Biomedical subjects

W F Stewart

Publications and source records attributed to W F Stewart.

At least 55 records · Page 3Linked to original sources

PubMed2000

Evaluation of a novel solubilized formulation of ibuprofen in the treatment of migraine headache: a randomized, double-blind, placebo-controlled, dose-ranging study.

A total of 729 migraine sufferers with moderate to severe baseline pain evaluated a single 200, 400 or 600 mg dose of a new liquigel formulation of ibuprofen over 8 h. Ibuprofen liquigels were significantly superior to placebo for cumulative headache response (pain reduced to mild or none) from 0.5 (600 mg) or 1 h (200 and 400 mg) to 8 h. At 2 h, respective headache response rates for ibuprofen 200, 400 and 600 mg and placebo were 64%, 72%, 72% and 50%. All three doses were also significantly superior to placebo for 2-h pain-free (25%, 28%, 29% and 13%, respectively) and for proportions with mild or no limitation of activity (2-8 h). Ibuprofen liquigels were generally superior to placebo for reducing photophobia, phonophobia, or nausea (1-4 h) and for global evaluation. All doses were well tolerated. These data demonstrate that ibuprofen liquigels relieve the pain, ancillary symptoms, and limitation of activity, of migraine.

Adult↗

PubMed2000

Upper gastrointestinal symptoms in a U.S. national sample of adults with diabetes.

BACKGROUND: Individuals with diabetes may be particularly susceptible to motility-related upper gastrointestinal (UGI) symptoms such as abdominal pain or discomfort, bloating, early satiety, nausea, and vomiting. We estimated the prevalence of UGI symptoms in a population-based sample of individuals with diabetes and determined whether cases and population controls differed in prevalence of UGI symptoms and in symptom features. METHODS: Individuals with diabetes (n = 483) and matched controls (n = 422) were recruited from a prior U.S. national health survey for a telephone interview on UGI symptoms. To confirm self-reported diabetes status, cases provided information on clinical management measures. Subjects were asked about UGI symptoms in the month before interview. Affirmative responses to initial questions triggered detailed questions about symptom frequency, timing, duration, and severity. Differences between cases and controls were evaluated. RESULTS: Cases not only had a significantly (P < 0.05) higher overall prevalence of one or more UGI symptoms in the past month (50%) than controls (38%), but they also reported a significantly greater number of UGI symptoms than controls. Almost 10% of cases reported three or more UGI symptoms in the past month compared with 2% of controls. Our study also identified UGI symptom features that were more relevant to cases and showed that one UGI symptom, heartburn, co-occurred significantly more often with UGI symptoms in cases than in controls. CONCLUSIONS: Upper GI symptoms are common in individuals with diabetes and more prevalent than in controls. The symptoms are non-specific and may reflect disruptions in motility or perception.

Adolescent↗

PubMed2000

Associations of tibial lead levels with BsmI polymorphisms in the vitamin D receptor in former organolead manufacturing workers.

We evaluated associations of tibial lead levels with polymorphisms in the vitamin D receptor (VDR) in 504 former organolead manufacturing workers with past exposure to lead. In this cross-sectional study, we measured tibial lead by (109)Cd K-shell X-ray fluorescence. Tibial lead was evaluated in subjects with different VDR genotypes defined using the BsmI restriction enzyme, adjusting for confounding variables. Study participants had a mean age +/- SD of 57.4 +/- 7.6 years. A total of 169 (33.5%) subjects were homozygous for the BsmI restriction site (designated bb), 251 (49.8%) were heterozygous (Bb), and 84 (16.7%) were homozygous for the absence of the restriction site (BB). Among all of the study subjects, tibial lead concentrations were low, with a mean +/- SD of 14.4 +/- 9.3 microg Pb/g bone mineral. There were only small differences in tibial lead concentrations by VDR genotype, with mean +/- SD tibial lead concentrations of 13.9 +/- 7.9, 14.3 +/- 9.5, and 15.5 +/- 11.1 in subjects with bb, Bb, and BB, respectively. In a multiple linear regression model of tibial lead concentrations, the VDR genotype modified the relation between age and tibial lead concentrations; subjects with the B allele had larger increases in tibial lead concentrations with increasing age (0.37, 0.48, and 0.67 microg/g per year of age in subjects with bb, Bb, and BB, respectively; the adjusted p-value for trend in slopes = 0.04). The VDR genotype also modified the relation between years since last exposure to lead and tibial lead concentrations. Subjects with bb evidenced an average decline in tibial lead concentrations of 0.10 microg/g per year since their last exposure to lead, whereas subjects with Bb and BB evidenced average increases of 0.03 and 0.11 microg/g per year, respectively (the adjusted p-value for trend in slopes = 0.01). Polymorphisms in the vitamin D receptor modified the relations of age and years since the last exposure to lead with tibial lead concentrations. Although controversy remains on the influence of the VDR genotype on bone mineral density, the data suggest that variant VDR alleles modify lead concentrations in bone, either by influencing lead content or calcium content or both.

