What is the effect of a workplace-based nutritional and behavioral intervention on adherence to Mediterranean diet principles at 12 months?

A recent JAMA Network Open study assessed the impact of nutritional and behavioral intervention on adherence to the Mediterranean diet among US firefighters.

Study: Effect of a Nutrition Intervention on Mediterranean Diet Adherence Among Firefighters. Image Credit: UliAb/Shutterstock.com


People with fire service careers are at a high risk of cardiovascular disease (CVD), obesity, and cancer. Even though firefighters are at an increased risk of asphyxiation, burns, and other accidents due to the nature of their job, the highest frequency of on-duty fatalities has been associated with left ventricular abnormalities, sudden cardiac death, and atherosclerosis.

In addition, this group also experiences obesity-associated cancers. Considering these observations, the official Fire Fighter Fatality Investigation and Prevention Program has focussed on reducing cardiovascular events in people with fire service careers. 

It must be noted that only a limited number of fire departments currently have suitable nutrition, fitness, and wellness programs.

Behavioral interventions based on education and information alone failed to bring any changes in lifestyle change among firefighters. However, multi-component interventions linked to nutritional and behavioral changes produced effective outcomes.

The lifestyles of firefighters are greatly influenced by the fire station culture and environment, which is associated with 48 hours per week of eating, sleeping, and responding to emergencies. A systematic review revealed that US firefighters have poor food environments, low physical activity, and poor dietary habits.

The benefits of the Mediterranean diet in preventing CVD have been indicated in many studies. The Mediterranean diet comprises fruits, vegetables, legumes, eggs, olives, whole grains, fish, and a moderate amount of wine. This diet fosters a variety of foods in moderation.

However, few studies are available regarding the impact of a healthy diet on developing non-communicable diseases among firefighters. A recent cross-sectional survey revealed that many US firefighters had shown interest in the Mediterranean diet and wanted to gather more information about this diet type.

About the study

The current study presented a one-year cluster-randomized clinical trial to analyze the effect of nutrition and behavior-based interventions on firefighters' adherence to the Mediterranean diet.

This randomized crossover trial recruited career firefighters from the fifty-two fire stations of two Indiana Fire Departments. The participants' eligibility criteria were to be above 18 years of age, regularly assigned to a particular fire station, available medical records for the last two years, and duty records.

At baseline, the age, sex, body mass index (BMI), marital status, smoking status, history of chronic diseases, and education level was recorded. Participants were randomly assigned to either the Mediterranean diet or control (usual care).

Study findings

A total of 485 US career firefighters were recruited in this trial, among which 94.4% of the participants were male. The mean age of the participants was 47 years. This cohort included Black, White, and other ethnicity (e.g., American Indian, Asian, Pacific Islander, Hispanic, and Native Hawaiian) participants.

The control group contained 244 firefighters from 25 fire stations, while the Mediterranean nutrition intervention group consisted of 240 firefighters from 27 fire stations.

The primary analyses indicated the effectiveness of the multi-component behavioral/environmental Mediterranean nutrition approach, which has significantly improved Mediterranean diet adherence.

The Mediterranean diet intervention group increased the mean Mediterranean diet score (mMDS) by 2.01 points at six months and 2.67 points at 12 months, around a 10% increase from baseline. 

Notably, considerable improvement in adherence to individual Mediterranean diet components was observed. For instance, significant improvement in fish consumption, nut intake, and a decrease in fast food and alcohol consumption was observed.

The findings of this study highlight the importance of workplace-based intervention strategies to improve nutrition among US firefighters.

The secondary analyses exhibited that the Mediterranean nutrition intervention group showed a significant decline in body fat and low-density lipoprotein (LDL) at six months compared with controls. However, no significant changes were observed for other cardiometabolic parameters.

The findings of the multiple imputation analyses were consistent with the primary analysis, showing a greater mMDS for the Mediterranean nutrition intervention group than the control group.

The multiple imputations also revealed greater improvements in particular Mediterranean nutrition interventions, such as increased fish and legume consumption and enhanced consumption of non-alcoholic beverages of nutritional quality at home.


One of the key strengths of this study is engaging the firefighters in both their work and home environments. The multiple imputation analyses enabled the correction of potential bias caused due to missing data.

The lack of personalized follow-up to determine long-term adherence to the Mediterranean diet is a limitation of this study. 

This study highlighted the effectiveness of a multi-component worksite intervention to promote Mediterranean diet adherence that could reduce health-related risk factors of US career firefighters.

After one year, the Mediterranean nutrition intervention group exhibited significantly improved dietary habits compared to the control group. In the future, a similar approach must be implemented in a diverse population of firefighters to validate the findings and promote generalizability. 

Journal reference:
  • Hershey, M. et al. (2023) "Effect of a Nutrition Intervention on Mediterranean Diet Adherence Among Firefighters", JAMA Network Open, 6(8), p. e2329147. doi: 10.1001/jamanetworkopen.2023.29147. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2808462

Posted in: Medical Science News | Medical Research News | Medical Condition News | Healthcare News

Tags: Alcohol, Atherosclerosis, Body Mass Index, Cancer, Cardiometabolic, Cardiovascular Disease, Chronic, Clinical Trial, Diet, Education, Fish, Food, Frequency, Lipoprotein, Nutrition, Obesity, Physical Activity, Smoking, Sudden Cardiac Death, Vegetables, Wine

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Written by

Dr. Priyom Bose

Priyom holds a Ph.D. in Plant Biology and Biotechnology from the University of Madras, India. She is an active researcher and an experienced science writer. Priyom has also co-authored several original research articles that have been published in reputed peer-reviewed journals. She is also an avid reader and an amateur photographer.