Suche
Relation
O'Connor LE, Hu EA, Steffen LM, Selvin E, Rebholz CM. Adherence to a Mediterranean diet and diabetes risk in a prospective cohort study in the USA.Nutr diabetes. 2020;10:8.
Study objective
The aim of this study was to assess whether Mediterranean eating habits would be associated with diabetes risk in a large, nationally representative US cohort of black and white men and women.
Draft
Observational study using the Alternate Mediterranean Diet (aMed) scores to assess the level of adherence to a Mediterranean diet while tracking a new diagnosis of diabetes. Researchers followed participants for a median of 22 years. They used Cox regression models to characterize associations of aMed with incident diabetes, adjusted for energy intake, age, sex, race and study center, and education for all participants and then stratified by race and body mass index (BMI).
Participant
The study included participants from the prospective cohort of the Atherosclerosis Risk in Communities Study without diabetes, cardiovascular disease, or cancer at baseline (N = 11,991; mean age 54 years, 56% female and 75% white). Participants were selected from 4 U.S. communities.
Study parameters assessed
Adherence to the Mediterranean diet assessed using the validated aMed score and incidence of diabetes.
Primary outcome measures
Over a median follow-up of 22 years, there were 4,024 cases of diabetes.
Key insights
Higher aMed scores were associated with a lower risk of diabetes (0.83 [0.73–0.94] for Q5 vs. Q1 [P<0.001]and 0.96 [0.95–0.98] for 1 point higher). Associations were stronger for black vs. white participants (0.74 vs. 0.87 for Q5 vs. Q1 and 0.95 vs. 0.97 for 1 point higher; interactionP<0.001); and weaker for obese vs. normal BMI (0.88 vs. 0.80 for Q5 vs. Q1 and 0.98 vs. 0.94 for 1 point higher; interactionP<0.01).
Practice implications
The Mediterranean diet (Med diet) is rich in fruits, vegetables, whole grains, legumes, nuts, fish and extra virgin olive oil (EVOO). It has been proven to be an effective dietary pattern for reducing many chronic diseases including diabetes mellitus (DM),1coronary heart disease,2neurodegenerative diseases,3and cancer.4Many of the large-scale studies conducted on the Med diet have used Mediterranean populations, raising the question of whether this dietary pattern would have the same beneficial results in a US population. Genetics and lifestyle are known factors that influence clinical outcomes. The Mediterranean lifestyle tends to focus more on family and social networks, physical activity, protected sleep patterns and other arguably enjoyable activities such as shared meals, evening walks and regular vacations. The effects of the Mediterranean lifestyle have yet to be adequately studied, making it difficult to predict its contribution to the results of the Med diet study.
The Med diet may be of particular importance to the black community, as the study researchers found additional benefits of the Med diet in this population.
This well-designed, large observational study is based on 4 US populations (Washington County, Maryland; suburban Minneapolis, Minnesota; Jackson, Mississippi; and Forsyth County, North Carolina) and aims to clarify the effects of the Med diet on DM specifically in the US population. A significant decrease in the incidence of DM was noted among those with the highest adherence to the Med diet (17% decrease) compared to the lowest adherence. There was also a 4% decrease in DM incidence with every 1-point increase in adherence to the Med diet, suggesting that the better the adherence, the greater the benefit. Higher consumption of nuts and legumes, moderate alcohol consumption, and lower consumption of red and processed meat had the strongest associations with the observed benefits. While previous studies have also shown the benefit of the Med diet specifically in the US population,5.6The larger sample size of this study and the inclusion of 4 different US populations and both men and women and black and white populations give us a clearer indication of the benefits of the Med diet.
The Med diet may be of particular importance to the black community, as the study researchers found additional benefits of the Med diet in this population. This subset of the study showed a 26% decrease in DM incidence (versus 17% in all groups) for those with the highest versus lowest adherence to the Med diet and a 5% decrease in DM incidence (versus 4% in all groups) for every 1-point increase in adherence to the Med diet. Given the particularly high risk of DM in the black population,7This information is particularly relevant as we look for tools to prevent DM.
The obese population studied showed less benefit from adherence to the Med diet. While researchers found some benefit (12% decrease in the obese subgroup vs. 17% for all groups for highest vs. lowest adherence; 2% decrease vs. 4% for all groups for each 1-point increase), statistical significance was not reached. Achieving and maintaining optimal weight is a fundamental goal in preventing and treating DM. While studies show that the Med diet is an effective weight loss tool,8A personalized approach to achieving ideal weight (which may or may not include the Med diet) would be appropriate before introducing the Med diet to reduce DM incidence in the obese population.