Fig. 4: A non-linear relationship between tea consumption and incident dementia.

There was a U-shaped association between tea consumption and incident dementia, and the consumption of around three cups per day showed the strongest protective effect (P for non-linearity = 7E^-04). P-value was computed using restricted cubic splines functions in the Cox proportional hazard regression model. The model was adjusted for age, sex, ethnicity, TDI, education, BMI, typical sleep duration, smoking status, alcohol status, total consumption of vegetables, total consumption of fruit, total consumption of fish and APOE4 status. HR Hazard ratios, CI Confidence interval, TDI Townsend deprivation index, BMI Body mass index, APOE4 apolipoprotein E4.