ABSTRACT: OBJECTIVES:Frailty is a major clinical geriatric syndrome associated with serious adverse events including functional disability, falls, hospitalisation, increased morbidity and mortality. The aim of this study was to study associations between a frailty phenotype and frailty characteristics well known from the literature. DESIGN:Registry-based cross-sectional study. SETTING:The target population consists of inhabitants above the age of 50 living in the Danish municipalities of Lolland and Guldborgsund. Excluded are incapacitated people, inhabitants unable to understand Danish or English and inhabitants without a permanent residence. PARTICIPANTS:7327 individuals aged 50+ years were included. OUTCOME MEASURES:We examined associations between the frailty measurement and factors known to be associated with frailty: sex, age, income insufficiency, education, comorbidity, self-assessed health, morbidity and mortality. RESULTS:7327 individuals aged 50+ years were included. Of these, 6.5% had ?3 frailty components (frail), 46.7% had 1-2 components (prefrail) and 46.9% had none (non-frail). Those who were frail were older and more likely female than those who were non-frail or prefrail. There was a stepwise decrease in educational level, and in self-assessed health with increasing frailty status, and a stepwise increase in difficulty in making ends meet, number of hospital contacts and mortality with increasing frailty status, p<0.0001 for each comparison. Compared with individuals who were non-frail, mortality was higher among those who were prefrail (HR: 2.90; 95%?CI: 1.30 to 6.43) or frail (HR: 8.21; 95%?CI: 3.37 to 20.0). CONCLUSIONS:Based on these findings, we consider the Lolland-Falster Health Study frailty assessment a valid instrument demonstrating the same characteristics as other validated frailty measures concerning associations with sex, age, income insufficiency, education, comorbidity, self-assessed health, morbidity and mortality. TRIAL REGISTRATION NUMBER:NCT02482896.