Obesity and migraine: The effect of age, gender and adipose tissue distribution

Migraine is a common and often disabling disorder that occurs more commonly in adult women than men of all ages. Migraine or probable migraine has been estimated to occur in 34.5% of adult women and 20.1% of adult men in the general population.1 The relationship between migraine or other headache disorders and markers of cardiovascular disease has been a focus of research interest in recent years.2 In particular, general obesity or total body obesity (TBO), as estimated by the body mass index (BMI), has been shown to be related to headache disorders in several clinical and epidemiologic studies.3-9 However, there is considerable uncertainty about the nature of the obesity/headache relationship and whether it is specific to migraine, or chronic daily headache, or headache in general. In a general population study in 2003, individuals with TBO and episodic headache were shown to be at an increased risk of incident chronic daily headache over a 1-year period relative to those without TBO (odds ratio [OR] = 5.3 [1.4-21.8]).3 Yet data relating obesity and episodic migraine have been conflicting. Two clinic-based studies suggested that migraine occurs with a higher relative frequency in those with TBO than those without TBO.4,5 However, 2 general population-based studies of adults did not find a relationship between migraine and TBO.6,7 A third study found an association between TBO and headache but not self-reported migraine.8 Finally, a recent general population study found that TBO was associated with the prevalence of migraine or severe headaches.9 Several factors may contribute to these conflicting reports. First, all but one9 of the prior studies evaluating migraine prevalence and obesity estimated BMI based on self-reported height and weight. Multiple studies in various disorders have shown that BMI is commonly underestimated when self-reported as compared with when it is measured, including in migraineurs.10-13 This measurement error might obscure the true relationship between migraine and obesity if it is differential. Second, the degree to which anthropometric measurements (such as the BMI and waist circumference [WC]) correlate with adipose tissue mass vs lean body mass varies by both age and gender.8,12-15 Specifically, aging has been shown to be associated with a progressive increase in the ratio between fat and lean body mass – even in those who manage to maintain a constant BMI as they become older. Thus, the degree to which BMI is proxy measurement for total body fat is age-dependent.13-15 In addition, adipose tissue distribution patterns are different in women and men, with younger women having more adipose tissue depots in a gluteo-femoral distribution than abdominally, while men of all ages and older women have more abdominal adipose tissue depots then young women.16-18 Third, multiple studies in various disorders, including cardiovascular disease and diabetes, have shown that abdominal obesity (Abd-O) may be a better predictor than general/TBO, as estimated by BMI, for disease risk and all-cause mortality.18-20 Furthermore, although Abd-O is generally present in those with TBO, the presence of Abd-O does not necessitate the presence of TBO. For example, in 2003-2004, it was estimated that 31% of men and 33% of women in the United States were obese by BMI; however, 42% of men and 61% of women in the United States were estimated to have Abd-O.18 Notably, one clinic-based study has suggested that Abd-O is a risk factor for chronic daily headache in women.21 In the present study, we further explore the relationship between migraine and obesity, examining separately the effects of TBO and Abd-O.We hypothesize that migraine prevalence is associated with TBO and Abd-O in an age and gender-dependent manner, and that the association with Abd-O is independent of TBO.