1 Department of Research, Cizik School of Nursing, University of Texas Health Science Center, Houston, TX, USA.
2 Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, USA.
Biol Res Nurs. 2019 Jul;21(4):400-406. doi: 10.1177/1099800419853633. Epub 2019 May 30.
Osteoarthritis (OA) is the most common cause of pain in people aged 45 years, and the knee is the most commonly affected joint. There is a growing interest in understanding the biological factors that influence pain among older adults, but few studies have examined the relationship between β-endorphin and experimental pain sensitivity in older adults with knee OA pain. The purpose of this study was to investigate the relationship between resting plasma levels of β-endorphin and experimental pain sensitivity. This study was a secondary analysis of data for 40 adults with knee OA pain in whom quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically induced pain. The mean age of the sample was 60 years ( = 9 years), and approximately half were female (53%). Regression analyses indicated that β-endorphin level was negatively related to pressure pain threshold (β = -17.18, = .02) and positively related to punctate mechanical pain (β = 17.13, = .04), after controlling for age, gender, and OA severity. We did not find a significant relationship between β-endorphin and heat pain tolerance. The results suggest that higher circulating levels of β-endorphin at rest are associated with increased sensitivity to mechanical pain in older adults with knee OA. These findings add to the literature regarding biological factors associated with pain sensitivity in older adults with chronic pain. Additional studies are needed to identify mediators of the relationship between β-endorphin and pain sensitivity in OA and other musculoskeletal pain conditions.
骨关节炎（OA）是 45 岁以上人群疼痛的最常见原因，膝关节是最常受影响的关节。人们越来越感兴趣的是了解影响老年人疼痛的生物学因素，但很少有研究探讨膝骨关节炎疼痛老年人β-内啡肽与实验性疼痛敏感性之间的关系。本研究旨在探讨静息状态下β-内啡肽水平与实验性疼痛敏感性之间的关系。本研究是对 40 名膝骨关节炎疼痛成年人数据的二次分析，其中使用定量感觉测试来测量对热和机械性疼痛的实验敏感性。样本的平均年龄为 60 岁（= 9 岁），大约一半为女性（53%）。回归分析表明，β-内啡肽水平与压痛阈值呈负相关（β=-17.18，=.02），与点状机械性疼痛呈正相关（β=17.13，=.04），控制年龄、性别和 OA 严重程度后。我们没有发现β-内啡肽与热痛耐量之间存在显著关系。结果表明，静息时循环中的β-内啡肽水平较高与膝骨关节炎老年人对机械性疼痛的敏感性增加有关。这些发现增加了关于与慢性疼痛老年人疼痛敏感性相关的生物学因素的文献。需要进一步研究以确定 OA 和其他肌肉骨骼疼痛疾病中β-内啡肽与疼痛敏感性之间关系的介质。
