Promoting healthy lifestyle habits among participants in cancer screening programs: Results of the randomized controlled Sti.Vi study.

Background: Unhealthy diets, physical inactivity, alcohol and tobacco consumption are among the leading risk factors for non-communicable diseases. It is estimated that around 40% of cancers could be prevented by adopting healthy lifestyles. Design and methods: The Stili di Vita (Sti.Vi) study was a randomized study for assessing the impact of healthy lifestyle interventions on anthropometric measures, metabolic parameters, and health outcomes among participants of cancer screening programs in Turin (Italy). Eligible women aged 50-54 years, invited to biennial mammography screening, and 58-years-old men and women, invited to a once-only sigmoidoscopy for colorectal cancer (CRC) screening were randomly allocated to Diet group (DG), Physical Activity group (PAG), Physical Activity plus Diet group (PADG), or control group (CG). Physical and eating habits, metabolic and anthropometric measurements, repeatedly collected, were the study outcomes. The active intervention, offered to participants assigned to the DG, PAG, and PADG arms, consisted of a basic module and an advanced module. The effect of the interventions was estimated through logistic regression or a difference in differences approach. A multiple imputation procedure was implemented to deal with missing values and Results: Out of the 8442 screened attendees, 1270 signed informed consent, while 1125 participants accomplished the baseline visit. Participants were equally distributed across the four treatments as following: 273 (24.3%) in DG, 288 (25.6%) in the PAG, 283 (25.1%) in PADG, and 281 (25%) in the CG. Participants assigned to DG or PADG increased their consumption of whole grains (OR = 1.77, 95% CI: 1.20-2.60 and OR = 1.55, 95% CI: 1.06-2.27, respectively) and legumes (OR = 1.77, 95% CI: 1.12-2.79 and OR = 2.24, 95% CI: 1.41-3.57, respectively), with respect to CG. The participants randomized to DG reduced processed meat and increased fruit consumption (OR = 2.57, 95% CI: 1.76-3.76 and OR = 2.38, 95% CI: 1.12-5.06, respectively). The effects were more evident in the CRC screening subgroup. No relevant difference was observed between PAG and CG. No impact was observed on physical activity habits. Conclusions: Our findings suggest that active interventions can increase awareness and induce diet changes. However, participation rate and compliance to the courses was quite low, innovative strategies to enhance participants' retention are needed, with the ultimate goal of increasing awareness and inducing positive lifestyle changes.