Spread of health behaviors in young couples: How relationship power shapes relational influence.

INTRODUCTION: Romantic relationships provide a context in which partners can influence each other's health behaviors (e.g., weight-related behaviors, substance use). Partner influence may be especially pronounced among newly parenting adolescent and young adult couples because of the desire to maintain relationships (and therefore openness to influence), and because parenting-related challenges can pose risk for uptake of unhealthy behaviors. Two understudied factors that might affect partner influence on health behaviors include relative power within the relationship and prior levels of engagement in health behaviors.

METHODS: The current study explored longitudinal partner influence effects in a sample of newly parenting adolescent and young adult females and their male partners (Ncouples = 157) recruited from four obstetrics/gynecology clinics in Connecticut between July 2007 and February 2011. Five health behaviors in two domains were explored: weight-related behaviors (unhealthy eating, exercise) and substance use (cigarette, alcohol, and marijuana use). Relationship power and previous levels of health behaviors were examined as moderators. Variations across gender were also examined.

RESULTS: Results of dyadic analysis showed partner influences for alcohol use. Partner influence depended on relationship power for eating, alcohol, and marijuana use, and on previous behavior for cigarette use. Results also varied by gender - only female-to-male influence was found for unhealthy eating and cigarette use. Higher relationship power was protective against smoking escalation for females.

DISCUSSION: These results differ from previous research findings mainly on male-to-female influences. Such asymmetries may reflect traditional female dominance in food preparation, as well as shifts in power balances postpartum. Targeting relational power dynamics may buffer the spread and escalation of unhealthy behaviors in young parents, with implications for the health of both members of a couple as well as their children.