The Environment and Headache: a Narrative Review

PURPOSE OF REVIEW

In this narrative review, we summarize the peer-reviewed literature published between 2017 and 2022 that evaluated ambient environmental risk factors for primary headache disorders, which affect more than half of the population globally. Primary headache disorders include migraine, tension-type headache (TTH), and trigeminal and autonomic cephalalgias (TAC).

RECENT FINDINGS

We identified 17 articles that met the inclusion criteria via PubMed or Google Scholar. Seven studies (41%) relied on data from US populations. The remaining studies were conducted in China, Taiwan, Germany, Ghana, Japan, the Netherlands, South Korea, and Turkey. Air pollution was the most frequently assessed environmental risk factor. Most studies were cross-sectional and focused on all-cause or migraine headaches; one study included TTH, and none included TAC. Short-term exposure to fine particulate matter (PM2.5) was not consistently associated with headache endpoints, but long-term exposure to PM2.5 was associated with migraine headache prevalence and severity across multiple studies. Elevated ambient temperature, changes in weather, oil and gas well exposure, and less natural greenspace, but not noise pollution, were also associated with headache. No studies considered water pollution, metal exposure, ultrafine particulate matter, or wildfire smoke exposure. There is a need for ongoing research focused on headache and the environment. Study designs with the greatest explanatory power may include longitudinal studies that capture the episodic nature of headache and case-crossover analysis, which control for time-invariant individual-level confounders by design. There is also a clear need for research that considers comorbid psychiatric illness and socioeconomic position as powerful modifiers of the effect of the environment on headache.

A prospective exploration of the urban exposome in relation to headache in the Dutch population-based Occupational and environmental health cohort study (AMIGO)

OBJECTIVE

Headache is one of the most prevalent and disabling health conditions globally. We prospectively explored the urban exposome in relation to weekly occurrence of headache episodes using data from the Dutch population-based Occupational and Environmental Health Cohort Study (AMIGO).

MATERIAL AND METHODS

Participants (N = 7,339) completed baseline and follow-up questionnaires in 2011 and 2015, reporting headache frequency. Information on the urban exposome covered 80 exposures across 10 domains, such as air pollution, electromagnetic fields, and lifestyle and socio-demographic characteristics. We first identified all relevant exposures using the Boruta algorithm and then, for each exposure separately, we estimated the average treatment effect (ATE) and related standard error (SE) by training causal forests adjusted for age, depression diagnosis, painkiller use, general health indicator, sleep disturbance index and weekly occurrence of headache episodes at baseline.

RESULTS

Occurrence of weekly headache was 12.5 % at baseline and 11.1 % at follow-up. Boruta selected five air pollutants (NO2, NOX, PM10, silicon in PM10, iron in PM2.5) and one urban temperature measure (heat island effect) as factors contributing to the occurrence of weekly headache episodes at follow-up. The estimated causal effect of each exposure on weekly headache indicated positive associations. NO2 showed the largest effect (ATE = 0.007 per interquartile range (IQR) increase; SE = 0.004), followed by PM10 (ATE = 0.006 per IQR increase; SE = 0.004), heat island effect (ATE = 0.006 per one-degree Celsius increase; SE = 0.007), NOx (ATE = 0.004 per IQR increase; SE = 0.004), iron in PM2.5 (ATE = 0.003 per IQR increase; SE = 0.004), and silicon in PM10 (ATE = 0.003 per IQR increase; SE = 0.004).

CONCLUSION

Our results suggested that exposure to air pollution and heat island effects contributed to the reporting of weekly headache episodes in the study population.

Healthcare utilisation and economic burden of migraines among bank employees in China: a probabilistic modelling study

BACKGROUND

Despite the recognised high prevalence of migraines among bank employees, yet their healthcare utilisation patterns and the economic burden of migraines remain underexplored.

AIM

To examine migraine-related healthcare utilisation among bank employees in China, and to estimate the economic burden of migraines.

METHODS

A cross-sectional survey was conducted in Guizhou province, China between May and October 2022. The HARDSHIP questionnaire was used to identify migraine-positive individuals and enquire about their healthcare utilisation and productivity losses. A probabilistic decision-analytic model with a micro-costing approach was used to estimate the economic burden from the perspectives of the healthcare system, employers, and society. All costs were expressed in 2022 United States dollars. One-way and probabilistic sensitivity analyses were performed.

RESULTS

Nearly half of individuals with migraines reported not seeking medical care. Only 21.8% reported seeking outpatient consultations, 52.5% reported taking medicines, and 27.1% reported using complementary therapies. Chronic migraine patients had significantly higher healthcare utilisation than episodic migraine patients. Among individuals with a monthly migraine frequency of 15 days or more, 63.6% took inappropriate treatments by excessively using acute medications. Migraines in the banking sector in Guizhou cost the healthcare system a median of $7,578.0 thousand (25th to 75th percentile $4,509.2-$16,434.9 thousand) per year, employers $89,750.3 thousand (25th to 75th percentile $53,211.6-$151,162.2 thousand), and society $108,850.3 thousand (25th to 75th percentile $67,370.1-$181,048.6 thousand). The median societal cost per patient-year is $3,078.1. Migraine prevalence and productivity losses were identified as key cost drivers.

CONCLUSIONS

The study points to the need to raise awareness of migraines across all stakeholders and to improve the organisation of the migraine care system. A substantial economic burden of migraines on the healthcare system, employers, and society at large was highlighted. These cost estimates offer evidence-based benchmarks for assessing economic savings from improved migraine management, and can also draw the attention of Chinese policymakers to prioritise migraine policies within the banking and other office-based occupations.

The association between ambient air pollution and migraine: a systematic review

Some studies have shown the effect of air pollution on migraine. However, it needs to be confirmed in larger-scale studies, as scientific evidence is scarce regarding the association between air pollution and migraine. Therefore, this systematic review aims to determine whether there are associations between outdoor air pollution and migraine. A literature search was performed in Scopus, Medline (via PubMed), EMBASE, and Web of Science. A manual search for resources and related references was also conducted to complete the search. All observational studies investigating the association between ambient air pollution and migraine, with inclusion criteria, were entered into the review. Fourteen out of 1417 identified articles met the inclusion criteria and entered the study. Among the gaseous air pollutants, there was a correlation between exposure to nitrogen dioxide (NO2) (78.3% of detrimental relationships) and carbon monoxide (CO) (68.0% of detrimental relationships) and migraine, but no apparent correlation has been found for sulfur dioxide (SO2) (21.2% of detrimental relationships) and ozone (O3) (55.2% of detrimental relationships). In the case of particulate air pollutants, particulate matter with a diameter of 10 μm or less (PM10) (76.0% of detrimental relationships) and particulate matter with a diameter of 2.5 μm or less (PM2.5) (61.3% of detrimental relationships) had relationships with migraine. In conclusion, exposure to NO2, CO, PM10, and PM2.5 is associated with migraine headaches, while no conclusive evidence was found to confirm the correlation between O3 and SO2 with migraine. Further studies with precise methodology are recommended in different cities around the world for all pollutants with an emphasis on O3 and SO2.

The World Health Organization Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders and the headache revolution: from headache burden to a global action plan for headache disorders

The World Health Organization (WHO) Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders was developed by WHO to address the worldwide challenges and gaps in provision of care and services for people with epilepsy and other neurological disorders and to ensure a comprehensive, coordinated response across sectors to the burden of neurologic diseases and to promote brain health across life-course. Headache disorders constitute the second most burdensome of all neurological diseases after stroke, but the first if young and midlife adults are taken into account. Despite the availability of a range of treatments, disability associated with headache disorders, and with migraine, remains very high. In addition, there are inequalities between high-income and low and middle income countries in access to medical care. In line with several brain health initiatives following the WHOiGAP resolution, herein we tailor the main pillars of the action plan to headache disorders: (1) raising policy prioritization and strengthen governance; (2) providing effective, timely and responsive diagnosis, treatment and care; (3) implementing strategies for promotion and prevention; (4) fostering research and innovation and strengthen information systems. Specific targets for future policy actions are proposed. The Global Action Plan triggered a revolution in neurology, not only by increasing public awareness of brain disorders and brain health but also by boosting the number of neurologists in training, raising research funding and making neurology a public health priority for policy makers. Reducing the burden of headache disorders will not only improve the quality of life and wellbeing of people with headache but also reduce the burden of neurological disorders increasing global brain health and, thus, global population health.

The association of serum vitamin D concentrations in paediatric migraine

INTRODUCTION

Migraine is a neurologic condition characterized by hypersensitivity to auditory, olfactory, visual, and cutaneous stimuli; vomiting and nausea; and severe headache. It is the most frequent headache syndrome in children and can be categorized in chronic and/or episodic. Multiple dietary supplements have been inaugurated for the management of migraine, the most prevalent of which is vitamin D.

BACKGROUND

In recent years, vitamin D deficiency has been a global public health problem, with 30-80% of the worldwide population having vitamin D deficiency. The significant role of vitamin D in neurological disorders is underlined by its key role in the brain function of the central nervous system (CNS). Current approaches in paediatric neurology include nonsteroidal anti-inflammatory drugs (NSAID) for the treatment of paediatric migraine, among others. Vitamin D is one of the dietary factors that has been linked to migraine, however, this association has mostly been examined in the adult population.

