The natural history of headache: predictors of onset and recovery.

The objective of this study was to determine predictors of onset of new headache episodes and recovery from headache over one year. A population-based cohort study was conducted, comprising a baseline postal survey to a random sample of adults aged>or=18 years, with follow-up survey after 1 year. Risk factor data at baseline were compared with headache status at follow-up in two groups: (i) those free of recent headache at baseline and (ii) those with a recent headache at baseline. In respondents free of recent headache at baseline, previous headache [risk ratio (RR) 4.15], the presence of other pain at baseline (RR 1.43), severe sleep problems (RR 1.67) and drinking caffeine (RR 1.99) increased the risk of a new headache episode during the follow-up year. In respondents with recent headache at baseline, less severe headaches at baseline predicted recovery during the follow-up year, as did the absence of anxiety [recovery ratio (ReR) 2.84] and of sleep problems (ReR 2.77). Risks for increased headache-related disability reflected those for onset of a new episode and these risks increased in strength for large increases in disability. Sleep problems and caffeine consumption increase the risk of developing headache and thus provide targets for prevention. Low levels of anxiety, sleep problems and the absence of other pain improve the likelihood of recovering and remaining free from headache.