Pain Medicine 2011; 12: 9–17 Wiley Periodicals, Inc.
ORIGINAL RESEARCH ARTICLE
pme_1029
9..17
Markus Paananen, BM,*† Simo Taimela, MD, DMSc,‡ Juha Auvinen, BM,*† Tuija Tammelin, PhD,* Paavo Zitting, MD,†§ and Jaro Karppinen, MD, DMSc*† *Finnish Institute of Occupational Health, Oulu; † Department of Physical Medicine and Rehabilitation, University of Oulu, Oulu;
‡
Department of Public Health, University of Helsinki, Helsinki; §
Institute of Health Sciences, University of Oulu, Oulu, Finland Reprint requests to: Markus Paananen, BM, Finnish Institute of Occupational Health, Aapistie 1, 90220 Oulu, Finland. Tel: +358 50 490 5348; Fax: +358 30 474 6110; E-mail:
[email protected].
Abstract Objective. To investigate how self-reported musculoskeletal pain and health-related quality of life (HRQoL) are associated among young adults. Design and Setting. The study population consisted of a subgroup of the Northern Finland Birth Cohort 1986 at the age of 19 (N = 874), who completed the 15-dimensional (15D) HRQoL questionnaire (score 0 to 1) and answered questions about six-month period prevalence of musculoskeletal pain in neck, shoulder, low back, and peripheral location. Results. Half of the males and one third of the females reported a 15D score of at least 0.98 and were selected as the reference group in the multinomial logistic regression analysis. Young adults who reported multiple pains had significantly lower 15D scores than those reporting pain in only one location or no pain at all. After adjustments for other health problems, psychosocial distress, parental occupation, and the young adults’ own employment status, the reporting of single musculoskeletal pain odds ratio (OR) 2.6 and multiple pains (ORs up to
11.9) among females, and multiple pains (ORs up to 4.6) among males were associated with a 15D score of 0.94 or less. Conclusions. The number of involved sites of selfreported musculoskeletal pain was associated with the level of reduction in HRQoL among young adults. Key Words. Musculoskeletal Pain; Multiple Pain; Comorbidity; Young Adults; Health-Related Quality of Life; Epidemiology
Introduction Epidemiological studies on musculoskeletal pain have mainly relied on self-reporting, which is the current “gold standard” for assessing pain conditions. Björkstén et al. concluded that the use of a questionnaire is a valid way of obtaining information regarding musculoskeletal pain [1], and this finding has been supported by others [2,3]. However, the validation of questionnaires is often insufficiently documented, and the clinical relevance of subjective reports of musculoskeletal pain may be questionable. The research of musculoskeletal pain has largely focused on clarifying the risk factors and determinants of pain without analyzing pain disability and its consequences on the quality of life. Understanding the determinants of the health-related quality of life (HRQoL) is essential in health care, and various instruments have been developed for the measurement of HRQoL [4–6]. These describe health-specific aspects of well-being and function in mental, physical, and emotional dimensions, following the World Health Organization’s definition of health [7]. The 15-dimensional (15D) is a generic, 15-dimensional, self-administered instrument for measuring HRQoL among individuals over 16 years of age [8]. It combines the advantages of a profile and a preference-based, single-index measure. A set of utility weights is used to generate the 15D score, a single-index number, on a 0–1 scale [9]. We have previously reported that young adults’ musculoskeletal pain is often experienced and reported in multiple sites of the body [10]. In this study, we investigated the relationship between self-reported musculoskeletal pains and HRQoL in young adulthood. We hypothesized that 9
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Impact of Self-Reported Musculoskeletal Pain on Health-Related Quality of Life among Young Adults
Paananen et al. reported musculoskeletal pain is associated with reduced HRQoL and that the association of pain and HRQoL becomes stronger as the number of pain sites increases. Methods Study Population
Musculoskeletal Pains Six-month period prevalences for musculoskeletal pains were obtained by asking: “Have you had any aches or pains during the last six months in the following areas of your body?” 1) neck or occipital area, 2) shoulders, 3) low back, 4) elbows, 5) wrists, 6) knees, and 7) ankle–foot area. The anatomical areas were also illustrated by a drawing. The response alternatives were: 1) no, 2) yes, but I have not consulted a physician, physiotherapist, nurse, or other health professional (defined as reporting pain), and 3) yes, and I have consulted a physician, physiotherapist, nurse, or other health professional (defined as consultation for pain). Reporting pain and consultation for pain were combined as one class, and pain was categorized into four separate body sites: 1) neck, 2) shoulder, 3) low back, and 4) peripheral (elbow, wrist, knee, or ankle–foot pain). In the analyses, young adults were divided into four groups according to the reported pain status during the last 6 months: 1) no pain, 2) pain in one site, 3) pain in two sites, and 4) pain in three or four sites. HRQoL The 15D instrument was chosen to describe the HRQoL [8]. It is a standardized, generic HRQoL questionnaire, and has proved to be a reliable and valid instrument also with extensive use in musculoskeletal research [11]. The 15D consists of 15 questions concerning mobility, vision, hearing, breathing, sleeping, eating, speech, elimination, usual activities, mental function, discomfort and symptoms, depression, distress, vitality, and sexual activity. Five 10
