Journal Wrap: Increasing Red Meat Intake Boosts Diabetes Risk

Studies have consistently shown that a diet high in red meat is linked with an elevated risk of developing type 2 diabetes mellitus (T2DM), but, in a long-term study recently published in JAMA Internal Medicine, An Pan, PhD, and colleagues questioned whether this risk would be impacted by changes in red meat consumption over time.

Rather than analyzing intake at a single point in time, the investigators of the current study collected repeated measurements of participants' diet, lifestyle factors, and medical histories every 4 years, from three cohort studies—the Health Professionals Follow-up Study, the Nurses' Health Study, and the Nurses' Health Study II. Overall, 1,965,824 person-years of follow-up were analyzed. In what the authors call "a natural experiment," or one in which individuals chose to change their diets and lifestyles without investigator-initiated interventions, several of the investigators' assumptions proved correct: increasing red meat intake was related to concurrent weight gain, increases in total energy (caloric) intake, and decreases in diet quality scores. Decreases in red meat consumption, however, had the opposite effect: reducing red meat by more than 0.50 servings per day from baseline led to a 14% lower risk during the entire subsequent follow-up.

Compared with individuals' whose red meat intake remained stable within each 4-year period, those who increased intake by more than 0.50 servings per day sustained a 48% higher risk in the subsequent 4-year period. Importantly, this increased risk was independent of initial red meat intake or modifications to other lifestyle factors, such as overall diet quality and body weight.

When Dr. Pan and colleagues adjusted the hazard ratios for BMI, there was a slight attenuation of the T2DM risk (pooled HR = 1.30; 95% CI 1.21-1.41), suggesting that the increased risk may be partly mediated through obesity and weight gain. "It is possible that obese individuals are already at a high risk of T2DM because of their body weight and higher initial red meat intake, and increasing red meat intake has only a modestly deleterious effect on the relative scale," they wrote. "However, the absolute risk associated with red meat intake among obese individuals is much greater, and thus limiting their red meat intake is still beneficial."

Pan A, Sun Q, Bernstein AM, et al. JAMA Intern Med. 2013 June 17. [Epub ahead of print]

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