Objective: The potential influence of dietary factors on inflammation is important for cancer prevention. Utilizing data from control participants (312 men, 911 women) in 2 nested case-control studies of cancer within the Multiethnic Cohort, we examined the associations of red and processed meat intake with serum levels of leptin, adiponectin, C-reactive protein (CRP), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 and the mediator effect of body mass index (BMI) on the above associations (if present).
Methods: Multivariable linear models were applied to assess the association between red and processed meat intake at cohort entry and serum biomarker levels measured 9.1 years later after adjusting for covariates and to determine the mediator effect of BMI.
Results: Overall red and processed meat intake was positively associated with serum leptin levels in men (β = 0.180, p = 0.0004) and women (β = 0.167, p < 0.0001). In women, higher red and processed meat consumption was significantly associated with higher CRP (β = 0.069, p = 0.03) and lower adiponectin levels (β = -0.082, p = 0.005). In mediation analyses with red and processed meat intake and BMI as predictors, the associations of red and processed meat with biomarkers decreased substantially (as indicated by percentage change in effect: leptin in men, 13.4%; leptin in women, 13.7%; adiponectin in women, -4.7%; CRP in women, 7.4%) and were no longer significant (p > 0.05), whereas BMI remained significantly associated with serum leptin (men: β = 3.209, p < 0.0001; women: β = 2.891, p < 0.0001), adiponectin (women: β = -1.085, p < 0.0001), and CRP (women: β = 1.581, p < 0.0001).
Conclusion: The current data suggest that the amount of excess body weight or the degree of adiposity may mediate the relations between dietary red and processed meat intake and serum biomarkers associated with obesity and inflammation.
Keywords: Red and processed meat; adiposity marker; body mass index; inflammation marker; mediator effect.