Is Migraine Primarily a Metaboloendocrine Disorder?

Association between weight status and migraine in the paediatric population: a systematic review and meta-analysis

Introduction

An association between weight status and migraine has been previously reported; however, this relationship has only been studied in adults, not in the paediatric population.

Objective

To evaluate the association between weight status and migraine in the paediatric population.

Methods

We searched PubMed/Medline, Scopus, Web of Science, Ovid Medline, and Embase using a cut-off date of May 2023. We included observational studies that evaluated the association between weight status (underweight, overweight, obese, and excess weight) and migraine in the paediatric population (children and adolescents). Normal weight was the comparator. The outcome was migraine (all types, episodic and chronic). We performed meta-analyses using a random-effects model to estimate the pooled effects for each outcome. Sensitivity analysis was performed based on study design and risk of bias (using the Newcastle-Ottawa Scale). Certainty of evidence was assessed using the GRADE approach.

Results

Eight studies (6 cross-sectional, 1 case-control and 1 cohort) covering 16,556 patients were included. The overall certainty of evidence was very low for the association between overweight, obesity, and excess weight with migraine. In the sensitivity analysis, meta-analyses of studies with a low risk of bias found that the overweight population probably had an increased odds of migraine (OR: 1.70; 95% CI: 1.14 to 2.53; I2 = 32.3%, p = 0.224) and that excess weight may increase the odds of migraine (OR: 1.58; 95% CI: 1.06 to 2.35; I2 = 83.7%, p = 0.002). Additionally, cohort and case-control studies found that obesity probably increases the odds of migraine. No studies analysed the association between underweight and migraine.

Conclusion

The associations between overweight, obesity, excess weight and migraine were uncertain, but studies with better methodological quality reported increased odds. Future longitudinal studies with proper confounding control are needed to disentangle their causal relationship.

Systematic review registration

PROSPERO, identifier CRD42021271533.

All Roads Lead to the Gut: The Importance of the Microbiota and Diet in Migraine

Migraine, a prevalent neurological condition and the third most common disease globally, places a significant economic burden on society. Despite extensive research efforts, the precise underlying mechanism of the disease remains incompletely comprehended. Nevertheless, it is established that the activation and sensitization of the trigeminal system are crucial during migraine attacks, and specific substances have been recognized for their distinct involvement in the pathomechanism of migraine. Recently, an expanding body of data indicates that migraine attacks can be prevented and treated through dietary means. It is important to highlight that the various diets available pose risks for patients without professional guidance. This comprehensive overview explores the connection between migraine, the gut microbiome, and gastrointestinal disorders. It provides insight into migraine-triggering foods, and discusses potential diets to help reduce the frequency and severity of migraine attacks. Additionally, it delves into the benefits of using pre- and probiotics as adjunctive therapy in migraine treatment.

Fructose supplementation shifts rat brain metabolism in experimental migraine

AIMS

We have previously demonstrated that fructose supplementation (FS), given in a scheme used for inducing metabolic syndrome (MS), elicited pain relief in the nitroglycerin (NTG)-elicited rat migraine model. Herein, we evaluated whether FS could reestablish the impaired metabolic pathways in NTG-injected rats.

MAIN METHODS

Male Wistar rats (N=40) were divided into two groups for receiving 10-% FS or tap water. After 45 days, they were subdivided into NTG-injected (10mg/kg; 15 days) or controls. After the fourth NTG injection, ¹⁸F-fluorodeoxyglucose ([¹⁸F] FDG) micro-PET scanning was accomplished. The day after, euthanasia was performed, and blood was collected for glycemia and LDH analysis. The levels of energy molecules, TBARS, PGC-1α, and MCTS1 were evaluated in the brain cortices. The activated satellite glial cells (SGC) were assessed in the trigeminal ganglion (TG).

KEY FINDINGS

There were no variations of glycemia or LDH serum levels. NTG-injected rats showed a significant increase in glucose uptake in the hypothalamus (HT) vs. NTG-free rats. The FS-NTG group showed increased metabolism in the superior colliculus (SC) vs. the NTG group. Moreover, the glucose uptake was amplified in the inferior colliculus (IC) of the FS-NTG vs. FS group. The cortical inosine levels were significantly higher in FS-NTG rats vs. NTG or FS groups, with no changes in TBARS or MCTS1 levels, despite a minor decrease of PGC1-α contents in the FS+NTG group. Finally, there was a significant increase of activated SGC around TG in the FS-NTG rats.

SIGNIFICANCE

We provide novel evidence linking nutrition and metabolism with migraine.

