Xuxi Zhang

promotion with regard to people with frailty and chronic conditions in order to provide  insights and directions in developing health promotion to support healthy ageing of older  people.   Frailty  With the demographic process of ageing all over the world, frailty is increasingly recognized  as one of the most serious public health challenges today. 10  According to Clegg et al. (2013)  and Hoogendijk et al. (2019), frailty develops as a consequence of decline in functioning  across multiple physiological systems, accompanied by an increased vulnerability to  stressors. 11, 12  Figure 1.1.1 shows the concept of frailty diagrammatically with the comparison  of the change in health state after a small stress event in life between a fit person and a frail  person; the frail person (the red line in Figure 1.1.1) may experience a larger deterioration in  functional abilities due to the vulnerability. 12 Figure 1.1.1 Vulnerability of frail elderly people to a sudden change in health status after a  minor illness * The  green line  represents a fit elderly individual who, after a minor stressor event such as an infection, has a  small deterioration in function and then returns to homoeostasis. The  red line  represents a frail elderly individual  who, after a similar stressor event, undergoes a larger deterioration, which may manifest as functional  dependency, and who does not return to baseline homoeostasis. The horizontal dashed line  represents the cutoff  between dependent and independent.  *  Reprinted from The Lancet, 381(9868), Clegg, A., Young, J., Iliffe, S., Rikkert, M. O., & Rockwood, K., Frailty in  elderly people, 752–762, Copyright (2013), with permission from Elsevier.  Despite discussions regarding the conceptualization of frailty over the past decades, three  important factors of frailty remaining consistent. 11, 13  Firstly, frailty is a multidimensional  concept with physical, psychological and social factors playing a role in its development. 11, 13 Secondly, frailty is an extreme consequence of the normal ageing process although its  prevalence increases with age. 11  Thirdly, frailty is dynamic which means the level of frailty of  an individual could change in either direction over time. 11, 14 It has been shown that frail people may have a higher risk of various negative outcomes such  as falls 15 , disability 16 , long‐term care 17 , hospitalization 16  and mortality 18 . To identify frail  people has been proposed as a step for better management and control of frailty. 10  However,  14 Chapter 1