Low back pain (LBP) is the most common problem worldwide. There are several negative consequences of LBP, such as sleep disorders, work leave, disability, depression, anxiety, and poor quality of life. In this study, we designed to evaluate the prevalence of sleep disturbance in patients with non-specific LBP(NSLBP), and cross-correlation among sleep disorder, anxiety, depression and pain intensity in patients with NSLBP.
In this study, we designed to evaluate the prevalence of sleep disturbance in patients with NSLBP, and cross-correlation among sleep disorder, anxiety, depression and pain intensity in patients with NSLBP.
A cross-sectional self-assessment questionnaire survey was carried out in an outpatient clinic. Anonymous assessments were used to characterize the presence of NSLBP, PSQI, VAS, SF-36 form, ODI, BAI and BDI. Cross-correlation among the severity of NSLBP and sleep disturbance, anxiety, depression and life quality were evaluated.
Patients with NSLBP have a higher incidence of sleep disorder, anxiety and depression, and higher ODI scores than healthy people without LPB (
Psychological and social factors play an important role in the development of NSLBP. NSLBP leads to sleep disorders, which decrease the sleep quality and increase the unpleasant emotions and memories in return; these can exacerbate the severity of LBP, with the cycle repeating to form a vicious circle.
Low back pain (LBP) is defined as mild to severe pain in the area of the lumbar, lumbo-sacral or sacroiliac regions (
Sleep is essential to keep the normal status of emotional, mental and physical health. Sleep disturbance lead to decreased work ability, increased sick leave, and a higher injury rate (
Pain and sleep disturbance can impair patients’ life quality, including physical activity, social integration and emotions (
In this study, we designed to evaluate the prevalence of sleep disturbance in patients with NSLBP compared with 112 age- and sex-matched healthy people without pain; then, cross-correlation among NSLBP, sleep disorder, anxiety and depression was analyzed. The results can provide a theoretical basis for the prevention and treatment of NSLBP. The questionnaires in this study are PSQI, SF-36, ODI, BAI and BDI.
Patients with non-specific LBP were enrolled from January 2014 to January 2016 in an orthopedic clinic of the First Affiliated Hospital of Sun Yat-sen University and Wenming Hospital; no limitation was set in the aspects of gender, age, height, weight, occupation, educational level and birth place. The chief compliance was LBP, which lasts more than one month. All patients signed informed consent forms after obtaining approval from the Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University. Patients had a certain education level and can understand questionnaire survey. All patients completed questionnaires and lumbar MRI were taken to find out organic diseases (
The exclusion criteria were: individuals whose reported age was <18 years or >65 years; LBP attributed to spine fracture, spine inflammation, spinal tumor, spinal tuberculosis, disc herniation, spinal stenosis, spondylolisthesis, aneurysm or lithiasis; individuals who have mental disorders, history of cancer or severe chronic physical disorders (e.g., hypertension, diabetes, coronary heart disease, chronic kidney disease, bronchitis, asthma, etc.) (
For the control group without LBP, the control age- and gender- matched asymptomatic subjects was enrolled from healthy volunteers without LBP, with the exclusion criteria of history of malignant tumors, psychiatric diseases, chronic systemic diseases.
Participants were evaluated by questionnaires including PSQI, VAS, SF-36, ODI, BAI and BDI.
