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W F Stewart

Publications and source records attributed to W F Stewart.

132 records · Page 8Linked to original sources
PubMedDate not supplied

Prevalence and burden of migraine in the United States: data from the American Migraine Study II.

OBJECTIVE: To describe the prevalence, sociodemographic profile, and the burden of migraine in the United States in 1999 and to compare results with the original American Migraine Study, a 1989 population-based study employing identical methods. METHODS: A validated, self-administered questionnaire was mailed to a sample of 20 000 households in the United States. Each household member with severe headache was asked to respond to questions about symptoms, frequency, and severity of headaches and about headache-related disability. Diagnostic criteria for migraine were based on those of the International Headache Society. This report is restricted to individuals 12 years and older. RESULTS: Of the 43 527 age-eligible individuals, 29 727 responded to the questionnaire for a 68.3% response rate. The prevalence of migraine was 18.2% among females and 6.5% among males. Approximately 23% of households contained at least one member suffering from migraine. Migraine prevalence was higher in whites than in blacks and was inversely related to household income. Prevalence increased from aged 12 years to about aged 40 years and declined thereafter in both sexes. Fifty-three percent of respondents reported that their severe headaches caused substantial impairment in activities or required bed rest. Approximately 31% missed at least 1 day of work or school in the previous 3 months because of migraine; 51% reported that work or school productivity was reduced by at least 50%. CONCLUSIONS: Two methodologically identical national surveys in the United States conducted 10 years apart show that the prevalence and distribution of migraine have remained stable over the last decade. Migraine-associated disability remains substantial and pervasive. The number of migraineurs has increased from 23.6 million in 1989 to 27.9 million in 1999 commensurate with the growth of the population. Migraine is an important target for public health interventions because it is highly prevalent and disabling.

Adolescent↗
PubMedDate not supplied

Different associations of blood lead, meso 2,3-dimercaptosuccinic acid (DMSA)-chelatable lead, and tibial lead levels with blood pressure in 543 former organolead manufacturing workers.

In this study, the authors' objective was to determine the influence of blood lead, meso 2,3-dimercaptosuccinic acid (DMSA)-chelatable lead, and tibial lead on systolic and diastolic blood pressures and on hypertension in 543 former organolead manufacturing workers. All workers had past exposure to inorganic and organic lead. The authors used linear regression to model systolic and diastolic blood pressure separately, and logistic regression was used for the modeling of hypertension status (i.e., systolic blood pressure > 160 mm Hg, diastolic blood pressure > or =96 mm Hg, or current use of antihypertensive medications). Blood lead, DMSA-chelatable lead, and tibial lead levels had means (standard deviations appear within parentheses) of 4.6 microg/dl (2.6 microg/dl), 19.3 microg (17.2 microg), and 14.4 microg/g (9.3 microg/g), respectively. The authors adjusted for covariates, and they found that blood lead was a predictor of (1) both systolic and diastolic blood pressures and (2) hypertension status in men < 58 y of age. DMSA-chelatable lead and tibial lead were not associated with any of the blood pressure measures. Systolic blood pressure was elevated by blood lead levels as low as 5 microg/dl. We speculate that lead may have a transient influence on blood pressure that is related to target dose levels obtained once release of lead from body stores has occurred.

Adult↗
PubMedDate not supplied

Migraine headaches and panic attacks.

Migraine headache and panic attacks are two common conditions which first occur at an early age and appear to have a number of underlying physiologic abnormalities in common. In a population-based telephone interview survey examining headache occurrence in approximately 10,000 subjects, 12-29 years old, we assessed the prevalence of panic disorder (and a less severe entity designated as panic syndrome) using an abbreviated version of the National Institute of Mental Health Diagnostic Interview Survey. Subjects with panic disorder or panic syndrome reported more frequent occurrence of headaches during the preceding week, as well as headaches of longer duration and substantially more headaches with migraine symptoms than individuals without a history of panic attack. Males with panic disorder were 7 times more likely than those without this condition to report the occurrence of a migraine headache in the previous week. In addition, 5.5% of males and 9.5% of females with panic disorder or panic syndrome reported 25% of the total migraine headaches described by all study subjects in the one-week recall period.

Adolescent↗
PubMedDate not supplied

Headache characteristics associated with physician consultation: a population-based survey.

In a population-based telephone interview survey of 9,380 Washington County, Maryland, residents 12-29 years of age who reported a headache in the prior year, only 26.7% of women and 13.6% of men had ever sought a physician's advice for a headache problem. Women (13.9%) were more than twice as likely as men (5.6%) to have consulted a doctor for this condition within the previous 12 months. The likelihood of seeking medical care for headache increased with age among women but not men. Married women were more likely to have consulted with a physician for a headache problem than single or divorced women. Men and women consulting a doctor for this disorder within the previous 12 months described recent headaches (within the prior week) that were more severe, of longer duration (women only), and more likely to have migraine characteristics than recent headaches of persons not seeking medical attention. Compared with persons never consulting a physician for a headache problem, men and women who sought medical care had elevated attack rates of certain, probable, and possible migraine and mixed migraine-tension type headaches within the preceding week. Differences in attack rates for migraine and mixed migraine-tension headaches between those who recently and those who more than 12 months ago sought a physician's advice were more striking for men than for women.

Adolescent↗
PubMedDate not supplied

Misclassification of genetic susceptibility biomarkers: implications for case-control studies and cross-population comparisons.

Phenotype and genotype markers of genetic susceptibility are of increasing interest in case-control studies of cancer. It is well established that bias to the odds ratio is caused by less-than-perfect assay sensitivity and specificity and varies with risk factor prevalence. As such, the observed variation in odds ratio between studies of genetic markers and cancer risk may be real, or may be attributed, in part, to variation in assay accuracy or in risk factor prevalence (e.g., prevalence differences between racial groups). The latter can be a particular concern when the prevalence of the "at risk" polymorphism in one or more populations is either very high (e.g., > 85%) or very low (e.g., < 15%). For example, even very high sensitivity (e.g., 98%) can produce substantial bias to the odds ratio when the risk factor prevalence is high. Under some prevalence conditions, however, assays with only moderate accuracy are sufficient and result in minimal bias to the odds ratio. Understanding misclassification in the context of marker prevalence may help to explain disparate findings in the literature and should assist investigators in selecting markers that are appropriate for future studies.

Bias↗