Original articleThe Mediterranean lifestyle (MEDLIFE) index and metabolic syndrome in a non-Mediterranean working population
Introduction
Metabolic syndrome is a condition of clustered cardio-metabolic (cardiovascular disease (CVD) and Type 2 Diabetes Mellitus (T2DM) risk factors, which requires at least three out of five criteria including hyperglycemia, raised blood pressure, elevated triglyceride levels, low HDL cholesterol levels, and abdominal obesity, respectively [1]. According to a representative sample of the United States (US) population from the National Health and Nutrition Examination Survey (NHANES), the prevalence of metabolic syndrome increased from 32.5% from 2011 to 2012 to 36.9% in 2015–2016, with significant increases in those aged 20–39 years, women, Asians, and Hispanics [2]. Metabolic syndrome has been largely attributed to an overconsumption of calories, in addition to more sedentary lifestyles worldwide, which has led to increasing obesity rates [3]. Such trends indicate a strong need for effective lifestyle modifications targeted at high risk populations to lower CVD and T2DM risk, as well as subsequent healthcare costs and disability [[1], [2], [3]].
US career firefighters often experience several lifestyle risk factors, including poor diet quality and suboptimal eating habits, physiological stress from strenuous physical activity at work, emotional stress, and environmental pollutants, in addition to low fitness [4,5]. Such lifestyle factors have led to a high prevalence of obesity and other chronic conditions, including hypertension, hypercholesterolemia, and high blood glucose, contributing to significant morbidity and disability among this working population [[5], [6], [7], [8]]. Existing evidence on dietary workplace interventions for health promotion support healthy dietary changes, such as the current Dietary Guidelines for Americans, which includes the Mediterranean dietary pattern (with its characteristic frugality), for the long-term prevention of diet-related chronic disease [9]. On the other hand, evidence supports workplace physical activity interventions to improve body composition [10]. However, evidence of the joint effect of multicomponent lifestyle patterns, including interrelated factors such as physical activity and sedentary behavior within a general way of living, on metabolic syndrome is limited [11,12].
MEDLIFE, as described and represented in a Mediterranean Diet Pyramid by the Mediterranean Diet Foundation's International Scientific committee, encompasses several distinctive habits beyond the Mediterranean diet, such as resting patterns, social structures, consumption of seasonal and diverse foods, and other healthy culinary techniques [13,14]. In 2014, a MEDLIFE index was developed and validated in a Spanish working population based on these recommendations [15,16]. To our knowledge, the MEDLIFE index has only been associated with lower CVD risk factors and mortality in Mediterranean populations [[16], [17], [18]]. Therefore, the aim of this cross-sectional study was to evaluate the association between the MEDLIFE index and metabolic syndrome in a non-Mediterranean working population at high CVD risk.
Section snippets
Study population and design
Feeding America's Bravest is a cluster-randomized diet intervention trial conducted among US career firefighters from the 44 fire stations of the Indianapolis Fire Department and the 6 fire stations of the Fishers Fire Department (both in Indiana, USA). The primary objective of this randomized controlled trial was to compare a Mediterranean diet nutritional intervention with multiple behavior change strategies (diet/lifestyle education, discounted access to key Mediterranean diet foods,
Study population characteristics
For included participants, MEDLIFE scores ranged from 2 to 17 points with a mean score of 8.8 ± 3.0 points. The average age of the total study population was 47 ± 7.6 years, ranging from 30 to 62 years. Males represented 95% of the study population with an average total daily energy intake of 2395 ± 909 kcal per day, whereas females had an average intake of 1886 ± 662 kcal per day. The prevalence of metabolic syndrome was 17.7%, abdominal obesity 38.2%, hyperglycemia 37.0%, hypertension 7.2%,
Principal findings
In a cross-sectional study with US career firefighters, those with better adherence to MEDLIFE exhibited a 71% lower odds of metabolic syndrome compared to participants with poorer adherence. MEDLIFE was inversely associated with abdominal obesity and hypertriglyceridemia, as well as total cholesterol, LDL cholesterol, and total-c:HDL cholesterol ratio, suggesting a more favorable cardiometabolic profile. Additional sensitivity analyses further supported the robustness of our findings.
Existing evidence and significance of the MEDLIFE index
To the
Conclusion
Adherence to MEDLIFE in a population of US career firefighters was significantly associated with a decreased prevalence of metabolic syndrome. Future findings from prospective studies on overall healthy lifestyle patterns, beyond diet and physical activity, could positively contribute towards the implementation of effective public health strategies for the primordial prevention of metabolic syndrome, its components, and other chronic diseases in non-Mediterranean populations, particularly among
Funding statement
This research was funded by the U.S. Department of Homeland Security, grant number EMW-2014-FP-00612.
Author contribution
Conceptualization, M.R.-C and M.S.-P; methodology, M.R.-C; formal analysis, M.S.H and M.R.-C; resources and data curation, M.S.-P, S.M, and C.C.; writing—original draft preparation, M.S.H; writing—review and editing, M.S.H, M.S.-P, M.R.-C, M.A.M.-G., C.C, and S.N.K; visualization, M.R.-C, M.S.-P, and C.C.; supervision and project administration, M.R.-C, M.S.-P, S.M and S.N.K; funding acquisition, S.N.K. All authors had full access to all of the data in this study and take complete
Conflicts of interest
Commercial sponsors of this study are: Kroger Company (coupons and customer loyalty discounts); Barilla America (Barilla Plus Products), Arianna Trading Company, Innoliva and Molino de Zafra, Spain (extra virgin olive oil samples and discounts) and the Almond Board of California (free samples of roasted unsalted almonds). The sponsors had no role in the overall study design; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish
Acknowledgment
The authors acknowledge the Advisory Board and the data advisory monitoring board (DAMB), Indianapolis Fire Department (IFD), Fishers Fire Department, Indianapolis Local 416 support, and the National Fire Organizations; International Association of Fire Fighters, National Volunteer Fire Council, National Fallen Firefighters’ Foundation, The Fire Protection Research Foundation, and International Association of Fire Chiefs that support the research, as well as the firefighters and their families
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