TOPLINE:

A higher intake of folate and vitamin B6 years before diagnosis of Parkinson’s disease (PD) was associated with reduced risk for mortality, whereas intake after diagnosis provided no survival benefit, new research showed. The protective effect was strongest with intake 12-16 years before diagnosis, especially from supplemental sources.

METHODOLOGY:

• Researchers assessed data from two large prospective cohort studies in the US: the Nurses’ Health Study and the Health Professionals Follow-up Study. They included more than 1500 patients with newly diagnosed PD (54% men) who had complete dietary data and a matched control cohort without PD.
• The cumulative average intakes of folate, vitamin B6, and vitamin B12 from dietary and supplemental sources were categorized into quartiles and assessed using participant-reported validated Food Frequency Questionnaires, with data collected in 1984 and 1986 and every 4 years thereafter; the last prediagnostic questionnaire was completed a median of 2.3 years before diagnosis.
• The mean age at diagnosis of PD was 72.8 years in women and 73.8 years in men. During 15 years of follow-up, there were 1005 deaths, 530 of which were PD-specific.
• The primary outcome was all-cause mortality. PD-specific mortality was also compared between the top and bottom quartiles before and after disease diagnosis.

TAKEAWAY:

• A higher cumulative average intake of folate and vitamin B6 before diagnosis was associated with a lower risk for all-cause mortality (adjusted hazard ratio [aHR], 0.78; P = .04; and aHR, 0.76; P = .03, respectively); this association was strongest for intakes up to 12-16 years before diagnosis.
• The cumulative average intake of vitamin B12 was linked to a nonsignificant reduction in mortality risk (aHR, 0.86), but stronger associations were observed for the intake of vitamin B12 from supplements (HR, 0.75).
• Intake of folate, vitamin B6, or vitamin B12 after a diagnosis of PD was not significantly associated with all-cause or PD-specific mortality.
• In the matched control group, a higher intake of folate was linked to lower risk for mortality (HR, 0.78), whereas intakes of vitamins B and B12 were not.

IN PRACTICE:

“Our findings suggest that B vitamins, which are inexpensive, safe, and easy to administer, could be considered as potential interventions in these trials. The impact of postdiagnostic intake of these vitamins warrants further investigation,” the investigators wrote.

SOURCE:

The study was led by Xinyuan Zhang, PhD, Brigham and Women’s Hospital and Harvard Medical School, Boston. It was published online on January 12 in Movement Disorders.

LIMITATIONS:

The study’s observational design may have led to residual confounding, particularly because the strongest associations were observed for supplemental intakes. Dietary intake was self-reported and may not have fully reflected true bioavailability or plasma levels. The study population consisted primarily of White individuals with good nutritional status, limiting the generalizability of the results. Selection bias may have existed if a higher intake of vitamin B was directly related to death or study dropout before diagnosis of PD. Additionally, potentially beneficial timepoints of vitamin B intake, such as during the onset of prodromal symptoms or at the start of dopaminergic therapy, were not assessed. 

DISCLOSURES:

This study was funded by the National Institutes of Health. The investigators reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.