Feeding America's Bravest: Mediterranean Diet-Based Interventions to Change Firefighters' Eating Habits

Aims and hypothesis:

Recognizing the benefits and safety of the Mediterranean diet in CVD prevention, the
investigators seek to develop behavioral change strategies in the fire service to modify the
existing food culture based on key principles of the Mediterranean diet. Using education,
participation and incentives, the investigators propose to motivate firefighters and their
families to incorporate Mediterranean diet principles at work and home. The research design
will allow us to measure the effectiveness of our Mediterranean Nutrition Interventions
(MDNIs) in the "field settings" of the fire services for changing eating behavior and
modifying CVD risk. Additionally, the cost-effectiveness of these strategies for future wider
implementation will be examined. Specifics aims are:

1. Develop a multi-pronged, MDNI behavior change strategies including: diet/lifestyle
education; discounted access to key Mediterranean diet foods; electronic education
platforms and reminders; and targeted incentives. MDNI components will be refined via
surveys, literature review and local/national firefighter input including
labor/management and fire service focus groups.

Hypothesis (1). Cost-effective, fire-service MDNIs will be developed for the career
randomized controlled trial (RCT).

2. Cluster Randomized Diet Intervention-Phase I- the Indianapolis Fire Department (IFD) has
over 1,000 members. All 45 IFD firehouses will be cluster randomized into two groups and
then individual members will be consented regarding study participation. Group 1 will
receive an active 12-month MDNI, while Group 2 will receive no intervention.

3. Cluster Randomized Diet Intervention -Phase II: Group 1 will cross-over to
"self-sustained continuation" for 12 months to examine persistence of behavior change
during this less intense, self-directed maintenance diet intervention. Group 2 will
cross-over to receive the MDNI for 6 months (assessing a shorter MDNI), followed by a
final 6 months of self-sustained continuation. Our existing modified Mediterranean diet
score (mMDS) will be further integrated with other validated scores and nutrition
questionnaires. Questionnaires, mMDS and clinical data will be collected longitudinally
throughout both phases of the RCT.

Hypotheses (2-3). Both MDNI lengths will improve mMDS, reduce weight, and improve
Cardiovascular Disease (CVD) risk profiles in career firefighters. The 12 month MDNI will
produce greater persistence of adherence than a 6 month MDNI. Cost-effective methods that
combine messaging and discounts for improving firefighters' diets will be developed and
validated, and these low cost methods will be adaptable for widespread translation and
implementation throughout the career fire service.

Implementation by Fire Service:

Our national surveys of career and volunteer firefighters demonstrate several common key
facts. Firefighters would like more nutrition information from the fire service and want to
learn more about healthy eating. Moreover, to succeed, the dietary approach must be
acceptable to firefighters. The Mediterranean diet does not require completely giving up any
food; and therefore, is easily adopted for long-term adherence. In our surveys, the
Mediterranean diet had the greatest appeal among five proposed diet descriptions. In
addition, the web-based tools, other educational materials and behavior change strategies
proposed to develop will be low-cost and cost-effective. With the support of fire service
partners, they should be practical for widespread implementation both on a local basis by
individual fire departments and regionally/nationally by fire service organizations.

Project/Statistical analyses:

Data recording, storage, management, cleaning and basic analyses will be performed using
SPSS. The data will be imported into Stata and SAS for more advanced statistical analyses
such as multivariable regression and longitudinal data analysis, as needed. Differences in
the mean values of a quantitative variable between two groups will be assessed using the
independent t-test whereas differences in mean values among three or more groups will be
examined using the analysis of variance (ANOVA) technique (or non-parametric Wilcoxon and
Kruskal-Wallis tests, respectively, as appropriate). Differences in qualitative
characteristics will be compared using the chi-square test, or Fisher's exact test, or
McNemar's test (for paired comparisons), as appropriate. Statistical significance for all
analyses will be p < 0.05, and all tests will be two-tailed.

