Genotoxic Evaluation of Mexican Welders Occupationally Exposed to Welding-Fumes Using the Micronucleus Test on Exfoliated Oral Mucosa Cells: Data set

<strong>Variables</strong> "case". Binary. Case exposed to welding fumes (1) or control (0) "age". Continuous. Participant's age in years. "bmi": Continuous. Body mass index (kg/m^2) "drink". Binary. Any level of alcohol consumption (1 positive, otherwise 0) "smoke". Binary. Any level of tobacco use (1 positive, 0 otherwise) "amalgam". Binary. Presence or absence of dental crowns (1 presence, 0 absence) "exp.years". Continuous. Number of years of exposure to welding-fumes. (0 for controls) "micronuclei". Discrete. Number of micronucleated cells per 2000 cells "binucleated". Discrete. Number of binucleated cells per 2000 cells "lobulated". Discrete. Number of lobed-nuclei cells per 2000 cells "pyknotic". Discrete. Number of pyknotic cells per 2000 cells "condensed". Discrete. Number of condensed-chromatin cells per 2000 cells "karyorrhexis"Discrete. Number of karyorrhectic cells per 2000 cells "karyolysis". Discrete. Number of karyolytic cells per 2000 cells Data set of n = 39 (20 welders and 19 controls). We obtained exfoliated epithelial cells from the participants' buccal mucosa by smearing the inside lining of the subjects' cheeks with a moistened wooden tongue-depressor. The smears were directly transferred to slides, and dried at room temperature. Afterwards, they were fixed in an 80% ethanol solution during 48 hours, and stained with acridine orange. An experienced reader, blind to the group to which samples belonged, observed the slides under 100x optic amplification with a Carl Zeiss IVFL Axiostar Plus microscope equipped with 450-490 nm fluorescence filters. Using the HUMNxl scoring criteria, she identified and counted the number of MNi and NA occurrences per 2000 observed cells per slide. The very low presence of women in the workforce of the welding industry in Mexico made impossible for us to find female welders, therefore all of the participants were male. Data are overdispersed and most variables do not follow a normal distribution. Use the `describe` function of the `psych` R package for descriptive statistics.

**变量说明**
- `case`：二分类变量，赋值1代表暴露于焊接烟尘的病例组，赋值0代表对照组。
- `age`：连续型变量，以年为单位的受试者年龄。
- `bmi`：连续型变量，体质量指数（单位：kg/m²）。
- `drink`：二分类变量，赋值1代表存在任何水平的酒精摄入，否则为0。
- `smoke`：二分类变量，赋值1代表存在任何水平的烟草使用，否则为0。
- `amalgam`：二分类变量，赋值1代表存在牙科汞合金冠，否则为0。
- `exp.years`：连续型变量，焊接烟尘暴露年限，对照组赋值为0。
- `micronuclei`：离散型变量，每2000个细胞中的微核细胞数量。
- `binucleated`：离散型变量，每2000个细胞中的双核细胞数量。
- `lobulated`：离散型变量，每2000个细胞中的分叶核细胞数量。
- `pyknotic`：离散型变量，每2000个细胞中的固缩核细胞数量。
- `condensed`：离散型变量，每2000个细胞中的染色质浓缩细胞数量。
- `karyorrhexis`：离散型变量，每2000个细胞中的核碎裂细胞数量。
- `karyolysis`：离散型变量，每2000个细胞中的核溶解细胞数量。

本数据集共纳入39名受试者，其中20名为焊工，19名为对照。本研究团队使用湿润的木质压舌板擦拭受试者颊黏膜内壁，采集脱落的上皮细胞，将样本直接涂布于载玻片后于室温晾干。随后将载玻片置于80%乙醇溶液中固定48小时，采用吖啶橙进行染色。由一名对样本分组不知情的经验丰富的阅片者，使用配备450-490nm荧光滤片的卡尔蔡司IVFL Axiostar Plus显微镜以100倍光学放大倍数观察载玻片。依据HUMNxl评分标准，该研究者计数每张载玻片每2000个观察细胞中的微核（MNi）及核异常（NA）细胞数量。

由于墨西哥焊接行业劳动力中女性占比极低，研究团队未能招募到女性焊工，因此所有受试者均为男性。本数据集存在过度离散现象，多数变量不服从正态分布，描述性统计可使用R语言`psych`包中的`describe`函数进行计算。