Primary headache disorders among the adult population of Mongolia: prevalences and associations from a population-based survey

DOI: https://doi.org/10.1186/s10194- 019- 1061- 5

Abstract-Summary In the ongoing Global Campaign endeavour to improve knowledge and awareness of headache prevalence worldwide, Mongolia is a country of interest.

It sits between Russia and China, in which prevalence is, respectively, much

higher and much lower than the estimated global mean.

The crude 1-year prevalence of any headache was 66.1% (95% CI: 64.0–68.2%),

with a strong female preponderance (OR: 2.2; p < 0.0001).

Age-and gender-adjusted prevalences were: migraine 23.1% (for females, OR = 2.2; p < 0.0001); tension-type headache (TTH) 29.1% (no gender difference); probable medication-overuse headache (pMOH) 5.7% (trending towards higher in females); other headache on ≥15 days/month 5.0% (for females, OR  =  2.2; p = 0.0008).

Any headache yesterday was reported by 410 (20.1%; for females, OR = 2.4;

p < 0.0001).

Only pMOH showed a strong association with age, peaking in middle years with

a five-fold increase in prevalence.

Migraine showed a consistent association with educational level, while pMOH showed the reverse, and was also more common among other groups than among participants who were single (never married).

Migraine was less common among rural participants than urban (OR: 0.80;

p = 0.0326), while pMOH again showed the reverse (OR: 2.4; p < 0.0001).

PMOH (but not migraine or TTH) was significantly associated with obesity (OR:

1.8; p = 0.0214).

Headache disorders are common in Mongolia, with, most notably, a very high prevalence of headache on ≥15 days/month corroborated by the high prevalence of headache yesterday.

1.1

Epidemiology

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Extended: The crude 1-year prevalence of any headache in the study population was 66.1% (95% CI: 64.0–68.2%), with a strong female preponderance (73.3% [70.7–75.7%] versus 55.4% [51.9–58.7%] in males; OR: 2.2; p < 0.0001).

The crude 1-year prevalence of migraine was 24.1% (n = 492), 8.7% (n = 178)

definite and 15.4% (n = 314) probable.

The crude 1-year prevalence of TTH was 29.2% (n = 596), 20.7% (n = 423) defi-

nite and 8.5% (n = 173) probable.

Migraine showed a consistent association with educational level, while pMOH showed the reverse (more common in the less well educated), this perhaps being reflected in its higher prevalence among the unemployed.

Migraine was less common among the latter (OR: 0.80; p = 0.0326).

Introduction Headache disorders are now acknowledged as the most prevalent cause of public ill health, affecting people in all countries, and as the second highest cause of disability worldwide [46–48].

GBD has been increasingly well informed during these years, notably by the population-based studies supported in countries around the world by Lifting The Burden (LTB) [36–49].

These had highly disparate findings: whereas prevalences were high in Russia for migraine (20.8%), TTH (30.8%) and, especially, headache on ≥15 days/month (10.5%), in China these were notably below global averages (9.3%, 10.8% and 1.0% respectively—even though headache disorders were still a substantial cause of public ill health here).

We focused on the headache disorders of public-health importance (migraine, TTH, medication-overuse headache [MOH] and other headache occurring on ≥15 days/month), the purposes being two-fold: to add to the global map of head- ache, and, more importantly, to inform public-health policy in the country.

Materials and methods The study was a cross-sectional, population-based survey among randomly-selected Mongolian adults (aged 18–65  years) conducted in accordance with published methodology [50, 51].

Survey it included, for all participants, demographic enquiry and a headache

screening question (“Have you had headache during the last year?”).

Although we did not measure the altitude of each household, we had altitude data for each of the survey areas (see “Sampling and selection” above), according to which we categorized this variable as <1000 m, 1000–2000 m or > 2000 m. We took waist measurement (ignoring those known to be pregnant) and recorded self- reported height and weight, calculating body-mass index (BMI) as (weight in Kg)/ (height in m)2.

Participants reporting headache on ≥15  days/month were first separated, and described as a distinct group, with those also reporting regular use of acute head- ache medication on >15  days/month (triptans and combination analgesics being used rarely in Mongolia) considered to have probable MOH (pMOH).

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1 Public Health

Results The crude 1-year prevalence of any headache in the study population was 66.1% (95% CI: 64.0–68.2%), with a strong female preponderance (73.3% [70.7–75.7%] versus 55.4% [51.9–58.7%] in males; OR: 2.2; p < 0.0001).

The crude 1-year prevalence of migraine was 24.1% (n = 492), 8.7% (n = 178)

definite and 15.4% (n = 314) probable.

The age- and gender-adjusted prevalence of migraine was 23.1%. The crude 1-year prevalence of TTH was 29.2% (n = 596), 20.7% (n = 423) defi-

nite and 8.5% (n = 173) probable.

The crude prevalence of other headache on ≥15 days/month was 5.3% (n = 108),

higher among females (6.7%) than males (3.2%; OR: 2.2; p = 0.0008).

Discussion Migraine was substantially more common among females than males, with age- and gender-adjusted 1-year prevalence of 23.1%.

Headache on ≥15 days/month (age- and gender-adjusted prevalence 10.7%) was

also more common in females than males.

Over half of cases (5.7%) were pMOH, which showed a strong association with

age, peaking in middle years with a five-fold increase in prevalence.

Migraine showed a consistent association with educational level, while pMOH showed the reverse (more common in the less well educated), this perhaps being reflected in its higher prevalence among the unemployed.

While headache disorders were common, the most noteworthy finding was the very high prevalence of headache on ≥15  days/month, corroborated by the high prevalence of headache yesterday (20.1%), which also showed a strong female association.

In Nepal, an LTB-supported study (using the same methodology) found a very strong relationship between migraine prevalence (and indices of severity) and alti- tude up to 2000 m [52, 53], which is not reflected here.

Conclusion The prevalence of headache disorders among the adult population of Mongolia is high, with a very similar picture to neighbouring Russia and in excess of global means. Headache on ≥15  days/month is very common, as is pMOH, a main

contributor.

This new evidence adds to knowledge of the global prevalence of headache.

Acknowledgement A machine generated summary based on the work of Luvsannorov, Otgonbayar; Tsenddorj, Byambasuren; Baldorj, Dorjkhand; Enkhtuya, Selenge; Purev, Delgermaa; Thomas, Hallie; Steiner, Timothy J. 2019 in The Journal of Headache and Pain.

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Epidemiology

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