Abstract
Background
Headaches are a worldwide health issue that impact almost all social strata, with a particular effect on the working population, leading to substantial financial cost to society. However, despite their significant socio-professional impact, data on this topic remain scarce in sub-Saharan Africa. The present study aims to assess the prevalence and impact of headaches among workers.
Methods
From November 2023 to June 2024, we conducted a cross-sectional analytical study of workers at the Société Camerounaise de Palmeraie (SOCAPALM), Dibombari plantation I Cameroon. Data were collected using the HARDSHIP (i.e. Headache-Attributed Restriction, Disability and Impaired Participation) questionnaire, with headache impact measured by the Headache Impact Test (HIT-6) and Headache-Attributed Lost Time (HALT-90) scores, and quality of life evaluated by the World Health Organization Quality of Life (WHOQoL-8) score. Qualitative variables were compared using chi-squared or Fisher's exact test, and quantitative variables were compared with analysis of variance. p < 0.05 was considered statistically significant.
Results
In total, 732 workers participated, 77% were male and they were aged 35.43 ± 9.15 years (mean ± SD). The 12-month prevalence of headache was 80.4%, with primary headaches being the most common (73%), including 21.7% with tension-type headache (TTH) and 16.9% with migraine. Over the last three months, there were 279 days of absenteeism due to headaches (0.47 ± 0.95 days), with migraine accounting for 48.0% of these days (1.08 ± 1.24 days). Impact scores (HIT-6 and HALT-90) showed that patients with migraine experienced the most significant effects (53.1% and 34.7%, respectively) and a poorer quality of life (odds ratio = 12.63; 95% confidence interval = 7.33–21.75; p < 0.001) compared to general headache and TTH sufferers. Female sex was associated with higher rates of headaches (odds ratio = 1.78; 95% confidence interval = 1.05–3.02; p < 0.001).
Conclusions
Headaches affect three-quarters of workers and has a significant socio-professional impact, including a higher rate of absenteeism among those affected. Migraine is the most disabling type of headache among workers.
This is a visual representation of the abstract.
Keywords
Introduction
Headache is pain in the head above the orbito-meatal line and/or the nuchal crest (1). According to the World Health Organization (WHO), the worldwide prevalence of headaches in adults (at least one episode of headaches in the past year) is estimated to be around 50%. Therefore, despite regional variations, headache is a worldwide problem affecting all populations, regardless of age, race, income level, or geographical location (2,3). Furthermore, headaches affect around 90% of people during their lifetime (4).
A recent adult population-based study in Cameroon, the first of its type in Central Sub-Saharan Africa, found that headache was a near-universal experience (lifetime prevalence: 94.8%); the one-year prevalence of headache was 77.1%, and tension-type headache (TTH) was the most common headache type (44.4%), followed by migraine (17.9%) (5).
Headaches is estimated to have a huge financial cost to society, mainly through lost working time and reduced productivity, with migraine alone being the second leading cause of disability in those aged 15–49 years (i.e. most of the working population). For example, in the UK, migraine alone is responsible for around 25 million lost working and school days a year, with TTH and chronic headaches having an similar financial cost (4). A 2022 Italian study found an average headache prevalence of 53.9% among Italian workers of all socio-professional categories, with a severe impact according to the Headache Impact Test (HIT-6) in 38.7% of participants (6). Our team have shown headache to be highly prevalent among adults in Cameroon. Using data collected contemporaneously from the same participants, we have reported high levels of burden attributed to it: those reporting any headache in the last year spend 9.8% of their time with headache, higher among the 13.1% of individuals with chronic daily headache than the 18.1% with migraine (4.6%) or the 44.8% with TTH (2.3%). At the population level, 6.1–7.4% of all time is spent with a headache, and this is associated with lost time from income-generating work comprising 2.5 days every 3 months (5). Although headaches cause enormous disability and have a significant financial impact on economies, there have been few studies of their economic impact in Africa. A 2017 study of headache in the workplace in Burkina Faso (7) found a prevalence of 8%, with a significant impact according to the HIT-6 score in 49.2% and a severe impact on quality of life in 41.1% of men and 29.7% of women.
In Africa, and Cameroon in particular, it has been noted that insufficient research has been conducted on workplace headaches, despite the importance of the problem, which causes enormous economic losses. With the aim of contributing to the development of solutions to this problem in our context, we proposed to study the prevalence and impact of headaches among workers at SOCAPALM (Société Camerounaise de Palmeraie), Dibombari plantation, as well as to describe the factors associated with the main types of headaches.
