Comorbidity of migraine and depression: investigating potential etiology and prognosis

BACKGROUND

An association between migraine and major depression has been observed in clinical and community samples. The factors that contribute to this association and their implications remain unclear.

OBJECTIVE

To determine the factors contributing to the association of migraine and major depression.

METHODS

A cohort study of persons aged 25 to 55 years with migraine (n = 496) or with other headaches of comparable severity (n = 151) and control subjects with no history of severe headaches (n = 539) randomly selected from the general community were interviewed first in 1997 and then reinterviewed in 1999.

RESULTS

Major depression at baseline predicted the first-onset migraine during the 2-year follow-up period (odds ratio [OR] = 3.4; 95% CI = 1.4, 8.7) but not other severe headaches (OR = 0.6; 95% CI = 0.1, 4.6). Migraine at baseline predicted the first-onset major depression during follow-up (OR = 5.8; 95% CI = 2.7, 12.3); the prospective association from severe headaches to major depression was not significant (OR = 2.7; 95% CI = 0.9, 8.1). Comorbid major depression did not influence the frequency of migraine attacks, their persistence, or the progression of migraine-related disability over time.

CONCLUSIONS

Major depression increased the risk for migraine, and migraine increased the risk for major depression. This bidirectional association, with each disorder increasing the risk for first onset of the other, was not observed in relation to other severe headaches. With respect to other severe headaches, there was no increased risk associated with pre-existing major depression, although the possibility of an influence in the reverse direction (i.e., from severe headaches to depression) cannot be securely ruled out.

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.

Diagnostic lessons from the spectrum study

Article abstract Migraine is a heterogeneous condition that causes symptoms that vary both among individuals and within individuals from attack to attack. We examined and reviewed several important lessons on the diagnosis of migraine learned from the distribution of headache types and patterns of treatment response in the Spectrum Study, including recruitment and diagnostic issues. The accuracy of an initial diagnosis, assigned by a clinician in the context of a clinical trial, was compared with the results of a final diagnosis, assigned by a neurologist, reviewing the initial evaluation as well as headache diaries for up to 10 attacks. Several lessons can be learned from the Spectrum Study. Recruitment difficulties teach us that disabling tension-type headache is difficult to find, suggesting that it is rare. Examination of the final diagnosis given after diary evaluations suggests that a diagnosis of migraine can usually be confirmed for patients with disabling headache. After reclassification of the final sample of 432 subjects, 24/75 (32%) patients initially clinically classified as having disabling episodic tension-type headache proved to have migraine or migrainous headache after a diary review. Among study participants, 90% of subjects with disabling headache (HIMQ score >250) had a migraine-related disorder. Treatment response suggests that, in migraineurs, tension-type headaches may have a pathophysiology similar to that of migraine. The diary data show that mild headaches in patients with disabling migraine often evolve into full-blown migraine. The Spectrum Study supports the view that, for patients with disabling episodic headache, migraine is often the correct diagnosis. In clinical practice, the suspicion of migraine should be high for patients experiencing episodic disabling headache. Assessment of headache-related disability may assist practitioners in making a diagnosis of migraine.

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.

Associations of lead biomarkers and delta-aminolevulinic acid dehydratase and vitamin D receptor genotypes with hematopoietic outcomes in Korean lead workers

OBJECTIVES

This study compares and contrasts associations of dimercaptosuccinic acid (DMSA)-chelatable lead, tibia lead, and blood lead with five hematopoietic outcomes and evaluates the effect modification of these relations by polymorphisms in the delta-aminolevulinic acid dehydratase (ALAD) and vitamin D receptor (VDR) genes.

METHODS

A cross-sectional study of 798 lead workers and 135 unexposed referents was performed.