PSQI is the 24-item survey that evaluates sleep quality, including subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance, use of sleep medication and daytime dysfunction (
Pain intensity of patients with NSLBP were assessed by VAS score, with 0 = no pain and 10 = extreme pain, which is widely used to measure pain with good validity and reliability (
SF-36 is the 36-item generic quality of life questionnaire. It has an eight scale profile of functional health and well being, including physical function, role function physical, body pain, general health perceptions, vitality, social functioning, role function emotional and mental health. The total score is 0 to 100, with 100 indicating the best possible score. The SF-36 has been recommended for comprehensively measuring the health and quality of life in participants with or without LBP (
ODI has six gradual statements per item and a total score 0–50, with 0–20% of total score indicating minimal disability, 21–40% moderate disability, 41–60% severe disability, 61–80% crippled, 81–100% total incapacitation. The ODI has been reported to have good validity, reliability and responsiveness in people with LBP (
BAI is a 21-item self report questionnaire designed to evaluate anxiety symptoms (
BDI is the standard questionnaire for evaluation of cognitive, affective and somatic symptoms of depression (
Statistical analysis were conducted using SPSS version 18 and SAS V9.3. The demographic data including age, sex, education, occupation, exercise, smoking, and drinking were evaluated between the two groups. Characteristics of study participants were summarized by means and SDs for continuous variables, by frequencies and percentages for categorical variables. The pain intensity, quality of daily life, dysfunctional and psychosocial factors were compared and analyzed between these two groups. For continuous variable, if the variable was normally distributed and had constant variances,
Characteristic | Sub-group | LBP patients ( |
Healthy control ( |
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---|---|---|---|---|---|
Gender (n) | Male | 325 (58.6%) | 68 (60.7%) | χ2 = 0.055 | |
Female | 230 (41.4%) | 44 (39.3%) | |||
Age (years) | 45.37 ± 9.23 | 42.13 ± 10.39 | |||
Height (meter) | 1.59 ± 0.11 | 1.59 ± 0.12 | |||
Weight (Kg) | 63.36 ± 11.41 | 62.18 ± 11.98 | |||
Body mass index | 25.50 ± 6.24 | 24.64 ± 4.98 | |||
Normal | 310(55.8%) | 45(40.2%) | χ2 = 74.96 | ||
Over-weight | 63(11.4%) | 50(44.6%) | |||
Obese | 182(32.8%) | 17(15.2%) | |||
Smoking (n) | Yes | 71 (12.8%) | 16 (14.3%) | χ2 = 0.183 | |
No | 484 (87.2%) | 96 (85.7%) | |||
Drinking (n) | Yes | 103 (18.6%) | 20 (17.9%) | χ2 = 0.030 | |
No | 452 (81.4%) | 92 (82.1%) | |||
Coffee drinking (n) | Yes | 102 (18.4%) | 14 (12.5%) | χ2 = 2.242 | |
No | 453 (81.6%) | 98 (87.5%) | |||
ODI score | 31.74 ± 13.65 | 7.36 ± 3.32 | |||
BAI score (n) | χ2 = 32.43 | ||||
No anxiety | 277 (49.9%) | 87 (77.7%) | |||
Mild anxiety | 163 (29.4%) | 21 (18.7%) | |||
Moderate anxiety | 105 (18.9%) | 4 (3.6%) | |||
Severe anxiety | 10 (1.8%) | 0 (0%) | |||
BDI score (n) | χ2 = 31.68 | ||||
Normal | 176 (31.7%) | 65 (58.0%) | |||
Mild depression | 314 (56.6%) | 45 (40.2%) | |||
Moderate depression | 63 (11.4%) | 2 (1.8%) | |||
Severe depression | 2 (0.3%) | 0 (0%) | |||
PSQI score (n) | |||||
Subjective sleep quality | 1.28 ± 0.66 | 0.92 ± 0.63 | |||
Sleep latency | 1.03 ± 0.77 | 0.76 ± 0.83 | |||
Sleep duration | 0.97 ± 0.60 | 0.48 ± 0.64 | |||
Sleep efficiency | 0.45 ± 0.53 | 0.27 ± 0.46 | |||
Sleep disturbance | 1.19 ± 0.62 | 0.82 ± 0.60 | |||
Use of sleep medication | 0.16 ± 0.38 | 0.04 ± 0.21 | |||
Daytime dysfunction | 0.78 ± 0.68 | 0.35 ± 0.55 |
Group A: patients with LBP; Group B: healthy control participants. Mean (SD).
