Acute effects of ambient nitrogen dioxide pollution on outpatient visits for neurological diseases in Xinxiang, China

BACKGROUND

Accumulating evidence suggests that exposure to air pollution acts as a potential trigger for neurological diseases (NDs), yet the current knowledge regarding the impact of ambient nitrogen dioxide (NO2) on the patients with NDs remains limited. In this study, we conducted a time-series study to evaluate the association between short-term exposure to NO2 and hospital visits for NDs in Xinxiang, China.

METHODS

An over-dispersed Poisson generalized additive model was used to analyze the association between ambient NO2 concentrations and daily outpatient visits for NDs from January 1, 2015 to December 31, 2017. The model adjusted for meteorological factors, temporal trends, day of the week, and public holidays. The concentrations of air pollutants were collected from four air quality stations in Xinxiang.

RESULTS

A total of 38, 865 outpatient visits for NDs were retrieved during the study period. 86.5% of the patients were below the age of 65 years. It was revealed that a 10 µg/m3 increase in NO2 at lag 0 was associated with a significant rise of 1.50% (95% CI: 0.45-2.56%) in outpatient visits for NDs, which was stronger during the cold season. However, the overall results from stratified analyses did not reach statistical significance.

CONCLUSIONS

Short-term exposure to NO2 is associated with increased outpatient visits for NDs. These findings underscore the need for implementing mitigating measures to reduce the neurological health effects of air pollutants.

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.

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.

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.

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.

Impacts of Climate Change and Air Pollution on Neurologic Health, Disease, and Practice: A Scoping Review

BACKGROUND AND OBJECTIVES

Although the international community collectively seeks to reduce global temperature rise to less than 1.5°C before 2100, irreversible environmental changes have already occurred, and as the planet warms, these changes will continue to occur. As we witness the effects of a warming planet on human health, it is imperative that neurologists anticipate how the epidemiology and incidence of neurologic disease may change. In this review, we organized our analysis around 3 key themes related to climate change and neurologic health: extreme weather events and temperature fluctuations, emerging neuroinfectious diseases, and pollutant impacts. Across each of these themes, we appraised and reviewed recent literature relevant to neurologic disease and practice.

METHODS

Studies were identified using search terms relating to climate change, pollutants, and neurologic disease in PubMed, OVID MEDLINE, EMBASE, PsycInfo, and gray literature. Studies published between 1990 and 2022 were included if they pertained to human incidence or prevalence of disease, were in English, and were relevant to neurologic disease.

RESULTS

We identified a total of 364 articles, grouped into the 3 key themes of our study: extreme weather events and temperature fluctuations (38 studies), emerging neuroinfectious diseases (37 studies), and pollutant impacts (289 studies). The included studies highlighted the relationships between neurologic symptom exacerbation and temperature variability, tick-borne infections and warming climates, and airborne pollutants and cerebrovascular disease incidence and severity.

DISCUSSION

Temperature extremes and variability both associated with stroke incidence and severity, migraine headaches, hospitalization in patients with dementia, and multiple sclerosis exacerbations. Exposure to airborne pollutants, especially PM2.5 and nitrates, associated with stroke incidence and severity, headaches, dementia risk, Parkinson disease, and MS exacerbation. Climate change has demonstrably expanded favorable conditions for zoonotic diseases beyond traditional borders and poses the risk of disease in new, susceptible populations. Articles were biased toward resource-rich regions, suggesting a discordance between where research occurs and where changes are most acute. As such, 3 key priorities emerged for further study: neuroinfectious disease risk mitigation, understanding the pathophysiology of airborne pollutants on the nervous system, and methods to improve delivery of neurologic care in the face of climate-related disruptions.

Wildfire smoke exposure and emergency department visits for headache: A case-crossover analysis in California, 2006-2020

OBJECTIVE

To evaluate the association of short-term exposure to overall fine particulate matter of <2.5 μm (PM_2.5 ) and wildfire-specific PM_2.5 with emergency department (ED) visits for headache.