Methods
Study design and setting
This was a cross-sectional and analytical study conducted from November 2023 to June 2024 at SOCAPALM, Dibombari plantation in Cameroon. SOCAPALM is an agro-industrial company founded in 1966, for which the main activity is the production of palm oil and latex from rubber trees. It has six plantations, each with modern technical, agricultural and industrial services, as well as a skilled workforce. On November 2023, SOCAPALM had 2591 direct employees, including 596 women. In addition, the indirect workforce also includes subcontractors (1397 employees) and temporary staff (769 employees). The Dibombari plantation has around 1481 employees (including 471 permanent employees, 160 temporary staff and around 850 subcontractors). We chose this company because it is a mixed company (agricultural and industrial). This gave us access to workers from almost every field of activity (agricultural, industrial, administrative, medical, teaching), giving us a more global view of headaches in the workplace as a function of the various sectors of activity.
Study population and sampling
The study population consisted of all workers employed at SOCAPALM during the study period, all employment categories (permanent, temporary, subcontractors). We included all consenting workers aged 18 years or older, who had been employed for at least six months. Workers on extended leave, those with severe cognitive impairments or those unable to communicate (inability to read or write in French or English) were excluded. Sampling was consecutive, non-exhaustive and non-probabilistic.
Data collection
We proceeded as follows; before collecting the data, we organized a training session on headache disorders with the occupational health and safety department and in agreement with the various heads of department, during which we informed the workers about the aim and the procedure of the study. We then submitted our questionnaire to each participant during a one-to-one interview (after the informed consent from each participant). For office and factory workers, we met them at their workstations, based on their availability. Field workers were met in the morning before leaving for the field or in the evening upon their return. When we collected the questionnaires, we ensured that the patients had understood all the questions and helped them to understand the headings if necessary. The questionnaire was administered by a family physician.
Instruments and measures
The questionnaires used included the sociodemographic, clinical and paraclinical profiles and therapeutic itinerary of people suffering from headaches. The definition and classification of headache was based on International Classification of Headache Disorders, 3rd edition (ICHD-3) criteria (8).
The Headache-Attributed Restriction, Disability and Impaired Participation (HARDSHIP) questionnaire is a tool designed to assess the impact of headaches on three aspects of daily life. (i) Activity restriction: this aspect evaluates the extent to which headaches limit a person's usual activities, such as work, leisure or family responsibilities (9). (ii) Headache-related disability: this aspect measures the severity of limitations caused by headaches, such as the inability to perform specific tasks or fully participate in professional or social life. (iii) Reduced participation: this aspect examines how headaches affect a person's ability to actively engage in their obligations and social or professional interactions.
The HIT-6 (Headache Impact Test-6) (10,11) is a questionnaire designed to measure the impact of headaches on quality of life. People are asked to answer a total of six questions. They focus on daily activities such as work, education, family situation and leisure. Each item is scored from 6 to 13 (i.e. a score ranging from 36 to 78). The score is divided into four levels of severity: low impact: score ≤49; certain impact: score between 50 and 55; significant impact: score between 56 and 59; and major impact: score ≥60.
Headache-Attributed Lost Time (HALT-90) (12) is a tool that assesses the number of days affected by a headache over the last three months. It is expressed in days: grade I (minimal or rare): between 0 and 5 days; grade II (mild or infrequent): between 6 and 10 days; grade III (moderate): between 11 and 19 days; and grade IV (severe): ≥ 20 days.
The World Health Organization Quality of Life (WHOQoL) score (13,14) assesses quality of life, ranging from 8 to 40. Poor quality of life comprises a score between 6 and 23 and good quality of life comprises a score between 24 and 40.
Definitions of operational terms
Permanent workers are employees recruited by the company and holding a permanent contract; Temporary workers are employees called upon by the company during peak periods (generally from February to May), generally holding a fixed-term contract. Subcontract workers are employees working on behalf of private individuals who have concession contracts for specific tasks with SOCAPALM. Presenteeism is the practice of going to work when physically or psychologically unable to do so.
The study was conducted according to the guideline of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) (15).
