Weakness: The most frequent criterion among pre-frail and frail older Portuguese.

Objective: In Portugal, the burden of pre-frailty and frailty in community-dwelling older adults is still unknown. The purpose of this study is to estimate the frequency of frailty in a Portuguese sample with ≥ 65years and to evaluate its associated factors. We also intend to identify which criterion has more impact on the diagnosis of frailty.

Methods: 1457 older adults with ≥ 65years from the Nutrition UP 65 study were evaluated in a cross-sectional analysis. Frailty was identified according to Fried et al. by the presence of three or more of the following factors: unintentional weight loss, self-reported exhaustion, slowness, weakness and low physical activity. Pre-frailty was defined as the presence of one or two of these criteria. The association between individuals' characteristics and frailty status was analysed through logistic regression analysis.

Results: The frequency of pre-frailty and frailty is 54.3% and 21.5%, respectively. In older adults classified as pre-frail or frail, 76.7% presented weakness and 48.6% exhaustion. In multivariate analyses, frailty was associated with age >75, lower education level, being single, divorced or widower, being professionally inactive, poor self-perception of health status, not drinking alcohol, being obese and undernourished or at undernutrition risk.

Conclusions: This condition is very prevalent in Portuguese older adults, one fifth are frail whereas half are pre-frail. Weakness identified by low handgrip strength is the most prevalent criterion in pre-frail and frail Portuguese older adults.