A Preliminary Analysis on the Feasibility and Short-Term Efficacy of a Phase-III RCT on Mindfulness Added to Treatment as Usual for Patients with Chronic Migraine and Medication Overuse Headache

This preliminary analysis of a single-blind phase-III RCT aims to compare the feasibility and short-term efficacy of mindfulness as an add-on to treatment as usual (TaU) in the management of patients with chronic migraine (CM) and medication overuse headache (MOH). Patients were randomized to either TaU (structured withdrawal of overused drugs, patient education and pharmacological prophylaxis) or TaU + MIND, wherein patients additionally received six 90 min weekly group sessions of mindfulness-based therapy. Repeated measures analyses were used to test whether patients in the two arms showed different course with regard to headache frequency and medication intake over a three-month period. Drop-out rates were not different between the two groups: 6/89 (6.7%) and 9/88 (10.2%) among those in TaU and TaU + MIND, respectively. A significant effect of time for all variables was shown, together with a significant effect of time by group, favoring TaU + MIND condition for headache frequency (p = 0.025) and NSAID intake (p = 0.007), controlling for age and CM duration. In total, 45/83 (54.2%) and 69/79 (75.9%) of the patients allocated to TaU and TaU + MIND, respectively, achieved 50% or more headache-day reduction (chi-squared 8.38, p = 0.004). Our preliminary analysis indicates that adding six mindfulness-based sessions to TaU was feasible and showed short-term efficacy in the treatment of patients with CM and MOH.

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.

Applying a biopsychosocial model to migraine: rationale and clinical implications

Migraine is a complex condition in which genetic predisposition interacts with other biological and environmental factors determining its course. A hyperresponsive brain cortex, peripheral and central alterations in pain processing, and comorbidities play a role from an individual biological standpoint. Besides, dysfunctional psychological mechanisms, social and lifestyle factors may intervene and impact on the clinical phenotype of the disease, promote its transformation from episodic into chronic migraine and may increase migraine-related disability.Thus, given the multifactorial origin of the condition, the application of a biopsychosocial approach in the management of migraine could favor therapeutic success. While in chronic pain conditions the biopsychosocial approach is already a mainstay of treatment, in migraine the biomedical approach is still dominant. It is instead advisable to carefully consider the individual with migraine as a whole, in order to plan a tailored treatment. In this review, we first reported an analytical and critical discussion of the biological, psychological, and social factors involved in migraine. Then, we addressed the management implications of the application of a biopsychosocial model discussing how the integration between non-pharmacological management and conventional biomedical treatment may provide advantages to migraine care.

Chronic Pain and Emotional Stroop: A Systematic Review

Chronic pain is an unpleasant sensory and emotional experience that persists for more than 3 months and is often accompanied by symptoms such as depression, fatigue, sleep disturbances, and cognitive impairment. Emotional dysregulation may also be involved in its etiology. Emotions are known to modulate the experience of pain by influencing cognition and behavior (emotional awareness, emotional expression and experience, and verbalizations). A useful task to explore emotional processing and emotional dysregulation is the emotional Stroop task. Despite the large number of studies using this task, their objectives are diverse; it is necessary to integrate them. The main objective of the present systematic review was to determine the extent of the abnormalities in behavioral performance (including attentional biases) and/or brain alterations in patients with chronic pain during the emotional Stroop task. This systematic review was conducted in accordance with the Cochrane Collaboration guidelines and Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. The protocol was previously registered in the Prospective Register of Systematic Reviews (PROSPERO) international database. The selected articles were extracted from the PubMed, Scopus, and Web of Science databases. Fifteen studies were identified as eligible for systematic review. The studies reported alterations in brain regions related to pain and emotional regulation, as well as attentional bias and higher response time latencies (related to the words’ emotional load) in patients with chronic pain. The results confirm the validity of the emotional Stroop task to measure emotions and selective attention. As attentional bias towards negative information is often seen in chronic pain patients, and given the relation between selective attention and greater activation of the brain areas associated with pain and emotional processing, this type of task plays a crucial role in research on emotional and attentional processes among chronic pain patients. Further, attentional bias towards negative information has been associated with higher levels of pain. Taken together, the results suggest the need for cognitive training and an emotional approach to chronic pain therapies, especially targeting attentional biases and negative mood.

Headaches and obesity

Obesity and headache disorders are two very common conditions in the general population that have been increasing in incidence over the last decades. Recent studies have shown a significant relationship between obesity and headaches, particularly migraine, with an important role in whether the disease is chronic. On the other hand, no such association was found with tension-type headaches. Studies showing an overlapping of hunger-control pathways and those involved in the pathophysiology of migraine may justify the close association between obesity and migraine. Moreover, a secondary headache for which obesity is a strong risk factor is idiopathic Intracranial Hypertension (pseudotumor cerebri), with several studies showing the impact of weight reduction/bariatric surgery in the treatment of the disease. In conclusion, since obesity is a modifiable risk factor, it is important for physicians treating patients with headaches, and particularly migraine, to be aware of the association between these two disorders.