Pittsburgh sleep quality index (PSQI), Visual Analogue Scale (VAS), SF-36 form, Oswestry disability index (ODI), Beck anxiety inventory (BAI) and Beck depression inventory (BDI).
A total of 555 NSLBP patients were enrolled. There were 325(58.6%) men, 230 (41.4%) women, with mean age 37.74 ± 11.10 years (age distribution in
A total of 112 healthy people without LBP were enrolled. There were 68 (60.7%) men, 44 (39.3%) women, with mean age 36.04 ± 11.55 years, weight 62.18 ± 11.98 kg, and height 159 ± 12 cm. Mean pain intensity on the VAS was 4.35 ± 1.61. 16 (14.3%) have a smoking habit, 20 (17.9%) have a drinking habit, ODI scores were 7.36 ± 3.32, 18 (16.1%) included healthy people have the symptom of anxious, with BAI scores of 7.64 ± 6.09, 13 (11.6%) have depression with BDI scores of 2.28 ± 2.20, and 14 (12.5%) have sleep disorders with PSQI scores of 3.28 ± 2.66 (
There was no significant difference in age, sex, height, weight, smoking and drinking habits between the two groups (
Characteristic | Sub-group (Cases) | VAS score | PQSI score | BAI score | BDI score | ODI score | |||||
---|---|---|---|---|---|---|---|---|---|---|---|
Score | Score | Score | Score | Score | |||||||
NSLBP | Yes (555) | 5.85 ± 2.52 | 15.95 ± 8.91 | 7.65 ± 4.63 | 31.74 ± 13.65 | ||||||
No (191) | 3.64 ± 2.73 | 9.90 ± 6.95 | 4.30 ± 3.41 | 7.36 ± 3.32 | |||||||
Severiety of NSLBP | Mild (293) | 2.57 ± 0.53 | 5.46 ± 2.47 | 14.90 ± 8.07 | 7.12 ± 4.37 | 29.36 ± 13.37 | |||||
Moderate (112) | 4.87 ± 0.83 |
6.00 ±2.39 |
15.89 ±9.29 |
7.86 ± 4.58 | 32.94 ±13.24 |
||||||
Severe (71) | 7.01 ±0.12 |
6.32 ±3.04 |
19.06 ±8.86 |
8.23 ± 5.36 | 33.15 ±15.30 |
||||||
Sleeping disorders | Yes (161) | 4.65 ± 1.70 | 8.78 ± 0.90 | 17.31 ± 9.85 | 8.53 ± 4.89 | 33.54 ± 14.26 | |||||
No (394) | 4.23 ± 1.57 | 4.65 ± 1.91 | 15.40 ± 8.44 | 7.30 ± 4.47 | 31.00 ± 13.34 | ||||||
Anxious | Yes (278) | 4.52 ± 1.64 | 6.39 ± 2.37 | 23.25 ± 6.16 | 7.95 ± 4.85 | 33.18 ± 13.19 | |||||
No (277) | 4.18 ± 1.57 | 5.31 ± 2.56 | 8.63 ± 3.72 | 7.36 ± 4.39 | 24.47 ± 14.07 | ||||||
Depression | Yes (379) | 4.28 ± 1.69 | 4.88 ± 2.92 | 14.72 ± 8.17 | 2.73 ± 1.14 | 29.13 ± 13.88 | |||||
No (176) | 4.39 ± 1.58 | 6.31 ± 2.18 | 16.53 ± 9.19 | 9.94 ± 3.78 | 32.95 ± 13.38 | ||||||
Smoking | Yes (71) | 4.59 ± 1.58 | 6.25 ± 2.49 | 18.06 ± 9.43 | 9.42 ± 4.91 | 31.38 ± 13.06 | |||||
No (484) | 4.32 ± 1.61 | 5.79 ± 2.52 | 15.64 ± 8.79 | 7.39 ± 4.53 | 31.79 ± 13.74 | ||||||
Drinking | Yes (103) | 4.68 ± 1.48 | 6.96 ± 2.25 | 17.96 ± 9.22 | 9.01 ± 4.53 | 34.42 ± 12.70 | |||||
No (452) | 4.21 ± 1.65 | 5.38 ± 2.49 | 15.49 ± 8.78 | 7.34 ± 4.59 | 31.12 ± 13.79 | ||||||
Coffee drinking | Yes (102) | 4.17 ± 1.70 | 5.62 ± 2.72 | 16.12 ± 9.21 | 7.83 ± 4.58 | 30.19 ± 12.94 | |||||
No (453) | 4.39 ± 1.59 | 5.91 ± 2.47 | 15.92 ± 8.85 | 7.61 ± 4.64 | 32.08 ± 13.79 | ||||||
Weight | Normal (310) | 4.34 ± 1.67 | 5.50 ± 2.53 | 15.73 ± 9.05 | 7.48 ± 4.46 | 30.10 ± 13.28 | |||||
Over weight (63) | 4.37 ± 1.38 | 6.71 ±2.39 |
16.40 ± 8.34 | 7.79 ± 4.55 | 35.90 ±14.02 |
||||||
Obese (182) | 4.38 ± 1.60 | 6.16 ±2.46 |
16.18 ± 8.90 | 7.91 ± 4.94 | 33.09 ±13.76 |
Represent there is statistical difference between patients with “mild NSLBP” and “moderate NSLBP”.