Statistical analysis
Data were recorded using Cspro, version 7.0 (https://www.csprousers.org) and analysed using Epi info, version 6.0 (https://www.cdc.gov/epiinfo), SPSS, version 23.0 (IBM Corp.) and Excel and Word 2013 (Microsoft Corp.). Quantitative variables are expressed as the mean ± SD (with minimum and maximum values), while qualitative variables are presented as frequencies and percentages. Qualitative variables were compared using the chi-squared test or Fisher's exact test, while quantitative variables were compared using analysis of variance. Univariate and multivariate logistic regression analyses were performed to identify factors associated with headaches. p < 0.05 was considered statistically significant.
Ethical considerations
Ethical approval was obtained from the Université des Montagnes Ethics Committee (Ref: 2024/092/UdM/PR/CEAQ) and administrative authorization was secured from SOCAPALM's General Management (Ref: DARHJC/DG/2024/16). Written informed consent was obtained from all participants. Confidentiality and anonymity were maintained throughout the study.
Results
Sociodemographic profile
Seven hundred thirty-two of the 1143 workers from all the departments of the company met all our pre-define criteria. Male workers represented more than three-quarters of the study population (n = 564; 77%). The sex ratio was male:female = 3.35:1. Participants were aged 35.43 ± 9.15 years (mean ± SD), ranging from 19 to 59 years. Our sample consisted mainly of palm grove agricultural workers (n = 301; 41.1%) and the least represented were those in the medical service (n = 8; 1.1%).
Prevalence and types of headaches
The lifetime prevalence of headaches was 98.8% (range 93.86–99.20%), with 723 of 732 participants reporting headaches at some point in their lives; in the past 12 months, 80.47% (range 76.45–84.49%) were affected (n = 589) and 9.29% (range 8.83–9.75%) (n = 68) reported headaches on the day before the survey. Primary headaches were most common (73%, n = 534), followed by secondary headaches (7.5%, n = 55), while 19.5% (n = 143) reported no headaches. TTH was most frequent (21.7%, n = 159), followed by migraine (16.9%, n = 124) and chronic daily headaches (3.2%, n = 23). Headache frequency varied, with 40.7% experiencing 6–11 days annually and 37.9% reporting 1–7 days monthly.
Clinical characteristics of migraine
For patients with migraine, the mean duration of headache episodes was from six to 10 hours for 39.5% of participants. The pain was described as pulsatile in 91.9% of cases and unilateral in 81.5%. Nausea (67.7%), photophobia (68.6%) and phonophobia (80.6%) were common symptoms, with physical activity worsening symptoms in 79% of cases.
Clinical characteristics of TTH
For workers with TTH, the most common episode duration was from six to 10 hours (39.6%). The pain was pressing in 87.4% of cases and bilateral in 92.6%. Symptoms such as nausea (4.4%), phonophobia (5.7%) and photophobia (10.1%) were less frequent, and physical activity aggravated symptoms in only 16.4% of cases.
Workplace impact of headaches
In the three months prior to our study, the total number of days lost from work was approximately 134 days for patients with migraine compared to 80 days for workers with TTH and 65 days for all other type of headaches, giving a total of 279 days lost for last three months due to headaches for all the workers. Workers with TTH missed an average of 0.50 ± 0.81 days compared to 1.08 ± 1.24 days for patients with migraine (p < 0.001). For patients with migraine, they were effectively present at work without doing anything for 122 days during the same period. This duration averaged 0.98 ± 0.92 days, which was significantly higher (p < 0.001) than the durations of 0.58 ± 0.79 days and 0.18 ± 0.61 days for TTH and other type of headaches sufferers, respectively (Table 1).
Assessment of absenteeism from work.
Therapeutic itinerary
More than half of patients with migraine (57.3%) had seen a health professional in the previous 12 months compared to 44% of those with TTH (44%) and 13.1% of those with other type of headaches (p = 0.001). Almost 81.5% of patients with migraine reported using medication within the previous three months, which is a far greater percentage than those with TTH (69.2%) and other type of headaches (31%) (Table 2).
Treatment itinerary for workers suffering from headaches.
Impact of headache with HIT-6, HALT-90 and WHOQoL-8
In the population of workers who had experienced headaches in the past three months, almost three-quarters (72.5%) had a low impact according to the HIT-6, while only 4.5% had a major impact. More than half of the workers with migraine (53.1%) had a deleterious impact and 74.2% with TTH had a minor impact according to the same test.