Adult↗

PubMed2000

Associations of blood lead, dimercaptosuccinic acid-chelatable lead, and tibia lead with polymorphisms in the vitamin D receptor and [delta]-aminolevulinic acid dehydratase genes.

A cross-sectional study was performed to evaluate the influence of polymorphisms in the [delta]-aminolevulinic acid dehydratase (ALAD) and vitamin D receptor (VDR) genes on blood lead, tibia lead, and dimercaptosuccinic acid (DMSA)-chelatable lead levels in 798 lead workers and 135 controls without occupational lead exposure in the Republic of Korea. Tibia lead was assessed with a 30-min measurement by (109)Cd-induced K-shell X-ray fluorescence, and DMSA-chelatable lead was estimated as 4-hr urinary lead excretion after oral administration of 10 mg/kg DMSA. The primary goals of the analysis were to examine blood lead, tibia lead, and DMSA-chelatable lead levels by ALAD and VDR genotypes, controlling for covariates; and to evaluate whether ALAD and VDR genotype modified relations among the different lead biomarkers. There was a wide range of blood lead (4-86 microg/dL), tibia lead (-7-338 microg Pb/g bone mineral), and DMSA-chelatable lead (4.8-2,103 microg) levels among lead workers. Among lead workers, 9.9% (n = 79) were heterozygous for the ALAD(2) allele and there were no homozygotes. For VDR, 10.7% (n = 85) had the Bb genotype, and 0.5% (n = 4) had the BB genotype. Although the ALAD and VDR genes are located on different chromosomes, lead workers homozygous for the ALAD(1) allele were much less likely to have the VDR bb genotype (crude odds ratio = 0.29, 95% exact confidence interval = 0.06-0.91). In adjusted analyses, subjects with the ALAD(2) allele had higher blood lead levels (on average, 2.9 microg/dL, p = 0.07) but no difference in tibia lead levels compared with subjects without the allele. In adjusted analyses, lead workers with the VDR B allele had significantly (p < 0.05) higher blood lead levels (on average, 4.2 microg/dL), chelatable lead levels (on average, 37.3 microg), and tibia lead levels (on average, 6.4 microg/g) than did workers with the VDR bb genotype. The current data confirm past observations that the ALAD gene modifies the toxicokinetics of lead and also provides new evidence that the VDR gene does so as well.

Adolescent↗

PubMed1999

Modelling disease progression in terms of exposure history.

We consider the relationship between accumulating exposure to a putative agent and the associated change in physiologic function. This type of problem is common to prospective studies of cognitive, pulmonary and cardiovascular function. A general model is proposed for data from prospective, observational studies with concurrent measures of exposures and continuous outcome measures. This model permits non-linearity in the relationship between exposure and outcome and is designed to describe outcome in terms of one's entire exposure history. As exposure data are often severely right-skewed, we use regression spline estimation methods which localize the influence of extreme points. We illustrate our methodology using data from a longitudinal epidemiologic investigation of the effects of amateur boxing on neuropsychologic function.

Adolescent↗

PubMed1999

An international study to assess reliability of the Migraine Disability Assessment (MIDAS) score.