Represent there is statistical difference between patients with “mild NSLBP” and “severe NSLBP”.
Represent there is statistical difference between patients with “moderate NSLBP” and “severe NSLBP”.
Represent there is statistical difference between patients with “normal weight” and “over weight”.
Represent there is statistical difference between patients with “normal weight” and “obese”.
Patients were divided into two groups according to the presence of sleep disorders, anxiety or depressive symptoms. Statistical analysis showed that NSLBP patients with sleep disorders have more severe anxiety, depression, increased VAS score and poor daily living (
We then analyzed the relationship of smoking, drinking habits and body mass index on anxiety, depression, quality of sleep and severity of LBP. Results confirmed that smoking habits can affect a patient’s anxiety and depression mood in NSLBP patients, resulting in the increased incidence of anxiety and depression. Drinking habits can lead to increased incidence of anxiety and depression, decreased quality of sleep, poor daily lives, declined work and social skills (
To further understand the correlation between the severity of NSLBP with sleep quality, mood and activities of daily living, Spearman correlation analysis was done. Results showed that VAS score was significantly correlated with PSQI, BDI, BAI and ODI (
In the multiple logistic regression model, all predictive variables were significant after controlling for age, gender, and other variables. The effect of NSLBP VAS score, BAI and BDI on sleep quality PSQI was analyzed, results showed that patients with VAS > 7 were associated with higher PSQI score(OR: 2.248, 95% CI [1.235–4.093]) in comparison to patients with VAS 0–3. Patients with moderate anxiety (BAI 26–35) were associated with higher PSQI score (OR: 2.253, 95% CI [1.357–3.741]) compared with patients without anxiety (
VAS | PSQI | BDI | BAI | ODI | |
---|---|---|---|---|---|
VAS | 1 | ||||
PSQI | 1 | ||||
BDI | 1 | ||||
BAI | 1 | ||||
ODI | 1 |
Characteristic | Regression coefficients | Standard error | OR 95% |
|||
---|---|---|---|---|---|---|
Lower limit | Upper limit | |||||
Moderate NSLBP | −0.2911 | 0.2187 | 0.1831 | 1.338 | 0.872 | 2.054 |
Severe NSLBP | −0.8101 | 0.3056 | 0.0080 | 2.248 | 1.235 | 4.093 |
Mild depression | −0.2152 | 0.2196 | 0.3271 | 1.240 | 0.806 | 1.907 |
Moderate depression | −0.5267 | 0.3248 | 0.1048 | 1.693 | 0.896 | 3.200 |
Severe depression | −0.4829 | 1.4887 | 0.7457 | 1.621 | 0.088 | 29.985 |
Mild anxiety | −0.2024 | 0.2210 | 0.3599 | 1.224 | 0.794 | 1.888 |
Moderate anxiety | −0.8125 | 0.2587 | 0.0017 | 2.253 | 1.357 | 3.741 |
Severe anxiety | 1.3847 | 1.0837 | 0.2013 | 0.250 | 0.030 | 2.094 |
The severity of NSLBP was divided into three groups: mild NSLBP (VAS 0–3), moderate NSLBP (VAS 4–6), severe NSLBP (VAS > 7). The severity of anxious symptom was also divided into three groups: mild anxiety (BAI = 15–25), moderate anxiety (BAI = 26–35), severe anxiety (BAI > 36). The severity of depression symptom was also divided into three groups, mild depression (BDI = 5–13), moderate depression (BDI = 14–20), severe depression (BDI > 21).