RESULTS

The DMSA-chelatable lead, tibia lead, and blood lead levels ranged in the lead (Pb) workers from 4.8 to 2103 g, -7 to 338 g Pb/g bone mineral, and 4 to 86 g/dl, respectively. The mean of the hemoglobin, hematocrit, zinc protoporphyrin (ZPP), and urinary (ALAU) and plasma (ALAP) delta-aminolevulinic acid levels of the lead workers were 14.2 (SD 1.4) g/dl, 42.4 (SD 4.4)%, 80.2 (SD 63.5) g/dl, 2.1 (SD 3.7) mg/l, and 17.7 (20.6) g/ml, respectively. After adjustment for the covariates, tibia lead was associated with all five hematopoietic outcomes, while blood lead and DMSA-chelatable lead were associated only with ZPP, ALAP, and ALAU. A comparison of the regression coefficients, total model adjusted R2 values, and delta R2 values revealed that blood lead was the best predictor of ZPP, ALAP, and ALAU. Only tibia lead was significantly associated with hemoglobin and hematocrit levels, but the additional variance explained by tibia lead was (<1%). No clear effect modification of the relations between the lead biomarkers and hematopoietic outcomes studied was caused by ALAD or VDR genotype.

CONCLUSIONS

Lead must have a chronic, cumulative effect on hemoglobin and hematocrit levels, and any speculated mechanism cannot merely involve short-term plasma or target organ lead levels.

Clinical utility of an instrument assessing migraine disability: the Migraine Disability Assessment (MIDAS) questionnaire

OBJECTIVE

We evaluated the agreement between Migraine Disability Assessment (MIDAS) scores and independent physician judgments about pain, disability, and treatment needs based on patient medical histories.

BACKGROUND

The MIDAS questionnaire measures headache-related disability as lost time due to headache from paid work or school, household work, and nonwork activities.

METHODS

Twelve histories from patients with migraine were presented to 49 primary and specialty care physicians unaware of the MIDAS scores. Physicians graded each patient for pain level (mild, moderate, or severe), level of disability (none, mild, moderate, or severe), and need for medical care (from 0 [lowest] to 100 [highest]). Physicians also identified MIDAS scores they associated with different degrees of disability and with the urgency to prescribe an effective treatment during the first consultation.

RESULTS

The physicians' perceptions of the need for medical care based on medical histories correlated with the MIDAS score (r =.69). Estimates of pain and disability by physicians were directly correlated with increasing MIDAS scores. Using the physicians' clinical judgments, the overall MIDAS score was categorized into four grades of increasing severity.

CONCLUSIONS

Scores on the MIDAS are highly correlated with physician judgments regarding patients' pain, disability, and need for medical care. These findings support the potential utility of the MIDAS questionnaire in clinical practice.

Coping strategies and health care-seeking behavior in a US national sample of adults with symptoms suggestive of overactive bladder

BACKGROUND

Although millions of individuals have symptoms suggestive of overactive bladder (OAB), few ever seek or receive medical treatment for their condition.

OBJECTIVE

The purpose of this study was to describe coping strategies and health care-seeking behavior in a community-based sample of adults with symptoms suggestive of OAB.

METHODS

A cross-sectional household telephone survey of an age- and sex-stratified sample of adults was conducted. The survey consisted of general health-related questions as well as questions related to OAB symptoms. A total of 4896 adults completed the interview Respondents were considered to have OAB if they reported > or = 1 symptom of urinary urgency, frequency, or urge incontinence. A follow-up questionnaire was then mailed to a subsample of the telephone interview respondents. The mailed questionnaire contained questions related to type and severity of OAB symptoms, coping strategies, medical care/treatment, feelings/beliefs about OAB, and quality of life. Half of the phone respondents with urinary incontinence (n = 638) and a random sample of all other phone respondents received the mailed questionnaire (n = 873); 1,034 questionnaires were returned.

RESULTS

Of the respondents with OAB, 69.6% tried > or = 1 nonmedical coping strategy. Respondents with incontinent OAB were significantly more likely than those with continent OAB or those with no OAB (controls) to use nonmedical coping strategies (incontinent OAB, 76.1%; continent OAB, 59.0%; controls, 31.9%; P < 0.001). Fewer than half of the respondents with OAB (43.5%) had spoken with a provider about OAB in the previous 12 months. Medical consultation was associated with sex, type and severity of OAB, number of nonmedical coping strategies tried, number of OAB information sources consulted, inclination to try new OAB medications, and feelings/beliefs about OAB. In 90% of patient-provider discussions about OAB, the patient initiated the topic.

