Association of elevation, urbanization and ambient temperature with obesity prevalence in the United States.

BACKGROUND: The macrogeographic distribution of obesity in the United States, including the association between elevation and body mass index (BMI), is largely unexplained. This study examines the relationship between obesity and elevation, ambient temperature and urbanization. METHODS AND FINDINGS: Data from a cross-sectional, nationally representative sample of 422603 US adults containing BMI, behavioral (diet, physical activity, smoking) and demographic (age, sex, race/ethnicity, education, employment, income) variables from the 2011 Behavioral Risk Factor Surveillance System were merged with elevation and temperature data from WorldClim and with urbanization data from the US Department of Agriculture. There was an approximately parabolic relationship between mean annual temperature and obesity, with maximum prevalence in counties with average temperatures near 18 °C. Urbanization and obesity prevalence exhibited an inverse relationship (30.9% in rural or nonmetro counties, 29.2% in metro counties with <250000 people, 28.1% in counties with population from 250000 to 1 million and 26.2% in counties with >1 million). After controlling for urbanization, temperature category and behavioral and demographic factors, male and female Americans living <500 m above sea level had 5.1 (95% confidence interval (CI) 2.7-9.5) and 3.9 (95% CI 1.6-9.3) times the odds of obesity, respectively, as compared with counterparts living ≥ 3000 m above sea level. CONCLUSIONS: Obesity prevalence in the United States is inversely associated with elevation and urbanization, after adjusting for temperature, diet, physical activity, smoking and demographic factors.

Patterns of medication use by chronic and episodic headache sufferers in the general population: results from the frequent headache epidemiology study.

Though symptomatic medication overuse is believed to play a role in progression from episodic headaches (EH) to chronic daily headaches (CDH), population-based data on this topic are limited. Our objective was to describe patterns of medication use among CDH and EH sufferers in a general population sample. We compared medications used to treat headache in CDH cases and EH controls identified from a large population-based computer-assisted telephone interview survey. CDH began within 5 years of the computer-assisted telephone interview. Questions on medication use focused on treatment prior to the onset of CDH for cases and on an equivalent period in the past for controls. We asked about the likelihood of treating, time waiting to treat, number of different medications used, first, second and third most frequently used headache pain medication, and total treatment days. Questions were also asked about the use of medication for non-headache pain. Current treatment patterns and past treatment patterns were assessed. Likelihood of use of specific medications was compared between CDH cases and EH controls after adjusting for age, sex, primary headache type and number of medications taken to treat pain. Our sample consists of 206 CDH cases and 507 EH controls. CDH subjects were more likely than EH controls to use over-the-counter/caffeine combination products, triptans, opioid compounds and 'other' prescription pain medications. Use of aspirin was protective. After adjustment, aspirin and ibuprofen were (negatively) associated with CDH [OR = 0.5 (0.3-0.9), OR = 0.7 (0.5-1.0)] and opioids remained positively associated with CDH [OR = 2.3 (1.3-3.9)]. For past use, CDH was positively associated with over-the-counter/caffeine combination products and opioid compounds and was negatively associated with use of aspirin. Only ibuprofen remained (negatively) associated with CDH after adjustment [OR = 0.6 (0.4-0.9)]. After adjusting for demographic factors, primary headache type and number of medications taken, CDH sufferers are more likely to use opioid-combination analgesics, and less likely to use aspirin or ibuprofen, than EH sufferers.

C-reactive protein in migraine sufferers similar to that of non-migraineurs: the Reykjavik Study.

