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Biomedical subjects

W F Stewart

Publications and source records attributed to W F Stewart.

At least 127 records · Page 7Linked to original sources
PubMed1987

The validity of questionnaire-reported work history in live respondents.

The ability of subjects to recall their year of hire, year of termination, and job title was studied by comparing reported information to that recorded in personnel records. Former shipyard workers were interviewed in 1982. A majority was first employed in one of two shipyards during the early 1940s and 1950s. kappa statistics and crude and adjusted measures of percent agreement were derived to determine whether reported work history agreed with what was recorded in the subjects' personnel record and to determine whether recall was associated with race, age of the respondent at the time of interview, years since leaving the yard, length of employment, and year of hire. After adjusting for other covariates, only the number of years since leaving the yard was associated with recall of year of hire and termination, but not job title. In addition, however, there were several other noteworthy findings. Individuals who were 65-69 years of age at the time of interview had the poorest recall. Recall of both the year of hire and the job title appears to improve with increasing length of employment.

Adolescent↗
PubMed1987

Comparison of methods for determining occupational exposure in a case-control interview study of chronic lymphocytic leukemia.

A comparison was made between two indirect methods for linking reported lifetime occupations and industries of employment with specific exposures and with directly reported exposure information, using data from a population-based case-control interview study of chronic lymphocytic leukemia (CLL). Exposures previously suspected of being associated with CLL were examined using a job-exposure matrix developed by Hoar et al and a linkage between observed occupational exposures and specific occupations, by industry, based on data collected in the National Occupational Hazard Survey (NOHS). In general, concordance on exposure for the two occupation-exposure linkage methods was fairly poor, although it was better for some of the exposures studied (butadiene and asbestos, for which most kappas were between 0.40 and 0.60) than for others (carbon tetrachloride and benzene with kappas ranging from 0.01 to 0.12). Higher proportions of cases and controls directly reported exposure to benzene and asbestos than was determined using the two more indirect methods, neither of which showed consistently greater agreement with direct reporting.

Epidemiologic Methods↗
PubMed1984

Migraine headache: epidemiologic perspectives.

Clinical and epidemiologic studies suggest that a number of factors are associated with the risk of migraine and precipitation of an attack. However, the degree to which causal associations can be inferred from reported studies is very limited and is a result of the methodological problems discussed throughout this review. The study of migraine in many ways parallels the pattern seen in early investigations of other conditions, such as rheumatoid arthritis and systemic lupus erythematosus, because a number of methodological problems had to be resolved in the study of these conditions before significant progress could be made. To achieve significant advances in the improvement of our understanding of the causes of migraine, a number of related issues must be addressed and resolved in future studies. Most noteworthy among these are Recognition of the probable heterogeneity of migraine, not merely in the manifestation of symptoms but, more importantly, in the existence of distinct etiologic subtypes. A number of findings suggest that some migraine subtypes are sensitive to certain precipitants, some appear to be a part of a more generalized constitutional disorder, and some are accompanied by a higher prevalence of migraine among family members. Efforts should be made in understanding the relationship between specific biochemical markers and traits (such as monoamine oxidase deficiency and tyramine sensitivity); precipitants related to the migraine attack; and epidemiologic characteristics such as age at onset and sex. Creation of a more precise, reliable, and practically useful definition of migraine. Without such a definition, it is difficult, if not impossible, to compare results between studies, to understand the relationship between risk factors and migraine subtypes, to understand properly associations identified in selected clinic populations, and, in general, to understand the epidemiology of migraine. More accurate characterization of the case group under study. More documentation of the age at onset, symptoms, frequency of attacks, and other characteristics related to migraine would be very useful to compare properly results between studies. Additional descriptive epidemiologic studies of migraine which would include reliable estimates of age-specific incidence, prevalence, remission rates, and natural history of the various migraine subtypes.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMedDate not supplied

Efficacy and safety of acetaminophen in the treatment of migraine: results of a randomized, double-blind, placebo-controlled, population-based study.

BACKGROUND: Although most persons with migraine treat their headaches with over-the-counter medication, systematic data on the safety and efficacy of widely used treatment, including acetaminophen, are sparse. METHODS: This is a randomized, double-blind, placebo-controlled study comparing oral acetaminophen, 1000 mg (two 500-mg Extra Strength Tylenol tablets), with identical placebo in the treatment of a single acute migraine attack. Eligible subjects met International Headache Society diagnostic criteria for migraine with or without aura. Patients who usually required bed rest with their headaches or who vomited more than 20% of the time were excluded. MAIN OUTCOME MEASURES: The percentage of subjects who, at 2 hours after dosing, experienced a change in baseline pain intensity from severe or moderate pain to mild or no pain (headache response); and pain intensity difference from baseline at the 2-hour postmedication assessment. RESULTS: The headache response rate 2 hours after dosing was 57.8% in the acetaminophen group and 38.7% in the placebo group (P =.002). Pain-free rates at 2 hours were 22.4% in the acetaminophen group and 11.3% in the placebo group (P =.01). The mean pain intensity difference from baseline 2 hours after dosing was 1.08 in the acetaminophen group and 0.73 in the placebo group (P<.001). At 2 hours, other migraine headache characteristics, such as functional disability (P =.002), photophobia (P =.02), and phonophobia (P =.08), were significantly improved after treatment with acetaminophen vs placebo. CONCLUSIONS: Acetaminophen was highly effective for treating pain, functional disability, photophobia, and phonophobia in a population-based sample of persons with migraine, excluding the most disabled persons with migraine. The drug also had an excellent safety profile and was well tolerated. Arch Intern Med. 2000;160:3486-3492.