Characteristic | Regression coefficients | Standard error | OR95% |
|||
---|---|---|---|---|---|---|
Lower limit | Upper limit | |||||
PSQI(two-category) | −0.4675 | 0.1862 | 0.0121 | 1.596 | 1.108 | 2.299 |
Mild depression | 0.0170 | 0.1841 | 0.9263 | 1.017 | 0.709 | 1.459 |
Moderate depression | 0.3497 | 0.2907 | 0.2289 | 1.419 | 0.803 | 2.508 |
Severe depression | 2.1709 | 1.4569 | 0.1362 | 8.766 | 0.504 | 152.377 |
Mild anxiety | 0.2453 | 0.1873 | 0.1903 | 1.278 | 0.885 | 1.845 |
Moderate anxiety | 0.4958 | 0.2408 | 0.0395 | 1.642 | 1.024 | 2.632 |
Severe anxiety | 0.8579 | 0.6348 | 0.1766 | 2.358 | 0.680 | 8.183 |
The severity of NSLBP was divided into three groups: mild NSLBP (VAS 0–3), moderate NSLBP (VAS 4–6), severe NSLBP (VAS > 7). The severity of anxious symptom was also divided into three groups: mild anxiety (BAI = 15–25), moderate anxiety (BAI = 26–35), severe anxiety (BAI > 36). The severity of depression symptom was also divided into three groups: mild depression (BDI = 5–13), moderate depression (BDI = 14–20), severe depression (BDI > 21).
Characteristic | Regression coefficients | Standard error | OR95% |
|||
---|---|---|---|---|---|---|
Lower limit | Upper limit | |||||
PSQI | −0.0850 | 0.0340 | 0.0126 | 0.919 | 0.859 | 0.982 |
Moderate NSLBP | 0.2261 | 0.1783 | 0.2048 | 1.254 | 0.884 | 1.778 |
Severe NSLBP | −0.0869 | 0.2682 | 0.7459 | 0.917 | 0.542 | 1.551 |
Mild depression | 0.1252 | 0.1847 | 0.4979 | 1.133 | 0.789 | 1.628 |
Moderate depression | 0.1412 | 0.2909 | 0.6275 | 1.152 | 0.651 | 2.037 |
Severe depression | 1.3460 | 1.3481 | 0.3181 | 3.842 | 0.274 | 53.958 |
The severity of NSLBP was divided into three groups: mild NSLBP (VAS 0–3), moderate NSLBP (VAS 4–6), severe NSLBP (VAS > 7). The severity of anxious symptom was also divided into three groups, mild anxiety (BAI = 15–25), moderate anxiety (BAI = 26–35), severe anxiety (BAI > 36). The severity of depression symptom was also divided into three groups: mild depression (BDI = 5–13), moderate depression (BDI = 14–20), severe depression (BDI > 21).