OBJECTIVE

The aim of this study is to investigate the association between serum vitamin D and paediatric migraine by conducting a review of existing literature. The main question is described with the PICO format (population, intervention, control, and outcomes), while the assessment of the present research is under the PRISMA guidelines for systematic reviews.

RESULTS/CONCLUSION

A systematic review of the literature reveals a remarkable association between vitamin D and migraine presentation in the paediatric population, affecting the frequency and duration of the episodes. That being the case, vitamin D supplementation could potentially improve the quality of life of paediatric patients suffering from migraine headaches.

Associations between migraine and possible risk factors in the Czech Republic

Introduction

Migraine is a widespread neurological disorder, growing increasingly common. However, the pathogenesis of the disease is often unclear and the evidence for the role of various risk factors is limited. This study aimed to identify risk factors associated with migraine and to contribute towards a better understanding of this disease.

Methods

Data from 3,247 questionnaires were analyzed for associations between migraine and sex, age, BMI, degree of education, and air pollution, along with other factors such as contact with friends, physical condition, health, anxiety, and depression. A cross-sectional study was conducted with an approximately equal distribution of the sample by age, gender and two analysed regions. Data were presented using basic descriptive statistics using the chi-square test. The model output was presented using a crude odds ratio (OR) and a fully adjusted OR. Three hundred and eight-six individuals (12%) suffered from migraine.

Results

In an adjusted model, the presented study found associations between the prevalence of migraine and sex, age, and level of education. Individuals with migraine statistically significantly more often suffered from depression, anxiety and other selected factors. However, the assumed significant association between the occurrence of migraine and pollution in the region has not been found.

Multimodal hypersensitivity derived from quantitative sensory testing predicts pelvic pain outcome: an observational cohort study

ABSTRACT

Multimodal hypersensitivity (MMH)-greater sensitivity across multiple sensory modalities (eg, light, sound, temperature, pressure)-is associated with the development of chronic pain. However, previous MMH studies are restricted given their reliance on self-reported questionnaires, narrow use of multimodal sensory testing, or limited follow-up. We conducted multimodal sensory testing on an observational cohort of 200 reproductive-aged women, including those at elevated risk for chronic pelvic pain conditions and pain-free controls. Multimodal sensory testing included visual, auditory, and bodily pressure, pelvic pressure, thermal, and bladder pain testing. Self-reported pelvic pain was examined over 4 years. A principal component analysis of sensory testing measures resulted in 3 orthogonal factors that explained 43% of the variance: MMH, pressure pain stimulus response, and bladder hypersensitivity. The MMH and bladder hypersensitivity factors correlated with baseline self-reported menstrual pain, genitourinary symptoms, depression, anxiety, and health. Over time, MMH increasingly predicted pelvic pain and was the only component to predict outcome 4 years later, even when adjusted for baseline pelvic pain. Multimodal hypersensitivity was a better predictor of pelvic pain outcome than a questionnaire-based assessment of generalized sensory sensitivity. These results suggest that MMHs overarching neural mechanisms convey more substantial long-term risk for pelvic pain than variation in individual sensory modalities. Further research on the modifiability of MMH could inform future treatment developments in chronic pain.

Exploring sensory sensitivity, cortical excitability, and habituation in episodic migraine, as a function of age and disease severity, using the pattern-reversal task

BACKGROUND

Migraine is a cyclic, neurosensory disorder characterized by recurrent headaches and altered sensory processing. The latter is manifested in hypersensitivity to visual stimuli, measured with questionnaires and sensory thresholds, as well as in abnormal cortical excitability and a lack of habituation, assessed with visual evoked potentials elicited by pattern-reversal stimulation. Here, the goal was to determine whether factors such as age and/or disease severity may exert a modulatory influence on sensory sensitivity, cortical excitability, and habituation.

METHODS

Two similar experiments were carried out, the first comparing 24 young, episodic migraine patients and 28 healthy age- and gender-matched controls and the second 36 middle-aged, episodic migraine patients and 30 healthy age- and gender-matched controls. A neurologist confirmed the diagnoses. Migraine phases were obtained using eDiaries. Sensory sensitivity was assessed with the Sensory Perception Quotient and group comparisons were carried out. We obtained pattern-reversal visual evoked potentials and calculated the N1-P1 Peak-to-Peak amplitude. Two linear mixed-effects models were fitted to these data. The first model had Block (first block, last block) and Group (patients, controls) as fixed factors, whereas the second model had Trial (all trials) and Group as fixed factors. Participant was included as a random factor in both. N1-P1 first block amplitude was used to assess cortical excitability and habituation was defined as a decrease of N1-P1 amplitude across Blocks/Trials. Both experiments were performed interictally.

RESULTS

The final samples consisted of 18 patients with episodic migraine and 27 headache-free controls (first experiment) and 19 patients and 29 controls (second experiment). In both experiments, patients reported increased visual hypersensitivity on the Sensory Perception Quotient as compared to controls. Regarding N1-P1 peak-to-peak data, there was no main effect of Group, indicating no differences in cortical excitability between groups. Finally, significant main effects of both Block and Trial were found indicating habituation in both groups, regardless of age and headache frequency.

CONCLUSIONS

The results of this study yielded evidence for significant hypersensitivity in patients but no significant differences in either habituation or cortical excitability, as compared to headache-free controls. Although the alterations in patients may be less pronounced than originally anticipated they demonstrate the need for the definition and standardization of optimal methodological parameters.

Topographic localization of migraine triggers and its association with headache frequency and severity

OBJECTIVE

Internal biological rhythm with or without external trigger may precipitate migraine. Classifying exogenous and endogenous triggers to a topographic localization may help in understanding the migraine. We report topographic localization of migraine triggers and its influence on headache frequency and severity.

METHODS

588 migraineurs, aged 16-69 years were included. Various endogenous and exogenous triggers were categorized to topographic localization- hypothalamic, pituitary, auditory, visual, somato-sensory, olfactory and gustatory. The relationship of topographic localization of triggers with episodic versus chronic migraine, and moderate versus severe headache were analyzed using univariate followed by multivariate analysis.

RESULTS

All migraineurs had triggers 584(99.9%) except 4(0.1%) patients. Presence of multiple triggers (99.4%), and combination of both endogenous and exogenous triggers (97.7%) was the rule. On topographic localization, hypothalamic trigger was the commonest (98.1%) followed by visual (84.1%), auditory (82.1%), somatosensory (76.1%), olfactory (26.2%), pituitary (24.1%), and gustatory (6.6%). 98.6% patients had combination of hypothalamic with pituitary triggers. Hypothalamic [Adjusted odds ratio (AOR) 4.50] and auditory triggers (AOR 0.34) independently predicted chronic migraine, and auditory (AOR 0.55) and gustatory (AOR 2.41) triggers predicted severity of headache.

CONCLUSION

Hypothalamic triggers are the commonest suggesting an innate susceptibility of migraine. Auditory trigger may precipitate frequent and severe headache.

Altered functional brain network patterns in patients with migraine without aura after transcutaneous auricular vagus nerve stimulation

Transcutaneous auricular vagus nerve stimulation (taVNS) shows excellent effects on relieving clinical symptoms in migraine patients. Nevertheless, the neurological mechanisms of taVNS for migraineurs remain unclear. In recent years, voxel-wise degree centrality (DC) and functional connectivity (FC) methods were extensively utilized for exploring alterations in patterns of FC in the resting-state brain. In the present study, thirty-five migraine patients without aura and thirty-eight healthy controls (HCs) were recruited for magnetic resonance imaging scans. Firstly, this study used voxel-wise DC analysis to explore brain regions where abnormalities were present in migraine patients. Secondly, for elucidating neurological mechanisms underlying taVNS in migraine, seed-based resting-state functional connectivity analysis was employed to the taVNS treatment group. Finally, correlation analysis was performed to explore the relationship between alterations in neurological mechanisms and clinical symptoms. Our findings indicated that migraineurs have lower DC values in the inferior temporal gyrus (ITG) and paracentral lobule than in healthy controls (HCs). In addition, migraineurs have higher DC values in the cerebellar lobule VIII and the fusiform gyrus than HCs. Moreover, after taVNS treatment (post-taVNS), patients displayed increased FC between the ITG with the inferior parietal lobule (IPL), orbitofrontal gyrus, angular gyrus, and posterior cingulate gyrus than before taVNS treatment (pre-taVNS). Besides, the post-taVNS patients showed decreased FC between the cerebellar lobule VIII with the supplementary motor area and postcentral gyrus compared with the pre-taVNS patients. The changed FC of ITG-IPL was significantly related to changes in headache intensity. Our study suggested that migraine patients without aura have altered brain connectivity patterns in several hub regions involving multisensory integration, pain perception, and cognitive function. More importantly, taVNS modulated the default mode network and the vestibular cortical network related to the dysfunctions in migraineurs. This paper provides a new perspective on the potential neurological mechanisms and therapeutic targets of taVNS for treating migraine.

