Prevalence of Headache in Puerto Rico

Hector Miranda, MD; Gilberto Ortiz, BS;Sandra Figueroa, BS; Diana Pena, BA; Josue Guzman, PhD

Background.—Headache is one of the most frequently reported disorders in the general adult population.Despite the fact that this disorder is common, no official estimate of the prevalence of headache exists in PuertoRico.

Purpose.—To examine the prevalence of headache and migraine, specifically, in Puerto Rico.Methods.—A telephone survey of 1610 individuals was conducted. The telephone calls were distributed using

the 1990 census adjusted to the population of Puerto Rico in 1998, and according to gender, geographical area, andage.

Results.—The prevalence of headache in Puerto Rico was 35.9% and migraine, in particular, 13.0%. Whenprevalence was fractionated by age, gender, and geographical areas, the prevalence of headache was similar for allages, with females exhibiting a 2:1 preponderance over males. In the younger population (between 20 and 50 yearsof age), the female-male ratio for migraine was 3:1, and the prevalence for migraine was lower in the Metropolitanarea.

Conclusion.—This study, the first of its type in Puerto Rico, demonstrates that headache (and migraine specif-ically) is a common disorder in this country.

Key words: prevalence, migraine, headache

(Headache 2003;43:774-778)

Headache is one of the most frequently reportedcomplaints in the general population.1-5 Despite thefact that this condition is common, the epidemiologicfeatures have long been imprecise and prone to in-dividual interpretation. Conversely, most of the epi-demiologic studies have been conducted on patientsseeking treatment, rather than persons from the gen-eral population.6

In Puerto Rico, a Caribbean island with a pop-ulation near 4 million, no epidemiologic studies onheadache or migraine, in particular, are available. To

From CEDOC Headache Management Center, San FranciscoHospital (Dr. Miranda, Mr. Ortiz, Ms. Figueroa, and Ms.Pena) and the Departments of Neurology, School of Medicine(Dr. Miranda) and Biostatistics and Epidemiology, GraduateSchool of Public Health (Dr. Guzman), Medical SciencesCampus, University of Puerto Rico, San Juan Puerto Rico.

Address all correspondence to Dr. Hector S. Miranda-Delgado,CEDOC Headache Center, San Francisco Tower, Suite 409, 365De Diego Avenue, San Juan, PR 00923.

Accepted for publication February 9, 2003.

examine these prevalences, a telephone survey of 1610individuals was conducted. The telephone calls weredistributed by gender, age, and geographical area, us-ing the statistics of the 1990 census and adjusted to the1998 population of Puerto Rico.

METHODSBased on a headache survey carried out by a local

telephone data-gathering firm, we proceeded to esti-mate several characteristics of interest for a prevalencestudy. We interviewed 1610 residents of Puerto Rico,selected by municipality. We divided the sample intogeographic regions according to the 1990 census andthe estimated population in 1998 (Table 1).

Once the sample distribution was determined,the residents were evaluated by a questionnaire thatwas prepared by CEDOC Headache ManagementCenter. The questionnaire asked for the prevalenceof headache during the past year. (The survey wasconducted during April and May of 2000.) If the in-dividual’s response was positive, the characteristics

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Headache 775

Table 1.—Population and Sample Distribution, 1990Census Region

InterviewRegion Population Sample Rate × 10000

Arecibo 464 012 280 6.0Bayamon 633 234 154 2.4Caguas 590 265 330 5.6Mayaguez 544 718 313 5.7Ponce 597 270 182 3.0Metropolitan 1 030 592 351 3.4Total 3 860 091 1610 4.2

and associated symptoms of the headache were alsoobtained.

For the purpose of this study, headache was di-vided into 2 classifications using the InternationalHeadache Society (IHS) criteria: either migraineheadache or other types of headache. We obtaineda general interview rate of 4.2 per 10000 residents.The regional rates ranged from 2.4 (Bayamon) to 6.0(Arecibo).

For statistical purposes, the sample was poststrati-fied by census region. Therefore, the estimations wereprobability weighted based on the population-sampleratio in each region. This is the finite population mul-tiplier that we applied. The analysis was programmedusing Stata statistical software.

RESULTSHeadache.—General Prevalence.—The preva-

lence of headache in Puerto Rico, based on a sampleof 1610 telephone interviews, was 35.9% (confidenceinterval [CI], 33.4 to 38.3).

Prevalence by Gender.—When we divided thesample by gender, we observed headache prevalencein males of 27% (CI, 22.6 to 31.0), and headache preva-lence in females of 40% (CI, 36.9 to 42.9).

Prevalence by Region.—Table 2 shows estimatesof headache prevalence by geographic regions ofPuerto Rico. The Arecibo region had the highestheadache prevalence at 48.9% (CI, 43.1 to 54.8), whilethe Metropolitan region had the lowest headacheprevalence at 21.9% (CI, 17.5 to 26.4).