According to the HALT-90 measure, for workers suffering from headaches in general, 72.8% of them had a minimal impact over the last three months: the number of days lost due to headaches (all activities combined) was between 0 and 5, and only 4.5% of workers in this category had a severe impact (number of days lost due to headaches greater than 20). Among the patients with migraine, almost 33.1% were classified as grade 3 (number of days lost due to headaches over the past three months greater than 10 days) and 1.6% of the workers were classified as grade 4 (number of days lost due to headaches over the past three months greater than 20). Among the workers with TTH, almost 69.2% were classified as grade 1 on the HALT-90 measure. None of them were classified as grade 4.
According to WHOQoL-8 test, patient with migraine were 12 times more likely to have a poor quality of life than headache-free workers (odds ratio (OR) = 12.628; 95% confidence interval (CI) = 7.33–21.75; p < 0.001), those suffering from TTH (OR = 0.894; 95% CI = 0.48–1.65; p < 0.001) and those with other type of headaches (OR = 0.231; 95% CI = 0.11–0.44; p < 0.001) (Table 3).
Impact of headache on quality of life.
CI = confidence interval; NA = not available; OR = odds ratio; WHOQoL-8 = World Health Organization Quality of Life score.
Factors associated with poor quality of life
Associated factors with headaches in general were women workers (OR = 1.948; 95% CI = 1.169–3.243; p < 0.009), age range between 30 to 39 years (OR = 1.566; 95% CI = 1.016–2.413; p < 0.041) and working in a palm grove (OR = 1.860; 95% CI = 1.238–2.793; p < 0.003). Working in rubber plantations was a protective factor (OR = 0.438; 95% CI = 0.287–0.667; p < 0.001) (Table 4).
Sociodemographic factors associated with headache in general.
CI = confidence interval; OR = odds ratio.
Discussion
The present study highlights a high prevalence of headaches (81.5%) among workers who were predominantly male and employed in the agricultural sector (60.9%). TTH (21.72%) and migraine (16.94%) were the most common types, significantly impacting productivity (absenteeism, presenteeism) and quality of life. Migraine, particularly debilitating, was associated with factors such as female gender, lack of sleep and sun exposure. TTH, although less severe, were linked to factory workers. The low use of healthcare services reflects limited access and widespread self-medication practices among workers.
Among the participants, 77% were male (n = 564), consistent with the findings obtained in Brazil (16), where women workers comprised 19.13%. This trend underscores the global challenges in women's employment identify by UN women (17). The employability of women in the physical workplace should be encouraged aiming to overcome this major gender disparity. The age of workers (35.43 ± 9.15 years) was similar to findings obtained in Brazil (35.4 years) (16) and Burkina Faso (38.5 years) (7). However, in Italy, where the population tend to be older, an average age of 45 ± 11.3 years was found (6). This is easily explained by the fact that Italy is a northern country with an ageing population compared to Africa.
The lifetime prevalence of headaches (86%) is comparable to rates reported in South Korea (18) but exceeds the 53.3% reported in the Netherlands (19). This disparity may reflect variations in awareness, preventive measures, and workplace interventions. European countries, for example, have implemented evidence-based interventions unavailable in sub-Saharan Africa.
A 12-month prevalence of 15% was reported in the Netherlands (19), whereas a higher rate (57%) was found in Japan (20), highlighting the impact of industrial stress and workload. The prevalence of migraine (16.9%) in the present study aligns with WHO's global estimate (14%) (2) and rates observed in South Korea (18.2%) (16), Brazil (17.3%) (18) and the Netherlands (15%) (19). Chronic daily headaches were less frequent (3.2%) but align with WHO estimates (4%) (21). In a recent study on the prevalence of primary headache disorders among the adult population in Cameroon a one-year headache prevalence of 77.1% was reported, with TTH at 44.4%, migraine at 17.9% and chronic daily headache 12.2% (5).
