Lipid_Accumulation_Gallstone_Risk_NHANES_datasets_and_variables_description.zip

Data for this study were derived from the National Health and Nutrition Examination Survey (NHANES) 2017–2020 cycle. The dataset includes original variables extracted from NHANES, processed variables, and the final variables selected for analysis. Participants were asked about their history of gallstones, resulting in an initial enrollment of 15,560 individuals. After applying inclusion and exclusion criteria, 3,294 participants were included in the final analysis.Gallstones were identified through the question, "Has a doctor ever told you that you have gallstones?"Anthropometric MeasuresAnthropometric measures, including waist circumference (WC) measured in centimeters and body mass index (BMI), were obtained by trained technicians at mobile examination centers. LAP was calculated using WC and triglyceride (TG) levels. Weight status was categorized into < 25.0 kg/m², 25.0–29.9 kg/m², and ≥ 30.0 kg/m².Covariates Included:Demographic Variables: Age (years, categorized into 20–39, 40–59, and ≥ 60), sex (male, female), and race (Non-Hispanic White, Non-Hispanic Black, other).Education: Classified as less than college or college and above.Alcohol Intake: Defined based on questionnaire responses regarding the frequency and quantity of alcohol consumption.Leisure Time Physical Activity: Measured in minutes and MET (Metabolic Equivalent of Task).Chronic Conditions: Including diabetes (defined by HbA1c levels or self-reported diagnosis) and hypertension (defined by blood pressure readings or self-reported diagnosis).Medication Use: Including cholesterol-lowering and triglyceride-lowering medications (yes/no).Dietary Variables: Total omega-3 fatty acid intake (TotalOmega) was calculated by summing three specific dietary variables: DR1TP205, DR1TP225, and DR1TP226, which represent different sources of omega-3 fatty acids. Other dietary variables were directly obtained from NHANES original datasets. To reduce the impact of multicollinearity, total energy intake, total dietary fiber intake, and total monounsaturated fatty acid intake were standardized using Z-score normalization (mean = 0, standard deviation = 1) and subsequently transformed into two principal components (PC1 and PC2) through principal component analysis (PCA).A detailed variable description document is provided alongside the dataset.Statistical AnalysisTo address the non-normal distribution of LAP and BMI, log transformations were performed: Ln-LAP was calculated using the formula ln⁡(LAP+0.8532+1)ln(LAP+0.8532+1) and Ln-BMI was calculated using the natural logarithm of BMI. Statistical analyses were performed using R version 4.4.0, employing appropriate sampling weights and conducting multivariable regression models to evaluate the association between LAP and gallstone risk.

本研究的数据来源于2017-2020周期的美国国家健康与营养调查（National Health and Nutrition Examination Survey, NHANES）。该数据集包含从NHANES提取的原始变量、经预处理的变量以及最终用于分析的筛选变量。
研究对象被问及胆结石患病史，初始招募15560名个体。经纳入与排除标准筛选后，最终有3294名参与者纳入本研究分析。胆结石的判定依据问卷问题：「医生是否曾告知你患有胆结石？」

人体测量学指标
人体测量指标包括以厘米为单位的腰围（waist circumference, WC）与身体质量指数（body mass index, BMI），由经过培训的技术人员在移动检查中心完成测量。脂质蓄积指数（Lipid Accumulation Product, LAP）通过腰围与甘油三酯（triglyceride, TG）水平计算得到。体重状态被划分为<25.0 kg/m²、25.0~29.9 kg/m²及≥30.0 kg/m²三个类别。

纳入协变量
1. 人口统计学变量：年龄（以岁为单位，划分为20~39岁、40~59岁及≥60岁三组）、性别（男、女）及种族（非西班牙裔白人、非西班牙裔黑人、其他）。
2. 教育程度：分为大学以下与大学及以上两类。
3. 饮酒情况：基于问卷中关于饮酒频率与饮酒量的应答进行定义。
4. 闲暇时间体力活动：以分钟数与代谢当量（Metabolic Equivalent of Task, MET）进行衡量。
5. 慢性疾病：包括糖尿病（依据糖化血红蛋白（HbA1c）水平或自我报告的确诊情况定义）与高血压（依据血压测量值或自我报告的确诊情况定义）。
6. 药物使用情况：包括降胆固醇与降甘油三酯药物使用情况（是/否）。
7. 膳食变量：总ω-3脂肪酸摄入量（TotalOmega）通过汇总三个特定膳食变量DR1TP205、DR1TP225与DR1TP226计算得到，上述变量代表不同来源的ω-3脂肪酸。其余膳食变量直接取自NHANES原始数据集。为降低多重共线性的影响，对总能量摄入量、总膳食纤维摄入量及总单不饱和脂肪酸摄入量进行Z分数标准化（均值=0，标准差=1），随后通过主成分分析（principal component analysis, PCA）转化为两个主成分（PC1与PC2）。

本数据集附带详细的变量说明文档。

统计分析
针对LAP与BMI的非正态分布特征，本研究对其进行对数变换：Ln-LAP采用公式ln(LAP + 0.8532 + 1)计算，Ln-BMI采用BMI的自然对数进行计算。统计分析使用R 4.4.0版本完成，采用合适的抽样权重，并构建多变量回归模型以评估LAP与胆结石患病风险之间的关联。