Research Of Epidemiological Characteristics Of Subjective Lactose Intolerance And Correlation Between Subjictive Lactose Intolerance And Functional Bowel Disorders In Hangzhou Residents

Background:Lactose is a carbohydrate found in milk, and lactose powder is used in a variety of roles by the food industry. Lactase deficiency (LD) is a condition in which the small intestine cannot digest this carbohydrate due to absent or insufficient amounts of lactase. The subjects are defined as having subjective lactose intolerance (SLI) if they report the abdominal cramps, bloating and diarrhea after ingesting of milk or other dairy products. LD is the leading cause for SLI. However the response is variable. Some tolerate moderate amounts of lactose without adverse effects. LD affects the majority of Chinese. Besides LD, other factors such as visceral hypersensitivity, intestinal motility, psychological factors, orocecal Transit Time, colonic flora changes also affect the gastrointestinal symptoms. Functional bowel disorders(FBDs)are common disorders that are characterized by various combinations of abdominal pain and/or discomfort, bloating and changes in bowel habits. FBDs are a result of complex interactions between biological, psychological, and social factors. The classification of FBDs is based on clinical symptoms. In accordance with ROMEâ…¢criteria it can be divided into functional constipation(FC), irritable bowel syndrome(IBS), functional diarrhea (FD), functional bloating(FB) and unspecific functional bowel disorders(UFBD). The relationship between SLI and symptomatic subtypes of FBDs is controversial.Aim:To investigate epidemiological characteristics of SLI and correlation between SLI and FBDs in Hangzhou residentsMethods:The research was done from September,2008 to June,2010. We picked up five of the six urban areas where a permanent of a community(residence for at least one year) were interviewed face-to-face by using a questionnaire survey which included basic information, gastrointestinal symptom questionnaire, life events scale, hospital allxiety and depression scale, dairy food intake. All datas were applied SPSS 16.0 software package, p<0.05 for the difference was considered as statistical significance.Results:1930 subjects fully completed the questionnaire. The prevalence of SLI was 19.7%.The differences of sex, age, education, career, income, smoking and alcohol between the SLI group and Non-SLI group were not statistical significant (p<0.05). The score of anxiety, depression and Life Events were higher in SLI group than in Non-SLI group(p value was 0.001, 0.001, 0.001 respectively).The prevalence of SLI were higher in IBS group(x2=28.518, p=<0.001).The prevalence of SLI was 44.3% in IBS-D group,19.0% in IBS-C group,41.4% in IBS-M group,29.2% in IBS-U group. The prevalences of SLI in people with IBS,FD,FC,FB,UFBD were 37.0%,35.5%,24.3%,30.1%,20.3%respectively, which were higher than that in Non-FBDs group (p<0.01). Conclusions:The results of our research indicated the high prevalence of SLI in Hangzhou residents. Psychological factors might play a role in SLI. IBS,FD,FC,FB,UFBDs might relate to SLI.