Department of Health Policy Science, Graduate School of Medical Science, Yamagata University, Yamagata, Japan.
Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan.
J Gerontol A Biol Sci Med Sci. 2023 Jun 1;78(6):973-979. doi: 10.1093/gerona/glac184.
The relationship between obesity and back pain in older populations is poorly understood. This study aimed to examine (a) the impacts of changes in obesity status on back pain risk and (b) the heterogeneity in the influence of changes in obesity status according to muscle strength.
We analyzed 6 868 participants in waves 4 (2008-2009), 6 (2012-2013), and 7 (2014-2015) of the English Longitudinal Study of Ageing. The exposure comprised continuous body mass index (BMI) values, whereas the outcome comprised self-reported moderate or severe back pain. The targeted minimum loss-based estimator was used to estimate the impacts of hypothetical changes in BMI in each wave under 10 scenarios encompassing a 5%-25% hypothetical reduction/increase in BMI. We also performed stratified analysis using handgrip strength at the baseline.
For the hypothetical reduction scenarios, a 10% (relative risk [RR]; 95% confidence interval [CI] = 0.82 [0.73-0.92], p = .001) reduction in BMI estimated a significantly lower back pain risk compared to the observed data. For the hypothetical increase scenarios, a 5% (RR [95% CI] = 1.11 [1.04-1.19], p = .002) increase in BMI estimated a significantly higher back pain risk. Increased BMI had a higher risk of back pain among those with weak strength when stratified by handgrip strength but not among those with strong strength.
Our study confirmed that weight gain leads to a greater risk of back pain as well as heterogeneity in the influence of changes in obesity status according to the handgrip strength.
肥胖与老年人腰痛之间的关系尚未明晰。本研究旨在检验：(a) 肥胖状态变化对腰痛风险的影响，以及 (b) 根据肌肉力量的不同，肥胖状态变化的影响存在异质性。
我们分析了参加英国老龄化纵向研究第 4 波（2008-2009 年）、第 6 波（2012-2013 年）和第 7 波（2014-2015 年）的 6868 名参与者。暴露因素包括连续的体重指数（BMI）值，而结果则包括自我报告的中度或重度腰痛。采用靶向最小损失估计量，根据涵盖 BMI 降低/升高 5%-25%的 10 种情景，来估计各波次中 BMI 假设变化的影响。我们还在基线时采用握力进行分层分析。
对于假设的 BMI 降低情景，BMI 降低 10%（相对风险 [RR]；95%置信区间 [CI] 为 0.82 [0.73-0.92]，p =.001），与观察数据相比，腰痛风险显著降低。对于假设的 BMI 增加情景，BMI 增加 5%（RR [95% CI] 为 1.11 [1.04-1.19]，p =.002），腰痛风险显著增加。在握力分层分析中，当 BMI 增加时，握力较弱者的腰痛风险更高，但握力较强者的腰痛风险无明显增加。
本研究证实，体重增加会导致腰痛风险增加，并且肥胖状态变化的影响存在异质性，这取决于握力。
