Tension Headache

The main elements of the GBD methods, both general and pertaining to migraine and tension-type headache, are described in the appendix. In the main text of this Article, we concentrate on methods pertaining to estimation of the burden of migraine and tension-type headache. A flowchart of the different steps in these methods is shown in the appendix.
In the GBD cause hierarchy, migraine and tension-type headache are individual disorders on Level 3, under neurological disorders (Level 2) and non-communicable diseases (Level 1). No further subdivision exists for headaches, so each reappears at Level 4. In GBD 2013 and GBD 2015, medication overuse headache was treated as a separate disorder, but in GBD 2016 it was considered a sequela of either migraine or tension-type headache. The burden of medication overuse headache was therefore added to the burdens estimated for these headache types according to a meta-analysis of three studies reporting the proportions of medication overuse headache resulting from migraine (73·4%, 95% uncertainty interval [UI] 63·9–82·0) or tension-type headache (26·6%, 18·0–36·1).4 (link), 5 (link), 6 (link)
In GBD, disease burden is estimated in disability-adjusted life-years (DALYs), which are the sum of years of life lost (YLLs) to premature mortality and years of life lived with disability (YLDs). Because GBD does not estimate any deaths from headache disorders as the underlying cause, DALYs for headaches are equivalent to YLDs. YLDs for each headache disorder are calculated from its prevalence and the mean time patients spend with that type of headache multiplied by the associated disability weight. The determination of headache disability weights through population and internet surveys was on the basis of lay descriptions (appendix).7 (link), 8 (link) The disability weight for migraine was 0·434, meaning that during an attack the affected person experiences health loss of 43·4% compared with a person in full health. The disability weight for medication overuse headache was 0·223 and for tension-type headache was 0·037. After all diseases were estimated separately, an adjustment was made to YLDs to account for comorbidity by use of simulation methods assuming a multiplicative, rather than additive, model. This adjustment led to a downward correction for YLDs for migraine in women and children by factors ranging from 2·1% (at ages 5–9 years) to 20·6% (at ages ≥95 years), reflecting a strong correlation between comorbidity and age. The corresponding figures in males were 2·1% and 20·7%, respectively.

The Institute for Health Metrics and Evaluation produces annual updates of the GBD study and includes a growing collaboration of scientists. Reported estimates span the period from 1990 to 2016. Annual updates allow incorporation of new data and methodological improvements to ensure that the most up-to-date information is available to policy makers to help make resource allocation decisions. In this analysis, we have aggregated results from GBD 2016 for 15 disease and injury outcomes that are generally cared for by neurological services. These include infectious conditions (tetanus, meningitis, and encephalitis), stroke, brain and other CNS cancers, TBI, spinal cord injury, Alzheimer's disease and other dementias, Parkinson's disease, multiple sclerosis, motor neuron diseases, idiopathic epilepsy, migraine, tension-type headache, and a residual category of other less common neurological disorders. Compared to a previous analysis based on GBD 2015,² (link) we added non-fatal outcomes of TBI and spinal cord injury. Medication overuse headache is no longer included as a separate cause but quantified as a consequence of the underlying headache types. For all neurological disorders combined we report here estimates of deaths and DALYs because aggregate incidence and prevalence estimates of combined neurological disorders are not useful for policy making.
In the methods section of this overview paper, we present a summary of the general methods of the GBD as they apply to neurological disorders. In the ten accompanying disease-specific papers, we have concentrated on methods that are specific to each disorder. Details on the methods of estimates for tetanus, encephalitis, and the residual category of other neurological disorders are provided in the appendix. The guiding principle of GBD is to assess health loss due to mortality and disability comprehensively, defining disability as any departure from full health. In GBD 2016, estimates were made for 195 countries and territories and 579 subnational locations, for 27 years starting from 1990, for 23 age groups, and for both sexes. Deaths were estimated for 264 diseases and injuries, whereas prevalence and incidence were estimated for 328 diseases and injuries. To allow meaningful comparisons between deaths and non-fatal disease outcomes as well as between diseases, data for deaths from and prevalence of neurological disorders are summarised in a single indicator, the DALY. DALYs are the sum of YLLs and YLDs. YLLs are estimated as the product of counts of deaths and a standard ideal remaining life expectancy at the age of death. The standard life expectancy is derived from the lowest observed mortality rates by age in any population in the world larger than 5 million people.¹³ (link) YLDs are estimated as the product of prevalence of individual consequences of disease (or sequelae) multiplied by their corresponding disability weights, which quantify the relative severity of sequelae as a number between 0 (representing full health) and 1 (representing death). Disability weights have been estimated in nine population surveys and an open-access internet survey in which respondents were asked to choose the healthier option between random pairs of health states that were presented with short descriptions of their main features.¹⁴ (link)

