1 Hijikata Y, et al. BMJ Open 2022;12:e052421. doi:10.1136/bmjopen-2021-052421 Open access Association of kyphotic posture with loss of independence and mortality in a community-based prospective cohort study: the Locomotive Syndrome and Health Outcomes in Aizu Cohort Study (LOHAS) Yasukazu Hijikata , 1 Tsukasa Kamitani, 1 Miho Sekiguchi, 2 Koji Otani, 2 Shin-ichi Konno, 2 Misa Takegami, 3 Shunichi Fukuhara, 4,5 Yosuke Yamamoto 1 To cite: Hijikata Y, Kamitani T, Sekiguchi M, et al. Association of kyphotic posture with loss of independence and mortality in a community-based prospective cohort study: the Locomotive Syndrome and Health Outcomes in Aizu Cohort Study (LOHAS). BMJ Open 2022;12:e052421. doi:10.1136/ bmjopen-2021-052421 ► Prepublication history and additional supplemental material for this paper are available online. To view these fles, please visit the journal online (http://dx.doi.org/10.1136/ bmjopen-2021-052421). Received 15 April 2021 Accepted 26 February 2022 For numbered affliations see end of article. Correspondence to Dr Yosuke Yamamoto; yamamoto.yosuke.5n@kyoto-u. ac.jp Original research © Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. ABSTRACT Objectives This study aimed to investigate the association between kyphotic posture and future loss of independence (LOI) and mortality in community-dwelling older adults. Design Prospective cohort study. Setting Two Japanese municipalities. Participants We enrolled 2193 independent community- dwelling older adults aged≥65 years at the time of their baseline health check-up in 2008. Kyphotic posture was evaluated using the wall-occiput test (WOT) and classifed into three categories: non-kyphotic, mild (>0 and ≤4 cm) and severe (>4 cm). Primary and secondary outcome measures The primary outcome was mortality and the secondary outcomes were LOI (new long-term care insurance certifcation levels 1–5) and a composite of LOI and mortality. A Cox proportional hazards model was used to estimate the adjusted HRs (aHRs). Results Of the 2193 subjects enrolled, 1621 were included in the primary analysis. Among these, 272 (17%) and 202 (12%) were diagnosed with mild and severe kyphotic postures, respectively. The median follow-up time was 5.8 years. Compared with the non-kyphotic group, the aHRs for mortality were 1.17 (95% CI 0.70 to 1.96) and 1.99 (95% CI 1.20 to 3.30) in the mild and severe kyphotic posture groups, respectively. In the secondary analysis, a consistent association was observed for LOI (mild: aHR 1.70, 95% CI 1.13 to 2.55; severe: aHR 2.08, 95% CI 1.39 to 3.10) and the LOI-mortality composite (mild: aHR 1.27, 95% CI 0.90 to 1.79; severe: aHR 1.83, 95% CI 1.31 to 2.56). Conclusion Kyphotic posture was associated with LOI and mortality in community-dwelling older adults. Identifying the population with kyphotic posture using the WOT might help improve community health. INTRODUCTION Kyphosis is described as an abnormal posture that develops because of the failure of the posture maintenance mechanism. When standing, lordotic segments (ie, the cervical and lumbar spine) and kyphotic segments (ie, the thoracic spine) must balance the occiput over the pelvic axis in an energy- efficient position. As the centre of gravity of the trunk shifts forward due to kyphosis in one segment of the spine, the other spinal segments, pelvis, hip joint and knee joint, cooperatively compensate to maintain overall sagittal balance. 1 Failure of this compensa- tory mechanism results in kyphotic posture, leading to various health problems. 2 3 A kyphotic posture is common among older individuals, with a reported prevalence of 20%–40%, 4 and is expected to increase as the population ages. Hence, the extent to which a kyphotic posture affects health is a serious concern. Strengths and limitations of this study ► The results were obtained from a relatively large co- hort of a community-based population. ► Only 1.5% (31) of the 2193 participants included in the study were lost to follow-up due to change of residence from the target area, which minimised the risk of information bias. ► We did not adjust for osteoporosis, a factor that might be associated with loss of independence and mortality through mechanisms other than kyphotic postures, such as fractures of the long bones. ► The wall-occiput test does not distinguish rigid ky- phosis from fexible kyphosis. ► Attributing causation is diffcult because of oth- er unmeasured confounders, including subclinical diseases. on May 9, 2022 by guest. Protected by copyright. http://bmjopen.bmj.com/ BMJ Open: first published as 10.1136/bmjopen-2021-052421 on 31 March 2022. Downloaded from