Frailty index as a predictor of all-cause and cause-specific mortality in a Swedish population-based cohort

Background: Frailty is a complex manifestation of aging and associated with increased risk of mortality and poor health outcomes. Younger individuals (under 65 years) typically have low levels of frailty and are less-studied in this respect. Also, the relationship between the Rockwood frailty index (FI) and cause-specific mortality in community settings is understudied. Methods: We created and validated a 42-item Rockwood-based FI in The Swedish Adoption/Twin Study of Aging (n=1477; 623 men, 854 women; aged 29-95 years) and analyzed its association with all-cause and cause-specific mortality in up to 30-years of follow-up. Deaths due to cardiovascular disease (CVD), cancer, dementia and other causes were considered as competing risks. Results: Our FI demonstrated construct validity as its associations with age, sex and mortality were similar to the existing literature. The FI was independently associated with increased risk for all-cause mortality in younger (