Red meat consumption has long been associated with an increased risk of type 2 diabetes mellitus (T2DM). However, whether changes in red meat intake are associated with subsequent T2DM risk remains unknown. To assess the relationship between changes in red meat consumption over a 4-year period and the subsequent 4-year risk of T2DM in US adults, Professor AnPan and his team from the Harvard School of Public Health conducted a study that found that long-term increases in red meat intake were associated with an increased risk of type 2 diabetes later in life, and that this association was partially mediated by body weight. The results of this study provide further evidence of the benefits of long-term red meat restriction for T2DM prevention. The findings were published online in the June 17, 2013 issue of JAMAinternalmedicine.
The study was a three-cohort prospective cohort study among men and women in the United States. 26,357 men were followed in the Health Professionals Follow-up Study (1986-2006), 48,709 women were followed in the Nurses’ Health Study (1986-2006), and 74,077 women were followed in the Nurses’ Health Study II (1991-2007). Diets were assessed using a validated food frequency questionnaire and were not updated once every 4 years. Risk ratios corrected for age, family history, race, marital status, initial red meat intake, smoking status, and initial and change in other lifestyle factors (physical activity, alcohol intake, total energy intake, and dietary quality) were calculated using time-dependent Cox proportional risk regression models. Results of the crossover cohort were pooled using inverse variance-weighted, fixed-effects meta-analysis. The main evaluation metric was the use of a supplementary questionnaire to confirm cases of T2DM occurrence.
The results of this study showed that 7540 cases of developing T2DM were recorded during the 1965,824 person-years of follow-up. In multivariable correction models, across cohorts, increased red meat intake during the 4-year interval was associated with an increased risk of T2DM during the subsequent 4-year period (all P trends <0.001). Compared with controls with no change in red meat intake, an increase in red meat intake of 0.50 or more servings per day was associated with a 48% increased risk of T2DM during the subsequent 4-year period (combined risk ratio, 1.48; 95% CI, 1.37-1.59), and this association was moderately attenuated after further correction for initial body mass index and concurrent weight gain (1.30; 95% CI, 1.21 -1.41). A reduction in red meat intake of more than 0.50 servings per day from baseline to the first 4-year follow-up was associated with a 14% reduction in the risk of T2DM throughout the subsequent follow-up to 2006 or 2007 (combined risk ratio, 0.86; 95% CI, 0.80-0.93). This study found that increased long-term red meat intake was associated with an increased risk of type 2 diabetes later, and that this association was partially mediated by body weight. The results of this study provide further evidence that long-term red meat restriction provides a benefit for T2DM prevention.