The present study is the most comprehensive analysis of the burden attributable to TTH in the MENA region. The age-standardised point prevalence per 100000 population was 24504.5 in 2019, which has increased by 2.0% since 1990. Moreover, TTH accounted for 8680.1 and 68.1 age-standardised incidence and YLD rates, respectively, which did not change greatly from 1990 to 2019. It is important to note that we found the burden attributable to TTH in the MENA region was larger than the corresponding global burden for both sexes and in all age groups. Therefore, investigating and understanding the level of disability caused by TTH might help policy makers, funding organisations, and the pharmaceutical industry in developing successful strategies for mitigating the burden of TTH and to allow an efficient allocation of resources.
Globally, TTH is the most prevalent neurological disorder and the third most prevalent disorder. According to reports from the GBD 2016 and 2017 studies, the age-standardised point prevalence of TTH has decreased since 1990 [7, 17]. At regional level, the GBD 2016 study reported an 8.5% reduction in the age-standardised point prevalence of TTH in the MENA region since 1990 [7]. In line with this finding, research in the Eastern Mediterranean Region (EMR) observed a similar decrease in the point prevalence of TTH from 1990 to 2016 [18]. These findings are in contrast to our research, which found a 2.0% increase. These differences may be due to variations in the methodologies used by the GBD 2016 and GBD 2019 projects.
Although no change was observed in the age-standardised YLD rates, the number of YLDs increased between 1990 and 2019. This potentially reflects population growth and changes in the age distribution, which has shifted towards a lower number of children and adolescents, as well as more young and middle aged adults. The recently stable YLD rates could indicate that no progress has been made in the treatment options and therapeutic approaches for increasing the quality of life for patients suffering from TTH. Additionally, the constant burden of TTH may be due to unchanged risk factors or underlying causes. Furthermore, access to health care facilities, and in particular the availability of analgesic medications as the most common headache-abortive agents for TTH, could further affect the rates of disability, which have not improved in the region since 1990, especially for low-income countries. A recent publication evaluated the factors affecting the health related quality of life (HRQoL) in TTH patients. They found that the incidence of TTH decreased the HRQoL of the affected patients. Furthermore, among TTH patients, age, female sex, and poor self-rated health were all associated with lower physical HRQoL, but depression was the only factor associated with lower mental HRQoL [19].
The age-standardised YLD rates due to TTH were higher in the MENA region than the corresponding global rates for both sexes and across all age groups. It has been postulated that anxiety and depression, as substantial and complicating comorbidities of TTH, play a key role in the exacerbation of headache symptoms and thus cause further significant disabilities [1, 19, 20]. A potential justification for the greater burden of TTH in the MENA region could be due to the higher incidence of several psychiatric comorbidities. According to recent GBD studies, the age-standardised incidence rate of depression and anxiety in MENA is around 30% higher than the global average [21, 22]. The present research found that Iran had the largest burden of TTH in MENA. Interestingly, previous research found Iran had the highest age-standardised incidence rates for both anxiety and depression [21, 22]. There may be a number of reasons for this, including the eight-year-war with Iraq, a poorly performing economy and international sanctions that targeted all sectors of Iran’s economy over the past three decades, resulting in a surge in the burden of psychological stress among the Iranian population [23, 24]. These findings highlight the urgent need for policy interventions which target these psychological comorbidities more effectively, in order to help reduce the disabilities caused by TTH.
Our findings showed that the TTH attributable YLD rate was higher for females than for males. Similar findings were obtained from worldwide data in 2016, where females had a 50% higher YLD rate than males. Furthermore, TTH was found to cause 0.9% of all YLDs across the globe, while the corresponding values were 1.0% for females and 0.8% for males [7]. Moreover, in a study aiming to measure the global burden of TTH in children and adolescent, females were responsible for the higher proportion of attributable burden [25]. Another recent study came to the conclusion that psychological comorbidities, such as depression, were the cause of the larger burden of TTH among females [26]. Moreover, another study concluded that female TTH sufferers tended to experience more intensive pain, depressive symptoms and a lower quality of life [27]. Consequently, more integrative planning to control the comorbidities of TTH in females might be helpful in addressing the corresponding burden.