BACKGROUND: The Migraine Disability Assessment (MIDAS) instrument is a five-item questionnaire developed to measure headache-related disability and improve doctor-patient communication about the functional consequences of migraine. OBJECTIVES: To examine the test-retest reliability and internal consistency of the five items and of the overall MIDAS score in population-based samples of migraine sufferers in two countries and to compare consistency across countries. METHODS: Using a clinically validated telephone interview, population-based samples of migraine-headache sufferers were identified in the United States (Baltimore, MD) and the United Kingdom (Merton and Sutton, Surrey). Eligible individuals completed the MIDAS questionnaire on two occasions an average of 3 weeks apart. The MIDAS score is derived from five questions about missed time from work and household work (one question each about missed days and days with at least 50% reduced productivity) and missed days of nonwork activities. RESULTS: A total of 97 migraine-headache sufferers from the United States and 100 from the United Kingdom completed the MIDAS questionnaire twice. Mean and median item values and overall MIDAS scores were similar between the United States and the United Kingdom. Test-retest Spearman correlations of individual items ranged from 0.46 to 0.78. No significant differences in item-specific correlations were observed between the United States and United Kingdom. The test-retest Pearson correlation of the MIDAS score (i.e., sum of lost days and reduced-effectiveness days in each domain) was 0.80 in the United States and 0.83 in the United Kingdom. The Cronbach alpha, a measure of internal consistency, was 0.76 in the United States and 0.73 in the United Kingdom. CONCLUSIONS: This is the first international population-based study to assess the reliability of a disability-related illness severity score for migraine. The reliability and internal consistency of the Migraine Disability Assessment score are similar to that of a previous questionnaire (Headache Impact Questionnaire). However, the Migraine Disability Assessment score requires fewer questions, is easier to score, and provides intuitively meaningful information on lost days of activity in three domains.

Adolescent↗

PubMed1999

Neurobehavioral function and tibial and chelatable lead levels in 543 former organolead workers.

OBJECTIVE: To evaluate the associations between tibial lead, dimercaptosuccinic acid (DMSA)-chelatable lead, and neurobehavioral function in former organolead manufacturing workers with past exposure to organic and inorganic lead. METHODS: Data were collected from 543 subjects with a mean age of 58 years and an average of 17.8 years since last lead exposure. Years since last exposure to lead was used to estimate tibial lead levels in the year of last occupational lead exposure, termed "peak tibial lead." Current tibial lead levels, measured by x-ray fluorescence, were extrapolated back using a clearance half-time of lead in tibia of 27 years, assuming first-order clearance from tibia. RESULTS: Peak tibial lead levels ranged from -2.2 to 105.9 microg Pb/g bone mineral, and DMSA-chelatable lead levels were between 1.2 and 136 microg. After adjustment for confounding variables, peak tibial lead was a significant negative predictor of performance on the Wechsler Adult Intelligence Scale-Revised vocabulary subtest (p = 0.02), serial digit learning test (p = 0.04), Rey Auditory-Verbal Learning Test (immediate recall and recognition, p = 0.03 for each), Trail Making Test B (p = 0.03), finger tapping (dominant hand [p = 0.02] and nondominant hand [p < 0.01]), Purdue pegboard (dominant hand, nondominant hand, both hands, and assembly, p < 0.01 for each), and Stroop Test (p < 0.01). Moreover, with one exception, average neurobehavioral test scores were poorer at higher peak tibial lead levels. DMSA-chelatable lead was only significantly associated with choice reaction time (p = 0.01). CONCLUSION: Peak tibial lead was consistently associated with poorer neurobehavioral test scores, particularly in the domains of manual dexterity, executive ability, verbal intelligence, and verbal memory.

Adult↗

PubMed1999

Burden of migraine in the United States: disability and economic costs.

BACKGROUND: Migraine is a common disabling disease but its economic burden has not been adequately quantified. OBJECTIVE: To estimate the burden of migraine in the United States with respect to disability and economic costs. METHODS: The following data sources were used: published data, the Baltimore County Migraine Study, MEDSTAT's MarketScan medical claims data set, and statistics from the Census Bureau and the Bureau of Labor Statistics. Disability was expressed as bedridden days. Charges for migraine-related treatment were used as direct cost inputs. The human capital approach was used in the estimation of indirect costs. RESULTS: Migraineurs required 3.8 bed rest days for men and 5.6 days for women each year, resulting in a total of 112 million bedridden days. Migraine costs American employers about $13 billion a year because of missed workdays and impaired work function; close to $8 billion was directly due to missed workdays. Patients of both sexes aged 30 to 49 years incurred higher indirect costs compared with younger or older employed patients. Annual direct medical costs for migraine care were about $1 billion and about $100 was spent per diagnosed patient. Physician office visits accounted for about 60% of all costs; in contrast, emergency department visits contributed less than 1% of the direct costs. CONCLUSIONS: The economic burden of migraine predominantly falls on patients and their employers in the form of bedridden days and lost productivity. Various screening and treatment regimens should be evaluated to identify opportunities to reduce the disease burden.

