Physical exercise reduces risk of dementia

Exercise might help prevent cognitive decline in high-risk patients with early Parkinson's disease (PD), new research suggests.

Investigators found PD patients who were APOE ε4 carriers had greater cognitive decline compared to non-APOE ε4 carriers, but the findings also revealed higher physical activity appeared to slow cognitive decline in this higher risk group.

The study was published online March 31 in the journal Neurology.

The APOE ε4 allele is known to be a "major risk factor" for Alzheimer's disease (AD), but "accumulating evidence shows that this allele also has a potential role in cognitive impairment in PD," the authors note.

Previous research shows physical activity has beneficial effects in PD, but the mechanism underlying these effects are "not well understood." Additional data suggest physical activity modifies the APOE ε4 effect on the development and progression of AD.

The current analysis included 173 patients recently diagnosed with PD but not yet treated for the condition. The cohort's mean age was 63.3 ± 10.0 years, age of PD onset was 59.4 ± 10.0 years, and 68% were male. Of these participants, 46 were APOE ε4 carriers.

Dopamine transporter (DAT) activity was assessed using imaging at enrollment, and again at years 2 and 4. Cognitive function was assessed at years 2, 3, and 4 using the Montreal Cognitive Assessment (MoCA) test.

Although APOE ε4 carriers tended to be younger than noncarriers, the age of PD onset did not differ between the 2 groups, and there were also no significant differences between the groups in demographic and clinical variables.

There were larger declines in MoCA scores in the APOE ε4 carriers vs the noncarriers (0.21 ± 1.40 and 0.08 ± 1.15, respectively).

The APOE ε4 allele was associated with a "steeper" rate of cognitive decline, compared to the non-APOE ε4 allele (estimate −1.33 [95% CI, −2.12 to −0.47,P = .002).

There was a significant interaction of physical activity, APOE ε4, and time: higher physical activity was associated with slower APOE ε4-related cognitive decline (estimate 0.007 [0.003 to 0.011, P = .001).

Both high- and low-intensity exercise were significantly associated with slower APOE ε4-related cognitive decline.