BACKGROUND

Studies have reported associations between PM_2.5 exposure and headache risk. As climate change drives longer and more intense wildfire seasons, wildfire PM_2.5 may contribute to more frequent headaches.

METHODS

Our study included adult Californian members (aged ≥18 years) of a large de-identified commercial and Medicare Advantage claims database from 2006 to 2020. We identified ED visits for primary headache disorders (subtypes: tension-type headache, migraine headache, cluster headache, and "other" primary headache). Claims included member age, sex, and residential zip code. We linked daily overall and wildfire-specific PM_2.5 to residential zip code and conducted a time-stratified case-crossover analysis considering 7-day average PM_2.5 concentrations, first for primary headache disorders combined, and then by headache subtype.

RESULTS

Among 9898 unique individuals we identified 13,623 ED encounters for primary headache disorders. Migraine was the most frequently diagnosed headache (N = 5534/13,623 [47.6%]) followed by "other" primary headache (N = 6489/13,623 [40.6%]). For all primary headache ED diagnoses, we observed an association of 7-day average wildfire PM_2.5 (odds ratio [OR] 1.17, 95% confidence interval [CI] 0.95-1.44 per 10 μg/m³ increase) and by subtype we observed increased odds of ED visits associated with 7-day average wildfire PM_2.5 for tension-type headache (OR 1.42, 95% CI 0.91-2.22), "other" primary headache (OR 1.40, 95% CI 0.96-2.05), and cluster headache (OR 1.29, 95% CI 0.71-2.35), although these findings were not statistically significant under traditional null hypothesis testing. Overall PM_2.5 was associated with tension-type headache (OR 1.29, 95% CI 1.03-1.62), but not migraine, cluster, or "other" primary headaches.

CONCLUSIONS

Although imprecise, these results suggest short-term wildfire PM_2.5 exposure may be associated with ED visits for headache. Patients, healthcare providers, and systems may need to respond to increased headache-related healthcare needs in the wake of wildfires and on poor air quality days.

Ambient NO2 exposure induces migraine in rats: Evidence, mechanisms and interventions

Migraine is a complex neurological disorder with a high disability rate. Although the precipitating factors of migraine remain unclear, previous studies suggest that when there is excess nitrogen dioxide (NO₂) pollution in the atmosphere, the medical demand due to migraine attacks increases sharply. However, the main role of NO₂ as a trigger for migraine is not yet well understood. The purpose of this study was to explore the relationship between NO₂ exposure and the occurrence of migraine as well as the possible underlying mechanisms. We first investigated whether repeated short-term NO₂ exposure could induce behavioural and biological migraine phenotypes in rats. Next, capsazepine (CZP) was used to block transient receptor potential cation channel subfamily V member 1 (TRPV1) in vivo, and CZP and vitamin E (VE) were used to verify the role of reactive oxygen species (ROS)-TRPV1 signalling in NO₂-induced migraine in primary trigeminal neurones in vitro. We demonstrated that short-term repeated NO₂ exposure can significantly induce migraine in rats, and its key molecular mechanism may be related to ROS burst and its downstream TRPV1 channel activation. The findings of this study will enhance the understanding of the neurotoxic mechanism of NO₂, provide new clues for identifying the aetiology of migraine, and lay a new experimental basis for implementing migraine-related preventive and therapeutic control measures.

Multivariate analysis of the impact of weather and air pollution on emergency department visits for night-time headaches among children: retrospective, clinical observational study

OBJECTIVES

To examine the association between the number of visits to the emergency department (ED) by children for night-time headaches and exposure to multifaceted factors, such as meteorological conditions and air pollution.

DESIGN

We conducted a clinical observational time-series analysis study.

SETTING

We reviewed consecutive patients younger than 16 years of age at the primary ED centre in Kobe city, Japan, during the night shift (19:30-7:00 hours) between 1 January 2011 and 31 December 2019.