Absenteeism↗

PubMed1999

Screening for dementia with the memory impairment screen.

OBJECTIVES: To validate a sensitive and specific screening test for AD and other dementias, assess its reliability and discriminative validity, and present normative data for its use in various applied settings. BACKGROUND: To improve discrimination in screening for AD and dementia, we developed the Memory Impairment Screen (MIS), a 4-minute, four-item, delayed free- and cued-recall test of memory impairment. The MIS uses controlled learning to ensure attention, induce specific semantic processing, and optimize encoding specificity to improve detection of dementia. METHODS: Equivalent forms of the MIS were given at the beginning and end of the testing session to assess alternate forms reliability. Discriminative validity was assessed in a criterion sample of 483 aged individuals, 50 of whom had dementia according to Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised) criteria. RESULTS: The MIS had good alternate forms reliability, high construct validity for memory impairment, and good discriminative validity in terms of sensitivity, specificity, and positive predictive value. We present normative data for use in settings with different base rates (prevalences) of AD and dementia. CONCLUSION: The MIS provides efficient, reliable, and valid screening for AD and other dementias.

Aged↗

PubMed1999

Treatment of menstruation-associated migraine with the nonprescription combination of acetaminophen, aspirin, and caffeine: results from three randomized, placebo-controlled studies.

This retrospective study sought to examine the benefits of the nonprescription combination of acetaminophen, aspirin, and caffeine (AAC; Excedrin Migraine, Bristol-Myers Squibb Company, New York, New York) for the treatment of menstruation-associated migraine compared with migraine not associated with menses. Data were derived from 3 double-masked, randomized, placebo-controlled, single-dose trials enrolling subjects who met the International Headache Society's diagnostic criteria for migraine with or without aura. Subjects with incapacitating disability (attacks requiring bed rest >50% of the time) and those who usually experienced vomiting > or =20% of the time were excluded. Retrospective analysis of the 1220 subjects included in the efficacy-evaluable data set indicated that 185 women treated menstruation-associated migraine, 781 women treated migraine not associated with menses, and 1 woman provided no information regarding menstrual status. At baseline and at 0.5, 1, 2, 3, 4, and 6 hours postdose, subjects assessed the intensity of headache pain, functional disability, nausea, photophobia, and phonophobia. Pain intensity, nausea, photophobia, and phonophobia were rated on a 4-point scale ranging from 0 = none to 3 = severe; functional disability was rated on a 5-point scale ranging from 0 = none to 4 = incapacitating. For both menstruation-associated migraine and migraine not associated with menses, the proportion of subjects with pain intensity reduced to mild or none (responders) was significantly greater with AAC than with placebo at all postdose time points from 0.5 through 6 hours (P< or =0.05), with no statistically significant difference in treatment effect between menstruation-associated migraine and migraine not associated with menses at any postdose time point. Migraine characteristics such as photophobia, phonophobia, and functional disability were significantly improved in AAC-treated subjects at all time points from 1 through 6 hours (P< or =0.01) in both the menstruating and nonmenstruating groups. Significant relief from nausea was experienced in both menstruation-associated migraine and migraine not associated with menses, but relief appeared earlier in the AAC nonmenstruating subjects (2 hours postdose, P< or =0.01) than in the menstruating subjects (6 hours postdose, P< or =0.05). Beginning at 3 hours postdose, significantly fewer subjects treated with AAC required rescue medication (P< or =0.05) for menstruation-associated migraine (AAC 6%, placebo 15%) and migraine not associated with menses (AAC 7%, placebo 14%). The most commonly used rescue medications in both the menstruating and nonmenstruating groups were nonsteroidal anti-inflammatory drugs, prescription combination analgesics/narcotics, and prescription migraine preparations. AAC was well tolerated in both menstruation-associated migraine and migraine not associated with menses; in general, adverse experiences were similar in both groups. The proportion of subjects who had 1 or more adverse experiences was significantly higher among those receiving AAC than among those receiving placebo (menstruation-associated migraine: AAC 26.4%, placebo 12.6%, P = 0.025; nonmenstruation-associated migraine: AAC 18.6%, placebo 11.4%, P = 0.005). Adverse experiences were similar in type and severity to those previously associated with single doses of acetaminophen, aspirin, or caffeine. Thus the nonprescription combination of AAC was highly effective in treating the pain, disability, and associated symptoms of both menstruation-associated migraine and migraine not associated with menses.