Employees of the banking sector in Guizhou Province in China: prevalence of migraine, symptoms, disability and occupational risk factors

BACKGROUND

Although studies have identified a high prevalence of migraine among employees in the banking sector, the symptoms of migraine, related disability and occupational risk factors are not well understood.

AIMS

To determine migraine prevalence, symptoms and disability among bank employees in Guizhou province in China and to examine occupational risk factors associated with migraine positivity and symptoms.

METHODS

In a cross-sectional survey, two-stage probability sampling was used to select bank employees in Guizhou province, China. From May to October 2022, uniformly trained interviewers conducted face-to-face interviews using the HARDSHIP questionnaire. Logistic regression was used to examine factors associated with migraine positivity and symptoms.

RESULTS

Of 1,985 contactable eligible subjects, 1,929 (male 45.4%, female 54.6%) completed the survey. The one-year prevalence of migraine was 27.2% (95% CI 25.2-29.2%). Of migraine-positive individuals, 11.2% had a monthly frequency ≥ 15 days, 11.8% had an attack duration > 72 h, and 14.9% had severe pain intensity. The median of days lost from work, housework and social activities due to migraine during a three-month period was 4, 3 and 2 days, respectively, with more than half (52.8%) patients reporting Grade III or IV disability. In multivariable analyses, positions in data analysis (OR = 1.8 [95% CI 1.2-2.8], p < 0.01) and information technology (OR = 3.8 [95% CI 1.7-8.3], p < 0.01) were occupational risk factors for migraine positivity. It was also found that professional positions were predictive of migraine attacks ≥ 15 days per month, administrative positions were predictive of duration > 72 h and severe pain intensity of migraine attacks, and working in remote branches was predictive of duration > 72 h.

CONCLUSIONS

Migraine is prevalent among employees in the banking sector in Guizhou province in China, with a large proportion of sufferers carrying a high burden of symptoms and disability. The practical implication of this study is that the risk factors identified here could be translated to the focus of workplace monitoring and interventions to manage and prevent migraine.

Multiple Chemical Sensitivity: It's time to catch up to the science

Multiple chemical sensitivity (MCS) is a complex medical condition associated with low dose chemical exposures. MCS is characterized by diverse features and common comorbidities, including fibromyalgia, cough hypersensitivity, asthma, and migraine, and stress/anxiety, with which the syndrome shares numerous neurobiological processes and altered functioning within diverse brain regions. Predictive factors linked to MCS comprise genetic influences, gene-environment interactions, oxidative stress, systemic inflammation, cell dysfunction, and psychosocial influences. The development of MCS may be attributed to the sensitization of transient receptor potential (TRP) receptors, notably TRPV1 and TRPA1. Capsaicin inhalation challenge studies demonstrated that TRPV1 sensitization is manifested in MCS, and functional brain imaging studies revealed that TRPV1 and TRPA1 agonists promote brain-region specific neuronal variations. Unfortunately, MCS has often been inappropriately viewed as stemming exclusively from psychological disturbances, which has fostered patients being stigmatized and ostracized, and often being denied accommodation for their disability. Evidence-based education is essential to provide appropriate support and advocacy. Greater recognition of receptor-mediated biological mechanisms should be incorporated in laws, and regulation of environmental exposures.

Relationship between visual display terminal working hours and headache/eyestrain in Korean wage workers during the COVID-19 pandemic: the sixth Korean Working Conditions Survey

Background

Prolonged use of visual display terminal (VDT) can cause eyestrain, dry eyes, blurred vision, double vision, headache and musculoskeletal symptoms (neck, shoulder, and wrist pain). VDT working hours among workers have greatly increased during the coronavirus disease 2019 (COVID-19) pandemic. Therefore, this study aimed to investigate the relationship between VDT working hours and headache/eyestrain in wage workers using data from the sixth Korean Working Conditions Survey (KWCS) (2020-2021) conducted during the COVID-19 pandemic.

Methods

We analyzed the sixth KWCS data of 28,442 wage workers aged 15 years or older. The headache/eyestrain that occurred in the last year was assessed. The VDT work group included workers who use VDT always, almost always, and three-fourth of the working hours, while the non-VDT work group included workers who use VDT half of the working hours, one-fourth of the working hours, almost never, and never. To analyze the relationship between VDT working hours and headache/eyestrain, the odds ratios (ORs) and 95% confidence interval (CI) were calculated using logistic regression analysis.

Results

Among the non-VDT work group, 14.4% workers experienced headache/eyestrain, whereas 27.5% workers of the VDT work group experienced these symptoms. For headache/eyestrain, the VDT work group showed adjusted OR of 1.94 (95% CI: 1.80-2.09), compared with the non-VDT work group, and the group that always used VDT showed adjusted OR of 2.54 (95% CI: 2.26-2.86), compared with the group that never used VDT.

Conclusions

This study suggests that during the COVID-19 pandemic, as VDT working hours increased, the risk of headache/eyestrain increased for Korean wage workers.

Effect of short-term air pollution exposure on migraine: A protocol for systematic review and meta-analysis on human observational studies

BACKGROUND

The World Health Organization (WHO) has identified air pollution as one of the greatest environmental risks to public health. High levels of ambient air pollution are known to have adverse health effects, but the relationship between exposure to air pollutants and migraine attack has not been established.

OBJECTIVES

This study aims to systematically review the effects of short-term exposure to fine and coarse particulate matter (PM), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide on migraine attack.

METHODS

The systematic review and meta-analysis will follow the WHO handbook for guideline development. Our protocol will comply with the guidelines of the Preferred Reporting Items for Systematic Review and meta-Analysis Protocols.

ELIGIBILITY CRITERIA

Original peer-reviewed studies conducted in the general population regardless of age and sex to investigate the association between short-term exposure to ambient air pollutants and migraine will be eligible for inclusion. Only time-series, case-crossover, and panel studies will be included.

INFORMATION SOURCES

We will search the electronic databases MEDLINE, Embase, Web of Science, Global Health, Cumulative Index to Nursing and Allied Health Literature in accordance with the pre-established search strategy. We will also check the reference list of included papers and previous reviews for supplementary search.

DATA SYNTHESIS METHOD

We will perform data extraction in accordance with the predesigned table. Using random-effects meta-analysis, we will present summary statistics (RRs and corresponding 95% CIs) associated with standardized increases in each pollutant level. Heterogeneity between studies will be assessed using 80% prediction intervals (PI). Subgroup analyzes will be performed to explore sources of heterogeneity, if any. The main findings will be presented in summary of finding table, visual display and narrative synthesis. We will review the impact of each air pollutant exposure separately.

EVIDENCE APPRAISAL

We will employ the adaption of Grading of Recommendations, Assessment, Development, and Evaluations tool to assess the confidence in the body of evidence.

Using Light to Facilitate Circadian Entrainment from Day to Night Flights

BACKGROUND: As part of a larger project to provide recommendations regarding limitations and best practices for shifting aviators from day to night operations, a study was conducted to assess the efficacy of high energy visible (HEV) light to shift the circadian rhythm in humans. The study attempted to replicate the patterns of military aviators who could be required to shift abruptly from day to night flight operations.METHODS: Simulated flight performance and salivary melatonin levels of 10 U.S. military aviators were collected over a 3-night period using a within-subject dim light melatonin onset (DLMO) study design. Data were collected in a laboratory with participants returning home to sleep following each of the three evenings/nights of data collection. Light treatment included a single 4-h exposure of blue-enriched white light (∼1000 lux) on night 2. Data collected included melatonin levels, light exposure, sleepiness, cognitive workload, and simulated flight performance.RESULTS: The average delay in melatonin onset was 1.32 ± 0.37 h (range: 53 min to 1 h 56 min). Sleepiness (P = 0.044) and cognitive workload (P = 0.081) improved the night following the light treatment compared to the baseline. No systematic differences were identified in flight performance.DISCUSSION: The HEV light treatment successfully delayed the circadian phase of all participants even though participants' ambient light levels (including daylight) outside the laboratory were not controlled. These findings were used to develop circadian synchronization plans for aviators who are asked to transition from day to night operations. These plans will be assessed in a follow-on study in an operational unit.Shattuck NL, Matsangas P, Reily J, McDonough M, Giles KB. Using light to facilitate circadian entrainment from day to night flights. Aerosp Med Hum Perform. 2023; 94(2):66-73.

Association between Migraine and Workplace Social Support in the Social Context of China: Using a Validated Chinese Version of the DCSQ

BACKGROUND

Workplace social support might have a protective function against migraine in the social context of China, as close co-worker relationships and collectivism are acknowledged as work values in Chinese society.

OBJECTIVES

This paper aimed to analyse the association between migraine and workplace social support. The validity and reliability of the Chinese version of the Support scale of the Demand-Control-Support Questionnaire (DCSQ) used were also determined.

