Effect of the Mediterranean Diet on BMI in Middle-Aged Hispanic Women with Pre-Obesity and Obesity Central Washington State

Background: Conclusive evidence has yet to emerge regarding the effectiveness and applicability of the Mediterranean diet on middle-aged Hispanic women, the largest female minority group in the United States who is at-risk of metabolic disorders. Objective: The aim of this study is to evaluate the effect of the Mediterranean diet (MED) on the BMI in middle-aged Hispanic women with pre-obesity and obesity in Central Washington State. Design: A prospective study was performed to determine the effect of Mediterranean diet on the BMI of 67 Hispanic women with pre-obesity and obesity between 45 to 65 years of age in Central Washington State. The study was carried out for eight weeks. Dietary adherence was monitored to ensure consistent results. Results: The proportion of Hispanic women who reported a reduction in BMI was 94%, with a decrease in mean BMI after eight weeks of 2.8 (95% CI: 2.5 to 3.0) and P = 0.02, with an odds ratio of 2.6. Multiple linear regression analysis was used to adjust for age, education, physical activity, and smoking. Conclusion: The reduction in BMI demonstrates that the Mediterranean diet can be a promising, culturally appropriate therapy to address the obesity epidemic that is prevalent among Hispanic women.


Introduction
Obesity is a risk factor for the two leading causes of death in the United States and the second leading cause of preventable death worldwide [1]. Classified as a chronic disease by Medicare in 2004, obesity is considered one of the most prevalent, costly, and preventable medical problems in the United States [2]. Over 50% of the population in rural areas of Central Washington State is characterized as Hispanic [3]. Despite being the largest, fastest-growing female minority group in the U.S., Hispanic women (Latinas) report higher rates of pre-obesity (BMI: 25 -29.9 kg/m 2 ), obesity (BMI ≥ 30 kg/m 2 ), and metabolic disorders [3] [4] [5]. With low-income, limited access to basic medical services, and high uninsured rates, Latinas in Central Washington State are a vulnerable population that creates great economic and public health burden in the country [6]. Studies confirm that a proper diet is an important component in the prevention and management of obesity. Previous studies on Mediterranean diet (MED) have focused on the anti-inflammatory and neurocognitive effect on non-Hispanic populations but have not determined its effectiveness and applicability on middle-aged Latinas in Central Washington State, which is an underserved population [7] [8]. The aim of this study is to examine the effect of the Mediterranean diet on the body mass indices (BMIs) in middle-aged Hispanic women with pre-obesity and obesity in Central Washington State.

Description of Diet
A cohort of 67 middle-aged Hispanic women was recruited with pre-obesity (BMI of 25 -29 kg/m 2 ) and obesity (BMI of ≥30 kg/m 2 ) and was placed on the Mediterranean diet for eight weeks. The low rates of coronary heart disease in the Mediterranean countries stimulated interest in the metabolic health benefits of this diet [9]. The important components of this lifestyle include a high polyphenol and fiber content, a rich variety of fruits and vegetables, healthy protein sources, and polyunsaturated fatty acids ( Figure 1 and Table 1). It is important to understand that the Mediterranean diet is a way of eating, not simply a compendium of recipes. Many observational studies show decreased rates in diabetes type 2, obesity, and cardiovascular disease in individuals adhering to a Mediterranean diet [10].

Sample Description
The population of interest consisted of all Hispanic women with pre-obesity or obesity, living in Central Washington State. Table 2 includes the eligibility criteria for both inclusion and exclusion of participants in the study. Passive recruiting methods were employed to enroll the participants through television announcements in local channels seen in the Northwest United States. Interviews were conducted on 83 responders, 16 were disqualified, based on the selection criteria (Table 2), thus 67 participants were integrated into the study. A probability sampling technique, known as stratified sampling, was employed to ensure adequate representation of females within the middle-aged range. Target Sample

Procedures
Anthropometric measures were obtained (using Health O Meter Professional scale), which included weight and height. Body Mass Index (BMI) was calculated as kilograms divided by meters squared. BMI is a recommended standardized marker of obesity because it is independent of variables, such as ethnicity and sex [14]. A trained research assistant weighted and measured women by using standardized procedures shown in Table 3. At the beginning of the study, the subjects received a nutritional assessment questionnaire (Appendix A), which included nutritional and dietary history, physical activity evaluation, weight history, weight loss pharmacotherapy history, surgical procedure history, and screening for motivational level to complete the program. Evaluation tools, including 24-hour dietary recall and food frequency questionnaires (Appendix B), were implemented at the end of each week, to enhance awareness of eating patterns and to measure adherence level. Group support programs were conducted every week, to promote stronger adherence with the dietary regimen. Written consent forms were obtained from all women in either Spanish or English prior to the study. The consent forms and recruitment script were carefully designed to avoid excessive information and reduce response bias.
Missing Cases. Two of the 67 participants dropped out during the eight-week study (attrition rate = 2.9%). The data of these participants was included as part of the final analysis, to reduce the likelihood of migration bias.

Screening for Covariates
This study examined for socio-demographic confounders that may impact BMI, such as age, education, smoking, and physical activity level. Multiple linear regression model was used to analyze the outcome variable and odds ratio to measure the association between exposure (e.g., following the MED) and the outcome (e.g., reduction in BMI).

