New Study Explores Attitudes, Subjective Norms and Perceived Behavioural Control in a Genetic-Based and a Population-Based Weight Management Intervention: A One-Year Randomized Controlled Trial

• Post by: Rebecca Clarke
• 10:04AM Jan 28, 2021
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Several studies demonstrate that the provision of personalized lifestyle advice, based on genetics, can help motivate individuals to engage in greater nutrition and physical activity changes compared to the provision of population-based advice. The theoretical mechanism behind this phenomenon is poorly understood.

A team of researchers led by Justine Horne, with Jason Gilliland, Marie-Claude Vohl, and Janet Madill published a study entitled: “Exploring Attitudes, Subjective Norms and Perceived Behavioural Control in a Genetic-Based and a Population-Based Weight Management Intervention: A One-Year Randomized Controlled Trial.” The objective of this study was to determine the impact of providing genetically tailored and population-based lifestyle advice on key constructs of the Theory of Planned Behaviour (TPB).

In order to study this, a pragmatic, cluster randomized controlled trial took place at the East Elgin Family Health Team, in Aylmer, Ontario, Canada. Participants were primarily Caucasian females enrolled in a weight management (Group Lifestyle Balance (GLB)) program. Weight management program groups were randomized to receive a population-based lifestyle intervention for weight management or a lifestyle genomics (LGx)-based lifestyle intervention for weight management (GLB+LGx). Attitudes, subjective norms and perceived behavioural control were measured at baseline, immediately after receiving a report of population-based or genetic-based recommendations and after 3-, 6- and 12-month follow-ups. Linear mixed models were conducted, controlling for measures of actual behavioural control. All analyses were intention-to-treat by originally assigned groups.

Results show significant changes in attitudes, subjective norms, and perceived behavioural control tended to be short-term in the GLB group and long-term for the GLB+LGx group. Short-term and long-term between-group differences in measures of subjective norms were discovered, favouring the GLB+LGx group. Thus, conclusions can be drawn that the Theory of Planned Behaviour can help provide a theoretical explanation for studies demonstrating enhanced behaviour change with genetic-based lifestyle interventions.

Citation: Justine Horne, Jason Gilliland, Marie-Claude Vohl, and Janet Madill (2020). “Exploring Attitudes, Subjective Norms and Perceived Behavioural Control in a Genetic-Based and a Population-Based Weight Management Intervention: A One-Year Randomized Controlled Trial.” Nutrients, 12(12), 3768; https://doi.org/10.3390/nu12123768