FABP2 and Parkinson disease: No within-participant temporal effects were detected, apart from a significant interaction between PD status and time (P = 0.04) for I-FABP, with a trend to increasing concentration in PD compared with the remainder (by mean 1.06 [0.98, 1.14] cf 0.95 [CI 0.89, 1.01] pg/ml/y).