Potential Confounders Physician-diagnosed health problems, psychosocial distress [13], parental occupation [14], and young adults’ own education were included in the analyses as potential confounding factors. The study subjects reported during the clinical examination whether they suffered from chronic illnesses, handicaps, or disabilities diagnosed by a physician. The presence of other health problems was dichotomized as having 1) no other health problem, and 2) having at least one other health problem. Psychosocial well-being was measured by the GHQ12, which is developed for the purpose of detecting psychiatric disorders among the general population [15]. The GHQ12 consists of 12 questions concerning recent concentration ability, level of happiness, sleep disturbances, self-esteem, and anxious/depressive symptoms. The GHQ scoring method of calculating total scores was used [15], and a score of four or more was chosen to indicate psychosocial distress [16]. As a proxy for socioeconomic status, parents’ occupational class/position (primarily father’s status) was categorized into five groups: 1) superior clerical employees, 2) self-employed, 3) lower clerical employees, 4) employees, and 5) students, senior citizens, unemployed, or unknown. The employment status of young adults was classified according to present condition into four groups: 1) student, 2) employed, 3) other, and 4) unemployed. Statistical Analyses As the prevalence of musculoskeletal pain differed between genders, the statistical analyses were stratified by gender. Because of the non-normal distribution of 15D scores, the nonparametric Mann–Whitney U-test was used for comparing total scores between the pain groups (Table 2). The P values were corrected by using the Benjamini–Hochberg method, which is a simple procedure for the case of multiple comparisons [17]. After the correction, P values of ⱕ0.05 were considered statistically significant. Statistical significance between the pain groups in regard to scores of 15D dimensions was tested by the Kruskal–Wallis procedure (Figures 2 and 3).
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The study population is a subgroup of the Northern Finland Birth Cohort 1986, which originally consisted of 9,479 members with an expected date of birth between July 1, 1985 and June 30 1986, from the two northernmost provinces of Finland. Between September 2003 and January 2004, a postal questionnaire with prepaid return envelope was sent to all members of the cohort living within 100 km of the city of Oulu (N = 2,969). All 2,012 members who returned the questionnaire (response rate 68%) were invited to a clinical examination at the Oulu Deaconess Institute in 2005. Finally, 874 young adults aged 19–20 participated in the clinical examination and completed the General Health Questionnaire (GHQ12), 15D questionnaire of HRQoL, and a questionnaire about musculoskeletal pain. The study conformed to the principles of the Declaration of Helsinki. The participants took part voluntarily and signed their informed consent. The data were handled on group level only and personal information was replaced by identification codes. The research protocol was approved by the Ethics Committee of the University Hospital of Oulu.
response alternatives are given for each question/ dimension from which an alternative that best describes the present health status is chosen. The overall scores and scores for each dimension were calculated by the valuation system based on utility weights from the general population on a 0–1 scale (0 = being dead, 1 = being totally healthy) [9]. A set of weights was obtained from a random sample of 2,500 persons aged more than 16 years through the multi-attribute utility method. The preference weights for each dimension were obtained by multiplying the dimension importance weight and within-dimension level value [9]. The minimum clinically significant change in 15D scores is defined as 0.03, meaning the difference that can be felt in health status [12]. Accordingly, for logistic regression analysis, 15D scores were trichotomized into the following: 1) 0.98–1.00, 2) 0.95–0.97, and 3) 0.94 or less, and young adults with a 15D score in the range of 0.98–1.00 were used as the reference group.
Musculoskeletal Pain and HRQoL pains. No pain at all during the last 6 months was reported by 22% of males and 9% of females. Pain in one anatomical location was reported by 30% of males and 17% of females, whereas pain in two distinct locations was reported by 20% of males and 25% of females. A considerable subgroup of young adults (28% of males and 49% of females) reported pain in three to four locations (Table 1). More females (17%) than males (9%) had psychosocial distress reaching a threshold score of four or more on the GHQ12. At least one other health problem was reported by 18% of males and 17% of females (Table 1).
Results HRQoL among the Pain Groups Study Population Characteristics Males had higher 15D scores than females, half of males and one-third of females reporting a 15D score of 0.98 or higher, indicating good HRQoL (Table 1). A larger proportion of females than males reported musculoskeletal
Young adults with multiple pains reported lower 15D scores than those reporting single pain or no pain at all (Figure 1). Among males, the statistically significant (P < 0.05) differences of 15D scores were observed between the painless and those with two, three, or four
Table 1 Prevalence of 15-dimensional (15D) scores, musculoskeletal pain, other health disorders, General Health Questionnaire (GHQ12) scores, young adults’ employment status, and parental occupation among 381 males and 493 females aged 19
15D scores for health-related quality of life 0.98–1.00† 0.95–0.97 ⱕ0.94 Pain group No pain 1 Pain location 2 Pain locations 3–4 Pain locations Other health disorders 0 1 or more GHQ12 scores 0–3 4–12‡ Young adults’ employment status Student Employed Other Unemployed Parental occupation Superior clerical employees Self-employed Lower clerical employees Employees Students, senior citizens, unemployed, unknown
Males % (N)
Females % (N)
49.7 (186) 27.3 (102) 23.0 (86)
31.3 (152) 26.8 (130) 41.9 (203)
22.2 29.6 20.3 28.0
9.0 17.0 24.7 49.3
P Value* for Gender Difference