Acetaminophen↗

PubMed1999

Validity of an illness severity measure for headache in a population sample of migraine sufferers.

The headache impact questionnaire (HImQ) is used to measure pain and activity limitations from headache over a 3-month recall period. In a prior study, the test-retest reliability of the eight-item HImQ score was found to be relatively high (0.86). In the current study, we examined the validity of the eight-item HImQ by comparing the overall score and individual items to equivalent measures from a 90-day diary. Pain and activity limitations due to headache were assessed in a population-based sample of 132 migraine headache sufferers enrolled in a 90-day daily diary study who completed the HImQ at the end of the study. The HImQ score was derived from four frequency-based questions (i.e. number of headaches, missed days of work, missed days of chores, or missed days of non-work activity) and four summary measures of average experience across headaches (i.e. average pain intensity, and average reduced effectiveness when having a headache at work, during household chores, and in non-work activity). Diary based measures were used as the gold standard in evaluating the HImQ score. Mean and median values of frequency-based HImQ items (e.g. number of headaches) were similar to equivalent diary measures, indicating no systematic bias. In contrast, HImQ measures of average experience across attacks (e.g. average pain intensity) overestimated equivalent diary measures and, in general, better approximated diary measures for migraine headaches, rather than all headaches. The highest correlations between HImQ and diary items were observed for headache frequency and average pain intensity, the two general headache measures, followed by measures of reduced effectiveness. Among frequency-based measures, the strength of the correlation was directly related to the magnitude of the mean. The higher the mean value, the higher the correlation. The correlation between the HImQ score and diary based score was 0.49. The HImQ score is moderately valid. Frequency-based items (e.g. number of missed work days) were found to be unbiased and the highest correlation coefficients were observed for frequency-based items with relatively high mean counts (number of headaches, number of missed non-work days). These findings have implications for measuring severity of chronic episodic conditions like headache, asthma, back pain, arthritis, epilepsy, and panic disorder, which can cause limitations to activities. The validity of illness severity measures may be improved by using frequency-based questions to assess both missed activity days and days with significantly reduced effectiveness or productivity (e.g. by 50% or more). By combining the count for both missed days and days where productivity is substantially reduced, the mean of the frequency-based measure will be increased, a factor which may improve the overall validity of the item. A severity measure can be derived from such items by simple addition and provides a scale with intuitively meaningful units.

Adolescent↗

PubMed1999

Reliability of the migraine disability assessment score in a population-based sample of headache sufferers.

BACKGROUND: The Migraine Disability Assessment (MIDAS) score is used to quantify headache-related disability. In a previous study, we showed that the MIDAS score was highly reliable in population-based samples of migraine headache sufferers in two countries. OBJECTIVES: To examine the test-retest reliability and internal consistency of the five items comprising the MIDAS score and the overall MIDAS score in a population-based sample of both migraine and nonmigraine headache sufferers. METHODS: Using a clinically validated telephone interview, a population-based sample of migraine and nonmigraine headache sufferers was identified in Baltimore, Maryland, USA. A total of 97 migraine cases and 80 nonmigraine subjects completed the MIDAS questionnaire on two occasions an average of 3 weeks apart. The MIDAS score is derived from five questions about missed time from work (or school) and household work (one question each about missed days and days with at least 50% reduced productivity) and missed days of nonwork activities. RESULTS: Among all headache sufferers the test-retest Spearman's correlations of individual MIDAS questions ranged from 0.67 to 0.73. The Spearman's correlation for the MIDAS score (i.e., sum of lost days and reduced effectiveness days in each domain) was 0.84. Cronbach's alpha, a measure of internal consistency, was 0.83. Mean and median item values and the overall MIDAS scores differed between migraine and nonmigraine cases. Even after adjusting for differences in headache frequency, the mean MIDAS scores differed substantially (i.e., 10.3 points) between migraine cases and nonmigraine cases. CONCLUSIONS: The reliability and internal consistency of the MIDAS score are high, as tested in a population-based sample of headache sufferers. MIDAS scores are substantially higher in migraine cases than in non-migraine cases, supporting the validity of the measure.

