Coffee Decreases Parkinson’s Tremors in Men, Study Suggests

Drinking coffee may reduce tremors in Parkinson’s disease patients, but only among men, a recent study suggests.

The study, “Sex-dependent Effects of Coffee Consumption on Newly Diagnosed Parkinson’s Disease,” was published recently in the journal BMC Neurology.

There is some evidence that drinking coffee reduces the risk of developing Parkinson’s disease, but the effect of coffee on motor symptoms in people who already have been diagnosed with Parkinson’s is less clear.

In this study, researchers recruited Parkinson’s patients (137 women, 147 men) and divided them into two groups: coffee drinkers (204 people), which included anyone who drinks coffee regularly, or used to, even if they don’t anymore, and; non-coffee drinkers (80 people) who never regularly drank coffee.

Compared to the non-coffee drinkers, coffee drinkers were disproportionately younger, male, better-educated, and were younger at symptom onset. Coffee drinkers had less motor impairment, as demonstrated by lower scores on the motor section of the Unified Parkinson Disease Rating Scale (UPDRS; 19.46 vs. 22.84); this included significantly lower scores for tremor (2.48 vs. 3.64), bradykinesia (slow movement; 2.48 vs. 10.83) and gait and posture (0.78 vs. 1.16).

Of note, resting tremor occurs when a person’s hands, arms, or legs shake even when they are at rest; action tremor occurs with the voluntary movement of a muscle.

When the researchers included other factors (age, sex, etc.) in their model, most of these differences were no longer statistically significant. However, tremor scores were still significantly lower among coffee drinkers. More specifically, coffee drinkers had significantly lower scores for tremors at rest (1.49 vs. 2.41), whereas scores for action tremors were not very much  different between the two groups once other variables were taken into account.

Furthermore, this association was dose-dependent. That is, the more coffee participants reported drinking, the lower their tremor scores tended to be.

Researchers then divided the patients by sex and performed a similar analysis. Interestingly, tremor scores were significantly lower among male coffee drinkers as compared to male non-coffee drinkers, but this association was not statistically significant for females. This suggests sex-dependent differences on the effects of coffee in Parkinson’s patients.

The researchers speculated that such differences may be attributable to hormones that are typically present at different levels between the sexes, most notably estrogen. But further research will be needed to determine whether this idea holds water.

“Coffee consumption and tremor severity are inversely related in male patients with de novo [Parkinson’s disease],” the researchers wrote. “Further investigations are needed to reveal the exact causal relationship between coffee consumption and tremor in [Parkinson’s disease] patients,” they added.