Prevalence of chronic low back pain and its associated factors in the general population of South Korea: a cross-sectional study using the National Health and Nutrition Examination Surveys

Table 3 Association between individual factors and chronic low back pain using multiple logistic regression

Variables	Odds radio	95% CI		p value
Age group
10–19	Reference
20–29	3.113	1.127	8.593	0.028
30–39	3.454	1.259	9.474	0.016
40–49	3.136	1.144	8.594	0.026
50–59	4.090	1.490	11.230	0.006
60–69	6.104	2.220	16.787	< 0.001
70–79	8.996	3.260	24.823	< 0.001
80–89	8.778	3.103	24.838	< 0.001
≥ 90	6.474	1.116	37.544	0.037
Gender
Male	Reference
Female	1.763	1.566	1.985	< 0.001
Alcohol consumption
None	Reference
≥ 1 drink/month	0.864	0.774	0.964	0.009
Household income^a
Low	reference
Low-moderate	0.869	0.756	0.999	0.048
Moderate-high	0.906	0.779	1.054	0.200
High	0.889	0.757	1.044	0.152
Education level^b
≤ 6 years	reference
7–9 years	0.741	0.628	0.874	< 0.001
10–12 years	0.604	0.514	0.710	< 0.001
≥ 13 years	0.447	0.367	0.545	< 0.001
Middle PA^c	1.520	1.339	1.726	< 0.001
Depressive symptom^d	1.551	1.374	1.750	< 0.001
Vitamin D^e
Insufficiency (< 20 ng/ml)	0.767	0.693	0.850	< 0.001
Normal (≥ 20 ng/ml)	Reference
Comorbidities
Stroke	1.532	1.169	2.007	0.002
Ischemic heart disease	1.590	1.207	2.094	0.001
Knee osteoarthritis	1.663	1.477	1.873	< 0.001
Asthma	1.434	1.164	1.767	0.001
COPD	2.091	1.378	3.173	0.001
Cancer^f	1.416	1.104	1.816	0.006

OR, Odds ratio; 95% CI, 95% confidence interval, PA; physical activity, COPD; chronic obstructive pulmonary disease
^aHousehold income level was calculated by dividing the total household monthly income with the obtained levels then grouped into quartiles
^bEducational 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)
^cMiddle physical activity was defined as mid-intensity physical activity for 5 or more days per week at least 30 min
^dDepressive symptom was defined as individuals in this survey who felt sad or depressive symptom for two consecutive weeks during the past one year
^eSerum vitamin D level were classified into two groups: Insufficiency (< 20 ng/ml) and normal (≥ 20 ng/ml)
^fHistory of major cancer: stomach, liver, colon, breast, uterine cervical, prostate or lung cancer

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