METHODS

Following international guidelines, this study was carried out in two stages. Stage I involved translations and pilot testing to assess content and face validity of the Chinese version of the DCSQ Support scale. Stage II was a cross-sectional survey (N = 677 bank employees) to evaluate structural validity, internal consistency and test-retest reliability of the Support scale, as well as to examine the association between workplace social support and a migraine-positive diagnosis.

RESULTS

A high level of social support in the workplace was associated with a 74% decreased likelihood of migraine (adjusted OR = 0.26, 95%CI: 0.14-0.46). Of the six aspects of workplace social support, co-worker support had the greatest protective effect (adjusted OR = 0.49, 95% CI: 0.39-0.60). The Chinese version of the DCSQ Support scale established satisfactory content and face validity (I-CVIs ≥ 0.78; S-CVI_AVE ≥ 0.90). Confirmatory factor analysis verified its one-dimensional theoretical factor, with adequate internal consistency (Cronbach's α 0.98; item-total correlations ≥ 0.80) and test-retest reliability (weighted Kappa coefficients 0.81-0.87; percentages agreement 85.23-88.92%).

CONCLUSIONS

In the Chinese social context, workplace social support could protect against migraine, with the strongest benefit coming from co-workers. This study also provides a Chinese-language DCSQ Support scale as a valid and reliable instrument for measuring workplace social support.

Migraine management: Non-pharmacological points for patients and health care professionals

Migraine is a highly prevalent disorder with an enormous burden on societies. Different types of medications are used for controlling both acute attacks and prevention. This article reviews some non-pharmacological recommendations aiming to manage migraine disorder better and prevent headache attacks. Different triggers of migraine headache attacks, including environmental factors, sleep pattern changes, diet, physical activity, stress and anxiety, some medications, and hormonal changes, are discussed. It is advised that they be identified and managed. Patients should learn the skills to cope with the trigger factors that are difficult to avoid. In addition, weight control, management of migraine comorbidities, lifestyle modification, behavioural treatment and biofeedback, patient education, using headache diaries, and improving patients' knowledge about the disease are recommended to be parts of migraine management. In addition, using neuromodulation techniques, dietary supplements such as riboflavin, coenzyme Q10 and magnesium, and acupuncture can be helpful. Non-pharmacological approaches should be considered in migraine management. Furthermore, the combination of pharmacological and non-pharmacological approaches is more effective than using each separately.

An observational study of self-reported migraine triggers and prospective evaluation of the relationships with occurrence of attacks enabled by a smartphone application (App)

OBJECTIVE

To investigate the relationship between self-reported triggers and the occurrence of migraine attacks using a smartphone application.

BACKGROUND

One of several issues around the study of migraine attack triggers is that limited available evidence supports whether self-reported triggers can induce a headache on a particular subject.

METHODS

This is an observational longitudinal cohort study of individuals with migraine registered to track their headaches prospectively using a smartphone application. For 90 days, participants entered daily data about triggers (potential triggers and premonitory symptoms) that may be associated with attack risk, as well as migraine symptoms. The statistical significance of univariate associations between each trigger and migraine recurrent events was determined for each individual. Statistically identified triggers were then compared to self-reported triggers.

RESULTS

In 328 individuals (290/328 [88.4%] female; mean [standard deviation] 4.2 [1.5] migraine attacks/month) the mean (standard deviation) number of triggers moderately or highly endorsed per individual was 28.0 (7.7) in individuals presented with up to 38 possible triggers. Of these, an average (standard deviation) of 2.2 (2.1) triggers per individual were statistically associated with increased risk of attacks. Even the most commonly endorsed triggers (sleep quality, stress, tiredness/fatigue, sleep duration, dehydration, neck pain, missed meals, eyestrain, mean barometric pressure, and anxiety) were statistically associated in fewer than one third of individuals suspecting each, with the exception of neck pain (117/302 [38.7%]).

CONCLUSIONS

Individuals with episodic migraine believe that many triggers contribute to their attacks; however, few of these withstand statistical testing at the individual level. Improved personal knowledge of potential triggers and premonitory symptoms may help individuals adopt behavioral changes to mitigate attack risk.

Something Stinks! Finding Ways to Manage Noxious Odours in the Operating Room and Other Clinical Settings A Randomized Controlled Trial

Objectives: The hospital can be saturated with noxious smells. Anecdotally, medical staff apply products to surgical masks to lessen the impact of these smells. This study aimed to determine the odour-masking ability of 4 inexpensive and convenient products. Methods: A randomized, single-blinded crossover study was conducted in Vancouver, Canada. Participants, 19 to 30 years old, were invited to participate. Participants with active allergies, upper respiratory tract infection, alteration to sense of smell, or failure of olfactory screen were excluded from the study. An experimental odour was used in lieu of a noxious surgical odour. After smelling the experimental odour without barriers, participants were re-exposed to the odour using 5 surgical masks in randomized order. Each mask was lined with a test product (cherry lip balm, tincture of benzoin, Mastisol, mint toothpaste, and control [plain mask]). Participants rated the effectiveness of products at masking the experimental odour from 0 to 100 (0 = completely ineffective, 100 = completely effective). Participants also rated the pleasantness of the products, recorded if the products made them feel unwell, and identified their preferred product overall. Results: Eighty participants were included in the study (33 male, 47 female), averaging 24.2 years of age. Mean odour-masking effectiveness for cherry lip balm was 66.5 (±24.6), tincture of benzoin: 62.6 (±25.0), Mastisol: 61.3 (±23.9), mint toothpaste: 57.5 (±27.4), and control: 21.9 (±21.8). All products performed better than the control (P < .001), but there was no significant difference in performance between products. Cherry lip balm was the most preferred odour-masking product (29 participants), followed by mint toothpaste (22), Mastisol (14), tincture of benzoin (10), and control (5). Conclusions: All tested products demonstrated equivalent odour-masking abilities. If health care professionals choose to use an odour-masking product, they should consider their own olfactory preferences.

Skin wetness sensitivity across body sites commonly affected by pain in people with migraine

Objective

The objective of this study was to evaluate skin wetness perception and thermal sensitivity in people with migraine and similar healthy controls.

Background

Environmental triggers, such as cold and humidity, are known triggers for pain in people with migraine. Sensory inputs might be implicated in such heightened responses to cold‐humid environments, such that a migraine‐induced hypersensitivity to cold wetness could be present in people with migraine. However, we lack empirical evidence on skin thermal and wetness sensitivity across skin sites commonly associated with reported pain in migraine, such as the forehead.

Methods

This prospective cross‐sectional observational study, conducted in a university hospital setting, evaluated skin wetness perceptions and thermal sensations to wet non‐noxious warm‐wet, neutral‐wet, and cold‐wet stimuli applied to the forehead, the posterior neck, and the index finger pad of 12 patients with migraine (mean and standard deviation for age 44.5 ± 13.2 years, 7/12 [58%] women) and 36 healthy controls (mean and standard deviation for age 39.4 ± 14.6 years, 18/36 [50%] women).

Results

On the forehead, people with migraine reported a significantly higher wetness perception than healthy controls across all thermal stimulus (15.1 mm, 95% confidence interval [CI]: 1.8 to 28.5, p = 0.027, corresponding to ~ 15% difference), whereas no significant differences were found on the posterior neck nor on the index finger pad. We found no differences among groups in overall thermal sensations (−8.3 mm, 95% CI: −24.0 to 7.3, p = 0.291; −7.8 mm, 95% CI: −25.3 to 9.7, p = 0.375; and 12.4 mm, 95% CI: −4.0 to 28.9, p = 0.133; forehead, posterior neck, and index finger, respectively).

Conclusion

These findings indicate that people with migraine have a heightened sensitivity to skin wetness on the forehead area only, which is where pain attacks occur. Future studies should further explore the underlying mechanisms (e.g., TRPM8‐mediated cold‐wet allodynia) that lead to greater perception of wetness in people with migraine to better understand the role of environmental triggers in migraine.

Migraine Attacks and Relevant Trigger Factors in Undergraduate Nursing Students in Hong Kong: A Cross-Sectional Study

Objective

This study aimed to examine the prevalence and features of migraine and explore the possible migraine triggers in a sample of university nursing students in Hong Kong.

Methods

A cross-sectional study using self-administered questionnaires was conducted in the Hong Kong Polytechnic University in 2016. The questionnaire included ID Migraine™ for migraine screening and items measuring the frequency, duration, severity, associated symptoms, and trigger factors of migraine. Years 2–5 undergraduate nursing students from the university completed the questionnaires. Binary logistic regression was conducted to examine the migraine-associated factors.

Results

A total of 702 nursing students, including 168 males and 534 females, were successfully screened. Their mean age was 20.8 ± 1.4 years. The overall prevalence of migraine reached 11.8%. Over half (67.5%) of the students with migraine experienced attacks at least once per month. Each attack had a median duration of 3 h (interquartile range: 1–4 h) and the mean pain intensity score of 6.4 ± 1.6. Students with a family history of migraine (adjusted odds ratio [OR]: 1.89; 95% confidence interval [CI]: 1.10, 3.25; p < 0.05) and poor general health status (Adjusted OR: 3.41, 95% CI: 1.05, 11.09; p < 0.05) were more likely to suffer from migraine than those without. The three most common migraine triggers were the lack of sleep (94.0%), change in sleep schedule (83.1%), and noise (81.9%). Female students were more likely to experience fatigue-triggered migraine than male students (85.9% vs 63.2%, p < 0.05).