C-reactive protein (CRP), a marker of inflammation, has been associated with cardiovascular disease. Risk of cardiovascular disease is increased in migraineurs with aura. Results from a clinical report, case-control and a cohort study suggest that CRP is elevated in migraineurs compared with non-migraineurs. We examined the proposed association in a case-control study nested within two large population-based studies. The relationship between migraine and CRP (high-sensitivity CRP) was studied in 5906 men and women aged 55.0 +/- 8.5 years in the Reykjavik Study and 1345 men and women aged 27.7 +/- 5.5 years from the Reykjavik Study for the Young. A modified version of the International Headache Society's criteria was used to categorize people into migraineurs (two or more symptoms) or non-migraineurs. Migraineurs with visual or sensory symptoms were further defined as having migraine with aura (MA) or without aura (MO). Multivariable-adjusted CRP levels were similar in migraineurs and non-migraineurs for men (0.83 vs. 0.79 mg/l, P = 0.44) and for women (0.87 vs. 0.87 mg/l, P = 0.90). When further stratified by migraine aura and age, no differences were found between non-migraineurs, MO and MA among men. In women, CRP levels were borderline higher in those with MO compared with non-migraineurs and those with MA (1.01 mg/l vs. 0.81 and 0.75 mg/l, P = 0.08 and P = 0.08) in age group 19-34 years, but significantly lower in age group 60-81 years (0.52 mg/l vs. 1.07 and 1.01 mg/l, P = 0.007 and P = 0.03). CRP levels were not increased among migraine sufferers compared with non-migraineurs. Older women migraineurs without aura had lower CRP values than non-migraineurs and migraineurs with aura.

Major life changes before and after the onset of chronic daily headache: a population-based study.

Chronic daily headache (CDH), when defined as > or = 15 headache days per month, affects 3-5% of the adult population. Major life changes are putative precipitating events for onset of chronic pain, including chronic headache. This study compared the occurrence of specific life events between CDH cases and episodic headache controls in a community sample. CDH cases (180+ headache days per year: n = 206) and episodic headache controls (2-104 headache days per year: n = 507) were identified from a randomly selected adult US population. Subjects were interviewed about the occurrence of certain major life changes or events (change of residence, employment status, marital status, related to their children, deaths of relatives or close friends, and 'extremely stressful' ongoing situations) occurring in a defined time period. Events that occurred during the same year or year before frequent headache onset in cases or in an equivalent time period in controls were considered to be antecedent events. Those that occurred after this time were considered subsequent events. Compared with episodic headache controls, CDH cases had more major life changes in the year before or same year as CDH onset. After adjusting for age, gender, headache type and year of event, the odds of CDH increased additionally with each antecedent event [odds ratio (OR) 1.20 (1.1, 1.3), P < 0.001], but not with subsequent events [OR 0.94 (0.8, 1.1), P < 0.4]. In secondary analyses, the association between antecedent events and CDH was significant only for the approximately half of CDH cases who were aged >/= 40 years [OR 1.33 (1.2, 1.50) vs. OR 1.04 (0.9, 1.2), P < 0.05 for interaction by age]. These results suggest that major life changes are associated with the onset of chronic daily headache, particularly in middle age.

Migraine in the United States: epidemiology and patterns of health care use.

OBJECTIVE: To determine the prevalence and distribution of migraine in the United States as well as current patterns of health care use. METHODS: A random-digit-dial, computer-assisted telephone interview (CATI) survey was conducted in Philadelphia County, PA, in 1998. The CATI identifies individuals with migraine (categories 1.1 and 1.2) as defined by the diagnostic criteria of the International Headache Society with high sensitivity (85%) and specificity (96%). Interviews were completed in 4,376 subjects to identify 568 with migraine. Those with 6 or more attacks per year (n = 410) were invited to participate in a follow-up interview about health care utilization and family impact of migraine; 246 (60.0%) participated. RESULTS: The 1-year prevalence of migraine was 17.2% in females and 6.0% in males. Prevalence was highest between the ages of 30 and 49. Whereas 48% of migraine sufferers had seen a doctor for headache within the last year (current consulters), 31% had never done so in their lifetimes and 21% had not seen a doctor for headache for at least 1 year (lapsed consulters). Of current or lapsed consulters, 73% reported a physician-made diagnosis of migraine; treatments varied. Of all migraine sufferers, 49% were treated with over-the-counter medications only, 23% with prescription medication only, 23% with both, and 5% with no medications at all. CONCLUSION: Relative to prior cross-sectional surveys, epidemiologic profiles for migraine have remained stable in the United States over the last decade. Self-reported rates of current medical consultation have more than doubled. Moderate increases were seen in the percentage of migraine sufferers who use prescription medications and in the likelihood of receiving a physician diagnosis of migraine.