Adolescent↗

PubMed1999

Epidemiology of constipation (EPOC) study in the United States: relation of clinical subtypes to sociodemographic features.

OBJECTIVE: Constipation is a common heterogeneous condition, possibly encompassing different clinical subtypes. Little is known about the comparative epidemiology of constipation subtypes. This study was conducted to estimate the prevalence of constipation subtypes and determine whether subtypes differ by sociodemographic factors. METHODS: Between June and September 1997, a telephone interview was conducted with individuals about their bowel habits in the preceding 3 months. Survey data on 15 constipation-related symptoms were used to identify individuals who met prespecified symptom criteria for the following mutually exclusive subgroups: functional constipation, irritable bowel syndrome (IBS), outlet obstruction or delay (outlet), both IBS and outlet (IBS-outlet), and frequent laxative users (i.e., at least every other day). A total of 10,018 eligible individuals in the United States 18 yr of age or older completed the interview. Test-retest reliability of reporting symptoms was assessed in a separate national survey. The Spearman's correlation coefficient for reporting symptoms ranged from 0.54 to 0.83; all but three symptoms had correlations above 0.68. RESULTS: The overall prevalence of constipation was 14.7%. By subtype, prevalence was 4.6% for functional, 2.1% for IBS, 4.6% for outlet, and 3.4% for IBS-outlet. An additional 1.8% of respondents reported laxative use at least every other day. Outlet was the most common subtype among women, whereas functional constipation was the most common subtype among men. The gender ratio varied by subtype, with elevated ratios for outlet (F/M = 1.65) and IBS-outlet (F/M = 2.27) subtypes. The age pattern differed among each of the four subtypes. Prevalence of functional subtype decreased with increasing age. In contrast, outlet subtype did not seem to vary by age, and IBS (both men and women) and IBS-outlet (women only) subtypes increased to age 35 yr and declined thereafter. Prevalence of functional constipation increased with increasing education. Outlet type was more common in nonwhites compared to whites. Finally, 45% of individuals with constipation reported having the condition for 5 yr or more. CONCLUSIONS: Constipation is a heterogeneous condition. Differences in epidemiological profile by age, sex ratio, and relation to other sociodemographical factors support the distinction of two and possibly more symptom-based subtypes.

Adolescent↗

PubMed1999

Predictors of dimercaptosuccinic acid chelatable lead and tibial lead in former organolead manufacturing workers.

OBJECTIVES: To identify predictors of tibial and dimercaptosuccinic acid (DMSA) chelatable lead in 543 organolead manufacturing workers with past exposure to organic and inorganic lead. METHODS: In this cross sectional study, tibial lead (by 109Cd K-shell x ray fluorescence), DMSA chelatable lead (4 hour urinary lead excretion after oral administration of 10 mg/kg), and several exposure measures were obtained on study participants, mean (SD) age 57.6 (7.6) years. RESULTS: Tibial lead concentrations ranged from -1.6 to 52.0 micrograms lead/g bone mineral, with a mean (SD) of 14.4 (9.3) micrograms/g. DMSA chelatable lead ranged from 1.2 to 136 micrograms, with a mean (SD) of 19.3 (17.2) micrograms. In a multiple linear regression model of tibial lead, age (p < 0.01), duration of exposure (p < 0.01), current (p < 0.01) and past (p = 0.05) cigarette smoking, and diabetes (p = 0.01) were all independent positive predictors, whereas height (p = 0.03), and exercise inducing sweating (p = 0.04) were both negative predictors. The final regression model accounted for 31% of the variance in tibial lead concentrations; 27% was explained by age and duration of exposure alone. DMSA chelatable lead was directly associated with tibial lead (p = 0.01), cumulative exposure to inorganic lead (y.microgram/m3, p = 0.01), current smoking (p < 0.01), and weight (p < 0.01), and negatively associated with diabetes (p = 0.02). The final model accounted for 11% of the variance in chelatable lead. When blood lead was added to this model of DMSA chelatable lead, tibial lead, cumulative exposure to inorganic lead, and diabetes were no longer significant; blood lead accounted for the largest proportion of variance (p < 0.001); and the total model r2 increased to 19%. CONCLUSIONS: The low proportions of variance explained in models of both tibial and chelatable lead suggest that other factors are involved in the deposition of lead in bone and soft tissue. In epidemiological studies of the health effects of lead, evaluation of associations with both these measures may allow inferences to be made about whether health effects are likely to be recent, and thus potentially reversible, or chronic, and thus possibly irreversible. The data also provide direct evidence that in men the total amount of lead in the body that is bioavailable declines with age.