PARTICIPANTS

In total, 265 191 children visited the ED; 822 presented with headache during the study period.

PRIMARY OUTCOME MEASURES

We investigated the effects of meteorological factors and air pollutants by multivariate analysis of Poisson regression estimates. A subanalysis included the relationship between the number of patients with night-time headaches and the above factors by sex. Furthermore, the effect of typhoon landing on patient visits for headache was also analysed. Headache was not classified because examinations were performed by general paediatricians (non-specialists).

RESULTS

The number of patients with night-time headaches displayed distinct seasonal changes, with peaks during the summer. Multivariate analysis of Poisson regression estimates revealed a significant positive relationship between the number of patients for headache and mean temperature. Subanalysis by sex indicated a positive relationship between the number of patients with headache and mean temperature in both sexes; however, it was significant only for females. No relationship was found between the number of patients with headache and air pollution. There was no change in the number of patients for night-time headaches 3 days before and after typhoon landing.

CONCLUSIONS

High temperature is the main factor for visiting ED for night-time headaches among children in Kobe city. Our results suggest that preventive measures against night-time headaches may be possible by reducing time spent outside during summer.

Sick of news? Television news exposure, collective stressful events and headache related emergency department visits

Stress is a well-known trigger for primary headache yet its impact is difficult to demonstrate in large epidemiological studies. Israeli national TV news is often referred to as the “tribal fire”, as many Israelis watch national news coverage following terror attacks or military operations. We examined the association between exposure to television news and their content with headache related Emergency Department visits. This retrospective cohort study included data on daily Emergency Department visits with a chief complaint of headache in Soroka University Medical Center, during 2002–2012. Data on daily television news viewership ratings were obtained from the Israeli Audience Research Board and its content from Channel 2 headlines, the highest rated TV news program. To estimate the short-term effects of news rating during the evening news on the number of daily headache visits, we applied generalized linear mixed models. 16,693 Emergency Department visits were included in the analysis. An increase in five units of daily rating percentages was associated with increase in Emergency Department visits the following day, relative risk (RR) = 1.032, (95% CI 1.014–1.050). This association increased with the age of the patients; RR = 1.119, (95% CI 1.075–1.65) for older than 60-year-old, RR = 1.044 (95% CI 1.010–1.078) for ages 40–60 and RR = 1.000 (95% CI 0.977–1.023) for younger than 40-year-old. We did not find a specific content associated with ED visit for headache. Higher television news ratings were associated with increased incidence of Emergency Department headache related visits. We assume that especially among older persons, news viewership ratings provide an indirect estimate of collective stress, which acts as a headache trigger for susceptible subjects.

Air pollution and occupational accidents in the Community of Madrid, Spain

Spain is the EU member country with the third highest total number of accidents in work and has the third highest incidence rate. We have performed a descriptive analysis of occupational accidents in the Community of Madrid (Spain) between 2005 and 2013 to study the impact of air quality on the prevalence of occupational accidents, clarifying how vulnerable to air pollution outdoor workers are. In order to evaluate the association between each air pollutant and work accidents, a quasi-Poisson generalized additive model was fitted. The accident rate followed a downward and statistically significant trend (p = 0.001). The year with the highest accident rate was 2006, with 4981 occupational accidents per 100,000. Occupational accidents follow a temporary pattern (there are differences in the number of accidents according to the month of the year and to the day of the week). Exposure to PM10 and NO₂ increases the risk of having an accident at work, especially for outdoor workers. An increase of 10 μg/m³ in daily concentration resulted in increases in accidents for outdoor workers of 2.5% for PM10 and 6.4% for NO₂.

Association between ambient temperature, particulate air pollution and emergency room visits for conjunctivitis

BACKGROUND

Numerous studies have confirmed the association of ambient temperature and air pollution with a higher risk of morbidities, yet few have addressed their effect on the ocular system. The purpose of this study was to assess the association between temperature, air pollution, and emergency room visits for conjunctivitis.