CONCLUSIONS

Individuals manage symptoms suggestive of OAB primarily by using nonmedical coping strategies rather than consulting health care providers. Results of this study support the need for improved clinical recognition of OAB and increased patient-provider communication about this condition.

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.

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.

Health-related quality of life among adults with symptoms of overactive bladder: results from a U.S. community-based survey

OBJECTIVES

To assess, by means of a survey, the impact of the symptoms of overactive bladder (urinary frequency, urgency, and urge incontinence) on the quality of life in a community-based sample of the U.S. population.

METHODS

A telephone survey was conducted in the United States among an age and sex-stratified sample of 4896 noninstitutionalized adults 18 years of age and older. From the responses to the telephone survey, a total of 483 individuals with symptoms of overactive bladder and 191 controls completed a mailed follow-up questionnaire to assess their quality of life using the Medical Outcomes Study Short-Form 20.

RESULTS

After adjustment for age, sex, and the use of medical care, the greatest differences in the quality-of-life scores between the patients with incontinent overactive bladders and the controls were in the health perception (17.6 points; P <0.001) and role functioning (13.0 points; P <0.001) scales. Those with an overactive bladder with the symptoms of frequency or urgency, or both, but without incontinence, also had significantly lower scores than did the controls in mental health (P = 0.026), health perception (P = 0.01), and bodily pain (P = 0.016).

CONCLUSIONS

These data indicate that individuals with an overactive bladder experience decrements in their quality of life relative to community controls. An important new finding from this study is that individuals with an overactive bladder, even without demonstrable urine loss, also have a poorer quality of life than that of controls.

Development and testing of the Migraine Disability Assessment (MIDAS) Questionnaire to assess headache-related disability

The MIDAS Questionnaire was developed to assess headache-related disability with the aim of improving migraine care. Headache sufferers answer five questions, scoring the number of days, in the past 3 months, of activity limitations due to migraine. The internal consistency, test-retest reliability, and validity (accuracy) of the questionnaire were assessed in separate population-based studies of migraine sufferers. In addition, the face validity, ease of use, and clinical utility of the questionnaire were evaluated in a group of 49 physicians who independently rated disease severity and need for care in a diverse sample of migraine case histories. The test-retest Pearson correlation coefficient for the total MIDAS score was approximately 0.8. The MIDAS score was valid when compared with a reference diary-based measure of disability; the overall correlation between MIDAS and the diary-based measure was 0.63. The MIDAS score was also correlated with physicians' assessments of need for medical care (r = 0.69). From studies completed to date, the MIDAS Questionnaire has been shown to be internally consistent, highly reliable, valid, and correlates with physicians' clinical judgment. These features support its suitability for use in clinical practice. Use of the MIDAS Questionnaire may improve physician-patient communication about headache-related disability and may favorably influence health-care delivery for migraine patients.

Associations of blood pressure and hypertension with lead dose measures and polymorphisms in the vitamin D receptor and delta-aminolevulinic acid dehydratase genes

