Mediterranean Diet Gets New Backing for Mortality Reduction

CAMBRIDGE, England, Dec. 10 -- High adherence to the Mediterranean diet appears to reduce both all-cause and disease-specific mortality, found a prospective cohort study. The NIH-AARP Diet and Health Study showed clear and significant inverse associations between high conformity to the Mediterranean diet and all-cause and cause-specific mortality, Panagiota N. Mitrou, Ph.D., of the University of Cambridge, and colleagues reported in the Dec. 10 issue of the Archives of Internal Medicine.
Action Points --->
Explain to patients that this cohort study added to a large body of evidence that shows that eating a healthy diet rich in vegetables, nuts, legumes, fruit, and fish can reduce their risk of death from CVD, or cancer, and promote a healthier and longer life.
Explain to patients who smoke that this study found that adhering to a healthy diet, specifically the Mediterranean diet, will benefit them by reducing their risk of death from cardiovascular disease, cancer, or all-causes.
The data among women, for example, showed a 22% decreased risk for all-cause mortality (P<0.001 for trend); a 14% decreased risk for cancer mortality (P=0.01 for trend); and 21% reduced risk for death due to cardiovascular disease (P=0.01 for trend) associated with "high conformity" to the diet.
The multivariate hazard ratios (HR) for high versus low compliance in men for all-cause mortality, cardiovascular mortality, and cancer mortality were 0.79 (95% confidence interval: 0.76 to 0.83), 0.78 (95% CI: 0.69 to 0.87), and 0.83 (95% CI: 0.76 to 0.91), respectively.
Additionally, when the scores were analyzed in one point increments, a 5% decrease (P<0.001) in all-cause mortality in men and women was evident. The authors also reported that, when smokers were excluded from the analysis, "associations were virtually unchanged."
The study included 214,284 men and 166,012 women, all members of the American Association of Retired Persons living in California, North Carolina, New Jersey, Pennsylvania, Florida, and Louisiana. The investigators used the so-called alternate Mediterranean diet. The alternate diet differs from the traditional Mediterranean diet in that it separates fruit and nuts into two groups, eliminates dairy, includes only whole grains, only red and processed meat (beef, pork, luncheon meats, and organ meats), and uses the same alcohol range for men and women (5-25 g/d).
Participants with chronic illnesses, including diabetes, renal disease, cardiovascular disease, and cancer, were excluded from the cohort. The study began in 1995-1996 with the administration of a questionnaire on demographic and health-related behaviors to 50 to 70-year-old members of the AARP. Data were available from 566,407 participants. Follow-up for all-cause mortality continued until Dec. 31, 2005.
During the initial five years of follow-up, from 1995-96 to 2000-2001, 12,105 deaths occurred, including 5,985 attributable to cancer, and 3,451 to cardiovascular disease. During the next five years of follow-up the mortality rate totaled 27,279 (18,126 men and 9,673 women).
The authors reported data largely from alternate Mediterranean diet score analyses because those results were modified for use in a U.S. population.
Greater conformity to the diet among men correlated with older age, body mass index from 18.5 to 30.0, higher levels of physical activity and education, being married, and not smoking. In women, the pattern was similar to that of men. However, marital status was not associated with conformity, while the use of menopausal hormone therapy was.
Data from a sensitivity analysis done using alternate sex-specific cut points showed that, while the distribution shifted toward a lower conformity overall, a higher conformity to the modified score was still associated with a significant risk reduction for all-cause mortality in both men and women.
Further, data from a stratified analysis of all-cause mortality in subgroups organized by smoking status and BMI showed a pronounced inverse relationship among smokers, "and especially among smokers with normal BMI (18.5-25.0)," the authors noted. Among men, the multivariate HR for high versus low conformity was 0.54 (95% CI: 0.50 to 0.59), and in women, the multivariate HR was 0.59 (95% CI: 0.53 to 0.66).
The authors concluded that while there is the possibility that the scoring system they used may not "adequately represent conformity with the traditional Mediterranean diet, it does include the key features of this diet and … may have a substantial beneficial impact on mortality in the United States." These data confirm those reported from earlier European studies.
This study was funded by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Division of Cancer Epidemiology and Genetics.
Primary source: Archives of Internal MedicineSource reference:Mitrou P, "Mediterranean dietary pattern and prediction of all-cause mortality in a U.S. population" Arch Intern Med 2007; 167: 2461-68.