We found that the number of prevalent, incidence and YLD cases attributable to TTH reached its peak in younger and middle-aged adults, and this declined with age. In accordance with our findings, globally TTH has been found to be particularly burdensome in those aged 15-49 years old [7, 17]. Although the majority of non-communicable diseases cause more disabilities in older ages, the finding that TTH affects younger people suggests that TTH may cause losses in productive work time, therefore leading to a huge economic burden which affects not only the individuals, but society as a whole [28,30,30]. In line with this, a study from Denmark found that in the previous year 12% of those employed had suffered from TTH and had missed at least one day of work because of a headache. Therefore, the total number of workdays lost due to TTH was estimated to be 820 days per 1000 employees per year [31].
The SDI level of the countries in the MENA region was not a major contributor to the size of the TTH burden, during the period 1990-2019. A similar trend was observed at the global level and also for the EMR countries [18, 32]. However, we found that the burden of TTH was slightly increased up to the SDI level of 0.65 and then decreased sharply for the remaining SDI levels. This finding might imply that the demographic, epidemiological and health transitions currently facing the world, and particularly in MENA [15], did not substantially affect the burden of TTH in low- and middle-income countries over the past three decades, while remarkably reduced the burden of TTH in high-income countries. Thus, it could be anticipated that the relative importance of TTH will increase in the near future for low- and middle-income countries, as the YLD rates for several disorders (e.g., infections, nutritional deficiencies, maternal and neonatal diseases and many non-communicable disorders) are greatly decreasing among these countries.
TTH is the most prevalent type of headache and has become a major public health concern, due to the disabilities imposed upon the population. However, the realisation that headache disorders are debilitating for a large number of affected people has been hindered by the facts that TTH does not caused death or a permanent and obvious disability, and many people routinely experience headaches [33, 34]. Furthermore, research has shown that subjects with TTH (16%) attend medical centers much less frequently than those with migraine (56%) [31]. Therefore, more attention should focus on improving the awareness of patients and providing education for healthcare personnel regarding simple TTH remedies and practices for the treatment of acute attacks and the prevention of further episodes. Moreover, since there is no specific and effective cure for TTH, it is necessary to allocate more resources to understanding the pathophysiology of this type of headache and thus discovering innovative treatments and preventive strategies. Concurrently, healthcare services should do a better job at reaching people with cost-effective medications to relieve pain and reduce the disabilities due to TTH, improving productivity at work for those effected.
We acknowledge present study has some limitations that must be considered when interpreting our findings. Firstly, restrictions in data sources is still a potential shortcoming of the headache burden estimates [7]. Furthermore, data about headaches is not accurately collected in many national health surveys. Therefore, the estimation of TTH would benefit from more accurate data gathering and registration in many health systems, preferably with definite time intervals. Secondly, several risk factors have been linked to the emergence of headaches, such as stress, anxiety, depression and sleep apnea, although the evidence for their impact is inadequate [19, 35,37,37]. It is interesting to note that these risk factors have not yet been included as risk factors in the GBD study [32] and should be evaluated against GBD criteria, as to whether they provide convincing or probable evidence of causation. Thirdly, the burden estimates of TTH may vary greatly across different countries in the MENA region, owing in part to differences in race, ethnicity and other demographic features of these populations [38]. Fourthly, we were not able to stratify our results according to the type of TTH, which are episodic TTH (ETTH) and chronic TTH (CTTH). However, the burden of headache has been found to be higher in CTTH than for ETTH patients [39]. The reliability and validity of our findings may be affected by several factors that necessitate high methodological quality investigations to be conducted in the future. The next round of GBD studies should incorporate new data sources from additional countries and with less methodological heterogeneity, which would help to obtain stronger evidence and the ability to draw more realistic conclusions.