METHODS

In this case-crossover study, the records of all emergency room visits to Soroka University Medical Center (SUMC) from 2009 to 2014 were reviewed for patients with conjunctivitis. Daily exposure to fine and coarse particulate matter and temperature were determined by a hybrid model involving satellite sensors. Mean relative humidity was obtained from the Ministry of Environmental Protection meteorological monitoring station located in Beer-Sheva.

RESULTS

Six hundred one patients were diagnosed with conjunctivitis in the SUMC emergency room. We discovered a positive association between temperature increments and incidence of conjunctivitis. The strongest effect was found during summer and autumn, with an immediate (lag0) incidence increase of 8.1% for each 1 °C increase in temperature (OR = 1.088, 95%CI: 1.046-1.132) between 24 and 28 °C in the summer and 7.2% for each 1 °C increase in temperature (OR = 1.072, 95%CI: 1.036-1.108) between 13 and 23 °C in the autumn. There was no statistically significant association between fine and coarse particulate matter and conjunctivitis incidence.

CONCLUSION

Temperature increases during summer and autumn are significantly associated with an increased risk of conjunctivitis. Conjunctivitis is not associated with non-anthropogenic air pollution. These findings may help community clinics and hospital emergency rooms better predict conjunctivitis cases and will hopefully lead to improved prevention efforts that will lower the financial burden on both the individual and the public.

Ambient Air Pollution Increases the Risk of Cerebrovascular and Neuropsychiatric Disorders through Induction of Inflammation and Oxidative Stress

Exposure to ambient air pollution is a well-established determinant of health and disease. The Lancet Commission on pollution and health concludes that air pollution is the leading environmental cause of global disease and premature death. Indeed, there is a growing body of evidence that links air pollution not only to adverse cardiorespiratory effects but also to increased risk of cerebrovascular and neuropsychiatric disorders. Despite being a relatively new area of investigation, overall, there is mounting recent evidence showing that exposure to multiple air pollutants, in particular to fine particles, may affect the central nervous system (CNS) and brain health, thereby contributing to increased risk of stroke, dementia, Parkinson's disease, cognitive dysfunction, neurodevelopmental disorders, depression and other related conditions. The underlying molecular mechanisms of susceptibility and disease remain largely elusive. However, emerging evidence suggests inflammation and oxidative stress to be crucial factors in the pathogenesis of air pollution-induced disorders, driven by the enhanced production of proinflammatory mediators and reactive oxygen species in response to exposure to various air pollutants. From a public health perspective, mitigation measures are urgent to reduce the burden of disease and premature mortality from ambient air pollution.

Impact of Air Pollution and Seasonal Haze on Neurological Conditions: A Review

Introduction: Air pollution is a global problem and seasonal haze from forest clearing and peat land burning in Indonesia is an annual phenomenon in Southeast Asia. As neurological disorders comprise 6.3% of the burden of disease globally, we reviewed evidence of the association between common neurological conditions and air pollution exposure, and summarised existing data on the impact of the haze phenomenon in Southeast Asia. Materials and Methods: A PubMed search for relevant studies on air pollution, Alzheimer’s disease (AD), dementia, epilepsy, haze, headache, migraine, stroke, Parkinson’s disease (PD) and neuromuscular conditions was performed. There were 52 articles which were relevant and were reviewed. Results: There were associations between short-term air pollution exposure with AD, epilepsy, ischaemic stroke and migraine. Long-term air pollution exposure was associated with AD, amyotrophic lateral sclerosis, dementia and ischaemic stroke. Evidence on the link between air pollution and PD was inconsistent. Currently, there is no specific data on the effects haze has on neurological conditions in Southeast Asia. Conclusion: Air pollution is associated with increased risk of certain common neurological disorders. More specific studies are needed to investigate the impact of seasonal haze on neurological conditions in Southeast Asia. Key words: Alzheimer’s disease, Epilepsy, Migraine, Parkinson’s disease, Stroke

Weather, ambient air pollution, and risk of migraine headache onset among patients with migraine

OBJECTIVE

Migraine is a common recurrent headache disorder affecting 14% American adults. Although weather and air pollution are often reported by patients with migraine as precipitating factors, previous studies have had mixed results.