Factors associated with the onset and remission of chronic daily headache in a population-based study.

The etiology and prognosis of chronic daily headache (CDH) are not well understood. The aim of this study is to describe factors that predict CDH onset or remission in an adult population. Potential cases (180+ headaches per year, n=1134) and controls (two to 104 headaches per year, n=798) were interviewed two times over an average 11 months of follow-up. Factors associated with CDH prevalence at baseline were evaluated. The incidence of CDH and risk factors for onset were assessed in controls whose headache frequency increased to 180+ per year at follow-up. Prognostic factors were assessed in CDH cases whose headache frequency fell at follow-up. CDH was more common in women, in whites, and those of less education. CDH cases were more likely to be previously married (divorced, widowed, separated), obese, and report a physician diagnosis of diabetes or arthritis. At follow-up, 3% of the controls reported 180 or more headaches per year. Obesity and baseline headache frequency were significantly associated with new onset CDH. In CDH cases, the projected 1-year remission rate to less than one headache per week was 14% and to less than 180 headaches per year was 57%. A better prognosis was associated with higher education, non-white race, being married, and with diagnosed diabetes. Individuals with less than a high-school education, whites, and those who were previously married had a higher risk of CDH at baseline and reduced likelihood of remission at follow-up. New onset CDH was associated with baseline headache frequency and obesity.

Epidemiology and economic impact of migraine.

Migraine is a very common disorder, affecting about 11% of adult populations in Western countries. Prevalence is highest during the peak productive years--between the ages of 25 and 55. The prevalence is higher in females than males at all post-pubertal ages, but the sex ratio varies with age. In the United States, migraine prevalence is higher in those with low income or education, perhaps because migraine interferes with work and school. Most migraineurs mane their headaches without conventional medical advice and generally treat their attacks with over-the-counter medication. The indirect costs of migraine greatly outweigh the cost of treatment, creating opportunities for cost-effective intervention. The public health burden of migraine is substantial due to its high prevalence and prominent temporary disability. The widespread disability produced by migraine is an important target for treatment.

Hippocampal shape analysis in Alzheimer's disease: a population-based study.

BACKGROUND: Hippocampal atrophy--particularly of the CA1 region--may be useful as a biomarker for Alzheimer's disease (AD) or the risk for AD. The extent to which the AD hippocampus can be distinguished in vivo from changes due to normal aging or other processes that affect the hippocampus is of clinical importance and is an area of active research. In this study, we use structural imaging techniques to model hippocampal size and regional shape differences between elderly men with incident AD and a non-demented comparison group of elderly men. METHODS: Participants are Japanese-American men from the Honolulu Asia Aging Study (HAAS). The HAAS cohort has been followed since 1965. The following analysis is based on a sub-group of men who underwent MRI examination in 1994-1996. Participants were diagnosed with incident AD (n=24: age=82.5+/-4.6) or were not demented (n=102: age=83.0+/-5.9). One reader, blinded to dementia diagnosis, manually outlined the left and right hippocampal formation using published criteria. We used 3D structural shape analysis methods developed at the Laboratory of Neuro Imaging (LONI) to compare regional variation in hippocampal diameter between the AD cases and the non-demented comparison group. RESULTS: Mean total hippocampal volume was 11.5% smaller in the AD cases than the non-demented controls (4903+/-857 mm(3) vs. 5540+/-805 mm(3)), with a similar size difference for the median left (12.0%) and median right (11.6%) hippocampus. Shape analysis showed a regional pattern of shape difference between the AD and non-demented hippocampus, more evident for the hippocampal body than the head, and the appearance of more consistent differences in the left hippocampus than the right. While assignment to a specific sub-region is not possible with this method, the surface changes primarily intersect the area of the hippocampus body containing the CA1 region (and adjacent CA2 and distal CA3), subiculum, and the dentate gyrus-hilar region.

Analysis and validation of automated skull stripping tools: a validation study based on 296 MR images from the Honolulu Asia aging study.