Evidence suggests that lead and selected genes known to modify the toxicokinetics of lead--namely, those for the vitamin D receptor (VDR) and delta-aminolevulinic acid dehydratase (ALAD)--may independently influence blood pressure and hypertension risk. We report the relations among ALAD and VDR genotypes, three lead dose measures, and blood pressure and hypertension status in 798 Korean lead workers and 135 controls without occupational exposure to lead. Lead dose was assessed by blood lead, tibia lead measured by X-ray fluorescence, and dimercaptosuccinic acid (DMSA)-chelatable lead. Among lead workers, 9.9% (n = 79) were heterozygous for the ALAD(2) allele, and there were no ALAD(2) homozygotes; 11.2% (n = 89) had at least one copy of the VDR B allele, and 0.5% (n = 4) had the BB genotype. In linear regression models to control for covariates, VDR genotype (BB and Bb vs. bb), blood lead, tibia lead, and DMSA-chelatable lead were all positive predictors of systolic blood pressure. On average, lead workers with the VDR B allele, mainly heterozygotes, had systolic blood pressures that were 2.7-3.7 mm Hg higher than did workers with the bb genotype. VDR genotype was also associated with diastolic blood pressure; on average, lead workers with the VDR B allele had diastolic blood pressures that were 1.9-2.5 mm Hg higher than did lead workers with the VDR bb genotype (p = 0.04). VDR genotype modified the relation of age with systolic blood pressure; compared to lead workers with the VDR bb genotype, workers with the VDR B allele had larger elevations in blood pressure with increasing age. Lead workers with the VDR B allele also had a higher prevalence of hypertension compared to lead workers with the bb genotype [adjusted odds ratio (95% confidence interval) = 2.1 (1.0, 4.4), p = 0.05]. None of the lead biomarkers was associated with diastolic blood pressure, and tibia lead was the only lead dose measure that was a significant predictor of hypertension status. In contrast to VDR, ALAD genotype was not associated with the blood pressure measures and did not modify associations of the lead dose measures with any of the blood pressure measures. To our knowledge, these are the first data to suggest that the common genetic polymorphism in the VDR is associated with blood pressure and hypertension risk. We speculate that the BsmI polymorphism may be in linkage disequilibrium with another functional variant at the VDR locus or with a nearby gene.

Associations of blood pressure and hypertension with lead dose measures and polymorphisms in the vitamin D receptor and delta-aminolevulinic acid dehydratase genes

Evidence suggests that lead and selected genes known to modify the toxicokinetics of lead--namely, those for the vitamin D receptor (VDR) and delta-aminolevulinic acid dehydratase (ALAD)--may independently influence blood pressure and hypertension risk. We report the relations among ALAD and VDR genotypes, three lead dose measures, and blood pressure and hypertension status in 798 Korean lead workers and 135 controls without occupational exposure to lead. Lead dose was assessed by blood lead, tibia lead measured by X-ray fluorescence, and dimercaptosuccinic acid (DMSA)-chelatable lead. Among lead workers, 9.9% (n = 79) were heterozygous for the ALAD(2) allele, and there were no ALAD(2) homozygotes; 11.2% (n = 89) had at least one copy of the VDR B allele, and 0.5% (n = 4) had the BB genotype. In linear regression models to control for covariates, VDR genotype (BB and Bb vs. bb), blood lead, tibia lead, and DMSA-chelatable lead were all positive predictors of systolic blood pressure. On average, lead workers with the VDR B allele, mainly heterozygotes, had systolic blood pressures that were 2.7-3.7 mm Hg higher than did workers with the bb genotype. VDR genotype was also associated with diastolic blood pressure; on average, lead workers with the VDR B allele had diastolic blood pressures that were 1.9-2.5 mm Hg higher than did lead workers with the VDR bb genotype (p = 0.04). VDR genotype modified the relation of age with systolic blood pressure; compared to lead workers with the VDR bb genotype, workers with the VDR B allele had larger elevations in blood pressure with increasing age. Lead workers with the VDR B allele also had a higher prevalence of hypertension compared to lead workers with the bb genotype [adjusted odds ratio (95% confidence interval) = 2.1 (1.0, 4.4), p = 0.05]. None of the lead biomarkers was associated with diastolic blood pressure, and tibia lead was the only lead dose measure that was a significant predictor of hypertension status. In contrast to VDR, ALAD genotype was not associated with the blood pressure measures and did not modify associations of the lead dose measures with any of the blood pressure measures. To our knowledge, these are the first data to suggest that the common genetic polymorphism in the VDR is associated with blood pressure and hypertension risk. We speculate that the BsmI polymorphism may be in linkage disequilibrium with another functional variant at the VDR locus or with a nearby gene.