Conclusion

Migraine prevalence was relatively high among undergraduate nursing students in Hong Kong. Sleep problem was the most frequent trigger factor. The students’ awareness of migraine attacks should be increased, and migraine management must be improved by avoiding common trigger factors in this population.

Neurofeedback Therapy for Sensory Over-Responsiveness-A Feasibility Study

Background: Difficulty in modulating multisensory input, specifically the sensory over-responsive (SOR) type, is linked to pain hypersensitivity and anxiety, impacting daily function and quality of life in children and adults. Reduced cortical activity recorded under resting state has been reported, suggestive of neuromodulation as a potential therapeutic modality. This feasibility study aimed to explore neurofeedback intervention in SOR. Methods: Healthy women with SOR (n = 10) underwent an experimental feasibility study comprising four measurement time points (T1—baseline; T2—preintervention; T3—postintervention; T4—follow-up). Outcome measures included resting-state EEG recording, in addition to behavioral assessments of life satisfaction, attaining functional goals, pain sensitivity, and anxiety. Intervention targeted the upregulation of alpha oscillatory power over ten sessions. Results: No changes were detected in all measures between T1 and T2. Exploring the changes in brain activity between T2 and T4 revealed power enhancement in delta, theta, beta, and gamma oscillatory bands, detected in the frontal region (p = 0.03−<0.001; Cohen’s d = 0.637−1.126) but not in alpha oscillations. Furthermore, a large effect was found in enhancing life satisfaction and goal attainment (Cohen’s d = 1.18; 1.04, respectively), and reduced pain sensitivity and anxiety trait (Cohen’s d = 0.70). Conclusion: This is the first study demonstrating the feasibility of neurofeedback intervention in SOR.

Rimegepant 75 mg for acute treatment of migraine is associated with significant reduction in monthly migraine days: Results from a long-term, open-label study

Background:

Rimegepant, a small molecule oral calcitonin gene-related peptide (CGRP) receptor antagonist, is approved for the acute and preventive treatment of migraine. We hypothesized that intermittent CGRP receptor blockade with rimegepant 75 mg acute treatment as needed (PRN) might result in reductions in monthly migraine days (MMD) over time, and was evaluated as the study objective.

Methods:

This was a post-hoc analysis of adults with ≥6 MMD at baseline who self-administered rimegepant 75 mg orally PRN for acute treatment of migraine up to 52-weeks in an open-label safety study (BHV3000-201; NCT03266588). Outcome measures (defined as median time to) and response rates (defined as proportion of patients reporting) were captured for ≥30% and ≥50% reduction of baseline MMD.

Results:

1044 participants with ≥6 MMD at baseline were analyzed. Median time to ≥30% reduction in MMD was 12 weeks (IQR; 4–40 weeks); median time to ≥50% reduction was 32 weeks (IQR; 12-NR weeks). Reduction in MMD was observed over time regardless of baseline migraine frequency, however higher baseline MMD were associated with a longer time to achieving ≥30% or ≥50% MMD reduction.

Conclusion:

In participants presenting with ≥6 MMD, PRN acute treatment of migraine attacks over 52-weeks with oral rimegepant 75 mg was observed to confer reductions in migraine frequency.

Trial registration:

NCT03266588

Inhibition of Nociception in a Preclinical Episodic Migraine Model by Dietary Supplementation of Grape Seed Extract Involves Activation of Endocannabinoid Receptors

Migraine is associated with peripheral and central sensitization of the trigeminal system and dysfunction of descending pain modulation pathways. Recently, dietary inclusion of grape seed extract (GSE) was shown to inhibit mechanical nociception in a preclinical model of chronic temporomandibular joint disorder, a condition often comorbid with migraine, with the antinociceptive effect mediated, in part, by activation of 5-HT3/7 and GABAB receptors. This study further investigated the mechanisms by which GSE inhibits mechanical nociception in a preclinical model of episodic migraine. Hyperalgesic priming of female and male Sprague Dawley rats was induced by three consecutive daily two-hour episodes of restraint stress. Seven days after the final restraint stress, rats were exposed to pungent odors from an oil extract that contains the compound umbellulone, which stimulates CGRP release and induces migraine-like pain. Some animals received dietary supplementation of GSE in their drinking water beginning one week prior to restraint stress. Changes in mechanical sensitivity in the orofacial region and hindpaw were determined using von Frey filaments. To investigate the role of the endocannabinoid receptors in the effect of GSE, some animals were injected intracisternally with the CB1 antagonist AM 251 or the CB2 antagonist AM 630 prior to odor inhalation. Changes in CGRP expression in the spinal trigeminal nucleus (STN) in response to stress, odor and GSE supplementation were studied using immunohistochemistry. Exposure of stress-primed animals to the odor caused a significant increase in the average number of withdrawal responses to mechanical stimulation in both the orofacial region and hindpaw, and the effect was significantly suppressed by daily supplementation with GSE. The anti-nociceptive effect of GSE was inhibited by intracisternal administration of antagonists of CB1 and CB2 receptors. GSE supplementation inhibited odor-mediated stimulation of CGRP expression in the STN in sensitized animals. These results demonstrate that GSE supplementation inhibits trigeminal pain signaling in an injury-free model of migraine-like pain via activation of endocannabinoid receptors and repression of CGRP expression centrally. Hence, we propose that GSE may be beneficial as a complementary migraine therapeutic.

Exploring alterations in sensory pathways in migraine

Background

Migraine is a neurological disorder characterized by intense, debilitating headaches, often coupled with nausea, vomiting and sensitivity to light and sound. Whilst changes in sensory processes during a migraine attack have been well-described, there is growing evidence that even between migraine attacks, sensory abilities are disrupted in migraine. Brain imaging studies have investigated altered coupling between areas of the descending pain modulatory pathway but coupling between somatosensory processing regions between migraine attacks has not been properly studied. The aim of this study was to determine if ongoing functional connectivity between visual, auditory, olfactory, gustatory and somatosensory cortices are altered during the interictal phase of migraine.

Methods

To explore the neural mechanisms underpinning interictal changes in sensory processing, we used functional magnetic resonance imaging to compare resting brain activity patterns and connectivity in migraineurs between migraine attacks (n = 32) and in healthy controls (n = 71). Significant differences between groups were determined using two-sample random effects procedures (p < 0.05, corrected for multiple comparisons, minimum cluster size 10 contiguous voxels, age and gender included as nuisance variables).

Results

In the migraine group, increases in infra-slow oscillatory activity were detected in the right primary visual cortex (V1), secondary visual cortex (V2) and third visual complex (V3), and left V3. In addition, resting connectivity analysis revealed that migraineurs displayed significantly enhanced connectivity between V1 and V2 with other sensory cortices including the auditory, gustatory, motor and somatosensory cortices.

Conclusions

These data provide evidence for a dysfunctional sensory network in pain-free migraine patients which may be underlying altered sensory processing between migraine attacks.

Subjective sensory sensitivity and its relationship with anxiety in people with probable migraine

OBJECTIVE

To better characterize differences in interictal sensory experience in adults with migraine and more comprehensively describe the relevance of anxiety to these experiences.

BACKGROUND

Evidence suggests that sensitivity to sensory input may not be limited to migraine attacks but continues between them. However, there is a need to better understand whether this is the case across senses, and to clearly distinguish sensory experience from measured sensory threshold, which are not straightforwardly related. Previous literature also indicates a co-occurrence between sensory sensitivity, migraine, and anxiety, but this relationship remains to be fully elucidated.

METHODS

The present cross-sectional study used online questionnaires to investigate how self-reported sensory experiences relate to migraine in a large community sample including 117 individuals with probable migraine and 827 without. Mediation analyses were also used to determine whether any relationship between migraine and sensory sensitivity was mediated by anxiety.

RESULTS

Significant increases in subjective reports of sensory sensitivity (d = 0.80) and sensory avoidance (d = 0.71) were found in participants with migraine. Anxiety symptoms partially mediated the relationship between subjective sensory sensitivity and migraine. Finally, visual, movement, and auditory subscales were found to provide unique explanatory variance in analyses predicting the incidence of migraine (area under the curve = 0.73, 0.69, 0.62 respectively).

CONCLUSION

Subjective sensory sensitivities are present between attacks and across senses in individuals with migraine. Anxiety symptoms are relevant to this relationship; however, sensory sensitivities appear to exist independent of this affective influence. The implications of interictal sensitivities for the daily lives of those with migraine should, therefore, be considered in clinical management wherever appropriate.

Industrial odour pollution and human health: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review to evaluate the association between residential or occupational short- and long-term exposure to odour pollution from industrial sources and the health status of the exposed population.

