Longer sitting time and low physical activity are closely associated with chronic low back pain in population over 50 years of age: a cross-sectional study using the sixth Korea National Health and Nutrition Examination Survey.

BACKGROUND CONTEXT: There is increasing evidence supporting an association between sitting time and low back pain (LBP). However, the degree of the association between the total daily sitting time and LBP in the general population is poorly understood.

PURPOSE: The present study aimed (1) to analyze the association between the duration of sitting time and LBP, and (2) to examine this association according to the degree of physical activity in population over 50 years of age with a nationally representative sample of Korean adults.

STUDY DESIGN: This is a cross-sectional study.

PATIENT SAMPLE: Data from version VI-2, 3 of the Korea National Health and Nutrition Examination Survey (KNHANES) performed in 2014 and 2015 were analyzed.

OUTCOME MEASURES: Multiple logistic regression was performed to find the rates of association between chronic LBP, level of sitting time, and physical activity.

METHODS: Nationwide health surveys and examinations were conducted in general Korean representative populations (n=7,550 in 2014, n=7,380 in 2015). Chronic LBP was defined as self-reported LBP lasting for more than 30 days during the past 3 months in a health survey. Sitting time and daily physical activity were evaluated using the long version of the International Physical Activity Questionnaires (IPAQ). The duration of sitting time was divided into two categories according to the median value (7 hours) and further divided into four categories using quartiles. Physical activity was also divided into low and high physical activity according to duration of mid- to high-intensity activities. There were no sources of funding and no conflicts of interest associated with the present study.

RESULTS: On multiple logistic regression analysis, sitting time more than 7 hours/day was significantly associated with LBP (adjusted odds ratio 1.33, p<.001). The risk of LBP increased with increasing duration of sitting time. In participants with low levels of physical activity, the duration of sitting time showed more positive association with LBP than that in all the participants and participants with high levels of physical activity.

CONCLUSIONS: Longer duration of sitting time is a risk factor for LBP. Furthermore, long duration of sitting time with low physical activity further increases the risk of LBP.