Coffee-drinking has eye-opening effect on blepharospasm

Keypoints:

A previous study had linked a beneficial effect on blepharospasm with cigarette smoking but had not accounted for caffeine intake in the analysis. In light of this analysis, Giovanni Defazio, MD, and colleagues undertook a study in which they assessed both factors.

"The data do not mean that we should be addressing our coffee intake. Rather, they offer new areas of research. If we are able to determine the exact mechanism of action, they would help in the development of treatments or preventive measures," said Dr. Defazio, associate professor of neurology, Department of Neurological and Psychiatric Sciences, University of Bari, Italy.

The participants were asked to supply information about their having previously ingested caffeinated coffee or smoked cigarettes. Those who replied in the affirmative were asked when they began and whether they had quit smoking or drinking coffee before the reference age, which was defined as the age of onset of dystonia or hemifacial spasm for case and hospital control patients, respectively.

The reference age of the population control subjects was obtained by subtracting the average disease duration of case subjects included in the corresponding age stratum from the age of the control subjects, the investigators explained. The number of years of coffee drinking or smoking, and the average daily number of cups of coffee or packs of cigarettes (one pack = 20 cigarettes) also were recorded.

Coffee link identified

The results of the study, which were reported in Neurology Neurosurgery and Psychiatry (2007;78:877-879), indicated that after adjusting for patient age, sex, referral center, disease duration, years of schooling, and years of coffee consumption or cigarette smoking, as appropriate, the effect of smoking was found not to be significant. A significant association, however, was found between drinking coffee and a beneficial effect on blepharospasm (cases versus hospital control patients: odds ratio, 0.37; 95% confidence interval, 0.20 to 0.67, and cases versus population control subjects: odds ratio, 0.44; 95% confidence interval, 0.23 to 0.85), the investigators reported.

Case patients reported that they drank a significantly lower mean number of cups of coffee per day compared with the hospital and population control subjects (1.8 cups versus 2.44 cups, respectively). In contrast, case patients and control subjects reported smoking a similar mean number of packs of cigarettes per day (0.92 pack versus 0.79 pack, respectively).