METHODS

The searches were conducted in Medline, EMBASE and Scopus in April 2021. Exposure to an environmental odour from industrial sources in population resident near the source or in workers was considered. We considered outcomes for which there was a biological plausibility, such as wheezing and asthma, cough, headache, nausea and vomiting (primary outcomes). We also included stress-related symptoms and novel outcomes (e.g. mood states). Risk of bias was evaluated using the OHAT tool. For primary outcomes, when at least 3 studies provided effect estimates by comparing exposed subjects versus not exposed, we pooled the study-specific estimates of odour-related effect using random effects models. Heterogeneity was evaluated with Higgins I2.

RESULTS

Thirty studies were eligible for this review, mainly cross-sectional (n = 23). Only one study involved school-age children and two studies involved workers. Only five studies reported odour effects on objective laboratory or clinical outcomes. Animal Feeding Operations and waste were the most common industrial sources. The overall odds ratios in exposed versus not exposed population were 1.15 (95% CI 1.01 to 1.29) for headache (7 studies), 1.09 (95% CI 0.88 to 1.30) for nausea/vomiting (7 studies), and 1.27 (95% CI 1.10 to 1.44) for cough/phlegm (5 studies). Heterogeneity was a moderate concern. Overall, the body of evidence was affected by a definitely high risk of bias in exposure and outcome assessment since most studies used self-reported information.

CONCLUSIONS

Findings underline the public health importance of odour pollution for population living nearby industrial odour sources. The limited evidence for most outcomes supports the need for high quality epidemiological studies on the association between odour pollution and its effects on human health.

The missing N1 or jittered P2: Electrophysiological correlates of pattern glare in the time and frequency domain

Excessive sensitivity to certain visual stimuli (cortical hyperexcitability) is associated with a number of neurological disorders including migraine, epilepsy, multiple sclerosis, autism and possibly dyslexia. Others show disruptive sensitivity to visual stimuli with no other obvious pathology or symptom profile (visual stress) which can extend to discomfort and nausea. We used event‐related potentials (ERPs) to explore the neural correlates of visual stress and headache proneness. We analysed ERPs in response to thick (0.37 cycles per degree [c/deg]), medium (3 c/deg) and thin (12 c/deg) gratings, using mass univariate analysis, considering three factors in the general population: headache proneness, visual stress and discomfort. We found relationships between ERP features and the headache and discomfort factors. Stimulus main effects were driven by the medium stimulus regardless of participant characteristics. Participants with high discomfort ratings had larger P1 components for the initial presentation of medium stimuli, suggesting initial cortical hyperexcitability that is later suppressed. The participants with high headache ratings showed atypical N1‐P2 components for medium stripes relative to the other stimuli. This effect was present only after repeated stimulus presentation. These effects were also explored in the frequency domain, suggesting variations in intertrial theta band phase coherence. Our results suggest that discomfort and headache in response to striped stimuli are related to different neural processes; however, more exploration is needed to determine whether the results translate to a clinical migraine population.

The Use of Electrical Nerve Stimulation to Treat Migraines: A Systematic Review

Migraines have been defined as an intense unilateral throbbing or pulsating sensation lasting anywhere between a few hours to multiple days. They are the sixth most prevalent disease in the United States, with approximately 18% of women and 6% of men experiencing some form of a migraine throughout their lifetime. In addition, they pose a significant economic burden, accounting for anywhere between $13 and $17 billion in medical costs annually in the United States. While there are a wide variety of treatments for migraines on the market, such as nonsteroidal anti-inflammatory drugs (NSAIDS), beta-blockers, and anti-epileptics, there is still no standard treatment. Moreover, each of these medications has a wide range of side effects, ranging from stomach ulcers to light-headedness. Within the last few decades, the presence of electrical nerve stimulation has emerged as a possible treatment option. These methods are almost free of harmful side effects and may be able to reduce the economic burden on those who suffer from migraines. However, studies have shown mixed results in regard to their efficacy. In this paper, we performed a systematic review to detail the current state of the literature regarding electrical nerve stimulation as a treatment modality for migraines.

Social Distancing in Chronic Migraine during the COVID-19 Outbreak: Results from a Multicenter Observational Study

BACKGROUND

The restrictions taken to control the rapid spread of COVID-19 resulted in a sudden, unprecedented change in people's lifestyle, leading to negative consequences on general health. This study aimed to estimate the impact of such changes on migraine severity during 2020 March-May lockdown.

METHODS

Patients affected by migraine with or without aura, diagnosed by expert physicians, completed a detailed interview comprehensive of: assessment of migraine characteristics; measure of physical activity (PA) levels; measure of the intake frequency of main Italian foods; the Insomnia Severity Index (ISI) questionnaire investigating sleep disorders.

RESULTS

We included 261 patients with a mean age of 44.5 ± 12.3 years. During social distancing, 72 patients (28%) reported a headache worsening, 86 (33%) an improvement, and 103 (39%) a stable headache frequency. A significant decrease of the PA levels during COVID-19 quarantine in the whole study sample was observed (median total metabolic equivalent task (METs) decreased from 1170 to 510; p < 0.001). Additionally, a significant difference was reported on median ISI scores (from 7 to 8; p < 0.001), which were increased in patients who presented a stable or worsening headache.

CONCLUSIONS

Our study confirmed that the restrictions taken during the pandemic have affected the practice of PA levels and sleep quality in migraine. Hence, PA and sleep quality should be assessed to find strategies for an improvement in quality of life.

Air pollution, methane super-emitters, and oil and gas wells in Northern California: the relationship with migraine headache prevalence and exacerbation

BACKGROUND

Migraine-an episodic disorder characterized by severe headache that can lead to disability-affects over 1 billion people worldwide. Prior studies have found that short-term exposure to fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and ozone increases risk of migraine-related emergency department (ED) visits. Our objective was to characterize the association between long-term exposure to sources of harmful emissions and common air pollutants with both migraine headache and, among patients with migraine, headache severity.

METHODS

From the Sutter Health electronic health record database, we identified 89,575 prevalent migraine cases between 2014 and 2018 using a migraine probability algorithm (MPA) score and 270,564 frequency-matched controls. Sutter Health delivers care to 3.5 million patients annually in Northern California. Exposures included 2015 annual average block group-level PM_2.5 and NO₂ concentrations, inverse-distance weighted (IDW) methane emissions from 60 super-emitters located within 10 km of participant residence between 2016 and 2018, and IDW active oil and gas wells in 2015 within 10 km of each participant. We used logistic and negative binomial mixed models to evaluate the association between environmental exposures and (1) migraine case status; and (2) migraine severity (i.e., MPA score > 100, triptan prescriptions, neurology visits, urgent care migraine visits, and ED migraine visits per person-year). Models controlled for age, sex, race/ethnicity, Medicaid use, primary care visits, and block group-level population density and poverty.

RESULTS

In adjusted analyses, for each 5 ppb increase in NO₂, we observed 2% increased odds of migraine case status (95% CI: 1.00, 1.05) and for each 100,000 kg/hour increase in IDW methane emissions, the odds of case status also increased (OR = 1.04, 95% CI: 1.00, 1.08). We found no association between PM_2.5 or oil and gas wells and migraine case status. PM_2.5 was linearly associated with neurology visits, migraine-specific urgent care visits, and MPA score > 100, but not triptans or ED visits. NO₂ was associated with migraine-specific urgent care and ED visits, but not other severity measures. We observed limited or null associations between continuous measures of methane emissions and proximity to oil and gas wells and migraine severity.

CONCLUSIONS

Our findings illustrate the potential role of long-term exposure to multiple ambient air pollutants for prevalent migraine and migraine severity.

The prevalence of migraine in Argentina: A reappraisal

BACKGROUND

Argentina has one of the largest territories in the world, which spreads over a lengthy latitudinal span. Its population is mainly composed of a mixture of South American natives and the descendants of numerous waves of European immigrants. Results from a previous study suggested that the prevalence of migraine in Argentina is the lowest in the region. Here we aimed to reassess the prevalence of migraine in Argentina applying a more sensitive and specific screening tool.

METHODS

We conducted a random computer assisted telephonic interview (n= 2500) using the Migraine Screen Questionnaire to evaluate the prevalence of migraine and some of its features among Argentinian adults.

RESULTS

The overall prevalence of migraine was 9.5% (14% in females and 5% in males). Estimated migraine prevalence rates ranged between 6.3% and 12% across different regions. The approximated prevalence of high frequency and chronic migraine were 1.9% and 1.5% of the total population respectively. Consumption of analgesics on 10 or more days per month was reported by 18% of migraine sufferers (≈1.7% of the population).

CONCLUSIONS

The prevalence of migraine in Argentina is higher than previously reported. Prevalence rates vary extensively across the territory. Specifically evaluating the determinants of these variations might be a promising avenue of research.

