Associations between headache and stress, alcohol drinking, exercise, sleep, and comorbid health conditions in a Japanese population

This cross-sectional large survey of headaches in a Tokyo population showed that men and women shared several factors associated with headache, but that women were much more susceptible to headaches. A multivariate analysis demonstrated that age, self-estimated degree of stress, reported number of comorbid poor health conditions, and less alcohol consumption were independently related to having headaches in both men and women. Since we used a simple questionnaire to ask subjects to indicate if the item “I have headaches” applied to them, it is impossible to classify the types of headaches in this study. One of the authors (M.Y.), a board-certified neurologist, informed the workers of a Tokyo company about the results of the health checkup and interviewed all 99 workers (29 men and 70 women aged 20–59 years; 7.0% of the present headache sufferers) who had replied that the questionnaire item “I have headaches” applied to them during the health checkup. Based on the information obtained during the interview, the author classified their headaches according to the International Classification of Headache Disorders, 2nd edn (ICHD-II) [7]. Migraine was diagnosed in 67% of them, tension-type headache in 20%, migraine with tension-type headache in 11%, and unspecified in 3%. The proportion of the subjects of this study who reported headaches was 5.4% of men and 15.4% of women. Large Japanese population-based studies have reported migraine headaches in 2.3–3.6% of men and 9.1–12.9% of women [8, 9], and the distribution of the subjects with headaches according to age in the present study was similar to that of the subjects who had migraine in these studies. Although we did not ask the time frame of the headache, these findings suggest that chronic headache sufferers tended to report that the item “I have headaches” applied to them and that a high proportion of the headache sufferers in our study had migraine. The subjects in this study consisted of workers or residents of Tokyo or neighboring areas, who had received an annual health checkup and who were more likely to be middle-aged women, probably in the middle-to-high socioeconomic bracket. These background factors at least partially explain the somewhat high headache prevalence in the subject population.

We confirmed that stress is a major precipitating factor of headaches, a finding consistent with the results of previous cross-sectional studies [10, 11] and a recent prospective study [12]. The present study also demonstrated a stepwise inverse relationship with ability to relieve stress as well as a positive association with stress level in both men and women. The two self-estimated aspects of stress had the greatest impact of all of the factors associated with having headaches in this study. Although in contrast to other quantifiable variables, self-estimated classification of stress may differ between men and women, the association between stress and headache was stronger in men than in women.

Previous studies have shown an association between the occurrence of headaches and the presence of pain elsewhere in the body [3, 4]. The present study demonstrated that headache sufferers not only tended to complain of other pain, but to report a variety of poor health conditions, and that having headaches was clearly associated with the number of poor health conditions in a stepwise fashion in both men and women. Increasing numbers of other painful areas [4] and combinations of chronic musculoskeletal complaints, gastrointestinal complaints, and psychiatric symptoms [13] have been reported to have a greater impact on the likelihood of headache occurrence. Whether the association is causal or the poor health conditions and headache share common background factors are topics for future research. However, since the comorbid conditions were all self-reported in a questionnaire, some of the strong associations between headache and poor health conditions may have been partly influenced by a tendency to answer all questions regarding complaints in a similar way (“reporting bias”) [13]. Further study is needed to clarify the associations by assessing the comorbid conditions in a more objective way.

The present study demonstrated an inverse dose–response relationship between headaches and alcohol consumption in both men and women. Previous data for the association have been less clear [4, 9‐11, 14, 15], but a large population-based cross-sectional study in Norway showed a tendency for the prevalence of headache to decrease with increasing alcohol consumption [16], and another large population-based cross-sectional study in the Netherlands showed that migraine sufferers were less likely to consume alcohol [17]. A recent prospective analysis of migraine sufferers in Austria showed that consumption of beer reduced the risk of headache and migraine, as well as the risk of headache persistence [12]. Our findings are consistent with the results of these studies. In the Norwegian study only 3% of the subjects reported drinking >14 standard units of alcohol per 2 weeks, whereas in our study 48% of the men and 12% of the women reported drinking ≥22 g ethanol per day. The drinking behavior of the Japanese is strongly governed by the Asian genetic polymorphism of ALDH2. ALDH2 genotyping among a subgroup of the present study population showed a much higher frequency of ALDH2-deficient individuals among the non/rare drinkers than the drinkers (75 vs. 33% of the men and 57 vs. 20% of the women). ALDH2-deficient individuals are more sensitive to alcohol flushing responses [18] and hangover [5, 6], in both of which headache is a major symptom. Intake of alcoholic beverages has been reported to be an aggravating factor of headache [4], especially migraine [19] and cluster headache [20]. Individuals with migraine have a higher risk of delayed alcohol-induced headache than those without it [21]. Possible mechanisms by which alcohol induces headache [22, 23] include a vasodilatory effect on the intracranial vasculature, altered cytokine pathways [24], endocrine and immune system disturbance, toxic effects of congeners, and acetaldehyde-mediated changes [5, 6, 18]. Japanese headache sufferers with inactive ALDH2 may be more vulnerable to severe alcohol-induced or hangover headache, than those without inactive ALDH2, and must avoid alcohol drinking. Another possible explanation of the inverse association between headache and alcohol drinking is related to the development of tolerance for headache in drinkers. Habitual drinking leads to the development of tolerance for alcohol-induced headache [6], which may affect the mechanisms by which common headaches occur. Third, non-drinking may influence other lifestyle factors associated with headache, since alcoholic beverages serve as a stress reliever or sleep aid in some persons. Further in-depth study of the association between headache classification and drinking habit is needed.

Furthermore, possible interactions between the ALDH2 genotype, alcohol consumption, and headache prevalence in Japanese subjects may differ according to the headache classification. We have developed a screening test for inactive ALDH2 that consists of the following two questions about current and past facial flushing: (1) Do you have a tendency to flush in the face immediately after drinking a glass (approximately 180 ml) of beer? (2) Did you have a tendency to flush in the face immediately after drinking a glass of beer during the 1st to 2nd year after you started drinking? When current or former flushing individuals were assumed to have inactive ALDH2, both the sensitivity and specificity of the test were approximately 90% among both Japanese men and women 40 years of age or more [25]. We are now conducting a large cross-sectional study in Tokyo workers by using the simple flushing questionnaire, a drinking questionnaire, and a headache questionnaire designed to diagnose headache type according to the ICHD-II criteria.

An inverse association between headaches and walking/exercise was observed in the present study, and the strength of association was somewhat greater in men than in women and was most prominent among the subjects who reported a walking/exercise frequency of “2 days/week”. A study conducted in Denmark reported a significant association between low physical activity and tension-type headache in men, but not in women or in subjects with migraine [10]. Physical activity influences several factors, including stress, stress release, muscle strength, and prostaglandin and hormone levels [26], and further epidemiological and mechanistic studies are required. In our study, both less sleep and excessive sleep in men and less sleep in women were positively associated with having headaches, findings consistent with those of previous studies [27, 28].

In conclusion, although women were more susceptible to headache, Japanese men and women in Tokyo shared factors associated with headache, including age, stress, having other poor health conditions, alcohol consumption, sleep, and exercise.