Changes in cognitive measures in a randomized controlled trial of a health promotion program for couples targeting diet and physical activity.

Purpose: To examine cognitive responses to a 4-month health promotion program targeting diet and physical activity in recently cohabiting couples.

Design: A three-group randomized controlled trial: no intervention (Controls), interactive group sessions and mail-outs (Interactive), and one group session followed by mail-outs (Mail).

Setting: Australian research studies unit.

Subjects: Seventy-eight of 137 couples cohabiting for < 2 years, recruited by advertising, completed the study.

Measures: Stages of change; health beliefs; self-efficacy; and perceived barriers to change evaluated by questionnaires at baseline, postintervention, and 1-year follow-up. Data were analyzed using mixed models, factor analysis, and linear regression.

Results: In the Mail group, the perceived importance of barriers to dietary change decreased by 19% at postintervention and 16% at 1-year follow-up; dietary self-efficacy increased by 9% and 3%, respectively. In the Interactive group, the perceived importance of barriers to dietary change decreased by 26% and 20%, and dietary self-efficacy increased by 14% and 12%, respectively. Similar trends for physical activity were not statistically significant. However, changes in self-efficacy and perceived barriers to change significantly predicted dietary and physical activity behaviors. A preponderance of higher socio-economic groups and the proportion of drop-out may have biased results.

Conclusions: Health promotion using partners' support and targeting diet and physical activity improves associated cognitive variables in couples. Most improvements were greater and more sustained with interactive group sessions.