Migraine, Brain Glucose Metabolism and the "Neuroenergetic" Hypothesis: A Scoping Review

Increasing evidence suggests that migraine may be the result of an impaired brain glucose metabolism. Several studies have reported brain mitochondrial dysfunction, impaired brain glucose metabolism and gray matter volume reduction in specific brain areas of migraineurs. Furthermore, peripheral insulin resistance, a condition demonstrated in several studies, may extend to the brain, leading to brain insulin resistance. This condition has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis, mainly during high metabolic demand. This scoping review examines the clinical, epidemiologic and pathophysiologic data supporting the hypothesis that abnormalities in brain glucose metabolism may generate a mismatch between the brain's energy reserve and metabolic expenditure, triggering migraine attacks. Moreover, alteration in glucose homeostasis could generate a chronic brain energy deficit promoting migraine chronification. Lastly, insulin resistance may link migraine with its comorbidities, like obesity, depression, cognitive impairment and cerebrovascular diseases. PERSPECTIVE: Although additional experimental studies are needed to support this novel "neuroenergetic" hypothesis, brain insulin resistance in migraineurs may unravel the pathophysiological mechanisms of the disease, explaining the migraine chronification and connecting migraine with comorbidities. Therefore, this hypothesis could elucidate novel potential approaches for migraine treatment.

Migraine: A Review on Its History, Global Epidemiology, Risk Factors, and Comorbidities

Migraine affects more than one billion individuals each year across the world, and is one of the most common neurologic disorders, with a high prevalence and morbidity, especially among young adults and females. Migraine is associated with a wide range of comorbidities, which range from stress and sleep disturbances to suicide. The complex and largely unclear mechanisms of migraine development have resulted in the proposal of various social and biological risk factors, such as hormonal imbalances, genetic and epigenetic influences, as well as cardiovascular, neurological, and autoimmune diseases. This review presents a comprehensive review of the most up-to-date literature on the epidemiology, and risk factors, as well as highlighting the gaps in our knowledge.

Metabolic profile changes in serum of migraine patients detected using 1H-NMR spectroscopy

Background

Migraine is a common brain disorder but reliable diagnostic biomarkers in blood are still lacking. Our aim was to identify, using proton nuclear magnetic resonance (¹H-NMR) spectroscopy, metabolites in serum that are associated with lifetime and active migraine by comparing metabolic profiles of patients and controls.

Methods

Fasting serum samples from 313 migraine patients and 1512 controls from the Erasmus Rucphen Family (ERF) study were available for ¹H-NMR spectroscopy. Data was analysed using elastic net regression analysis.

Results

A total of 100 signals representing 49 different metabolites were detected in 289 cases (of which 150 active migraine patients) and 1360 controls. We were able to identify profiles consisting of 6 metabolites predictive for lifetime migraine status and 22 metabolites predictive for active migraine status. We estimated with subsequent regression models that after correction for age, sex, BMI and smoking, the association with the metabolite profile in active migraine remained. Several of the metabolites in this profile are involved in lipid, glucose and amino acid metabolism.

Conclusion

This study indicates that metabolic profiles, based on serum concentrations of several metabolites, including lipids, amino acids and metabolites of glucose metabolism, can distinguish active migraine patients from controls.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01357-w.

The association between obesity and migraine and possible mechanisms of action: an integrative literature review

IntroductionObesity is a multifactorial disease and is defined by the excessive accumulation of adipose tissue that can cause harm to human health. The presence of obesity is an important risk factor for migraine chronification. However, not much is known about the link between the two diseases. MethodsIn this study, an integrative literature review was conducted to better understand the mechanisms of interaction between migraine and obesity. Therefore, a search of PubMed and the Virtual Health Library (VHL) was performed with the following keywords: enxaqueca e obesidade; enxaqueca e obesidade e inflamação; enxaqueca e obesidade e neuropeptídeos; migraine and obesity; migraine and obesity and inflammation; migraine and obesity and neuropeptides. ResultsThe search identified 22 articles. After reading and analyzing the articles, three thematic categories emerged: 1) Obesity as an Aggravating Factor for Migraine 2) Mechanisms Studied between Obesity and Migraine 3) The Effect of Weight Loss on Migraine Symptoms. ConclusionsThe chronic low-grade inflammation associated with obesity can cause a predisposition to migraine chronification. The abnormal secretion of adipokines, dysregulation of the sympathetic nervous system, and hypothalamic dysfunction have been suggested to be the main shared mechanisms between both diseases.

