Abstract P273: A Mediterranean Diet Nutrition Intervention Increases Adherence in
Feeding America's Bravest
: A Stepped-Wedge Cluster-Randomized Controlled Trial
Authors: Hershey Maria Soledad , Chang Chia-Rui , Sotos-Prieto Mercedes , Moffatt Steven , Kales Stefanos 
Published: March 2023

Background:
United States (US) career firefighters represent a working population at high risk for cardiovascular disease that may benefit from a Mediterranean diet (MedDiet) nutrition intervention (MDNI). The
Feeding America’s Bravest
trial was the first workplace randomized controlled trial with nutrition education, behavior change, and incentives strategies promoting adherence to the MedDiet within US firehouses and homes. We assessed the hypothesis that a 12-month MDNI with a novel worksite behavior change approach would increase adherence to the MedDiet.

Methods:
486 US career firefighters within the Indianapolis and Fishers Fire Departments were enrolled and cluster randomized by fire station to either a MDNI or control group and completed 6-month (n=336) and 12-month follow-up (n=260). Stepwise-selection regression analyses and nested least-squares linear regression models determined the contribution of each item to the between person variability of a modified Mediterranean Diet Score (mMDS). To assess the intervention effect, an intention-to-treat analysis used multilevel mixed-effects linear regression models for repeated measures to evaluate between-group and within-group mean differences in mMDS from baseline to 6-months and baseline to 12-months adjusting for age, sex, physical activity, race, and waist circumference with clusters as the random effects parameter.

Results:
Among 484 US career firefighters (95% male with mean age of 47 years (SD=7.5; range: 26-68) observed mean scores (SD) in the MDNI group were 23.41 (6.34) at baseline, 25.26 (5.73) at 6-months, and 24.79 (6.15) at 12-months, and in the control group; 22.87 (6.78), 26.20 (6.15), and 26.68 (6.42), respectively. Between person variability of mMDS scores was largely due to the cooking oil used at home, fried foods, beverages at home, vegetables, and quantity of alcohol. Adjusted mean changes in mMDS showed statistically significant improvements among the MDNI group at 6-months by 1.28 points (pts.) (95%CI: -0.24 to 2.81) and 1.93 pts. (95%CI: 0.39 to 3.46) at 12 months compared to the control group. Multiple imputation methods supported these findings showing 6-month improvements of 1.23 pts. (95%CI: 0.22 to 2.25) and 1.63 pts. (95%CI: 0.58 to 2.67) at 12-months in the MDNI group compared to the control group.

Conclusions:
In conclusion, firefighters’ increased mMDS scores evidenced the effect of a multicomponent MDNI in a non-Mediterranean working population at high cardiovascular risk. Although more research is warranted, these findings support MedDiet promotion among the US fire service and other similar workforces. Furthermore, the intervention strategies used in this trial; cooking demonstrations, positive reinforcement, family involvement, and discounted access to staple MedDiet foods, may serve as effective nutrition worksite approaches for reducing the burden of chronic disease.