Predictors of pain tolerance and beliefs. DOI: 10.6084/m9.figshare.2289385

The primary content of this repository includes the data, codebook, and analysis scripts (with associated markdown outputs and plots) for random forest analyses of predictors of cold-pain tolerance (cold-pain-tolerance.Rmd, cold-pain-tolerance.md), pressure-pain tolerance (pressure-pain-tolerance.Rmd, pressure-pain-tolerance.md), and acceptance of pain behaviours in males (apbq-male.Rmd, apbq-male.md) in healthy black and white young adults of both sexes in South Africa. Only complete cases were used in the random forest analysis (pain tolerances: 156/212 participants; ABPQ-M: 167/212 participants).<br>The repository also includes the data and codebook used in all bivariate analyses. These analyses were completed using GraphPad Prism 6.0, and the results have not been uploaded to the repository (please contact [e-mail] or [e-mail] for more information).<br>In all cases the data provided are the cleaned, analysis data. Original hardcopies of completed questionnaires are on file.<br>License<br>The 'pain-sex-ethnicity' respository by Peter Kamerman and Antonia Wadley is licensed under a Creative Commons Attribution 4.0 International License.<br>Overview of the study<br>Background: Sex and ethnicity influence pain sensitivity and pain beliefs. However, studies on relationships between sex, ethnicity and pain largely have emanated from the US and Europe. <br>Objectives: To determine effects of sex and ethnicity on pain sensitivity and beliefs we compared cold and pressure pain tolerance in South African male and female individuals of African ancestry and European ancestry. We also assessed whether psychosocial factors (including pain beliefs) predicted sex and ethnic differences in pain sensitivity and beliefs. <br>Methods: We recruited 106 individuals of African ancestry (62 female, 44 male) and 106 individuals of European ancestry (55 female, 51 male). Participants underwent a cold-pressor test and pressure algometry to determine tolerance to noxious thermal and mechanical stimuli. Socioeconomic status, pain catastrophizing, depression, anxiety and pain beliefs were assessed as predictors of differences in pain tolerance. <br>Results: Cold pain tolerance was lower in individuals of African ancestry than in individuals of European ancestry (for both sexes), and pressure pain tolerance was lower in female than male students (for both ethnicities). Pain intensity at tolerance was similar for all groups in both tests. Men were less accepting of men expressing pain than were women, with males of African ancestry being the least accepting. Regression tree analysis identified that being of African ancestry, and particularly being a female of African ancestry predicted lower cold pain tolerance. Anxiety and ownership of assets (as a measure of socioeconomic status) were identified as additional variables of interest for predicting cold pain tolerance on random forest analysis but the associations were borderline. Both regression tree and random forest analysis identified female sex as the only significant predictor of pressure-pain tolerance, with females having lower pressure-pain tolerance than men. Regression tree analysis identified sex and ethnicity as important predictors of APBQ-M score, such that being female predicted greater APBQ-M scores, and amongst males, being of African ancestry predicted significantly lower APBQ-M scores than did being of European ancestry. Random forest also identified depression and ownership of assets as variables of interest. <br>Conclusions: Despite a different cultural and social background from US and European cohorts, we saw similar patterns of sex and ethnic differences in tolerance to cold and pressure stimuli in an African cohort. Traditional psychosocial predictors of pain sensitivity were identified as being of interest but were not strongly associated

本研究仓库的核心内容包含用于冷痛耐受性（cold-pain tolerance）、压痛耐受性（pressure-pain tolerance）以及男性疼痛行为接受度量表（Acceptance of Pain Behaviors Questionnaire-Male, APBQ-M）预测因素分析的随机森林（random forest）分析所需的数据、代码本与分析脚本（附带关联的markdown输出文件与绘图文件），对应分析脚本及文档分别为cold-pain-tolerance.Rmd、cold-pain-tolerance.md，pressure-pain-tolerance.Rmd、pressure-pain-tolerance.md，以及apbq-male.Rmd、apbq-male.md，研究对象为南非健康的非洲血统与欧洲血统年轻两性青年。本随机森林分析仅纳入完整有效案例：冷痛与压痛耐受性分析纳入212名参与者中的156名，APBQ-M分析纳入212名参与者中的167名。
本仓库同时涵盖所有双变量分析（bivariate analysis）所用的数据与代码本。所有双变量分析均通过GraphPad Prism 6.0完成，但其分析结果未上传至本仓库（如需更多信息，请联系[e-mail]或[e-mail]）。
本仓库提供的所有数据均为清洗后的分析数据集，已填写问卷的原始纸质副本均已归档。
授权说明
本由Peter Kamerman与Antonia Wadley维护的"pain-sex-ethnicity"研究仓库采用知识共享署名4.0国际许可协议（Creative Commons Attribution 4.0 International License）进行授权。
研究概况
研究背景：性别与种族会影响疼痛敏感性及疼痛信念。然而目前有关性别、种族与疼痛之间关联的研究大多源自美国与欧洲地区。
研究目的：为明确性别与种族对疼痛敏感性及疼痛信念的影响，本研究对比了南非非洲血统与欧洲血统的男女青年的冷痛与压痛耐受性；同时探究社会心理因素（含疼痛信念）能否预测疼痛敏感性与疼痛信念在性别及种族层面的差异。
研究方法：本研究共招募106名非洲血统个体（女性62名，男性44名）与106名欧洲血统个体（女性55名，男性51名）。所有参与者均接受冷压试验（cold-pressor test）与压力测痛法（pressure algometry），以明确其对伤害性热刺激与机械刺激的耐受性。本研究同时评估了社会经济地位、疼痛灾难化思维（pain catastrophizing）、抑郁、焦虑及疼痛信念等指标，将其作为疼痛耐受性差异的预测因素。
研究结果：非洲血统个体的冷痛耐受性低于欧洲血统个体（两性均如此）；压痛耐受性则表现为女性低于男性（两种族均如此）。两项测试中，各分组的痛耐受阈值对应的疼痛强度均无显著差异。相较于女性，男性对男性表达疼痛的接受度更低，其中非洲血统男性的接受度最低。回归树分析（regression tree analysis）显示，非洲血统（尤其是非洲血统女性）可预测更低的冷痛耐受性。随机森林分析则识别出焦虑与资产持有量（作为社会经济地位的衡量指标）为冷痛耐受性预测的潜在相关变量，但二者的关联均处于临界显著性水平。回归树与随机森林分析均显示，女性性别是压痛耐受性唯一的显著预测因素，女性的压痛耐受性低于男性。回归树分析显示，性别与种族是APBQ-M量表得分的重要预测因素：女性的APBQ-M量表得分更高；在男性群体中，非洲血统者的APBQ-M量表得分显著低于欧洲血统者。随机森林分析则识别出抑郁与资产持有量为潜在相关变量。
研究结论：尽管本研究队列的文化与社会背景与美国及欧洲队列存在差异，但在非洲裔研究队列中，我们仍观察到冷、压痛刺激耐受性在性别与种族层面的差异模式与欧美队列一致。既往研究中用于预测疼痛敏感性的经典社会心理因素虽被识别为潜在相关变量，但与本研究观察到的差异并无强关联。