Prevalence by Age.—Estimates of headacheprevalence, by age of the interviewee, are shown in

Table 2.—Estimates of Headache Prevalence by Region

Prevalence 95% Confidence DesignRegion (SE), % Interval Effect

Arecibo 48.9 (3.0) 43.1-54.8 .69Bayamon 43.5 (4.0) 35.6-51.4 1.72Caguas 40.3 (2.7) 35.0-45.6 .74Mayaguez 33.6 (2.7) 28.3-38.8 .72Ponce 39.6 (3.6) 32.4-46.7 1.37Metropolitan 21.9 (2.3) 17.5-26.4 1.30

Table 3. The highest prevalence of headache was foundin the 40- to 49-year age group (44%; CI, 37.5 to 50.5).Those 50 years or older were in the group of lowestprevalence (27.3%; CI, 23.8 to 30.8).

Prevalence by Region and Gender.—Table 4presents estimates of headache prevalence divided bygeographic region and gender. Females with the high-est headache prevalence resided in the Arecibo re-gion, 54.8% (CI, 48.0 to 61.5). Males with the high-est headache prevalence were of the Caguas region,35.1% (CI, 25.5 to 44.6). The Metropolitan region wasfound to have the lowest headache prevalence for fe-males, 25.5% (CI, 19.9 to 31.1). This region also hadthe lowest headache prevalence for males, 13.7% (CI,6.8 to 20.6). In all regions, headache prevalence washighest in females.

Prevalence by Age and Gender.—According toTable 5, women between 30 and 39 years of age(51.1%; CI, 43.2 to 59.0) and men between 20 and29 years of age (35.5%; CI, 25.3 to 45.8) had the highestheadache prevalence. The lowest headache prevalencewas found in women (30.3%; CI, 26.1 to 34.5) and men

Table 3.—Estimates of Headache Prevalence by Age

Age Prevalence 95% Confidence DesignGroup, y (SE), % Interval Effect

<20 40.5 (4.3) 32.0-49.1 1.132-29 41.1 (3.2) 34.8-47.3 1.243-39 43.7 (3.3) 37.2-50.1 1.014-49 44.0 (3.3) 37.5-50.5 1.1050+ 27.3 (1.8) 23.8-30.8 1.12

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Table 4.—Estimates of Headache Prevalence by Regionand Gender

Region and Prevalence 95% Confidence DesignGender (SE), % Interval Effect

AreciboMales 31.4 (5.5) 20.5-42.3 .69Females 54.8 (3.4) 48.0-61.5 .69

BayamonMales 34.0 (6.9) 20.4-47.6 1.72Females 47.7 (4.8) 38.2-57.2 1.72

CaguasMales 35.1 (4.8) 25.5-44.6 .75Females 42.5 (3.2) 36.1-48.8 .75

MayaguezMales 24.1 (4.6) 15.1-33.1 .73Females 37.2 (3.2) 30.9-43.5 .73

PonceMales 31.9 (5.6) 20.8-42.9 1.37Females 44.2 (4.7) 35.0-53.4 1.37

MetropolitanMales 13.7 (3.5) 6.8-20.6 1.37Females 25.5 (2.9) 19.9-31.1 1.29

(18.6%; CI, 12.4 to 24.7) who were aged 50 or older. Inall age groups, the highest headache prevalence was infemales.

Migraine.—General Prevalence.—The prevalenceof migraine in Puerto Rico, based on a sample of

Table 5.—Estimates of Headache Prevalence by Ageand Gender

Age, y and Prevalence 95% Confidence DesignGender (SE), % Interval Effect

<20Males 34.5 (6.7) 21.3-47.6 1.13Females 44.5 (5.7) 33.4-55.7 1.14

2-29Males 35.5 (5.2) 25.3-45.7 1.32Females 44.4 (4.0) 36.5-52.4 1.21

3-39Males 28.8 (5.2) 18.6-39.1 1.02Females 51.1 (4.0) 43.2-59.0 1.00

4-49Males 25.4 (5.7) 14.3-36.6 1.10Females 50.6 (3.9) 43.0-58.3 1.10

50+Males 18.6 (3.1) 12.4-24.7 1.16Females 30.3 (2.1) 26.1-34.5 1.11

Table 6.—Estimates of Migraine Prevalence by Region

Prevalence 95% Confidence DesignRegion (SE), % Interval Effect

Arecibo 19.3 (2.4) 14.7-23.9 .69Bayamon 13.0 (2.7) 7.6-18.3 1.72Caguas 14.2 (1.9) 10.5-18.0 .75Mayaguez 13.1 (1.9) 9.3-16.8 .73Ponce 16.5 (2.7) 11.1-21.9 1.37Metropolitan 9.2 (1.6) 6.1-12.3 1.28

1610 telephone interviews, was 13.5% (CI, 11.7 to15.2).

Migraine Prevalence by Gender.—When we di-vided the sample by gender, we observed an estimatedmigraine prevalence in males of 6.0% (CI, 3.8 to 8.2),and migraine prevalence in females of 16.7% (CI, 14.4to 19.1).