Characteristic | Regression coefficients | Standard error | OR95% |
|||
---|---|---|---|---|---|---|
Lower limit | Upper limit | |||||
PSQI | 0.0426 | 0.0350 | 0.2233 | 1.043 | 0.974 | 1.118 |
Moderate NSLBP | 0.0485 | 0.1858 | 0.9792 | 1.005 | 0.698 | 1.446 |
Severe NSLBP | 0.4121 | 0.2717 | 0.1294 | 1.510 | 0.886 | 2.572 |
Mild anxiety | 0.1801 | 0.1913 | 0.3465 | 1.197 | 0.823 | 1.742 |
Moderate anxiety | 0.2192 | 0.2492 | 0.3791 | 1.245 | 0.764 | 2.029 |
Severe anxiety | −0.0766 | 0.6482 | 0.9060 | 0.926 | 0.260 | 3.300 |
The severity of NSLBP was divided into three groups: mild NSLBP (VAS 0–3), moderate NSLBP (VAS 4–6), severe NSLBP (VAS > 7). The severity of anxious symptom was also divided into three groups: mild anxiety (BAI = 15–25), moderate anxiety (BAI = 26–35), severe anxiety (BAI > 36). The severity of depression symptom was also divided into three groups, mild depression (BDI = 5–13), moderate depression (BDI = 14–20), severe depression (BDI > 21).
In this study we investigated the association between pain intensity and sleep quality in non-specific LBP patients, together with the relationship between pain intensity, patients’ life quality, ODI score and emotions. Most of the previous studies on LBP and sleep disturbance focused on patients with persistent pain (
In this study, we found pain intensity is associated with the influence of sleep disturbance, woth severe NSLBP patients having more sleep disturbance. This is similar to previous study, which demonstrated that pain intensity was the most likely influence factor in LBP patients to be associated with sleep disturbance (
Pain has been reported to have bidirectional relationship with sleep; pain hinders sleep, while sleep disturbance also decreases pain thresholds and the mental capacity to manage pain (
Studies have indicated that LBP was associated with patients’ emotional status (
In relationship of sleep quality and emotional status, significant correlation between depression, anxiety, and sleep disturbance was well established (
Anxiety disorders has been reported to be present in up to 60% of patients with chronic pain (
LBP is a disabling disease which restricts life quality, and psychological factors may have a larger impact on disability and quality of life than pain itself (
The strength of the present study is that the results are based on the large prospective cohort study. A medical assistant in our research group distributed and helped patients to fill the questionnaire, which can improve the reliability of results. The response rate of our participants was more than 98%. We used a standard definition of non-specific LBP by experts in the field (
The current study have some limitations. In this cohort study, the accuracy and completeness of the data within the database were dependent on the self-reported questionnaire, which may affect the internal validity of our study. The cross-sectional nature of the analyses limits causal inferences regarding the relationship between depression, anxiety and pain outcomes. Depression and anxiety were assessed with self-report measures rather than in standardized clinical interviews to diagnose specific mental disorders. Findings may not generalize to all racial and ethnic groups, as our samples were mostly southern Chinese. Age distribution may influence the depression scores in low back pain (
The identification of interplay among pain intensity, sleep disturbance and emotion in patients with NSLBP has several potential uses. First, there are cross-relationship among pain intensity, sleep disturbance, anxiety and depression; Second, LBP also influenced by the social and psychological status of the patients and their quality of life (
In this study, we evaluate the cross-correlation among sleep disorder, anxiety, depression and pain intensity in patients with NSLBP. Psychological and social factors play an important role in the development of NSLBP. NSLBP lead to sleep disorder, which decrease the sleep quality and increase the unpleasant emotions and memories in return; these can exacerbate the severity of LBP, the cycle can repeating to form a vicious circle.
The authors declare there are no competing interests.
The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):
First Affiliated Hospital of Sun Yat-sen University
Total 555 NSLBP patients and total 112 healthy people without LBP.
The following information was supplied regarding data availability:
The raw data has been supplied as