Can an active lifestyle offset the relationship that poor lifestyle behaviours have on frailty?

To examine the association of lifestyle behaviours (LSB) with physical activity (PA) and frailty; also, to examine if associations differ by sex and age.

24,828 individuals [49.6 ± 17.6 years (range: 20-85), 51.6 % female] from the National Health and Nutrition Examination Survey (cycles 2009-2018) were included. Individuals were divided into Active (≥150 min/week of moderate-to-vigorous physical activity (MVPA)) and Inactive (<150 min/week MVPA) based on self-reported PA. Frailty was measured by a 46-item Frailty Index (FI). LSB consisted of stationary time, sleep, diet quality, and alcohol and smoking habits. LSB was summed into a score [0-5]. Linear regression models were used with each LSB in isolation and the summed LSB with frailty.

There were 7,495 (30.1 %) Active and 17,333 (69.8 %) Inactive individuals. The FI was lower in the Active participants (Active: 0.10 ± 0.08; Inactive: 0.15 ± 0.12; p < 0.01). A worse LSB score was associated with an increased FI in all behaviours but females who binge drink and smoke (p-all>0.14). For inactive individuals, all LSBs were associated with an increased FI except those who binge drink and male smokers (p = 0.08). There was a significant association between increased summed LSB and an increased FI (β range: Active, 0.024-0.037; Inactive, 0.028, 0.046. p-all<0.01); the Active group had a lower FI at every age group than the Inactive group (p < 0.001).

PA was associated with a lower FI even among those with a poor LSB score. This association is dependent on age, with older individuals reporting a stronger association.