Metabolic Aspects of Migraine: Association With Obesity and Diabetes Mellitus

Migraine is a disabling neurovascular disorder, characterized by moderate to severe unilateral headaches, nausea, photophobia, and/or phonophobia, with a higher prevalence in women than in men, which can drastically affect the quality of life of migraine patients. In addition, this chronic disorder is related with metabolic comorbidities associated with the patient's lifestyle, including obesity and diabetes mellitus (DM). Beyond the personal and socioeconomic impact caused by migraine, obesity and DM, it has been suggested that these metabolic disorders seem to be related to migraine since: (i) they are a risk factor for developing cardiovascular disorders or chronic diseases; (ii) they can be influenced by genetic and environmental risk factors; and (iii) while clinical and epidemiological studies suggest that obesity is a risk factor for migraine, DM (i.e., type 1 and type 2 DM) have been reported to be either a protective or a risk factor in migraine. On this basis, and given the high worldwide prevalence of migraine, obesity, and DM, this article provides a narrative review of the current literature related to the association between the etiology and pathophysiology of migraine and these metabolic disorders, considering lifestyle aspects, as well as the possible involvement of neurotransmitters, neuropeptides, and/or sex hormones. While a link between migraine and metabolic disorders has been suggested, many studies are contradictory and the mechanisms involved in this association are not yet sufficiently established. Therefore, further research should be focused on understanding the possible mechanisms involved.

Migraine and stress-an exploratory cross-country study of external stress factors

OBJECTIVE

The data collected by the Global Burden of Disease 2016 project indicate that migraine ranks second in high-income countries with very competitive and flexible labour markets, and first in low- and middle-income countries suffering from civic unrest and conflict. This raises the question whether external stress factors may be correlated with migraine years lived with disability per 100,000 inhabitants (YLD). The objective of this exploratory study is to test the hypothesis that external stress factors are correlated with the prevalence and severity of migraine at the country level. The analysis uses two country groups: developed and developing countries. For the first group, the proxy variables for stress are labour productivity and unemployment rate. For the second group, the proxy variables measure conflict-related deaths and share of migrant/refugee population.

RESULTS

The results show a positive relationship between the stress variables on the one hand and migraine YLD on the other hand for both country groups. Almost all results are statistically significant at p < 0.01. These exploratory findings suggest that societal stress factors may be potential candidates for modifiable factors for the prevalence and/or severity of migraine at the country level.

A Bidirectional View of Migraine and Diet Relationship

Migraine is a common headache with a large negative impact on health. Several endogenous and exogenous factors can influence the severity and frequency of migraine, for example, lifestyle factors including dietary factors. Consequently, lifestyle modifications and dietary considerations have been reported beneficial to moderate clinical features of migraine. Much effort has been invested in determining the lifestyle factors (eg, stress, exercise, sleep, and diet) that trigger migraine to develop recommendations and guidelines for prevention. Diet has also been investigated with a major focus on the content of the diet and to a lesser extent on the amount, pattern, and quality of diet. Identification of dietary factors in migraine has led to nutritional interventions with a major focus on elimination of triggers, and weight control strategies. Several so-called migraine diets have consequently been proposed, for example, the ketogenic diet. Some theories have considered epigenetic diets or functional food to help in altering components of migraine pathogenesis; however, these theories are less investigated. In contrast, evidence is being accumulated to support that some mechanisms underlying migraine may alter dietary choices, for example type, amount, or patterns. Since a causative relationship is not yet established in migraine-diet relationship as to which comes first, this concept is equally valuable and interesting to investigate. Only limited epidemiological data are available to demonstrate that dietary choices are different among patients with migraine compared with individuals without migraine. Differences are reflected on quality, composition, pattern, and the amount of consumption of dietary components. This view emphasizes a potential bidirectional relationship between migraine and diet rather than a one-way influence of one on the other. This targeted review presents examples from current literature on the effects of diet on migraine features and effects of migraine on dietary choices to draw a perspective for future studies.

Primary headache subtypes and thyroid dysfunction: Is there any association?

BACKGROUND

Primary headaches, and particularly migraine and tension-type headache (TTH) as well as hypothyroidism are common medical conditions. To date, numerous studies have suggested a possible bidirectional relationship between migraine and hypothyroidism, although certain studies had contradictory results.

OBJECTIVE

To investigate whether there is any association between primary headache subtypes and thyroid disorders.

METHODS

A retrospective study of consecutive patients aged ≥18 years referred to the Headache Outpatient Clinic of Aeginition Hospital and diagnosed with primary headache and any thyroid disorder.