METHODS

We prospectively collected migraine headache onset data using electronic questionnaires from 98 adults with episodic migraine in the Greater Boston area (2016-2017). Each participant was followed for an average of 45 days for a total of 4406 days of observation. Temperature, relative humidity, and barometric pressure data were obtained from local weather station. Daily average fine particulate matter, daily maximum 1-hour sulfur dioxide, daily maximum 1-hour nitrogen dioxide, daily maximum 8-hour ozone, and daily maximum 8-hour carbon monoxide from local air pollution monitors. We conducted a repeated measures analysis using fixed effects logistic regression models. In the models we adjusted for day of week, a natural cubic spline term of day of the year with 4 degrees of freedom, and a participant identifier. We additionally adjusted for linear terms of temperature and relative humidity in the air pollution analyses. We also applied logistic regression models with generalized estimating equation (GEE) and autoregressive correlation structure in the sensitivity analysis.

RESULTS

The mean age was 35 years and 88% were women. Mean temperature was 56.9 °F, relative humidity 67.3%, and fine particulate matter 7.3 μg/m³. Higher relative humidity was associated with higher odds of migraine headache, but the association was only observed in warm season (April-September). Higher levels of daily maximum 8-hour ozone and daily maximum 8-hour carbon monoxide appeared to be associated with higher odds of migraine headache onset in cold season (October-March). Although the associations for ozone and relative humidity were attenuated and no longer statistically significant in the overall GEE analysis, the differing associations by season remained.

CONCLUSIONS

We found that higher relative humidity was associated with higher odds of migraine headache onset in warm season, and traffic-related gaseous pollutants may be associated with higher odds of migraine headache onset in cold season.

Do exposure to outdoor temperatures, NO2 and PM10 affect the work-related injuries risk? A case-crossover study in three Italian cities, 2001-2010

OBJECTIVES

Studies on the effect of temperature on rates of work-related injuries (WRIs) are very recent, and are evolving in depth and scope. However, less is known about potential effects of air pollutants. Our objective was to analyse the association between WRI and NO₂, PM₁₀ and air temperature in three major Italian cities, and to identify groups of workers more at risk in Italy.

DESIGN

Time-stratified case-crossover study.

SETTINGS

Milan, Turin, Rome, years 2001-2010.

PARTICIPANTS

A total of 468 816 WRI occurred between 2001 and 2010 in Milan, Turin and Rome were extracted from the Italian national workers' compensation authority database.

MAIN OUTCOMES

Associations between WRI and temperature, PM₁₀, NO₂, separately in the warm and in the cold season (WS, May-September; CS, November-February). Effect modification was studied by economic sector, occupational activity and indoor/outdoor job activity.

RESULTS

Exposure to NO₂ (lag 0-8) showed the highest effect on the risk of WRI,with ORs ranging from 1.20 (95% CI 1.16 to 1.24) in Milan to 1.30 (95% CI 1.24 to 1.37) in Turin in the WS. The effect of exposure to PM₁₀ was milder but consistent across all cities: ORs from 1.09 (95% CI 1.05 to 1.12) in Turin to 1.15 (95% CI 1.11 to 1.18) in Rome. Temperature was associated with risk of WRI only among those working in construction (highest association in Rome 1.06; 95% CI 1.01 to 1.12), transportation (highest association in Milan 1.05; 95% CI 0.96 to 1.14) and the energy industry (highest association in Milan 1.57; 95% CI 1.03 to 2.38) in the WS in all cities. A weak effect of low temperatures was observed in the CS only in Rome.

CONCLUSIONS

Exposures to NO₂ resulted as strongest hazard for WRIs, mainly in warm months, while the independent effect of temperature was significant only in specific subgroups of workers. These results could be considered to better plan safety prevention programmes.