Acetaminophen↗
PubMedDate not supplied

Stratified care vs step care strategies for migraine: the Disability in Strategies of Care (DISC) Study: A randomized trial.

CONTEXT: Various guidelines recommend different strategies for selecting and sequencing acute treatments for migraine. In step care, treatment is escalated after first-line medications fail. In stratified care, initial treatment is based on measurement of the severity of illness or other factors. These strategies for migraine have not been rigorously evaluated. OBJECTIVE: To compare the clinical benefits of 3 strategies: stratified care, step care within attacks, and step care across attacks, among patients with migraine. DESIGN AND SETTING: Randomized, controlled, parallel-group clinical trial conducted by the Disability in Strategies Study group from December 1997 to March 1999 in 88 clinical centers in 13 countries. PATIENTS: A total of 835 adult migraine patients with a Migraine Disability Assessment Scale (MIDAS) grade of II, III, or IV were analyzed as the efficacy population; the safety analysis included 930 patients. INTERVENTIONS: Patients were randomly assigned to receive (1) stratified care (n = 279), in which patients with MIDAS grade II treated up to 6 attacks with aspirin, 800 to 1000 mg, plus metoclopramide, 10 mg, and patients with MIDAS grade III and IV treated up to 6 attacks with zolmitriptan, 2.5 mg; (2) step care across attacks (n = 271), in which initial treatment was with aspirin, 800 to 1000 mg, plus metoclopramide, 10 mg. Patients not responding in at least 2 of the first 3 attacks switched to zolmitriptan, 2.5 mg, to treat the remaining 3 attacks; and (3) step care within attacks (n = 285), in which initial treatment for all attacks was with aspirin, 800 to 1000 mg, plus metoclopramide, 20 mg. Patients not responding to treatment after 2 hours in each attack escalated treatment to zolmitriptan, 2.5 mg. MAIN OUTCOME MEASURES: Headache response, achieved if pain intensity was reduced from severe or moderate at baseline to mild or no pain at 2 hours; and disability time per treated attack at 4 hours for all 6 attacks, compared among the 3 groups. RESULTS: Headache response at 2 hours was significantly greater across 6 attacks in the stratified care treatment group (52.7%) than in either the step care across attacks group (40.6%; P<.001) or the step care within attacks group (36.4%; P<.001). Disability time (6 attacks) was significantly lower in the stratified care group (mean area under the curve [AUC], 185.0 mm. h) than in the step care across attacks group (mean AUC, 209.4 mm. h; P<.001) or the step care within attacks group (mean AUC, 199.7 mm. h; P<.001). The incidence of adverse events was higher in the stratified care group (321 events) vs both step care groups (159 events in across-attack group; 217 in within-attack group), although most events were of mild-to-moderate intensity. CONCLUSION: Our results indicate that as a treatment strategy, stratified care provides significantly better clinical outcomes than step care strategies within or across attacks as measured by headache response and disability time. JAMA. 2000;284:2599-2605.

Adult↗
PubMedDate not supplied

A change point model for estimating the onset of cognitive decline in preclinical Alzheimer's disease.

Dementia is characterized by accelerated cognitive decline before and after diagnosis as compared to normal ageing. Determining the time at which that rate of decline begins to accelerate in persons who will develop dementia is important both in describing the natural history of the disease process and in identifying the optimal time window for which treatments might be useful. We model that time at which the rate of decline begins to accelerate in persons who develop dementia relative to those who do not by using a change point in a mixed linear model. A profile likelihood method is proposed to draw inferences about the change point. The method is applied to data from the Bronx Ageing Study, a cohort study of 488 initially non-demented community-dwelling elderly individuals who have been examined at approximately 12-month intervals over 15 years. Cognitive function was measured using the Buschke Selective Reminding test, a memory test with high reliability and known discriminative validity for detecting dementia. We found that the rate of cognitive decline as measured by this test in this cohort increases on average 5.1 years before the diagnosis of dementia.

Aged↗
PubMedDate not supplied

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.