Migraine Prevalence by Region.—Table 6 reportsthe estimates of migraine prevalence by geographicregion. The Arecibo region had the highest migraineprevalence which was 19.3% (CI, 14.7 to 23.9), whilethe Metropolitan region had the lowest prevalence at9.2% (CI, 6.1 to 12.3).

Migraine Prevalence by Age.—Estimates of mi-graine prevalence, based on the person’s age, areshown in Table 7. The highest migraine prevalence wasfound in the 40- to 49-year age group (23.0%; CI, 17.4to 28.7). Those 50 years or older were in the group oflowest prevalence (10%; CI, 7.6 to 12.3).

Migraine Prevalence by Region and Gender.—Estimates of migraine prevalence by geographic re-gion and gender are presented in Table 8. The highest

Table 7.—Estimates of Migraine Prevalence by Age

Age Prevalence 95% Confidence DesignGroup, y (SE), % Interval Effect

<20 15.1 (3.2) 8.9-21.4 1.142-29 10.2 (1.9) 6.4-13.9 1.173-39 16.9 (2.4) 12.2-21.6 .944-49 23.0 (2.9) 17.4-28.7 1.1550+ 10.0 (1.2) 7.6-12.3 1.11

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Table 8.—Estimates of Migraine Prevalence by Regionand Gender

Region Prevalence 95% Confidence Designand Gender (SE), % Interval Effect

AreciboMales 12.8 (4.0) 5.0-20.7 .69Females 21.4 (2.8) 15.9-27.0 .69

BayamonMales 0 (0) 0-0Females 18.7 (3.8) 11.3-26.1 1.72

CaguasMales 6.2 (2.4) 1.4-11.0 .75Females 17.6 (2.5) 12.7-22.5 .75

MayaguezMales 5.7 (2.5) 0.8-10.6 .73Females 15.9 (2.4) 11.1-20.7 .73

PonceMales 10.1 (3.6) 3.0-17.3 1.37Females 20.3 (3.8) 12.9-27.8 1.37

MetropolitanMales 4.2 (2.1) 0.2-8.3 1.38Females 11.4 (2.1) 7.3-15.4 1.26

prevalence of migraine in females (21.4%; CI, 15.9 to27.0) and males (12.9%; CI, 5.0 to 20.7) was foundin the Arecibo region. The lowest prevalence of mi-graine in females (11.4%; CI, 7.3 to 15.4) was in theMetropolitan region. Males in the Bayamon region

Table 9.—Estimates of Migraine Prevalence by Ageand Gender

Age, y Prevalence 95% Confidence Designand Gender (SE), % Interval Effect

<20Males 8.7 (3.9) 1.0-16.5 1.11Females 19.3 (4.5) 10.4-28.2 1.14

2-29Males 3.8 (1.7) 0.3-7.2 .94Females 14.1 (2.8) 8.5-19.6 1.20

3-39Males 10.8 (3.6) 3.7-17.9 1.04Females 20.0 (3.1) 13.9-26.0 .92

4-49Males 7.5 (3.4) 0.8-14.1 1.08Females 28.6 (3.6) 21.5-35.7 1.15

50+Males 3.9 (1.5) 0.9-6.9 1.10Females 12.1 (1.5) 9.1-15.1 1.12

reported zero migraine prevalence. In all regions, themigraine prevalence was highest in females.

Migraine Prevalence by Age and Gender.—Thehighest migraine prevalence in females was reportedin the 40- to 49-year age group (28.6%; CI, 21.6 to35.7). Men in the 30- to 39-year age group had thehighest migraine prevalence, 10.8% (CI, 3.7 to 17.9).The lowest migraine prevalence in females was in the50 years or older age group (12.1%; CI, 9.1 to 15.1)and in males, the age group between 20 and 29 years(3.8%; CI, 0.3 to 7.2). In all age groups, the highestmigraine prevalence was in females.

COMMENTSOur study shows that the prevalence of all types of

headache in Puerto Rico was 35.9%, which is compat-ible with other published reports that used IHS crite-ria.5,7 The prevalence of migraine was 13.0%, againcompatible with the reported prevalences in otherWestern community-based studies.1,8,9

When the prevalence was analyzed by ages, thedifference by age group was not statistically significantexcept for the patient of more than 50 years in whomthe prevalence of headache decreased remarkably. Nostatistically significant difference was found when theprevalence was divided by geographical region. Theratio of females to males was 1.5:1.

No significant age effect was found in the preva-lence of migraine except for the group of more than50 years in whom the prevalence is statistically lowerthan the other age groups. The prevalence of migrainewas found to be lower in the Metropolitan area of theisland, but this difference is not statistically significant.This lower ratio probably is associated with the acces-sibility of services in this area.

Our study, the first of its type in Puerto Rico re-garding prevalence of headache on the island, is com-patible with other studies published in Western coun-tries. This study revealed that headache (and migraine,in particular) is more common in women than in menwith a ratio of 3:1. Compatible with other studies, wefound a lower prevalence in the age group between 20to 50 years.

In conclusion, our study demonstrates the preva-lence of headache and migraine in Puerto Rico and

778 July/August 2003

gives the health authorities a reliable base to betteruse of educational and treatment resources.

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