Primary headache characters and coping strategies among medical students of Umm Al-Qura University in the Western Region of Saudi Arabia

Objectives:

To assess the headache patterns among medical students of Umm Al-Qura College of Medicine, Makkah, Kingdom of Saudi Arabia. Medical students represent a vulnerable group for primary headache disorders, as they are exposed to various physical and psychological stressors.

Methods:

We carried an observational, cross-sectional study, and collected data during February, 2017 using electronic questionnaires. The international classification of headache disorders, third edition (ICHD-3) beta edition was used to classify headache into 10 types.

Results:

A total of 623 responses (82.2%) were received out of 758 participants. The one-year headache prevalence was 558 (89.6%). The most common diagnosis among both genders was frequent tension-type headache (TTH) (n=173, 31.0%), followed by probable infrequent TTH (n=114, 20.4%) and probable frequent TTH (n=63, 11.3%).The greatest proportions of students who reported an impact of their academic level were found among the chronic TTH, migraine without and with aura (n=2, 40.0%; n=14, 34.4%; n=11, 33.3%). Migraine without aura was more prevalent among females (n=29, 10.5%) than males (n=10, 3.5%). Self-medication was common (62.5%-100.0%). Simple analgesics (67.4%-80.0%), sleeping (54.3%-80.0%) and caffeine intake (28.3%-60.0%) were the top 3 therapies that were practiced.

Conclusion:

The prevalence of headache among Umm Al-Qura university (UQU), Makkah, Kingdom of Saudi Arabia’s medical students appears higher than the prevalence among the general population. This may have a significant impact on academic performance and necessitates special attention. We recommend further studies on interventions to reduce the prevalence and impact of this prevalent problem.

Induction of chronic migraine phenotypes in a rat model after environmental irritant exposure

Air pollution is linked to increased emergency department visits for headache and migraine patients frequently cite chemicals or odors as headache triggers, but the association between air pollutants and headache is not well understood. We previously reported that chronic environmental irritant exposure sensitizes the trigeminovascular system response to nasal administration of environmental irritants. Here, we examine whether chronic environmental irritant exposure induces migraine behavioral phenotypes. Male rats were exposed to acrolein, a transient receptor potential channel ankyrin-1 (TRPA1) agonist, or room air by inhalation for 4 days before meningeal blood flow measurements, periorbital cutaneous sensory testing, or other behavioral testing. Touch-induced c-Fos expression in trigeminal nucleus caudalis was compared in animals exposed to room air or acrolein. Spontaneous behavior and olfactory discrimination was examined in open-field testing. Acrolein inhalation exposure produced long-lasting potentiation of blood flow responses to a subsequent TRPA1 agonist and sensitized cutaneous responses to mechanical stimulation. C-Fos expression in response to touch was increased in trigeminal nucleus caudalis in animals exposed to acrolein compared with room air. Spontaneous activity in an open-field and scent preference behavior was different in acrolein-exposed compared with room air-exposed animals. Sumatriptan, an acute migraine treatment blocked acute blood flow changes in response to TRPA1 or transient receptor potential vanilloid receptor-1 agonists. Pretreatment with valproic acid, a prophylactic migraine treatment, attenuated the enhanced blood flow responses observed after acrolein inhalation exposures. Environmental irritant exposure yields an animal model of chronic migraine in which to study mechanisms for enhanced headache susceptibility after chemical exposure.

Mortality risks from a spectrum of causes associated with wide-ranging exposure to fine particulate matter: A case-crossover study in Beijing, China

BACKGROUND

Exposure to fine particulate matter (≤2.5μm in aerodynamic diameter; PM_2.5) has been shown to be associated with an increased risk of mortality due to cardiovascular, respiratory, and other pulmonary diseases. However, fewer studies have investigated the relationship between ambient PM_2.5 and human mortality for a wider range of causes of death, or for more specific causes of death within these broader categories, especially at the high PM_2.5 concentrations currently experienced in Chinese megacities. Beijing, China, has a very large population and a wide range of PM_2.5 exposures, allowing a prime opportunity to estimate such risks across a broad spectrum of causes, including rarer causes of death.

