Introduction:
Chronic fatigue syndrome is characterized by debilitating fatigue that is not relieved with rest and is associated with physical symptoms. Chronic fatigue syndrome includes severe fatigue lasting longer than six months, as well as the presence of at least four of the following physical symptoms: post-exertional malaise; unrefreshing sleep; impaired memory or concentration; muscle pain; polyarthralgia; sore throat; tender lymph nodes; or new headaches.
Low back pain (LBP) is a complex condition with multiple contributors. The degree of LBP varies depending on the activities of daily living. However, the association between LBP in activities of daily living and fatigue remains unknown.
This study aimed to investigate the association between LBP and fatigue in a Japanese population-based cohort.
Methods:
Participants aged >50 years were recruited from inhabitants of a mountain village in Japan. The participants completed the following patient-reported outcome measures.
LBP intensity was measured on an 11-point pain intensity numerical rating scale (NRS). The extent of LBP in the following situations/positions was assessed using the NRS: 1. morning awakening; 2. walking; 3. standing; 4. forward-bending; 5. sitting; and 6. lying down.
The extent of fatigue was measured using the Chalder Fatigue Questionnaire (CFQ; 0-42), which includes the subscales “physical score (0-24)” and “mental score (0-18)”. Participants whose CFQ score of more than or equal to fifteen were defined as a CFQ-positive group.
LBP-related Quality of life (QOL) was measured using the Oswestry Disability Index.
The association between CFQ and each parameter was statistically evaluated.
Results:
A total of 323 participants (71.6 years old [50-95]) were analyzed in this study, and 40.1% (n=132) had LBP.
The CFQ total score of all participants ranged from 0 to 33, and the average CFQ total score was 13.8 ± 7.4 (physical score: 8.0 ± 4.6, mental score: 5.7 ± 3.3). 155 participants (46.7% of the total) were in the CFQ-positive group. There were no significant correlations between CFQ score and age, sex, body height, and body weight. CFQ scores of participants with LBP were significantly higher than those without LBP. CFQ scores were significantly correlated with NRS scores of LBP in activities of daily living (P < 0.01, correlation coefficient. 0.15-0.35), especially NRS scores of LBP in standing and walking. Moreover, CFQ scores were significantly correlated with the ODI score (P < 0.01, correlation coefficient. 0.40-0.49).
The percentage of the participants who had LBP in the CFQ-positive group was significantly higher than in the CFQ-negative group.
Multiple regression analysis showed that the NRS scores of LBP in the standing and forward-bending were significantly associated with the CFQ total, physical, and mental scores (P<0.05). The NRS scores of LBP in the sitting were also significantly associated with the CFQ mental score (P<0.05).
Conclusion:
Fatigue was associated with LBP and LBP-related QOL among residents of a Japanese mountain village. Especially, physical fatigue was significantly associated with the extent of LBP in standing.