Adolescent↗
PubMedDate not supplied

2000 Wolfe Award. Sumatriptan for the range of headaches in migraine sufferers: results of the Spectrum Study.

BACKGROUND: Migraineurs experience a spectrum of headaches: migraine, migrainous, and episodic tension-type as defined by the International Headache Society (IHS). OBJECTIVE: To evaluate the effectiveness of sumatriptan, 50-mg tablets, in treating the spectrum of headaches in IHS-diagnosed migraineurs. DESIGN/METHODS: Migraineurs with severe disability (Headache Impact Questionnaire score 250 or greater) were enrolled in a randomized, double-blind, placebo-controlled, crossover study. Patients treated up to 10 headaches with sumatriptan, 50 mg, or placebo (4:1). Headache features, recorded prior to treatment, were used to classify each headache using IHS criteria. Headache response (moderate or severe pain reduced to mild or no pain) and pain-free response were recorded at 2 and 4 hours postdose (primary endpoint). Because patients treated multiple attacks, statistical methods controlling for within-subject correlation were used. RESULTS: Two hundred forty-nine migraineurs treated 1576 moderate or severe headaches: migraine (n = 1110), migrainous (n = 103), and tension-type (n = 363). Sumatriptan was superior to placebo for headache response 4 hours postdose (primary endpoint) across all headache types (migraine, 66% versus 48%; P<.001; migrainous, 71% versus 39%; P<.01; tension-type, 78% versus 50%, P<.001). Sumatriptan was also superior to placebo for pain-free response 4 hours postdose for migraine (41% versus 24%, P<.001) and tension-type headaches (56% versus 36%, P =.001). Sumatriptan provided superior pain-free response 2 hours postdose for migraine (18% versus 7%, P<.0001) and tension-type headache (28% versus 14%, P =.0005) compared with placebo. CONCLUSION: Sumatriptan, 50-mg tablets, are effective for the full spectrum of headaches experienced by patients with disabling migraine due to a sumatriptan-responsive mechanism.

Administration, Oral↗
PubMedDate not supplied

Treatment of mild headache in disabled migraine sufferers: results of the Spectrum Study.

OBJECTIVE: To evaluate the effectiveness of sumatriptan, 50-mg tablets, versus placebo for early intervention while head pain was mild in patients with disabling migraine. METHODS: A post hoc analysis was performed in a subgroup of patients from a large, randomized, placebo-controlled study of patients with disabling headache who treated while pain was mild. Pain-free response 2 and 4 hours postdose, headache recurrence, and safety were examined. Significance tests were performed only for the first-treated attacks. RESULTS: Twenty-six patients with disabling headache treated 46 mild and 166 moderate or severe headaches. For the first-treated headaches while pain was mild, pain-free rates were significantly higher for sumatriptan than placebo 4 hours postdose (78% versus 0%, P =.02), but not 2 hours postdose (52% versus 0%, P =.22). Across all headaches treated while pain was mild, pain-free responses were higher for sumatriptan than placebo 4 hours (85% versus 17%) and 2 hours (50% versus 0%) postdose compared with placebo. When the same patients treated headaches while pain was moderate or severe, pain-free rates were lower than that reported for treatment during mild pain. There was a trend toward lower headache recurrence in headaches treated while pain was mild compared with moderate or severe pain (13% versus 18%). No drug-related adverse events were reported in the headaches treated while pain was mild. CONCLUSIONS: Patients with disabling migraine may benefit from early intervention with sumatriptan, 50 mg, while pain is mild.

Administration, Oral↗
PubMedDate not supplied

Migraine diagnosis and treatment: results from the American Migraine Study II.

OBJECTIVE: A population-based survey was conducted in 1999 to describe the patterns of migraine diagnosis and medication use in a representative sample of the US population and to compare results with a methodologically identical study conducted 10 years earlier. METHODS: A survey mailed to a panel of 20 000 US households identified 3577 individuals with severe headache meeting a case definition for migraine based on the International Headache Society (IHS) criteria. Those with severe headache answered questions regarding physician diagnosis and use of medications for headache as well as headache-related disability. RESULTS: A physician diagnosis of migraine was reported by 48% of survey participants who met IHS criteria for migraine in 1999, compared with 38% in 1989. A total of 41% of IHS-defined migraineurs used prescription drugs for headaches in 1999, compared with 37% in 1989. The proportion of IHS-defined migraineurs using only over-the-counter medications to treat their headaches was 57% in 1999, compared with 59% in 1989. In 1999, 37% of diagnosed and 21% of undiagnosed migraineurs reported 1 to 2 days of activity restriction per episode (P<.001); 38% of diagnosed and 24% of undiagnosed migraineurs missed at least 1 day of work or school in the previous 3 months (P<.001); 57% of diagnosed and 45% of undiagnosed migraineurs experienced at least a 50% reduction in work/school productivity (P<.001). CONCLUSIONS: Diagnosis of migraine has increased over the past decade. Nonetheless, approximately half of migraineurs remain undiagnosed, and the increased rates of diagnosis of migraine have been accompanied by only a modest increase in the proportion using prescription medicines. Migraine continues to cause significant disability whether or not there has been a physician diagnosis. Given the availability of effective treatments, public health initiatives to improve patterns of care are warranted.

Adolescent↗