Adult↗

PubMed1998

Epidemiology of tension-type headache.

CONTEXT: Tension-type headache is a highly prevalent condition. Because few population-based studies have been performed, little is known about its epidemiology. OBJECTIVES: To estimate the 1-year period prevalence of episodic tension-type headache (ETTH) and chronic tension-type headache (CTTH) in a population-based study; to describe differences in 1-year period prevalence by sex, age, education, and race; and to describe attack frequency and headache pain intensity. DESIGN: Telephone survey conducted 1993 to 1994. SETTING: Baltimore County, Maryland. PARTICIPANTS: A total of 13 345 subjects from the community. MAIN OUTCOME MEASURES: Percentage of respondentswith diagnoses of headache using International Headache Society criteria. Workdays lost and reduced effectiveness at work, home, and school because of headache, based on self-report. RESULTS: The overall prevalence of ETTH in the past year was 38.3%. Women had a higher 1-year ETTH prevalence than men in all age, race, and education groups, with an overall prevalence ratio of 1.16. Prevalence peaked in the 30- to 39-year-old age group in both men (42.3%) and women (46.9%). Whites had a higher 1-year prevalence than African Americans in men (40.1% vs. 22.8%) and women (46.8% vs 30.9%). Prevalence increased with increasing educational levels in both sexes, reaching a peak in subjects with graduate school educations of 48.5% for men and 48.9% for women. The 1-year period prevalence of CTTH was 2.2%; prevalence was higher in women and declined with increasing education. Of subjects with ETTH, 8.3% reported lost workdays because of their headaches, while 43.6% reported decreased effectiveness at work, home, or school. Subjects with CTTH reported more lost workdays (mean of 27.4 days vs 8.9 days for those reporting lost workdays) and reduced-effectiveness days (mean of 20.4 vs 5.0 days for those reporting reduced effectiveness) compared with subjects with ETTH. CONCLUSIONS: Episodic tension-type headache is a highly prevalent condition with a significant functional impact at work, home, and school. Chronic tension-type headache is much less prevalent than ETTH; despite its greater individual impact, CTTH has a smaller societal impact than ETTH.

Absenteeism↗

PubMed1998

Efficacy and safety of acetaminophen, aspirin, and caffeine in alleviating migraine headache pain: three double-blind, randomized, placebo-controlled trials.

OBJECTIVE: To assess the effectiveness of the nonprescription combination of acetaminophen, aspirin, and caffeine in alleviating migraine headache pain. DESIGN: Three double-blind, randomized, parallel-group, single-dose, placebo-controlled studies. SETTING: Private practice, referral centers, and general community. PATIENTS: Migraineurs with moderate or severe headache pain who met International Headache Society diagnostic criteria for migraine with aura or without aura. The most severely disabled segment of migraineurs, including those whose attacks usually required bed rest, or who vomited 20% or more of the time, were excluded. Of the 1357 enrolled patients, 1250 took study medication and 1220 were included in the efficacy-evaluable data set. INTERVENTION: Two tablets of the nonprescription combination of acetaminophen, aspirin, and caffeine or placebo taken orally as a single-dose treatment of 1 eligible acute migraine attack. MAIN OUTCOME MEASURES: Pain intensity difference from baseline; percentage of patients with pain reduced to mild or none. RESULTS: Significantly greater reductions in migraine headache pain intensity 1 to 6 hours after dose were seen in patients taking the acetaminophen, aspirin, and caffeine combination than in those taking placebo in each of the 3 studies. Pain intensity was reduced to mild or none 2 hours after dose in 59.3% of the 602 drug-treated patients compared with 32.8% of the 618 placebo-treated patients (P< .001; 95% confidence interval [CI], 55%-63% for drug, 29%-37% for placebo); at 6 hours after dose, 79% vs 52%, respectively, had pain reduced to mild or none (P<.001; 95% CI, 75%-82% vs 48%-56%). In addition, by 6 hours after dose, 50.8% of the drug-treated patients were pain free compared with 23.5% of the placebo-treated patients (P<.001; 95% CI, 47%-55% for drug, 20%-27% for placebo). Other migraine headache characteristics, such as nausea, photophobia, phonophobia, and functional disability, were significantly improved 2 to 6 hours after treatment with the acetaminophen, aspirin, and caffeine combination compared with placebo (P< or =.01). CONCLUSIONS: The nonprescription combination of acetaminophen, aspirin, and caffeine was highly effective for the treatment of migraine headache pain as well as for alleviating the nausea, photophobia, phonophobia, and functional disability associated with migraine attacks. This drug combination also has an excellent safety profile and is well tolerated.

