Prevalence of frailty and contributory factors in three Chinese populations with different socioeconomic and healthcare characteristics

Background: Frailty predicts dependence and mortality, and is an important health indicator for aging populations. Comparing frailty prevalence between populations of the same ethnicity but different socioeconomic, lifestyle, health and social care systems, and environmental characteristics would address the role of these factors in contributing to frailty. Methods: We compare frailty prevalence and contributory factors across three Chinese populations: Beijing rural, Beijing urban, and Hong Kong (urban). Older people aged 65 years and above living in the community were invited to respond to a general health questionnaire covering demographic, socioeconomic, medical and drug histories, geriatric syndromes, assessment of physical and cognitive functioning, psychological wellbeing and nutritional status. Frailty is defined as an index calculated from multiple deficits > = 0.25 (FI). The ratio of FI/life expectancy at birth was used as an indicator of compression of morbidity. Risk factors and attributable fraction for frailty were compared across the three cohorts. Results: The prevalence of frailty increases with age in all three cohorts, and was lower among rural compared with urban (Beijing and Hong Kong) populations. The highest FI/LE ratio was observed in the Beijing urban population, followed by Hong Kong, with the Beijing rural population having the lowest ratio. Risk factors for frailty were similar in all three populations. Those having the highest ORs were multi-morbidity (number of diseases > = 3), polypharmacy (number of drugs > = 4), age 85+, female gender, followed by low education level, and physical inactivity. For all three cohorts, age and multi-morbidity constitute the highest attributable fraction, and were highest in the Beijing rural cohort. A major difference between the Beijing and Hong Kong cohorts is the high AF from polypharmacy in Beijing and the 'protective' contribution of being married; and the effect of being a teetotaler in the Hong Kong cohort. Conclusions: This comparison draws attention to the importance of frailty prevention for ageing populations.