Exclusive olive oil use is associated with lower 20-year cumulative type 2 diabetes incidence across BMI categories and Mediterranean diet adherence trajectories in ATTICA study

Despite the recognized role of diet in type 2 diabetes (T2D) prevention, evidence on the long-term association between olive oil consumption and T2D remains limited. The ATTICA study included 2000 adults free of CVD and T2D at baseline and followed them for 20 years. Dietary intake was assessed using a validated FFQ, and participants were classified into three olive oil use categories (no, mixed and exclusive olive oil use). Exclusive olive oil use was associated with lower 20-year cumulative incidence of T2D (OR = 0.51, 95%CI: 0.33–0.80, p = 0.004), with stronger associations among overweight (OR = 0.45, 95%CI: 0.22–0.91) and obese participants (OR = 0.23, 95%CI: 0.07–0.73). The association was also significant among participants with persistently low Mediterranean diet adherence (OR = 0.29, 95%CI: 0.11–0.80, p = 0.016). Exclusive olive oil use may represent a simple and sustainable dietary strategy associated with lower long-term odds of developing T2D, particularly among metabolically vulnerable individuals overall.