Caffeine consumption, chronic headache linked

The use of caffeine in its dietary or medical forms appears to be a modest risk factor for the onset of chronic daily headache, regardless of the type of headache, a population based study in Neurology concludes. Chronic daily headache (CDH), defined as headache occurring >=15 days/month, is regularly associated with medication overuse, note Ann Scher and colleagues in their report. The role of caffeine in its development is of interest because of wide exposure to the chemical in its dietary and medicinal incarnations. It is the only substance shown to cause withdrawal headache under placebo-controlled double-blind conditions, so caffeine consumption and withdrawal headache might contribute to the development of CDH, although analytic epidemiologic studies are lacking, they note.To investigate the possible association they recruited population-based cases and controls from the Baltimore, MD, Philadelphia, PA, and Atlanta, GA, metropolitan areas. Overall, the 507 controls reported 2 to104 headache days/year, and the 206 cases reported >=180 headache days/year. Participants were asked about their current and past dietary caffeine consumption and medication use for headache. High caffeine exposure was defined as being in the upper quartile of dietary consumption or using a caffeine-containing over-the-counter analgesic as the preferred headache treatment."In comparison with episodic headache controls, CDH cases were more likely overall to have been high caffeine consumers before onset of CDH," the authors report. "No association was found for current caffeine consumption (i.e., post CDH)."Further analysis revealed associations in younger (age "This association might indicate a causal relationship between caffeine consumption and CDH onset or might be secondary to unmeasured confounding factors. For example, sleep disturbances and depression are related to caffeine consumption and are possible predisposing factors for CDH development for some individuals. Although the relationships reported herein remained similar after adjusting for current depression and current sleep problems, we do not have data on the pre-CDH status of these factors," they conclude.Reference...