family member of the deceased. The completed seven waves of CLHLS had collected DNA samples from 24,693 participants, including 4,849 centenarians, 5,190 nonagenarians, 5,274 octogenarians, 4,770 aged 65-79, and 4,609 aged 40-64. The 8th wave of CLHLS is ongoing and expected to be completed by the end of July 2018.