Characteristics of 8,014 twin study participants with and without gastroesophageal reflux disease (GERD).

aPearson’s chi-square test estimating the associations between GERD and sex, age, education, body mass index and tobacco smoking separately.采用皮尔逊卡方检验（Pearson’s chi-square test）分别评估胃食管反流病（Gastroesophageal Reflux Disease, GERD）与性别、年龄、受教育程度、体质量指数以及吸烟行为之间的关联。