As population-based epidemiologic studies may acquire images from thousands of subjects, automated image post-processing is needed. However, error in these methods may be biased and related to subject characteristics relevant to the research question. Here, we compare two automated methods of brain extraction against manually segmented images and evaluate whether method accuracy is associated with subject demographic and health characteristics. MRI data (n = 296) are from the Honolulu Asia Aging Study, a population-based study of elderly Japanese-American men. The intracranial space was manually outlined on the axial proton density sequence by a single operator. The brain was extracted automatically using BET (Brain Extraction Tool) and BSE (Brain Surface Extractor) on axial proton density images. Total intracranial volume was calculated for the manually segmented images (ticvM), the BET segmented images (ticvBET) and the BSE segmented images (ticvBSE). Mean ticvBSE was closer to that of ticvM, but ticvBET was more highly correlated with ticvM than ticvBSE. BSE had significant over (positive error) and underestimated (negative error) ticv, but net error was relatively low. BET had large positive and very low negative error. Method accuracy, measured in percent positive and negative error, varied slightly with age, head circumference, presence of the apolipoprotein eepsilon4 polymorphism, subcortical and cortical infracts and enlarged ventricles. This epidemiologic approach to the assessment of potential bias in image post-processing tasks shows both skull-stripping programs performed well in this large image dataset when compared to manually segmented images. Although method accuracy was statistically associated with some subject characteristics, the extent of the misclassification (in terms of percent of brain volume) was small.

Cardiovascular risk factors and migraine: the GEM population-based study.

BACKGROUND: Migraine, particularly with aura, is a risk factor for early-onset ischemic stroke. The underlying mechanisms are unknown, but may in part be due to migraineurs having an increased risk profile for cardiovascular disease. In this study, the authors compare the cardiovascular risk profile of adult migraineurs to that of nonmigraineurs. METHODS: Participants (n = 5,755, 48% men, age 20 to 65 years) are from the Genetic Epidemiology of Migraine (GEM) study, a population-based study in the Netherlands. A total of 620 current migraineurs were identified: 31% with aura (MA), 64% without aura (MO), and 5% unclassified. Controls were 5,135 individuals without lifetime migraine. Measured cardiovascular risk factors included blood pressure (BP), serum total and high-density lipoprotein cholesterol (TC, HDL), smoking, oral contraceptive use, and the Framingham risk score for myocardial infarction or coronary heart disease (CHD) death. RESULTS: Compared to controls, migraineurs were more likely to smoke (OR = 1.43 [1.1 to 1.8]), less likely to consume alcohol (OR = 0.58 [0.5 to 0.7]), and more likely to report a parental history of early myocardial infarction. Migraineurs with aura were more likely to have an unfavorable cholesterol profile (TC > or = 240 mg/dL [OR = 1.43 (0.97 to 2.1)], TC:HDL ratio > 5.0 [OR = 1.64 (1.1 to 2.4)]), have elevated BP (systolic BP > 140 mm Hg or diastolic BP > 90 mm Hg [OR = 1.76 (1.04 to 3.0)]), and report a history of early onset CHD or stroke (OR = 3.96 [1.1 to 14.3]); female migraineurs with aura were more likely to be using oral contraceptives (OR = 2.06 [1.05 to 4.0]). The odds of having an elevated Framingham risk score for CHD were approximately doubled for the migraineurs with aura. CONCLUSIONS: Migraineurs, particularly with aura, have a higher cardiovascular risk profile than individuals without migraine.

Habitual snoring as a risk factor for chronic daily headache.

Frequent headache is associated with a variety of sleep disorders. The authors compared the prevalence of snoring in a group of chronic daily headache (CDH) subjects (n = 206) with a control group of episodic headache subjects (n = 507). Habitual snoring was more common in the CDH subjects than in the control subjects (24 vs 14%; p < 0.05); the difference remained after adjusting for factors related to sleep-disordered breathing (OR = 2.9; p < 0.005). If this association proves causal, sleep-disordered breathing may provide a target for therapeutic interventions for chronic daily headache.

Prevalence of frequent headache in a population sample.

