Umeå University's logo

OBJECTIVES: Thiamine deficiency (TD) and phosphate depletion increase the risk for cognitive disturbances. This study investigates whether plasma levels of thiamine (P-THIAM), thiamine-monophosphate (P-TMP), and phosphate (P-PHOS) are associated with mild cognitive decline (MCI) in patients with Parkinson's disease (PD).

DESIGN AND STUDY POPULATION: This case-control study includes baseline data from a cohort of newly diagnosed patients identified in the New Parkinsonism in Umeå study (NYPUM) (N = 75) and an age and sex matched control group (n = 24).

MEASUREMENTS: Mini Nutritional Assessment (MNA-score) and concentrations of P-THIAM, P-TMP, and P-PHOS at baseline were compared between PD patients with mild cognitive impairment (PD-MCI) and PD patients with normal cognition (PD-NC). Neuropsychological assessments of MCI were performed at time of diagnosis.

RESULTS: Compared to patients with NC, patients with MCI had lower levels of P-THIAM and P-TMP as well as lower scores on both the Mini Mental State Examination (MMSE) and MNA-screening test. In addition, patients with MCI were older and had more motor problems. The multiple logistic regressions adjusted for age and sex revealed that higher levels of P-THIAM and the MNA-total score were associated with a lower risk of having MCI. Higher MNA-total score and higher P-THIAM and P-PHOS concentrations decreased the risk of MCI in male patients, but not in female patients. The decreased risk of MCI with higher P-TMP levels was lost after adding age and sex to the model. Bivariate correlations between P-PHOS and P-TMP were shown for the total PD population and controls as well as for males with MCI (r = 0.533; n = 22; p = 0.011), but not for males with NC (r = 0.314; n = 19; p = 0.204). An inverse partial correlation (adjusted for age, sex and UPDRS III) was shown for P-THIAM and MNA-total (r = -0.315,p = 0.009) and -final (part II) (r = -0.395,p = 0.001) score for the PD population (n = 75).

CONCLUSIONS: Higher P-THIAM and P-PHOS concentrations and higher MNA-total score were associated with a lower risk of MCI in male PD patients, findings that indicate that nutritional factors may influence cognitive function in males in the early phase of PD.