Table 1.
Characteristics of the study population according to chronic low back pain.
| Variables | Without CLBP (n = 14,345) |
CLBP (n = 2693) |
p-Value |
|---|---|---|---|
| Age, year | 47.3 (± 16.1) | 59.1 (± 16.0) | <0.001 |
| Age, n (%) | |||
| 10–19 | 174 (1.2%) | 4 (0.1%) | <0.001 |
| 20–29 | 1932 (13.5%) | 142 (5.3%) | |
| 30–39 | 3143 (21.9%) | 269 (10.0%) | |
| 40–49 | 3052 (21.3%) | 310 (11.5%) | |
| 50–59 | 2423 (16.9%) | 439 (16.3%) | |
| 60–69 | 2038 (14.2%) | 698 (25.9%) | |
| 70–79 | 1296 (9.0%) | 665 (24.7%) | |
| 80–89 | 275 (1.9%) | 161 (6.0%) | |
| ≥90 | 12 (0.1%) | 5 (0.2%) | |
| Gender, n (%) | |||
| Male | 6444 (44.9%) | 758 (28.1%) | <0.001 |
| Female | 7901 (55.1%) | 1935 (71.9%) | |
| Height, cm | 162.4 (± 9.1) | 157.3 (± 9.3) | <0.001 |
| Weight, kg | 62.5 (± 11.5) | 59.0 (± 10.3) | <0.001 |
| BMI, kg/m2 | 23.6 (± 3.4) | 23.8 (± 3.3) | 0.002 |
| Obesity, n (%) * | |||
| Underweight (<18.5) | 683 (4.8%) | 106 (4.0%) | 0.001 |
| Normal (18.5–24.9) | 9080 (64.1%) | 1644 (61.6%) | |
| Obese (>25) | 4403 (31.1%) | 918 (34.4%) | |
| Smoking status, n (%) | |||
| Non/Ex-smoker | 11,018 (76.9%) | 2304 (85.7%) | <0.001 |
| Current smoker | 3318 (23.1%) | 274 (14.3%) | |
| Alcohol consumption, n (%) | |||
| None | 6453 (45.0%) | 1688 (62.7%) | <0.001 |
| ≥1 drink/month | 7892 (55.0%) | 1005 (37.3%) | |
| Occupation, n (%) | |||
| Unemployed (student, housewife, etc.) | 5791 (40.4%) | 1375 (51.1%) | <0.001 |
| Office work | 2891 (20.2%) | 187 (6.9%) | |
| Sales and services | 1893 (13.2%) | 221 (8.2%) | |
| Agriculture, forestry and fishery | 1102 (7.7%) | 524 (19.5%) | |
| Machine fitting and simple labor | 2668 (18.6%) | 386 (14.3%) | |
| Household income, n (%) † | |||
| Low | 2572 (18.4%) | 976 (36.9%) | <0.001 |
| Low-moderate | 3510 (25.1%) | 645 (24.4%) | |
| Moderate-high | 3881 (27.8%) | 554 (20.9%) | |
| High | 4008 (28.7%) | 471 (17.8%) | |
| Education level, n (%) ‡ | |||
| ≤6 years | 3462 (24.1%) | 1503 (55.8%) | <0.001 |
| 7–9 years | 1594 (11.1%) | 316 (11.7%) | |
| 10–12 years | 5289 (36.9%) | 563 (20.9%) | |
| ≥13 years | 4000 (27.9%) | 311 (11.5%) | |
| Physical activity, n (%) § | |||
| Walk | 6570 (46.0%) | 1263 (47.1%) | 0.32 |
| Middle PA | 1903 (13.3%) | 514 (19.1%) | <0.001 |
| High PA | 2276 (15.9%) | 408 (15.2%) | 0.34 |
| Depressive symptom, n (%) || | 1987 (13.9%) | 698 (25.9%) | <0.001 |
| Comorbidities, n (%) | |||
| Hypertension | 2591 (18.1%) | 879 (32.6%) | <0.001 |
| Dyslipidemia | 968 (6.7%) | 305 (11.3%) | <0.001 |
| Stroke | 261 (1.8%) | 134 (5.0%) | <0.001 |
| Ischemic heart disease | 258 (1.8%) | 133 (4.9%) | <0.001 |
| Knee osteoarthritis | 2119 (14.8%) | 1052 (39.1%) | <0.001 |
| Asthma | 512 (3.6%) | 215 (8.0%) | <0.001 |
| COPD | 114 (0.8%) | 57 (2.1%) | <0.001 |
| Diabetes | 1004 (7.0%) | 310 (11.5%) | <0.001 |
| Chronic kidney disease | 48 (0.3%) | 17 (0.6%) | 0.022 |
| Liver cirrhosis | 23 (0.2%) | 10 (0.4%) | 0.022 |
| Cancer ¶ | 356 (2.5%) | 145 (5.4%) | <0.001 |
Numeric parameters are expressed as mean and standard deviation in parentheses. Categorical parameters are expressed as counts and percentages in parentheses. CLBP, chronic low back pain; BMI, body mass index; PA, physical activity; COPD, chronic obstructive pulmonary disease. * Body mass index was categorized into underweight (<18.5 kg/m2), normal (18.5–24.9 kg/m2), and obese (≥25.0 kg/m2). † Household income level was calculated by dividing the total household monthly income with the obtained levels then grouped into quartiles. ‡ Educational level was divided into the following four groups: ≤6 years (elementary school), 7–9 years (middle school), 10–12 years (high school), and ≥13 years (college or university). § Physical activity was defined as three categories: walking was defined as walking activity for 5 or more days per week at least 30 min, middle physical activity was defined as mid-intensity physical activity for 5 or more days per week at least 30 min, and high physical activity was defined as high-intensity physical activity for 3 or more days per week at least 20 min. || Depressive symptom was defined as individuals in this survey who felt sad or had a depressive symptom for two consecutive weeks during the past one year. ¶ History of major cancer: stomach, liver, colon, breast, uterine cervical, prostate, or lung cancer.