Patients were identified through a systematic review of clinical records of adolescents referred to the Headache Center, Division of Neurology, of the Bambino Gesù Children’s Hospital in Rome, from September 2018 to January 2022.
Data on the clinical characteristics of headaches, the therapy administered, and the diagnosis at discharge were collected in a headache diary given at the first consultation and returned by the family at the second consultation. Every patient underwent a neurological examination. Only the patients with a diagnosis of migraine, with or without aura, according to the criteria of the International Classification of Headache Disorder, Third Version (ICHD-3) [23 ] were included. Tension-type headaches, trigeminal autonomic cephalalgias, secondary headaches, or patients suffering from any other neurological disease were excluded from our study.
According to the date of referral, patients were grouped into “pre-COVID” (PC, from September 2018 to February 2020) or “COVID” (C, from March 2020 to January 2022). The “COVID” group was further divided into “COVID 1” (C1, from March to October 2020, characterized by lockdown, the start of remote video lessons, and summer holidays) and “COVID 2” (C2, from November 2020 to January 2022, characterized by return to school and/or remote video lessons, summer holidays, and the extension of COVID-19 restrictions) (Figure 1).
According to their frequency, patients were classified into two groups: (1) high frequency (HF; participants complaining of more than 4 attacks per month); (2) low frequency (LF; adolescents with 4 or fewer episodes per month). A cut-off of 4 attacks per month was established because this is generally the frequency above which to consider starting migraine prophylaxis in childhood [24 (link),25 (link)].
The delimitation point was chosen for three reasons: (1) the numbers of patients suffering from chronic and intermediate frequency attacks were too low to allow reliable statistical comparison; (2) a simple distinction between chronic and episodic patients would have resulted in including non-chronic patients with a high frequency of attacks in the same group as individuals with a very low frequency of attacks; (3) the chosen demarcation point was rationalized to distinguish patients who needed prophylactic treatment from those who did not.
In addition, the average number of migraine episodes in the previous two months was assessed. Pain intensity was classified into severe (SI) and mild (MI) based on interference with daily activities. Patients were classified into those who were receiving prophylaxis treatment (PT) (with treatment terminated before 4 weeks) and those who were not (NT). In addition, subjects were divided according to the time of year in which they were evaluated at the Day Hospital of the Headache Center (school term or summer). School-related information, including the grade of school attended, type of teaching, and school performance, were collected by psychological interview.
The type of teaching was divided into in-person and remote teaching, while students’ performance was classified into two groups: good/very good (grades 7–10) and sufficient/insufficient (grades 0–6). The psychological screening was performed by psychologists (MPC and ST) with expertise in pediatric psychological evaluation. The psychological tests were administered in a single sitting. All patients were required to be able to read, understand, and answer every item on the questionnaires.
The Institutional Review Board of Bambino Gesù Children Hospital provided approval for this study.
Written informed consent for patient information to be published was provided by the parents of subjects involved in the research.

Participants and healthy controls were identified and enrolled with previous published methods [16 (link), 17 (link)]. Eligible participants were aged 18 to 65 years and had a diagnosis of persistent post-traumatic headache in accordance with the 3^rd edition of the International Classification of Headache Disorders (ICHD-3), [18 (link)]. Another inclusion criterion was that mild TBI had to have occurred at least 12 months before enrollment. Participants were excluded if they had a history of more than one TBI as well as any history of whiplash injury, medication-overuse headache, or a primary headache disorder, except for infrequent episodic tension-type headache (TTH). Contraindications to MRI were also considered reasons for exclusion. Detailed eligibility criteria have been published elsewhere [19 (link)].
Healthy controls were eligible for inclusion if they were aged 18 to 65 years and had no history of TBI, whiplash injury, primary headache disorder (except for infrequent episodic TTH), neurologic or psychiatric disorders, and cardiovascular disease. Controls were also excluded if they had first-degree relatives with any primary headache disorder or reported daily intake of any medication other than oral contraceptives.