Migraine accounted for significant absenteeism, with an average of 1.08 ± 1.24 days lost, compared to 0.5 ± 0.81 for TTH and 0.47 ± 0.95 for other type headaches (p < 0.001). Similarly higher absenteeism was reported for migraine, probably due to symptoms such as nausea, vomiting and sensitivity to light and sound, which severely impair work capacity (22). In addition, aura symptoms such as visual disturbances contribute to the disabling nature of migraine (22). In a study on the burdens attributable to headache disorders in Cameroon from a population-based door-to-door survey, those reporting any headache in the last year spend 9.8% of their time with headache, which was higher among the 13.1% of individuals with chronic daily headache than the 18.1% with migraine (4.6%) or the 44.8% with TTH (2.3%). At the population level, 6.1–7.4% of all time is spent with a headache, and this is associated with lost time from income-generating work of 2.5 days every three months (23). In this agricultural area, improving workplace interventions, such as stress management programs or ergonomic adjustments, can reduce absenteeism. Early treatment by a health worker using paracetamol can reduce pain intensity and consequently reduce absenteeism.
Days spent at work without productivity (presenteeism) were almost equal to days missed. Unlike studies conducted in Malaysia (24), which found the impact of presenteeism to be much greater than absenteeism, presenteeism was lower in the present study, possibly due to the high proportion of temporary workers whose absence directly affects their income. Consequently, workers may choose to work despite discomfort to avoid financial losses (24).
Only 30.7% of workers sought medical consultations for headaches, which is consistent with findings of low consultation rates (19%) in the general population (25), whereas a higher rate (77%) was found in urban Philippines (26). This difference may be due to better access to healthcare in urban settings versus a rural area of our study. Self-medication was common, facilitated by the easy availability of over-the-counter analgesics (25,26).
The HIT-6 impact measure found significant headache-related effects in 12.2% of workers, which is lower than the 51.1% deleterious impact found in office-based workers (7). Office work, characterized by prolonged sitting and exposure to a computer screen, is associated with severe headaches according to several studies (27). The impact of migraine on work was four times greater than other type headaches, measures by the HALT-90 scores, similar to the findings reported in South Korea (18). The distinctive symptoms of migraine cause significant disruption to the socio-professional lives of workers (18). In terms of quality of life, patients with migraine had significantly higher odds of poor outcomes than workers without headaches, confirming the findings reported by WHO (28).
Associated factors
Regarding gender and age: female workers were 1.95 times more likely to report headaches, consistent with previous findings (72.3% women) (6). Migraines were most prevalent among workers aged 30–39 years, potentially due to hormonal influences such as fluctuating oestrogen levels.
Regarding occupational factors, administrative and permanent workers reported higher headache prevalence, likely linked to prolonged screen exposure and job stability. Rubber plantation work appeared protective against headaches (29). Economic challenges were also a significant risk factor, supporting the previous observation that financial strain doubled migraine risk (30).
Limitations of the study
The present study was conducted in a rural area of almost 4500 hectares with was very difficult to access. Covering the entire area required fairly high levels of resources, and most of the company's workers (over 60%) were recruited without any real level of education and had difficulties in handling the two official languages, so that more than half of the workforce had to be excluded from the study from the outset. Furthermore, we carried out our study during a period of high production activity (peak period) and it was very difficult to get the workers together in groups to fill in the gaps, and so we conducted individual interviews.
Conclusions
More than three-quarters of the workers at SOCAPALM's Dibombari plantation reported experiencing headache in the previous 12 months. Headaches were the main cause of absenteeism, visits to the company infirmary and self-medication. Furthermore, workers with headaches were more likely to report a poor quality of life than those without headaches, with patients with migraine having a twelve-fold increase in risk. Factors associated with headaches in general included female sex, age between 30 and 39 years, and working in a palm grove. Employment on rubber plantations was found to be a protective factor.
This study highlights a high prevalence of headaches (81.5%) among workers, predominantly male and employed in the agricultural sector (60.9%). TTH (21.72%) and migraines (16.94%) were the most common types, significantly impacting productivity (absenteeism, presenteeism) and quality of life. Migraines, particularly debilitating, were associated with factors such as female gender, lack of sleep and sun exposure. TTH, although less severe, were linked to factory workers.
Footnotes
Acknowledgements
We are grateful for the support and collaboration of Dr SAID SANI Aboubakar, SOCAPALM's company doctor.
Declaration of conflicting interest
The authors declare no known competing financial interests or personal relationships that could have influenced the work reported in this paper.
Funding
This research received no specific grant from funding agencies in the public, commercial or not-for-profit sectors. The authors received no financial support for the research, authorship and/or publication of this article.
Ethical statement
Ethical approval was obtained from the Université des Montagnes Ethics Committee and written informed consent was obtained from all participants.