Analysis
This study compared the difference in means between the BMI before and after the MED administration. The statistical significance of the difference in means of BMI was assessed using the t-test. A one-sided (lower-tailed) t-test was selected with the alpha level set at 0.05. The lower-tailed result was of interest, because only a reduction in BMI in individuals with pre-obesity and obesity is clinically meaningful. Next, multivariable linear regression analysis was used to adjust for the effects of potential confounders, such as age (as a continuous variable), education, smoking, and physical activity (as dichotomous variables), respectively ( Table 4). All statistical analyses were conducted in 2019 with IBM SPSS Statistics, version 24.0. The t-test statistics were one-sided and statistical significance was defined as P < 0.05. International Journal of Clinical Medicine

Socio-Demographic Characteristics
A cohort of 67 middle-aged Hispanic women were recruited with pre-obesity and obesity and were placed on the Mediterranean diet for eight weeks. The participants self-reported to adhere to the Standard American Diet (SAD) before the study. The summary statistics for this study are presented in Table 5

Main Finding
Of the 67 Hispanic women that were enrolled in this cohort study with  the study, most of the participants had pre-obesity (71%) and the remaining obesity (29%). At the end of the eight-week interval, a group (51%) of Hispanic women who had previous pre-obesity, reported a BMI within a normal range. The subjects who experienced more dramatic reductions in BMIs reported higher motivation to continue this diet as a way of life. Whether weight reduction was defined using BMI or waist-to-hip ratio, the results were similar. Thus, MED was a positive moderator of BMI. Adjusting for age, physical activity levels, education, and smoking status using multiple linear regression analysis did not affect these results. Whether a manual professional-grade weight scale or a digital scale was used, the results were consistent throughout the study.  and premature death, creating a great economic burden [16]. Hispanics tend to have less access to scheduled healthcare services, decreased medical compliance, and are twice as likely to visit the emergency room as the general population [17]. Because Hispanics have the highest uninsured rates in the U.S. and most of them belong to low-income families, an emphasis on prevention can yield greater health benefits for this rapidly growing population. Food plays a central role that accounts for the high prevalence of obesity, hypertension, and diabetes, among Hispanics [18]. Thus, early detection of poor lifestyle habits, such as an obesity-promoting diet, should be addressed diligently, which will allow more time to plan and monitor the progress of patients. These results indicate that clinicians should consider the use of the MED with their Hispanic patients, as an effective primary prevention strategy to improve their BMIs. Clinical studies demonstrate the linear relationship that exists between systolic blood pressure and BMI, and that having a BMI lower than 25 kg/m 2 is a promising primary prevention strategy in addressing hypertension [19]. Thus, implementing the Mediterranean diet, as a positive moderator of BMI, may be effective in the prevention and management of chronic diseases. In addition, this study found that the improvement in quality of life was greatest in those who reported stronger adherence to the Mediterranean diet. One possible explanation for this result is that the MED is rich in anti-inflammatory and antioxidant phytonutrients, which help decrease the low-grade, systemic inflammation in individuals with obesity [20]. Thus, the decrease in inflammatory burden and oxidative stress results in systemic improvement in physiology and metabolic function. The Mediterranean diet provides a dietary basis that corrects many of the pathophysiologic mechanisms of obesity, diabetes type 2, and coronary heart disease [21].

Discussion
Although other research studies have underscored the health-promoting benefits of the MED, this study adds the practicality and efficacy of this nutritional therapy in working with the Hispanic population. Prompt action from clinicians and health professionals is needed to address obesity in Hispanics, since pedia-International Journal of Clinical Medicine tric obesity is also higher among Hispanics [22]. Unless aggressive preventive measures and policies are set in motion, this generational obesity-gradient will continue to devastate many lives, strengthen racial/ethnic disparities, and increase healthcare cost. Most Hispanic women with pre-obesity and obesity have serious weight-related medical problems, thus addressing the obesity epidemic among Hispanic women and minorities in general should be America's number one public health priority.
While the sample size of this study was one of the main limitations, this study had five major strengths. First, the sample was representative of the general Hispanic population in the United States, which is characterized by low socioeconomic status. Second, the completion rate of the nutrition program by the subjects was high. Third, adjustment for potential confounders was performed to ensure the validity of the results. Fourth, the study is recent and reflects current health behavior trends in regions with high density of Hispanics. Finally, this study confirms that it is possible to achieve significant changes in BMI in a short period of time, by employing an interdisciplinary approach that includes social support and weekly nutritional assessments. The clinical and public health relevance of these findings are emphasized by the fact that lifestyle factors strongly influence the development of chronic diseases, thus promoting and educating underserved populations can produce remarkable changes in the health of these individuals. By further exploring and promoting the health-enhancing benefits of the Mediterranean diet, health professionals and clinicians will continue to make important contributions to stop the obesity epidemic that is disproportionately affecting minorities and accentuating health disparities.

Sources of Support
No sources of financial support were involved that could influence the results of this study.

Data Share
Data described in this manuscript will be made publicly and freely available without restrictions at the URL indicated by this journal.

Funding
No source of funding was involved that influenced the results of this study.

Conflict of Interest
Author Eloy Espinoza, MD, MPH declares that he has no conflict of interest.

Ethical Approval
All procedures performed in this study were done in accordance and acceptance with the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Are you regularly exposed to second-hand smoke?