Intraneuronal abeta-amyloid precedes development of amyloid plaques in Down syndrome

CONTEXT

Down syndrome patients who live to middle age invariably develop the neuropathologic features of Alzheimer disease, providing a unique situation in which to study the early and sequential development of these changes.

OBJECTIVE

To study the development of amyloid deposits, senile plaques, astrocytic and microglial reactions, and neurofibrillary tangles in the brains of young individuals (<30 years of age) with Down syndrome.

METHODS

Histologic and immunocytochemical study of a series of autopsy brains (n = 14, from subjects aged 11 months to 56 years, with 9 subjects <30 years) examined at the Office of the Chief Medical Examiner of the State of Maryland and The Johns Hopkins Hospital.

RESULTS

The principal observations included the presence of intraneuronal Abeta immunostaining in the hippocampus and cerebral cortex of very young Down syndrome patients (preceding the extracellular deposition of Abeta) and the formation of senile plaques and neurofibrillary tangles.

CONCLUSIONS

We propose the following sequence of events in the development of neuropathologic changes of Alzheimer disease in Down syndrome: (1) intracellular accumulation of Abeta in neurons and astrocytes, (2) deposition of extracellular Abeta and formation of diffuse plaques, and (3) development of neuritic plaques and neurofibrillary tangles with activation of microglial cells.

Epidemiology of migraine

Migraine is a highly prevalent headache disorder that has a substantial impact on the individual and society. Over the past decade, substantial advances in research have increased understanding of the pathophysiology, diagnosis, epidemiology, and treatment of the disorder. This article reviews data on the epidemiology and impact of migraine. It also highlights the increased awareness of migraine, citing examples from the popular media and the Internet.

Characterization of toxicokinetics and toxicodynamics with linear systems theory: application to lead-associated cognitive decline

We present a theoretical approach to analysis of toxicokinetics and toxicodynamics using linear systems theory. In our approach, we define two impulse response functions that characterize the kinetic behavior of an environmental agent in the body and the dynamic time-course behavior of its effect on the body. This approach provides a formalism for understanding the relation among exposure, dose, and cumulative biologically effective dose and for understanding the implications of an effect time-course on cross-sectional and longitudinal data analyses. We use lead-associated cognitive decline as a specific example where the approach may be applied.

Relation of alleles of the sodium-potassium adenosine triphosphatase alpha 2 gene with blood pressure and lead exposure

Lead is associated with elevated blood pressure, although the mechanism of action is unknown. Genetic differences in sodium-potassium adenosine triphosphatase (Na(+)-K(+)ATPase) could explain some of the variation in the strength of the blood pressure-blood lead relation that has been observed in previous studies. In 1996-1997, the authors studied the association of blood pressure, hypertension prevalence, and polymorphisms in the gene for the alpha 2 subunit of Na(+)-K(+)ATPase (ATP1A2) among 220 former organolead manufacturing workers from New Jersey. Subjects were genotyped for a restriction fragment length polymorphism (RFLP) on the ATP1A2 gene. The association between blood lead and blood pressure was stronger among persons who were homozygous for the variant allele. Genotype was also associated with hypertension (adjusted odds ratio = 7.7; 95% confidence interval: 1.9, 31.4). Finally, the variant allele was 1.8 times more common among African Americans than among Caucasians. The RFLP may indicate susceptibility to the effect of lead on blood pressure. Moreover, the alpha 2 gene (or a closely linked gene) may contribute to the pathophysiology of hypertension. However, because the number of subjects (especially African Americans) with the susceptible genotype in this study was small, these observations should be considered preliminary.

Associations of tibia lead, DMSA-chelatable lead, and blood lead with measures of peripheral nervous system function in former organolead manufacturing workers

BACKGROUND

The goals of the present study were to compare and contrast associations of blood lead, DMSA-chelatable lead, current tibia lead, and back-extrapolated "peak" tibia lead with four peripheral nervous system (PNS) sensory and motor function measures in older males with past exposure to organic and inorganic lead.