RESULTS

Out of 427 patients (males/females=76/351), 253 (59.3%) were diagnosed with migraine without aura, 53 (12.4%) with TTH, 49 (11.5%) with migraine with aura, 29 (6.8%) with medication-overuse headache, 23 (5.4%) with mixed-type headache (migraine with/without aura and TTH), nine (2.1%) with cluster headache, and 11 (2.6%) with other types of primary headaches. The prevalence of any type of thyroid disorder was 20.8% (89/427 patients). In the total sample, 27 patients (6.3%) reported hypothyroidism, 18 (4.2%) unspecified thyroidopathy, 14 (3.3%) thyroid nodules, 12 (2.8%) Hashimoto thyroiditis, 12 (2.8%) thyroidectomy, three (0.7%) thyroid goiter, and three (0.7%) hyperthyroidism. Further statistical analysis between categorical variables did not reveal any significant association between headache subtypes and thyroid dysfunction.

CONCLUSIONS

No specific association was found between primary headache subtypes and specific thyroid disorder. However, a high prevalence of thyroid dysfunction in general and specifically hypothyroidism was demonstrated among patients with primary headaches, which lays the foundation for further clarification in prospective longitudinal studies.

Migraine and tension headache comorbidity with hypothyroidism in Egypt

Background

Migraine, tension type headache (TTH), and hypothyroidism are clinical problems that affect patient daily activities and quality of life.

Objectives

The purpose of this study was to investigate the potential association between hypothyroidism in patients with migraine and TTH.

Patients and methods

Two hundred and twelve patients with migraine and TTH and one hundred control subjects underwent clinical evaluation, assessment of thyroid hormones, and thyroid ultrasound.

Results

Subclinical and overt hypothyroidism were significantly higher in patients with migraine and TTH (P = 0.001) than control subjects. Patients with migraine and TTH showed significantly more abnormal thyroid gland morphology than healthy control (P = 0.027). Hypothyroidism is significantly expressed in chronic TTH more than TTH with infrequent or frequent TTH (P = 0.009).

Conclusions

Patients having migraine and TTH more prone to develop hypothyroidism when compared with control group. Also patients with chronic TTH are susceptible to develop hypothyroidism (either subclinical or overt) when compared with patients having frequent or infrequent TTH.

What is Needed for Evidence-Based Dietary Recommendations for Migraine: A Call to Action for Nutrition and Microbiome Research

BACKGROUND

The gastrointestinal symptoms of migraine attacks have invited numerous dietary hypotheses for migraine etiology through the centuries. Substantial efforts have been dedicated to identifying dietary interventions for migraine attack prevention, with limited success. Meanwhile, mounting evidence suggests that the reverse relationship may also exist - that the biological mechanisms of migraine may influence dietary intake. More likely, the truth involves some combination of both, where the disease influences food intake, and the foods eaten impact the manifestations of the disease. In addition, the gut's microbiota is increasingly suspected to influence the migraine brain via the gut-brain axis, though these hypotheses remain largely unsubstantiated.

OBJECTIVE

This paper presents an overview of the strength of existing evidence for food-based dietary interventions for migraine, noting that there is frequently evidence to suggest that a dietary risk factor for migraine exists but no evidence for how to best intervene; in fact, our intuitive assumptions on interventions are being challenged with new evidence. We then look to the future for promising avenues of research, notably the gut microbiome.

CONCLUSION

The evidence supports a call to action for high-quality dietary and microbiome research in migraine, both to substantiate hypothesized relationships and build the evidence base regarding nutrition's potential impact on migraine attack prevention and treatment.

Integrating Pathophysiology in Migraine: Role of the Gut Microbiome and Melatonin

BACKGROUND

The pathoetiology and pathophysiology of migraine are widely accepted as unknown.

METHODS

The current article reviews the wide array of data associated with the biological underpinnings of migraine and provides a framework that integrates previously disparate bodies of data.

RESULTS

The importance of alterations in stress- and pro-inflammatory cytokine- induced gut dysbiosis, especially butyrate production, are highlighted. This is linked to a decrease in the availability of melatonin, and a relative increase in the N-acetylserotonin/melatonin ratio, which has consequences for the heightened glutamatergic excitatory transmission in migraine. It is proposed that suboptimal mitochondria functioning and metabolic regulation drive alterations in astrocytes and satellite glial cells that underpin the vasoregulatory and nociceptive changes in migraine.

CONCLUSION

This provides a framework not only for classical migraine associated factors, such as calcitonin-gene related peptide and serotonin, but also for wider factors in the developmental pathoetiology of migraine. A number of future research and treatment implications arise, including the clinical utilization of sodium butyrate and melatonin in the management of migraine.