RCT: During the first 12 months of the RCT, groups 1 and 2 will be compared directly on an
intention to treat basis according to the randomization of each subject's fire house. This
type of analysis- disregarding the personal level of compliance or engagement of any
particular participant- is most rigorous and appropriate because our primary interest is to
test the effect of the behavior change strategies. As several outcomes will be assessed on
each participant throughout the study (3 annual medical exams and 5 semi-annual assessments
(where weight, mMDS, etc. will be evaluated)), repeated measures techniques, such as mixed
modeling and generalized estimating equation models, will be utilized to estimate changes
over time on key outcomes. The investigators will take into consideration the specific
variance-covariance structure of correlated measurements. After adjusting for baseline and
time-dependent covariates, changes in the outcomes of interest will be assessed and compared
among groups. The investigators expect our greatest power to be for within-group changes
(paired comparisons).

For the RCT, sensitivity analyses have been performed and demonstrate that even in the worst
case scenario where only 500 firefighters would be enrolled, the study is well-powered for
intention to treat comparisons of MDNI vs usual care. Several conservative examples are given
below for very small changes. However, consistent with previous studies, the investigators
expect the MDNI to actually produce larger changes that would be more easily measured. The
first example assumes the MDNI can achieve a small increase in the mMDS of 6 points (about
1.0 times the population's baseline SD based on our cross-sectional study of mMDS).

Barriers:

Several potential barriers to successful completion of the MDNIs have been identified and
taken specific steps to prevent and surmount these barriers. Some question whether
firefighters will follow the diet at home as well as work. First, our preliminary work
demonstrates that firefighters eat better at home than work. Second, our proposal recognizes
the family's importance and has incorporated measures to educate and involve family members
who share meals and may do much of the shopping and cooking. Another challenge is MDNI cost
for sustainability and wider implementation. Therefore, an economist has been added to our
team with expertise in food and nutrition to ensure that the interventions developed are low
cost, cost-effective and sustainable. MDNIs are very most cost-effective measures from a
societal perspective. An additional challenge identified in the career randomized trial is
the potential movement of firefighters from one station to another during the study period.
This is one of the reasons the investigators chose the Indianapolis fire department: 90% of
members are permanently assigned to a fire house. Thus, there will be minimal loss/change of
firefighters' intervention assignments over the course of the project. Finally, our current
proposal facilitates the challenge of national implementation by directly addressing both the
career and volunteer fire services.

Human Subjects: Recruitment- Previously, the investigators have been very successful in
participant recruitment for our FEMA-sponsored studies. For example, about 90% of IFD members
approached have consented to our current FEMA cardiac imaging study. Additionally, the
research proposal has been endorsed by significant fire service partners, which should
increase trust and willingness to participate. The extent to which consented participants
personally engage in the MDNIs is voluntary, and the additional time commitment required for
the study is nominal- for the RCT: a weigh-in, blood pressure check, waist circumference
measure and questionnaire completion every six months; and for the demonstration project only
a web-based survey every six months. Moreover, our study designs are such that all
firefighters who consent will receive the MDNI at some point and have an opportunity for
health benefits. Therefore, no problems identifying and recruiting the necessary participants
for the RCT and demonstration project are expected.

Confidentiality and IRB:

Any RCT data from the proposal transferred to Harvard is extracted in de-identified form
without personal identifiers and is maintained in a confidential manner. PHI linkages to
de-identified data are maintained in locked, safe locations at PSM's clinical facilities.
Harvard researchers have access only to de-identified data ensuring that the research has a
very low risk of breaching any confidentiality. For the demonstration project, consent forms
and names will be linked to study codes to be used in all electronic data collection. The
linkages to volunteer names will be maintained in a locked, safe location at Harvard. All
electronic data will be restricted to authorized personnel and will be password protected.
All protocols, questionnaires and procedures will be approved by Harvard's IRB and DHS before
any participants are contacted/recruited.

Inclusion Criteria:

- those permanently assigned to one of the 45 IFD stations

- with a fire department-provided medical exam in the last two years

- at least 18 years of age

- full duty status at the time of consent

Exclusion Criteria:

- those without a recorded fire department exam in the last two years

- less than 18 years of age

- restrictions on duty at the time of consent.