METHODS

Data were collected from former organolead manufacturing workers with an average of 16 years since last occupational lead exposure. Current tibia lead levels were measured by (109)Cd x-ray fluorescence. Sensory pressure thresholds (index and pinky fingers) and pinch and grip strength were measured with the Pressure-Specified Sensory Device (PSSD).

RESULTS

In adjusted analyses, none of the four lead biomarkers was associated with sensory pressure threshold of the index finger or pinch or grip strength. In contrast, all four biomarkers were associated (P < or = 0.10) with pressure threshold of the pinky finger. The final linear regression models accounted for a small proportion of the variance in the sensory (1-3%) and motor measures (10-21%).

CONCLUSIONS

This study found no strong association between lead biomarkers and selected PNS sensory or motor function measures among former organolead manufacturing workers with no recent occupational exposure to lead. Previously reported CNS findings in this cohort suggest that the PNS may be less sensitive to the chronic toxic effects of lead in this dose range among adults. It is also possible that the PNS has a greater capacity for repair than does the CNS, or that the PNS measures were less sensitive for detection of lead-related health outcomes than were the CNS measures.

Associations of blood lead, dimercaptosuccinic acid-chelatable lead, and tibia lead with neurobehavioral test scores in South Korean lead workers

The authors performed a cross-sectional study to evaluate associations between blood lead, tibia lead, and dimercaptosuccinic acid (DMSA)-chelatable lead and measures of neurobehavioral and peripheral nervous system function among 803 lead-exposed workers and 135 unexposed controls in South Korea. The workers and controls were enrolled in the study between October 1997 and August 1999. Central nervous system function was assessed with a modified version of the World Health Organization Neurobehavioral Core Test Battery. Peripheral nervous system function was assessed by measuring pinch and grip strength and peripheral vibration thresholds. After adjustment for covariates, the signs of the beta coefficients for blood lead were negative for 16 of the 19 tests and blood lead was a significant predictor of worse performance on eight tests. On average, for the eight tests that were significantly associated with blood lead levels, an increase in blood lead of 5 microg/dl was equivalent to an increase of 1.05 years in age. In contrast, after adjustment for covariates, tibia lead level was not associated with neurobehavioral test scores. Associations with DMSA-chelatable lead were similar to those for blood lead. In these currently exposed workers, blood lead was a better predictor of neurobehavioral performance than was tibia or DMSA-chelatable lead, mainly in the domains of executive abilities, manual dexterity, and peripheral motor strength.

Headache types and panic disorder: directionality and specificity

OBJECTIVE

To examine the relationship of migraine and other severe headaches with panic disorder.

METHODS

Representative samples of persons with migraine, non-migrainous severe headaches, and controls with no history of severe headaches, identified by a telephone survey, were interviewed in person, using a standardized psychiatric interview. Cox proportional hazards models with time-dependent covariates were used to examine the relationship of headaches with first-onset panic disorder and vice versa.

RESULTS

Lifetime prevalence of panic disorder was significantly higher in persons with migraine and in persons with other severe headaches, compared with controls. Migraine and other severe headaches were associated with an increased risk for first onset of panic disorder (hazards ratios = 3.55 and 5.75). Panic disorder was associated with an increased risk for first onset of migraine and for first onset of other severe headaches, although the influences in this direction were lower (hazards ratios = 2.10 and 1.85).

CONCLUSIONS

Comorbidity of panic disorder is not specific to migraine and applies also to other severe headaches. The influence is primarily from headaches to panic disorders, with a weaker influence in the reverse direction. The bidirectional associations, despite the difference in the strength of the associations, suggest that shared environmental or genetic factors might be involved in the comorbidity of panic disorder with migraine and other severe headaches.

Migraine's impact today. Burden of illness, patterns of care

Migraine is a common disorder that causes severe headaches and associated nausea, photophobia, phonophobia, and temporary disability. Though the pain and other symptoms of migraine can be effectively managed, the condition remains underdiagnosed and undertreated. In this article, Drs Lipton, Stewart, Reed, and Diamond consider the scope and distribution of the migraine problem and the current patterns of care in the United States.

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.