Migraine and Diet

Migraine is characterized by recurrent attacks of disabling headaches, often accompanied by sensory and motor disturbances. Clinical manifestations of migraine are influenced by dietary behaviors and dietary elements. Several dietary triggers for migraine have been identified, leading to the definition of strategies such as elimination diets, ketogenic diets, and comprehensive diets, mainly to help prevent migraine. Although inconsistency is present in the literature and no consensus exists, the available data are promising in supporting beneficial dietary interventions for some migraine patients. Several factors influence the net outcome, including age, sex, genetics, and environmental factors. Advancement in understanding the underlying mechanisms of migraine pathogenesis and how dietary factors can interfere with those mechanisms has encouraged investigators to consider diet as a disease-modifying agent, which may also interfere with the gut–brain axis or the epigenetics of migraine. Future work holds potential for phenotyping migraine patients and offering personalized recommendations in line with biopsychosocial models for the management of migraine. Diet, as an important element of lifestyle, is a modifiable aspect that needs further attention. Well-designed, systematic, and mechanism-driven dietary research is needed to provide evidence-based dietary recommendations specific to migraine. This narrative review aims to present the current status and future perspective on diet and migraine, in order to stimulate further research and awareness.

Cross-trait analyses with migraine reveal widespread pleiotropy and suggest a vascular component to migraine headache

BACKGROUND

Nearly a fifth of the world's population suffer from migraine headache, yet risk factors for this disease are poorly characterized.

METHODS

To further elucidate these factors, we conducted a genetic correlation analysis using cross-trait linkage disequilibrium (LD) score regression between migraine headache and 47 traits from the UK Biobank. We then tested for possible causality between these phenotypes and migraine, using Mendelian randomization. In addition, we attempted replication of our findings in an independent genome-wide association study (GWAS) when available.

RESULTS

We report multiple phenotypes with genetic correlation (P  < 1.06 × 10-3) with migraine, including heart disease, type 2 diabetes, lipid levels, blood pressure, autoimmune and psychiatric phenotypes. In particular, we find evidence that blood pressure directly contributes to migraine and explains a previously suggested causal relationship between calcium and migraine.

CONCLUSIONS

This is the largest genetic correlation analysis of migraine headache to date, both in terms of migraine GWAS sample size and the number of phenotypes tested. We find that migraine has a shared genetic basis with a large number of traits, indicating pervasive pleiotropy at migraine-associated loci.

Migraine pathways and the identification of novel therapeutic targets

Introduction: Migraine is a chronic neurovascular disorder characterized by recurrent headache attacks associated with neurological and autonomic symptoms. The pathophysiological mechanisms of the disease are extremely complex, involving hypothalamic and trigeminovascular activation, cortical spreading depression, release of pro-inflammatory peptides, peripheral and central sensitization. The underlying cellular and molecular mechanisms have been scarcely investigated. Recently, genetic studies have suggested that different metabolic pathways could be involved in the pathogenesis of migraine.Areas covered: This review focuses on cellular and molecular mechanisms involved in migraine, suggesting a role for circadian clocks, ion channels, synaptic plasticity, vascular factors, ion metal homeostasis, and impaired glucose metabolism in the pathogenesis of the disease. Accordingly, the article proposes new therapeutic targets that may be of particular relevance for disease prevention.Expert opinion: Several complex molecular mechanisms are involved in setting the genetic threshold for migraine and the pathogenesis of headache attacks. Most promising new therapeutic targets are the modulation of hypothalamic activity and ion channels involved in pain transmission. Further studies in animals and humans are necessary to enhance the elucidation of the molecular mechanisms of migraine and open new avenues for disease prevention.

Excess abdominal fat is associated with cutaneous allodynia in individuals with migraine: a prospective cohort study

OBJECTIVE

To investigate the specific relationship between cutaneous allodynia (CA) and the percentages of body fat (BF) and abdominal fat in migraineurs. Additionally, we compared serum levels of inflammatory biomarkers in patients with and without CA.

BACKGROUND

Excess abdominal fat might facilitate progressive changes in nociceptive thresholds causing central sensitization, clinically reflected as CA, which could drive migraine progression.

METHODS

This prospective cohort study included 80 patients with migraine (mean age 39 years, 81.2% female) and 39 non-migraine controls. We analysed each participant's height, body weight, and body mass index (BMI). The amount and distribution of BF was also assessed by air displacement plethysmography (ADP) and ViScan, respectively. We analysed serum levels of markers of inflammation, during interictal periods.

RESULTS

We studied 52 patients with episodic migraine (EM) and 28 with chronic migraine (CM). Of the 80 patients, 53 (53.8%) had CA. Migraineurs with CA had a higher proportion of abdominal fat values than patients without CA (p = 0.04). The independent risk factors for CA were the use of migraine prophylaxis (OR 3.26, 95% CI [1.14 to 9.32]; p = 0.03), proportion of abdominal fat (OR 1.13, 95% CI [1.01 to 1.27]; p = 0.04), and presence of sleep disorders (OR 1.13, 95% CI [00.01 to 1.27]; p = 0.04). The concordance correlation coefficient between the ADP and BMI measurements was 0.51 (0.3681 to 0.6247). CA was not correlated with the mean plasma levels of inflammatory biomarkers.