Long-Term Ambient Air Pollutant Exposure and Risk of Recurrent Headache in Children: A 12-Year Cohort Study

Although studies have suggested environmental factors to be triggers of headache, the contribution of long-term air pollution exposure to recurrent headaches is poorly understood. Hence, we executed this nationwide cohort study to investigate associations between levels of ambient air pollutants and risks of recurrent headaches in children in Taiwan from 2000 to 2012. We used data from the Taiwan National Health Insurance Research Database and linked them to the Taiwan Air Quality Monitoring Database. Overall, 218,008 children aged < 18 were identified from 1 January 2000, and then followed until they were diagnosed by a physician for ≥3 times with recurrent headaches or until 31 December 2012. We categorized the annual average concentration of each air pollutant (fine particulate matter, total hydrocarbon, methane, sulfur dioxide, and nitrogen dioxide) into quartiles (Q1–Q4). We measured the incidence rate, hazard ratios (HRs), and the corresponding 95% confidence intervals for recurrent headaches. stratified by the quartiles. A total of 28,037 children (12.9%) were identified with recurrent headaches. The incidence rate and adjusted HR for recurrent headaches increased with higher-level exposure of air pollutants, except sulfur dioxide. We herein demonstrate that long-term ambient air pollutant exposure might be a risk factor for childhood recurrent headaches.

Anxiety, Depression, and Body Weight in Children and Adolescents With Migraine

Background: There is a lack of studies that explore the possible association between body weight, psychological symptoms, and migraine severity in pediatric populations. The purpose of the study was to explore: (1) the association between body weight and the frequency of migraine attacks, (2) the possible differences in anxiety and depression symptoms according to the frequency of attacks and body weight, and (3) the possible mediating role of anxiety and/or depression in the association between body weight and frequency of migraine attacks in children.

Methods: One hundred and eleven children/adolescents with migraine were included (47 boys and 64 girls; mean age 11.7; ±2.4 years). The patients were classified as: (1) high frequency patients, reporting from weekly to daily episodes and (2) low frequency patients, with ≤3 episodes per month. According to their body mass index percentiles, the patients were divided in “Normal weight” (from ≥5 to <85 percentile), “Overweight” (from ≥85 to <95 percentile), and “Obese” (≥95 percentile). Given the low number of obese patients, the overweight and obese groups were considered together in the “Overweight” group. Anxiety and depression symptoms were assessed by the Self-Administered Psychiatric Scales for Children and Adolescents (SAFA).

Results: Fifty-four patients were normal in weight (49.6%), while 56 patients (50.4%) were overweight. The overweight patients showed a higher frequency of migraine attacks (64.7%; p < 0.05). Patients with a high frequency of attacks reported higher scores in all SAFA-Anxiety subscales (SAFA-A Tot: F = 15.107; p = 0.000). Overweight patients showed a significantly higher score in the “Separation anxiety” subscale (F = 7.855; p = 0.006). We found a mediating role between the overweight and high frequency for total anxiety (z = 2.11 ± 0.03; p < 0.05) and social anxiety (z = 2.04 ± 0.03; p < 0.05).

Conclusions: Our results suggest that, among the children suffering from migraine, the overweight status is associated with a higher frequency of attacks and separation anxiety symptoms. In particular, our study provides the first evidence of the role of anxiety in linking overweight and the frequency of migraine attacks in children and adolescents.

Triggers of Primary Headaches: Issues and Pathways Forward

The triggers of primary headaches have considerable significance for our understanding and management of headache and migraine. Triggers explain the variance in headaches - why they occur when they do. Trigger management is generally viewed as an important component of a comprehensive treatment approach for headaches. Historically, however, triggers have not had a prominent place in the headache literature. This situation began to change 20 to 30 years ago, and the pace of change has increased exponentially in recent times. Nevertheless, the field is beset with issues that have held it back from achieving more. This review will focus on elaborating those issues with the goal of suggesting ways forward. The first issue considered will be the definition of a trigger, and how specific triggers are labeled. Consideration will then be given to a classification system for triggers. The review will discuss next the evidence relating to whether self-reported triggers can, indeed, precipitate headaches, and how the capacity to elicit headaches may be acquired or extinguished. Attention will be given to the very important clinical issue of trigger management. Finally, the pathways forward will be proposed. Perhaps the most useful thing to accomplish at this point in time would be agreement on a definition of headache triggers, a list of triggers, and a classification system for triggers. This would greatly assist in comparing research on triggers from different research groups as well as eliminating some of the issues identified in this review. An authoritative body such as the American Headache Society or the International Headache Society, could establish a multidisciplinary committee that would complete these tasks. Consideration should also be given to incorporating triggers into the International Classification of Headache Disorders as an axis or via the use of codes, as this would raise the profile of triggers in assessment and management.

Individual differences of maladaptive brain changes in migraine and their relationship with differential effectiveness of treatments

Migraine is a difficult disorder to identify with regard to its pathophysiological mechanisms, and its treatment has been primarily difficult owing to interindividual differences. Substantial rates of nonresponsiveness to medications are common, making migraine treatment complicated. In this review, we systematically analyzed recent studies concerning neuroimaging findings regarding the neurophysiology of migraine. We linked the current imaging research with anecdotal evidence from interindividual factors such as duration and pain intensity of migraine, age, gender, hormonal interplay, and genetics. These factors suggested the use of nonpharmacological therapies such as transcranial magnetic stimulation, transcranial direct current stimulation, and placebo therapy for the treatment of migraine. Finally, we discussed how interindividual differences are related to such nondrug treatments.

Neuroprotective Effect of Enriched Chicken Bone Broth as a Dietary Supplement in a Model of Migraine Mediated by Early Life Stress

Early life stress is a risk factor for development of migraine, a prevalent painful neurological disease characterized by sensitization and activation of trigeminal neurons. Secondary early life stress was previously shown to cause increased expression of neuronal proteins implicated in peripheral and central sensitization. Recently, dietary supplementation of chicken bone broth was shown to attenuate trigeminal nociception in an orofacial pain model. Accordingly, the focus of this study was to determine the effects of early life stress and dietary inclusion of bone broth on trigeminal nociceptor sensitization and activation in a model of episodic migraine. Adult Sprague-Dawley male sender rats subjected to primary traumatic stress were placed next to breeding or pregnant female rats that served as receiver rats (secondary traumatic stress) and in proximity to the offspring until weaning. Unstressed and stressed young adult offspring were tested for mechanical nocifensive response after exposure to a pungent odor known to be a migraine trigger, and in response to daily supplementation of bone broth. Early life stress promoted a primed state of trigeminal nociceptors that were activated by the pungent odor in both genders. Female animals exhibited a higher basal sensitization level and prolonged nociception compared with males. Supplementation of bone broth beginning at the time of weaning inhibited basal and triggered trigeminal mechanical sensitivity. Early life stress caused development of a sensitized trigeminal system that is implicated in migraine pathology and dietary supplementation with bone broth suppressed trigeminal sensitization, and thus may provide neuroprotective activity for reducing migraine risk.

Inhibition of Trigeminal Nociception by Non-invasive Vagus Nerve Stimulation: Investigating the Role of GABAergic and Serotonergic Pathways in a Model of Episodic Migraine

Migraine is a prevalent neurological disease that is characterized by unpredictable episodic attacks of intense head pain. The underlying pathology involves sensitization and activation of the trigeminal system. Although non-invasive vagus nerve stimulation (nVNS) is recommended for the treatment of migraine, the abortive mechanism of action is not well-understood. The goal of this study was to compare the ability of nVNS and sumatriptan to inhibit trigeminal activation in two animal models of episodic migraine and to investigate the receptor mechanism of action of nVNS. Nocifensive head withdrawal response was investigated in adult male Sprague Dawley rats using von Frey filaments. To induce trigeminal nociceptor sensitization, complete Freund's adjuvant was injected in the trapezius muscle and trigeminal neurons were activated by exposure to a pungent odor or injection of the nitric oxide donor sodium nitroprusside. Some animals received nVNS or sumatriptan as treatment. Some animals were injected intracisternally with antagonists of GABAA, 5-HT3 or 5-HT7 receptors prior to nVNS since these receptors are implicated in descending modulation. While unsensitized animals exposed to the pungent odor or nitric oxide alone did not exhibit enhanced mechanical nociception, sensitized animals with neck muscle inflammation displayed increased trigeminal nocifensive responses. The enhanced nociceptive response to both stimuli was attenuated by nVNS and sumatriptan. Administration of antagonists of GABAA, 5-HT3, and 5-HT7 receptors in the upper spinal cord suppressed the anti-nocifensive effect of nVNS. Our findings suggest that nVNS inhibits trigeminal activation to a similar degree as sumatriptan in episodic migraine models via involvement of GABAergic and serotonergic signaling to enhance central descending pain modulation.

The relationship between exposure to hot/cold weather and the clinical features of headaches in patients with migraine and tension-type headaches

Background and purpose: This study investigates the relationship between exposure to hot/cold weather and the characteristic clinical features of headaches in patients with migraine and tension-type headaches.Methods: This cross-sectional study was conducted with the participation of 190 patients with migraine, and 140 patients with tension-type headaches. The patients were evaluated using a form that collected data on their sociodemographic profile, the clinical features of their headaches, any accompanying symptoms and their relationships with changes in the weather (hot/cold). The headaches of all the participants in the study were thought to be triggered by exposure to hot/cold weather.Results: In the patients with migraine, the exposure to hot/cold weather as a trigger was not found to have a significant relationship with age, body mass index or the characteristic clinical features of headaches (p > 0.05). In patients with tension-type headaches, exposure to hot/cold weather as a trigger was found to have a significant relationship with body mass index (p = 0.019), but not with age or the characteristic clinical features of headaches (p > 0.05).Conclusions: In obese patients with tension-type headache, it was found that hot weather triggered headache more than cold weather. In patients with migraine and tension-type headaches, no relationship was found between exposure to hot/cold weather as a trigger and the clinical features of headaches. The accurate identification of the factors precipitating headaches by both clinicians and patients can help lower the frequency of headaches.

