Relationship between estimated dietary consumption of linoleic acid and arachidonic acid and their circulating concentrations in plasma phospholipids, evaluated using restricted cubic splines and adjusted for age, gender, race, BMI, and use of lipid lowering medications. The solid lines and shaded areas represent the central risk estimates and 95% CIs, respectively. Median intakes of linoleic acid and arachidonic acid were 6% of total energy (14.1g/day) and 0.08% of total energy (0.17g/day), respectively. Strong evidence was seen for both overall positive association (P < 0.001) and nonlinearity (P < 0.001) of the relationship between dietary and circulating linoleic acid. In contrast, little evidence of either an overall relationship (P = 0.24) or nonlinearity (P = 0.40) was evident for dietary and circulating arachidonic acid.