title: Zero-Inflated Models for Identifying Relationships Between Body Mass Index and Gastroesophageal Reflux Symptoms: A Nationwide Population-Based Study in China.
abstract: That obesity leads to gastroesophageal reflux is a widespread notion. However, scientific evidence for this association is limited, with no rigorous epidemiological approach conducted to address this question. This study examined the relationship between body mass index (BMI) and gastroesophageal reflux symptoms in a large population-representative sample from China.
  
  
  
  We performed a cross-sectional study in an age- and gender-stratified random sample of the population of five central regions in China. Participants aged 18-80 years completed a general information questionnaire and a Chinese version of the Reflux Disease Questionnaire. The zero-inflated Poisson regression model estimated the relationship between body mass index and gastroesophageal reflux symptoms.
  
  
  
  Overall, 16,091 (89.4 %) of the 18,000 eligible participants responded. 638 (3.97 %) and 1738 (10.81 %) experienced at least weekly heartburn and weekly acid regurgitation, respectively. After adjusting for potential risk factors in the zero-inflated part, the frequency [odds ratio (OR) 0.66, 95 % confidence interval (95 % CI) 0.50-0.86, p = 0.002] and severity (OR 0.66, 95 % CI 0.50-088, p = 0.004) of heartburn in obese participants were statistically significant compared to those in normal participants. In the Poisson part, the frequency of acid regurgitation, overweight (OR 1.10, 95 % CI 1.01-1.21, p = 0.038) and obesity (OR 1.19, 95 % CI 1.04-1.37, p = 0.013) were statistically significant. BMI was strongly and positively related to the frequency and severity of gastroesophageal reflux symptoms. Additionally, gender exerted strong specific effects on the relationship between BMI and gastroesophageal reflux symptoms.
  
  
  
  The severity and frequency of heartburn were positively correlated with obesity. This relationship was presented distinct in male participants only.
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Health Services Management, Second Military Medical University, Shanghai, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Zhang
authors.affiliation: General Office, Binzhou Central Hospital, Binzhou, China.
authors.forename: Ruijie
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China. horse_ma88@yeah.net.
authors.forename: Xiuqiang
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Health Statistics, Second Military Medical University, Shanghai, China. hejia63@yeah.net.
authors.forename: Jia
authors.initials: J
authors.lastname: He
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D050177:Overweight / Q000150:complications* / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult
keywords: Acid regurgitation; Body mass index; Gastroesophageal reflux symptoms; Heartburn