CONCLUSIONS

There is a relation between excess abdominal fat and CA. Abdominal obesity might contribute to the development of central sensitization in migraineurs, leading to migraine chronification.

The good, the bad, and the ugly facets of insulin resistance

Insulin is a potent anabolic hormone, and binding to its receptor activates downstream intracellular signaling pathways that regulate the nutrient metabolism, fluid homeostasis, growth, ionic transport, maintenance of vascular tone, and other functions. Insulin resistance (IR) is a condition characterized by subnormal cellular response to physiological levels of insulin. The IR is divided into three types (prereceptor, receptor, and postreceptor) based on the site of pathology. Beta cells attempt to overcome the IR by increasing the release of insulin, leading to hyperinsulinemia. IR is the predisposing factor for many metabolic and cardiovascular disorders. From the evolutionary perspective, the presence of IR offers a survival advantage in the face of starvation or stress. In this brief review, we discuss the different facets of insulin resistance and appraise the readers about the hitherto neglected beneficial advantages.

The future of pharmacogenetics in the treatment of migraine

Migraine is considered one of the most disabling neurological disorder with a high socioeconomic burden. Pharmacological management includes many classes of drugs which in the most cases, are administrated in polytherapy. The therapeutic scheme of migraineurs is often affected by comorbidities which need concomitant medications, thus increasing the risk of side effects related to drug-drug interactions. Pharmacogenetics is a promising tool to achieve a personalized cure based on individual genetic profile while the availability of free online knowledge bases allows to check the potential DDIs of selected medications. Combining, these approaches may offer to clinicians a useful tool to improve the appropriateness of migraine polytherapy choice, aiming to increase the efficacy and reduce the toxicity of pharmacological treatments.

The metabolic face of migraine - from pathophysiology to treatment

Migraine can be regarded as a conserved, adaptive response that occurs in genetically predisposed individuals with a mismatch between the brain's energy reserve and workload. Given the high prevalence of migraine, genotypes associated with the condition seem likely to have conferred an evolutionary advantage. Technological advances have enabled the examination of different aspects of cerebral metabolism in patients with migraine, and complementary animal research has highlighted possible metabolic mechanisms in migraine pathophysiology. An increasing amount of evidence - much of it clinical - suggests that migraine is a response to cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity and that the attack itself helps to restore brain energy homeostasis and reduces harmful oxidative stress levels. Greater understanding of metabolism in migraine offers novel therapeutic opportunities. In this Review, we describe the evidence for abnormalities in energy metabolism and mitochondrial function in migraine, with a focus on clinical data (including neuroimaging, biochemical, genetic and therapeutic studies), and consider the relationship of these abnormalities with the abnormal sensory processing and cerebral hyper-responsivity observed in migraine. We discuss experimental data to consider potential mechanisms by which metabolic abnormalities could generate attacks. Finally, we highlight potential treatments that target cerebral metabolism, such as nutraceuticals, ketone bodies and dietary interventions.

A Randomized Double-Blind, Cross-Over Trial of very Low-Calorie Diet in Overweight Migraine Patients: A Possible Role for Ketones?

Here we aimed at determining the therapeutic effect of a very low-calorie diet in overweight episodic migraine patients during a weight-loss intervention in which subjects alternated randomly between a very low-calorie ketogenic diet (VLCKD) and a very low-calorie non-ketogenic diet (VLCnKD) each for one month. In a nutritional program, 35 overweight obese migraine sufferers were allocated blindly to 1-month successive VLCKD or VLCnKD in random order (VLCKD-VLCnKD or VLCnKD-VLCD). The primary outcome measure was the reduction of migraine days each month compared to a 1-month pre-diet baseline. Secondary outcome measures were 50% responder rate for migraine days, reduction of monthly migraine attacks, abortive drug intake and body mass index (BMI) change. Only data from the intention-to-treat cohort (n = 35) will be presented. Patients who dropped out (n = 6) were considered as treatment failures. Regarding the primary outcome, during the VLCKD patients experienced -3.73 (95% CI: -5.31, -2.15) migraine days respect to VLCnKD (p < 0.0001). The 50% responder rate for migraine days was 74.28% (26/35 patients) during the VLCKD period, but only 8.57% (3/35 patients) during VLCnKD. Migraine attacks decreased by -3.02 (95% CI: -4.15, -1.88) during VLCKD respect to VLCnKD (p < 0.00001). There were no differences in the change of acute anti-migraine drug consumption (p = 0.112) and BMI (p = 0.354) between the 2 diets. A VLCKD has a preventive effect in overweight episodic migraine patients that appears within 1 month, suggesting that ketogenesis may be a useful therapeutic strategy for migraines.

