*2.6. Participation*

After providing written consent, 415 subjects were enrolled in the Obuse study. The inclusion criteria were residents aged 50–90 years who were randomly selected by town administrative staff from the Obuse resident registry and who consented to participate in the study. The exclusion criteria were subjects with acute LBP, vertebral fracture, spinal infection, or spinal tumor within 3 months prior to the study, as well as those unable to undergo whole-spine radiographs in a standing position. Four people with missing radiographic data were excluded, leaving a total of 411 (201 male and 210 female) Japanese participants. All subjects were measured for physical characteristics and lifestyle habits. The baseline characteristics of the cohort are summarized in Table 1. The protocol of the investigation was approved by our Institutional Review Board (no. 2792). This study was reported in accordance with the STROBE guidelines.

**Figure 1.** Obuse town resident participant flowchart.


**Table1.** Baselinecharacteristics.

BMI: body mass index, SD: standard deviation.
