Dietary inflammatory potential and physical activity adherence as synergistic predictors of systemic inflammation in post-myocardial infarction patients: a retrospective cohort study

Background After a myocardial infarction (MI), one of the major factors responsible for bad outcomes is systemic inflammation. It is known that diet and physical activity (PA) have separate effects on inflammation, but it is still unclear what the combined effects are in patients who have already suffered a heart attack. Methods Over 6 months, 1,700 post-MI patients in this retrospective cohort study were monitored. The validated questionnaires assessed dietary intake and physical activity adherence, and patients were classified by DII (high vs. low) and PA adherence (high vs. low). Important biomarkers included high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF- α ), and a composite inflammation score. Multivariable regression analyses were performed. Results The group of patients classified as having low DII and high PA, showed the least amount of inflammation (hs-CRP: 2.31 ± 1.12 mg/L; IL-6: 3.8 ± 1.4 pg./mL; TNF- α : 4.7 ± 1.7 pg./mL; composite score: −0.72 ± 0.55), while the group with high DII and low PA ( n = 470) exhibited inflammation at its highest level (hs-CRP: 4.89 ± 2.05 mg/L; IL-6: 6.4 ± 2.3 pg./mL; TNF- α : 7.1 ± 2.5 pg/mL; composite score: +0.89 ± 0.74; p < 0.001). The multivariable analysis provided evidence of independent relationships between DII ( β = +0.18; p < 0.001) and PA ( β = −0.14; p < 0.001) and the composite inflammation score, as well as a notable interaction effect ( β = −0.07; p = 0.001). Conclusion The dietary inflammatory potential and PA adherence of the patients, both independently and in combination, could predict the level of systemic inflammation in post-MI patients. These findings support lifestyle interventions as the primary component of post-MI secondary prevention.