The Role of Combined Modifiable Lifestyle Behaviors between Stressful Life Events and Allostatic Load in Australian Adults

Abstract

Behavioral stress response is a proposed pathway that links exposure to stressors to elevated allostatic load, yet there is little empirical evidence. We tested the role of combined modifiable lifestyle behaviors in the mechanistic pathway between stressful life events and allostatic load among Australian adults. A latent profile analysis was performed to identify latent subgroups with distinct behavioral clusters based on five modifiable lifestyle behaviors (smoking, sedentary behaviour, physical activity, alcohol consumption, and diet quality). Subsequently, a path analysis was applied using a sequential mediational model to test the mediating effect of behavioral clusters in the associations between stressful life events and three measures of allostatic load (high-risk quartiles, high-risk deciles, and system risk index). The indirect effects via behavioral clusters were estimated using the product of coefficient approach. Three behavioral clusters: "least healthy lifestyle", "moderately healthy lifestyle", and "most healthy lifestyle" emerged from our analytic sample. Compared to the "moderately healthy lifestyle" group, the "most healthy lifestyle" participants had significantly lower allostatic load (p<0.01). Mediation analyses revealed non-significant indirect associations via the "least healthy lifestyle" and "most healthy lifestyle" clusters compared to the "moderately healthy lifestyle" group. Findings were consistent across allostatic load indices. This study confirms previous findings on the salutary effect of healthy lifestyle behaviors on allostatic load. The behavioural clusters did not explain the association between stressful life events and allostatic load. Future analyses should consider the optimal measurement intervals, moderating role of social support, and account for the time-varying nature of lifestyle behaviours.