Prevalence and risk factors associated with headache amongst medical staff in South China

BACKGROUND

A previous study by our team reported the prevalence of primary headache disorders and factors associated with headache among nurses in three hospitals in North China. The aim of this cross-sectional survey was to learn more about how medical nurses in South China were affected by headache. Additionally, we determined the prevalence of headache and measured the impact of headache among doctors in mainland China for the first time.

METHODS

Stratified random cluster sampling was used to select 280 physicians and 365 nurses from various departments in four hospitals in Sanya, which is one of southernmost cities in China. Information was collected on demographic data, occupational factors and headache characteristics by using a structured questionnaire.

RESULTS

Among 645 medical staff, 548 (85%) responded (doctors = 240, nurses = 308). Among the medical staff, the 1-year prevalence of primary headache disorders was 50%, with 25.9% experiencing migraine and 24.1% experiencing tension-type headache (TTH). The prevalence of migraine in female doctors was higher than that in female nurses, although this difference was not significant (32.4% vs. 29.8%, P = 0.628). Multivariate analysis showed that being female and working in other specialties (Emergency Department & Radiology Department) remained independent risk factors for migraine in doctors (OR 2.314 and 3.223). In nurses, being married was a risk factor for migraine (OR 3.728), and job titles remained an independent risk factor for migraine and TTH (OR 2.294 and 4.695). Working more than 6 night-shifts per month was associated with an increased prevalence of migraine and TTH in doctors; the same was true in nurses for migraine, but not for TTH.

CONCLUSION

The prevalence of primary headache disorders in both nurses and doctors is higher than that in the general population in South China. Our study shows that occupation, geography and sex may play an important role. Further, female doctors are more susceptible than female nurses to migraine. The risk factors relevant to headache that were found in this study should provide an important reference for promoting occupational health in medical staff, especially female doctors in China.

Multisensorial Perception in Chronic Migraine and the Role of Medication Overuse

Multisensory processing can be assessed by measuring susceptibility to crossmodal illusions such as the Sound-Induced Flash Illusion (SIFI). When a single flash is accompanied by 2 or more beeps, it is perceived as multiple flashes (fission illusion); conversely, a fusion illusion is experienced when more flashes are matched with a single beep, leading to the perception of a single flash. Such illusory perceptions are associated to crossmodal changes in visual cortical excitability. Indeed, increasing occipital cortical excitability, by means of transcranial electrical currents, disrupts the SIFI (ie, fission illusion). Similarly, a reduced fission illusion was shown in patients with episodic migraine, especially during the attack, in agreement with the pathophysiological model of cortical hyperexcitability of this disease. If episodic migraine patients present with reduced SIFI especially during the attack, we hypothesize that chronic migraine (CM) patients should consistently report less illusory effects than healthy controls; drugs intake could also affect SIFI. On such a basis, we studied the proneness to SIFI in CM patients (n = 63), including 52 patients with Medication Overuse Headache (MOH), compared to 24 healthy controls. All migraine patients showed reduced fission phenomena than controls (P < .0001). Triptan MOH patients (n = 23) presented significantly less fission effects than other CM groups (P = .008). This exploratory study suggests that CM - both with and without medication overuse - is associated to a higher visual cortical responsiveness which causes deficit of multisensorial processing, as assessed by the SIFI. PERSPECTIVE: This observational study shows reduced susceptibility to the SIFI in CM, confirming and extending previous results in episodic migraine. MOH contributes to this phenomenon, especially in case of triptans.

Association Between Occupational Physicochemical Exposures and Headache/Eyestrain Symptoms Among Korean Indoor/Outdoor Construction Workers

Background

Headache/eyestrain symptoms are common health problems that people experience in daily life. Various studies have examined risk factors contributing to headache/eyestrains, and physicochemical exposure was found to be a leading risk factor in causing such symptoms. The purpose of this study was to examine the relationship of headache/eyestrain symptoms with physicochemical exposure among Korean construction workers depended on worksite.

Methods

This study used data from the 4th Korean Workers Conditions Survey and selected 1,945 Korean construction workers as participants. Multivariable logistic regression analysis was used to determine the relationship.

Results

Exposure to vibrations among all construction workers affected the moderate exposure group [odds ratio (OR) 1.53, 95% confidence interval (CI) 1.01–2.32], the high exposure group (OR 1.77 95%CI 1.17–2.67), and the indoor high exposure group (OR 1.61, 95%CI 1.02-2.55) and among outdoor construction workers, the moderate group (OR 6.61, 95%CI 15.4–28.48) and the high group (OR 6.61, 95%CI 1.56–27.98). When exposed to mist, dust, and fumes, the indoor high exposure group was significantly affected (OR 1.63, 95%CI 1.07–2.47). All construction workers exposed to organic solvents were affected, high exposure group (OR 1.69, 95%CI 1.15–2.49) and indoor high exposure group (OR 1.77, 95%CI 1.08–2.89). The high exposure group in all construction worker (OR 1.70, 95%CI 1.20–2.42) and the indoor high exposure group (OR 1.83, 95%CI 1.17–2.89) also were affected by secondhand smoking exposure.

Conclusion

Many physicochemical exposure factors affect headache/eyestrain symptoms among construction workers, especially indoor construction workers, suggesting a deficiency in occupational hygiene and health environments at indoor construction worksites.

Vitamin D in migraine headache: a comprehensive review on literature

INTRODUCTION

As a primary headache, migraine has been established as the first leading disability cause worldwide in the subjects who aged less than 50 years. A variety of dietary supplements have been introduced for migraine complementary treatment. As an anti-inflammatory and antioxidant agent, vitamin D is one of these agents which has been of interest in recent years. Although higher prevalence of vitamin D deficiency/insufficiency has been highlighted among migraineurs compared to controls, there is not any consensus in prescribing vitamin D in clinical practice. Therefore, in the current review, in addition to observational and case-control studies, we also included clinical trials concerning the effects of vitamin D supplementation on migraine/headache.

METHODS

Based on a PubMed/MEDLINE and ScienceDirect database search, this review study includes published articles up to June 2019 concerning the association between migraine/headache and vitamin D status or supplementation.

RESULTS

The percentage of subjects with vitamin D deficiency and insufficiency among migraineurs and headache patients has been reported to vary between 45 and 100%. In a number of studies, vitamin D level was negatively correlated with frequency of headaches. The present findings show that supplementation with this vitamin in a dose of 1000-4000 IU/d could reduce the frequency of attacks in migraineurs.

CONCLUSION

It seems a high proportion of migraine patients might suffer from vitamin D deficiency/insufficiency. Further, the current evidence shows that in addition to routine drug therapy, vitamin D administration might reduce the frequency of attacks in migraineurs. However, these results have yet to be confirmed.

Sensory Modulation Disorder (SMD) and Pain: A New Perspective

Sensory modulation disorder (SMD) affects sensory processing across single or multiple sensory systems. The sensory over-responsivity (SOR) subtype of SMD is manifested clinically as a condition in which non-painful stimuli are perceived as abnormally irritating, unpleasant, or even painful. Moreover, SOR interferes with participation in daily routines and activities (Dunn, 2007; Bar-Shalita et al., 2008; Chien et al., 2016), co-occurs with daily pain hyper-sensitivity, and reduces quality of life due to bodily pain. Laboratory behavioral studies have confirmed abnormal pain perception, as demonstrated by hyperalgesia and an enhanced lingering painful sensation, in children and adults with SMD. Advanced quantitative sensory testing (QST) has revealed the mechanisms of altered pain processing in SOR whereby despite the existence of normal peripheral sensory processing, there is enhanced facilitation of pain-transmitting pathways along with preserved but delayed inhibitory pain modulation. These findings point to central nervous system (CNS) involvement as the underlying mechanism of pain hypersensitivity in SOR. Based on the mutual central processing of both non-painful and painful sensory stimuli, we suggest shared mechanisms such as cortical hyper-excitation, an excitatory-inhibitory neuronal imbalance, and sensory modulation alterations. This is supported by novel findings indicating that SOR is a risk factor and comorbidity of chronic non-neuropathic pain disorders. This is the first review to summarize current empirical knowledge investigating SMD and pain, a sensory modality not yet part of the official SMD realm. We propose a neurophysiological mechanism-based model for the interrelation between pain and SMD. Embracing the pain domain could significantly contribute to the understanding of this condition’s pathogenesis and how it manifests in daily life, as well as suggesting the basis for future potential mechanism-based therapies.