Acetaminophen↗

PubMed1998

Reliability of an illness severity measure for headache in a population sample of migraine sufferers.

OBJECTIVES: To examine the reliability and related measurement properties of an illness severity measure for headache derived from responses to a 16-item self-administered questionnaire, the Headache Impact Questionnaire (HImQ), and to determine if there is support for combining measures of pain and disability into a single scaled measure of severity. METHODS: A population-based sample of migraine headache sufferers completed the HImQ twice, an average of 38 days apart. The HImQ included questions about number of headaches in the last 3 months, headache duration, last headache, pain intensity (two questions), need for bedrest (two questions), disability in specific domains of activity (seven questions about interference with ability to work, do household chores, and engage in non-work activity), and symptoms (two questions). RESULTS: Test-retest correlations of individual questions ranged from 0.65 to 0.93. In principal components analysis, a single factor with significant loading emerged. One measure of pain intensity (average pain score from 0 to 10) and items related to disability (i.e., missed days due to headache, and reduced effectiveness because of headache) in defined activity domains (work for pay, housework, nonwork activities) had the greatest weights on this single factor, supporting prior work on combining measures of pain and disability into a single scale. The HImQ score was derived as the sum of average pain intensity and total lost time in each of the three domains of activity, expressed as lost days. The latter was derived as the sum of actual missed days in each activity domain and reduced effectiveness day equivalents in each activity with a headache. The test-retest correlation was 0.77 for all eligible subjects and 0.85 when one influential outlier was removed. Cronbach's alpha was 0.83. CONCLUSIONS: The HImQ score, based on eight items, is a highly reliable and internally consistent measure of headache severity.

Activities of Daily Living↗

PubMed1998

Medical consultation for migraine: results from the American Migraine Study.

BACKGROUND: Migraine headaches are often disabling but usually responsive to treatment. Nonetheless, many people with migraine never consult a doctor for headaches. In a sample of the US population, we sought to determine the proportion of active migraineurs who ever consulted a doctor for headache and to identify the headache characteristics and sociodemographic factors associated with consulting. METHOD: A mailed questionnaire survey was sent to 15,000 US households, selected from a panel to be representative of the US population. Of 20,468 eligible respondents ranging in age from 12 to 80 years, 2479 met a case definition for migraine. We mailed a second questionnaire to all migraineurs identified on the first survey and achieved a 69.4% response rate. The second survey assessed headache characteristics, patterns of medical care use, medication use, and method of payment for health care. RESULTS: Sixty-eight percent of female and 57% of male migraineurs reported having ever consulted a doctor for headache. Consultation was more likely with increasing age and in women who ever married. In females, several headache characteristics including pain intensity, number of migraine symptoms, attack duration, and disability were associated with consultation. Of those who never consult, 61% report severe or very severe pain and 67% report severe disability or the need for bed rest with their headaches. CONCLUSION: The results of this survey indicate that a significant proportion of migraine sufferers never consult doctors for their headaches. Given that a large proportion of persons who never consult report high levels of pain and disability, these data suggest that there are opportunities to appropriately increase health care utilization for migraine. Given that 40% of migraineurs who have ever consulted do not report a physician diagnosis of migraine, there is a need to improve headache diagnosis and/or doctor-patient communication about migraine.

Adolescent↗