Relationship of Migraine and Tension-Type Headache With Hypothyroidism: A Literature Review

BACKGROUND

Migraine, tension-type headache, and hypothyroidism constitute very common medical conditions. Headache is one of the most common symptoms of hypothyroidism, occurring in approximately one-third of the patients. To date, data about the relationship between migraine and tension-type headache and thyroid dysfunction, and in particular hypothyroidism have been contradictory, while the underlying pathophysiological basis explaining this association is still unclear.

OBJECTIVE

In this review, we investigated the association between primary headaches and hypothyroidism, with the aim of shedding light on its pathophysiological basis.

METHODS

We conducted a systematic search in the MEDLINE database using both subject headings and keywords for headache, migraine, tension-type headache, thyroid hormones, and hypothyroidism, and we also examined manually the reference lists of all articles that met the inclusion criteria. Included studies were related to headache and thyroid disease comorbidity, with emphasis on hypothyroidism (ideally demonstrated by hormonal measurements), and with the term headache including migraine, tension-type headache, and headache attributed to hypothyroidism (HAH) based on the International Classification of Headache Disorders IIIb. Quality of studies was assessed by the Newcastle-Ottawa scale.

RESULTS

Of a total of 640 identified articles, 9 studies were included. Overall, there was vast heterogeneity across the included studies concerning population, study design and outcomes. Two studies investigated the HAH, with emphasis on the clinical characteristics of headache (time of onset, localization, quality, intensity, and response to hormonal replacement treatment). Five studies investigated comorbidity between migraine and thyroid disorders, especially hypothyroidism, and in the majority of them a positive association was demonstrated. One study found that headache, and particularly migraine, may increase the risk of developing hypothyroidism. Finally, only 1 study on chronic tension-type headache found coexistence of migraine and hypoactivity of the hypothalamus-pituitary-thyroid axis. The strengths and limitations of these studies are analyzed and possible pathophysiological mechanisms are suggested.

CONCLUSIONS

The existing data are considered inadequate to answer with certainty the relationship between headaches and thyroid disorders. According to our analysis, it seems that suggestions for a possible bidirectional association between headaches and especially migraine and hypothyroidism could exist. It hence lays the foundation for further research into the aforementioned association and its pathogenesis via large prospective multicenter studies.

Potential Protective Mechanisms of Ketone Bodies in Migraine Prevention

An increasing amount of evidence suggests that migraines are a response to a cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity. The ketogenic diet (KD), a diet mimicking fasting that leads to the elevation of ketone bodies (KBs), is a therapeutic intervention targeting cerebral metabolism that has recently shown great promise in the prevention of migraines. KBs are an alternative fuel source for the brain, and are thus likely able to circumvent some of the abnormalities in glucose metabolism and transport found in migraines. Recent research has shown that KBs-D-β-hydroxybutyrate in particular-are more than metabolites. As signalling molecules, they have the potential to positively influence other pathways commonly believed to be part of migraine pathophysiology, namely: mitochondrial functioning, oxidative stress, cerebral excitability, inflammation and the gut microbiome. This review will describe the mechanisms by which the presence of KBs, D-BHB in particular, could influence those migraine pathophysiological mechanisms. To this end, common abnormalities in migraines are summarised with a particular focus on clinical data, including phenotypic, biochemical, genetic and therapeutic studies. Experimental animal data will be discussed to elaborate on the potential therapeutic mechanisms of elevated KBs in migraine pathophysiology, with a particular focus on the actions of D-BHB. In complex diseases such as migraines, a therapy that can target multiple possible pathogenic pathways seems advantageous. Further research is needed to establish whether the absence/restriction of dietary carbohydrates, the presence of KBs, or both, are of primary importance for the migraine protective effects of the KD.

Targeting MTHFR for the treatment of migraines

INTRODUCTION

Migraine is a common neurovascular disorder classified by the World Health Organization as one of the most debilitating diseases. Migraine is a complex disease and is a consequence of an interaction between genetic, epigenetic and environmental factors. The MTHFR gene is one of the few replicated genetic risk factors for migraine and encodes an enzyme that is crucial for the folate and the methionine cycles. Individuals carrying the T allele of the MTHFR C677T polymorphism have increased plasma concentrations of homocysteine which leads to endothelial cell injury and alterations in coagulant properties of blood. Areas covered: This review focuses on the recent advances in genetics and the role of the MTHFR gene and homocysteine metabolism in migraine etiopathogenesis. The article summarizes the potential of targeting MTHFR and homocysteine for disease prevention. Expert opinion: Determination of MTHFR C677T polymorphisms as well as measurement of homocysteine concentrations may be useful to migraine patients, particularly those suffering from migraine with aura. Preliminary studies support the use of folate, vitamin B6 and vitamin B12 for the prevention of migraine. However, the results of these studies await replication in larger randomized controlled clinical trials.