Predictors of pain tolerance and beliefs

<b>About</b>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><b>License</b>The 'pain-sex-ethnicity' respository by Peter Kamerman and Antonia Wadley is licensed under a Creative Commons Attribution 4.0 International License.<br><b>Overview of the study</b><i>Background: </i>Studies on relationships between sex, ethnicity and pain largely have emanated from the US and Europe. We compared cold (CPT) and pressure pain tolerance (PPT) in male and female South Africans of African and European ancestry and assessed whether psychosocial factors (including pain beliefs) predicted differences in pain tolerance. <br><i>Methods:</i> We recruited 106 (62 female) students of African ancestry and 106 (55 female) of European ancestry and subjected them to a cold-pressor test and pressure algometry. Socioeconomic status (SES), pain catastrophizing, depression, anxiety and pain beliefs were assessed as predictors of pain tolerance. <br><i>Results: </i>CPT was lower in students of African compared to European ancestry (for both sexes), and PPT was lower in female than male students (for both ethnicities). Females were very accepting of men expressing pain and males less so. Males of African ancestry were least accepting but still tolerant. Multivariate analysis identified African ancestry, and particularly being a female of African ancestry as strong predictors of lower CPT. Anxiety was a weak predict of CPT. Sex was the only strong predictor of PPT on multivariate analysis (PPT females &lt; males) and catastrophizing was a weak predictor . Female sex and African ancestry were strong predictors of acceptance of expression of pain in males. SES was a weak predictor of APBQ-M. <br><i>Conclusions: </i>Despite a different cultural and social background from US and European cohorts, we saw similar patterns of sex and ethnic differences in CPT and PPT in an African cohort. Traditional psychosocial predictors of pain sensitivity predicted variation in the outcome variables but were not strong predictors.<br>

### 关于本仓库
本仓库的核心内容包含针对南非健康黑人与白人青年群体的三项随机森林（random forest）分析所用的数据集、编码手册与分析脚本（附带关联的Markdown输出文件与可视化图表），分别用于分析冷痛耐受力（cold-pain tolerance, CPT）（对应文件：cold-pain-tolerance.Rmd、cold-pain-tolerance.md）、压力痛耐受力（pressure-pain tolerance, PPT）（对应文件：pressure-pain-tolerance.Rmd、pressure-pain-tolerance.md）以及男性疼痛行为接受度（APBQ-M）（对应文件：apbq-male.Rmd、apbq-male.md）。本次随机森林分析仅采用完整有效样本：冷痛与压力痛耐受力分析纳入156/212名受试者，男性疼痛行为接受度分析纳入167/212名受试者。

本仓库同时涵盖所有双变量分析（bivariate analyses）所用的数据集与编码手册。此类分析采用GraphPad Prism 6.0完成，但其分析结果并未上传至本仓库（如需获取更多信息，请联系[e-mail]或[e-mail]）。

本仓库提供的所有数据集均为经过清洗的分析用数据，原始填写完成的问卷纸质原件均已归档留存。

### 许可协议
本由Peter Kamerman与Antonia Wadley维护的`pain-sex-ethnicity`代码仓库，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
目前关于性别、种族与疼痛之间关联的研究大多源自美国与欧洲。本研究针对拥有非洲与欧洲血统的南非男女群体，比较其冷痛耐受力（CPT）与压力痛耐受力（PPT）的差异，并评估社会心理因素（包括疼痛信念）是否可预测疼痛耐受力的差异。

#### 研究方法
本研究共招募106名非洲血统学生（其中62名为女性）与106名欧洲血统学生（其中55名为女性），对所有受试者进行冷压试验（cold-pressor test）与压力测痛法（pressure algometry）检测。同时评估社会经济地位（socioeconomic status, SES）、疼痛灾难化思维（pain catastrophizing）、抑郁、焦虑以及疼痛信念作为疼痛耐受力的预测因子。

#### 研究结果
无论男女，非洲血统学生的冷痛耐受力均低于欧洲血统学生；而在两个血统群体中，女性学生的压力痛耐受力均低于男性学生。女性对男性表达疼痛的接受度较高，男性则相对较低。非洲血统男性对男性疼痛表达的接受度最低，但仍处于可接受范围。多变量分析（multivariate analysis）显示，非洲血统（尤其是非洲血统女性）是冷痛耐受力降低的强预测因子，焦虑为冷痛耐受力的弱预测因子。对于压力痛耐受力，性别是多变量分析中唯一的强预测因子（女性压力痛耐受力低于男性），疼痛灾难化思维为弱预测因子。女性性别与非洲血统是男性疼痛行为接受度的强预测因子，社会经济地位为APBQ-M的弱预测因子。

#### 研究结论
尽管本研究的受试群体与欧美队列拥有不同的文化与社会背景，但在非洲裔受试群体中，我们仍观察到与欧美队列一致的性别与种族差异模式，即冷痛耐受力与压力痛耐受力的性别、种族差异。以往用于预测疼痛敏感性的经典社会心理因素虽可解释结局变量的变异，但并非强有力的预测因子。