PURPOSE: Patients with daily or near-daily headaches are commonly seen in neurology practices and in headache subspecialty centers, but there is little information on the prevalence of this condition in the general population. We present the first US-based study describing the prevalence and characteristics of frequent headache in the general population. METHODS: In Baltimore County, Maryland, 13 343 individuals 18 to 65 years of age were selected by random-digit dialing and interviewed by telephone about their headaches. Subjects reporting 180 or more headaches per year were classified as having frequent headache. Three mutually exclusive subtypes of frequent headache were identified: frequent headache with migrainous features, chronic tension-type headache, and unclassified frequent headache. RESULTS: The overall prevalence of frequent headache was 4.1% (5.0% female, 2.8% male; 1.8:1 female to male ratio). Frequent headache was 33% more common in Caucasians (4.4%) than in African Americans (3.3%). In both males and females, prevalence was highest in the lowest educational category. Among frequent headache sufferers, more than half (52% female, 56% male) met criteria for chronic tension-type headache, almost one third (33% female, 25% male) met criteria for frequent headache with migrainous features, and the remainder (15% female, 19% male) were unclassified. Overall, 30% of female and 25% of male frequent headache sufferers met International Headache Society (IHS) criteria for migraine (with or without aura). CONCLUSIONS: Frequent headache is common in the general population and is more prevalent in Caucasians and in those with less than a high school education. Chronic tension-type headache is more common than frequent headache with migrainous features, though the latter is more disabling. Although more common in females than males, the female preponderance of frequent headache is less marked than in migraine. The sex ratio varies by frequent headache subtype.

The prevalence and disability burden of adult migraine in England and their relationships to age, gender and ethnicity.

This study estimates the 1-year prevalence of migraine in adults in England in relation to the major demographic variables of age, gender and ethnicity, and describes some of its features, including aspects of consequential disability. A telephone survey was conducted of a random sample (n = 4007) of the population aged 16-65 years of mainland England using a previously validated diagnostic interview. The response rate was 76.5%. Overall, 7.6% of males and 18.3% of females reported migraine with or without aura within the last year meeting diagnostic criteria closely approximate to those of the International Headache Society. Prevalence of migraine varied with age, rising through early adult life and declining in the late 40s and early 50s. Prevalence was higher in Caucasians than in other races. Attack rates were > or = 1/month in most migraineurs, and most experienced interference with daily activities in > or = 50% of their attacks. On average, an estimated 5.7 working days were lost per year for every working or student migraineur, although the most disabled 10% accounted for 85% of the total. Results were in keeping with those from surveys in other countries. If these findings in mainland England are projected to the entire UK population, we estimate that 5.85 million people aged 16-65 years experience 190 000 migraine attacks every day and lose 25 million days from work or school each year because of them. Migraine is an important public health problem in the UK, associated with very substantial costs.

Patterns of health care utilization for migraine in England and in the United States.

OBJECTIVE: To assess patterns of medical consultation, diagnosis, and medication use in representative samples of adults with migraine in England and the United States. METHODS: Validated computer-assisted telephone interviews were conducted in the United Kingdom (n = 4,007) and the United States (n = 4,376). Individuals who reported six or more headaches per year meeting the criteria for migraine were interviewed. RESULTS: Patients with migraine in the United Kingdom were more likely to have consulted a doctor for headache at least once in their lifetime (86% vs 69%, p < 0.0001), but also were more likely to have lapsed from medical care (37% vs 21%, p < 0.001). In the United States, patients with migraine who had consulted made more office visits for headache and were more likely to see a specialist. In the United States, but not in the United Kingdom, women with migraine were more likely than men to consult doctors for headache. Patients with migraine in the United Kingdom were more likely to receive a medical diagnosis of migraine (UK 67%, US 56%; p < 0.05). Patterns of medication use were similar in both countries, with most people treating with over-the-counter (OTC) medications. Substantial disability occurred in a high proportion of those who never consulted (UK 60%, US 68%), never received a correct medical diagnosis (UK 64%, US 77%), and treated only with OTC medication (UK 72%, US 70%). CONCLUSION: Medically unrecognized migraine remains an important health problem both in the United States and the United Kingdom. Furthermore, there may be barriers to consultation for men in the United States that do not operate in the United Kingdom.