London—People who drink coffee are less likely to develop primary late onset blepharospasm, according to results of a multicenter case control study conducted in Italy and published online ahead of print in the Journal of Neurology Neurosurgery and Psychiatry.

One to two cups per day were needed for the protective effect to be seen, and the effect was proportional to the amount of coffee consumed. Also, the age of onset of the eye spasm was found to be later in patients who drank more coffee: 1.7 years for each additional cup per day.

Previous studies have suggested that smoking protects against development of blepharospasm, but this study did not show a significant protective effect.

The study included 166 patients with primary late onset blepharospasm. Serving as controls were 228 patients with hemifacial spasm and 187 people who were relatives of patients.

“The most obvious candidate for the protective effect is caffeine, but the low frequency of decaffeinated coffee intake in Italy prevented us from examining the effects of caffeine on blepharospasm,” the authors wrote.

Caffeine may block adenosine receptors, they proposed.

“Considering that the caffeine content of a cup of Italian coffee (60 to 120 mg) is similar to the average content of a cup of American coffee (95 to 125 mg), the protective effect on the development of blepharospasm might be exerted at caffeine doses greater than 120 to 240 mg, comparable with the caffeine doses suggested to be protective in Parkinson’s disease,” according to the authors.