OBJECTIVE

To estimate the relative risk of cause-specific mortality associated with PM_2.5 for a spectrum of causes of death, as well as characterize the time course of cause-specific mortality following PM_2.5 exposure, in a location where PM_2.5 concentrations are representative of common exposures in Chinese megacities.

METHODS

We collected daily data on mortality counts of Beijing residents and Beijing weather and air pollution measurements for January 1, 2009 to December 31, 2012. We used a time-stratified case-crossover study design to estimate the association between ambient PM_2.5 concentrations and risk of death from several broad causes of death and from more refined specific causes within these broader categories. Primary results were estimated for risks the day of and the day following exposure (lag 0-1), but the time pattern of associated risk was also explored up to seven days following exposure.

RESULTS

Increased concentrations of PM_2.5 were associated with increased risks at lag days 0-1 of all-cause mortality (0.26% increase per 10μg/m³; 95% confidence interval [CI]: 0.12%-0.39%), non-accidental deaths (0.25%; 95% CI: 0.11%-0.38%), circulatory deaths (0.39%; 95% CI: 0.21%-0.59%), respiratory deaths (0.43%; 95% CI: 0.05%-0.81%), intentional self-harm deaths (1.94%; 95% CI: 0.19%-3.73%) and nervous system deaths (0.9%; 95% CI: -0.2%-2%), although the observed increase was not statistical significant for the final one rarer cause of death. In addition to these five broad death outcomes, risk also increased following PM_2.5 exposure at lag days 0-1 for deaths from several specific causes, including most of the specific circulatory causes considered. The largest observed increased risk by far was for one of the rarest causes of death considered, extrapyramidal and movement disorders (2.35%; 95% CI: 0.03%-4.72%).

CONCLUSIONS

This study indicates that exposure to PM_2.5 in a study location more representative of exposures in developing cities is associated with an increased risk of mortality from broad range of causes of death, including some causes rarely studied previously in association with PM_2.5 exposure.

The impact of ambient air pollution on suicide mortality: a case-crossover study in Guangzhou, China

BACKGROUND

Preventing suicide is a global imperative. Although the effects of social and individual risk factors of suicide have been widely investigated, evidence of environmental effects of exposure to air pollution is scarce. We investigated the effects of ambient air pollution on suicide mortality in Guangzhou, China during 2003-2012.

METHODS

A conditional logistic regression analysis with a time-stratified case-crossover design was performed to assess the effects of daily exposure to three standard air pollutants, including particulate matter less than 10 μm in aerodynamic diameter (PM10), sulphur dioxide (SO2) and nitrogen dioxide (NO2), on suicide mortality, after adjusting for the confounding effects of daily mean temperature, relative humidity, atmospheric pressure and sunshine duration. Further analyses were stratified by season, gender, age group, educational attainment and suicide type.

RESULTS

Between 2003 and 2012, there were a total of 1 550 registered suicide deaths in Guangzhou. A significant increase in suicide risk were associated with interquartile-range increases in the concentration of air pollutant, with an odds ratio of 1.13 (95 % confidence interval (CI): 1.01, 1.27) and 1.15 (95 % CI: 1.03, 1.28) for PM10 and NO2 at lag 02, and 1.12 (95 % CI: 1.02, 1.23) for SO2 at lag 01, respectively. The suicide risks related to air pollution for males and people with high education level were higher than for females and those with low education level, respectively. Significant air pollution effects were found on violent suicide mortality and in cool season but not on non-violent suicide mortality or in warm season.

CONCLUSIONS

Suicide risk was positively associated with ambient air pollution levels. This finding would provide important information for the health impact assessment of air pollution and for the development of effective strategies and interventions for the prevention of suicide.