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Aim: To validate 4-sample lactose hydrogen breath testing (4SLHBT) compared to standard 13-sample LHBT in the clinical setting., Methods: Irritable bowel syndrome patients with diarrhea (IBS-D) and healthy volunteers (HVs) were enrolled and received a 10 g, 20 g, or 40 g dose lactose hydrogen breath test (LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h (13 measurements). The detection rates of lactose malabsorption (LM) and lactose intolerance (LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT., Results: Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups (P < 0.001). 4SLHBT showed excellent diagnostic concordance with standard LHBT (97%-100%, Kappa​​ 0.815-0.942) with high sensitivity (90%-100%) and specificity (100%) at all three lactose doses in both groups., Conclusion: Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.

Lactose absorption capacity was examined in 641 apparently healthy adolescents and adults (447 males and 194 females with an average age of 22.9 years and an age range of 16-46 years) using a field version of the lactose tolerance test with breath hydrogen determination. In the total sample, 89 lactose absorbers and 552 lactose malabsorbers were identified. Lactose malabsorption was most frequent in a subgroup of Han (Chinese) from northeastern China (229 of 248 subjects, 92.3%). Among 198 Mongols from Inner Mongolia, there were 174 lactose malabsorbers (87.9%). The frequency of lactose malabsorption was lowest in a group of Kazakhs, traditional herders from the northwestern region of Xinjiang (149 of 195 subjects, 76.4%). Reported symptoms of lactose intolerance were significantly more frequent in lactose malabsorbers. The findings in northern Han are similar to the reported lactose malabsorption frequency in southern (mainly overseas) Chinese, and correspond with the absence of animal milk from traditional Chinese diets. The relatively low prevalence of lactose malabsorption among the Kazakhs suggests that lactose persistence may be frequent in herding pastoralist populations of southwest Asia.

A total of 852 healthy Chinese children from 1 month to 14 years of age were investigated for lactose malabsorption using the breath hydrogen test. A lactose load of 2 g/kg was administered to 528 children and 1 g/kg to another 324 children. The incidence of lactose malabsorption was significantly different among various age groups and between the two different lactose dosages. While the incidence of malabsorption increased strikingly from the age of 3 to the age of 5 years, the age effect remained constant after the age of 6 years. The lactose load of 2 g/kg induced a higher incidence of malabsorption in study subjects than 1 g/kg did, and the dose effect increased for those aged below 5 years and decreased above 5 years. Small-intestinal lactase was also studied in 34 children aged from 2 months to 15 years. The lactase activity was highest in children 2 years old or younger, gradually decreasing with increasing age. In conclusion, lactase activity in Chinese children decreases gradually after 3 years of age, a finding that correlates well with the results of the breath hydrogen test.

Background: This study aimed to identify the specific areas of knowledge gaps regarding lactose intolerance among neonatologists in Chinese outpatient settings as well as to assess the availability of lactose intolerance testing in hospitals. Methods: A total of 278 neonatologists in outpatient settings from 144 hospitals were surveyed. To explore the awareness level, diagnosis, and treatment of neonatal lactose intolerance among neonatologists in outpatient settings, a multicenter cross-sectional survey was designed. Descriptive analysis based on frequency and percent distribution was performed for all variables. Results: Most respondents were senior doctors (256, 92.09%) from general hospitals and maternity/maternal and child health hospitals, had over 10 years of experience, and were dominantly associate chief physicians and chief physicians (211, 75.90%). A significant proportion of the participants (236, 84.89%) believed that neonatal lactose intolerance tends to be overlooked during clinical practice. When the most common symptoms of neonatal lactose intolerance were surveyed, diarrhea was selected by 142 (51.08%) respondents, followed by bloating and milk regurgitation or emesis (71, 25.54%). Other symptoms included unexplained crying (36, 12.85%), stool with milk flap or foam (15, 5.40%), and increased venting (14, 5.04%). Furthermore, the survey results indicated that the most common method for diagnosing neonatal lactose intolerance in the respondents' hospitals was qualitative test for urinary galactose (78, 28.06%). Of the respondents, 137 (49.28%) stated that their hospital could not test for lactose intolerance. For treating lactose intolerance, the neonatologists primarily opted for exogenous lactase rather than lactose-free formula milk. Conclusions: This study sheds light on Chinese neonatologists' awareness of neonatal lactose intolerance, revealing some knowledge gaps. The expeditious popularization and conduct of lactose intolerance-related examinations in hospitals will have a positive stimulative effect on the management of lactose intolerance in newborns. [ABSTRACT FROM AUTHOR]

Lactose malabsorption was investigated in 169 Chinese children aged between two and 16 years using the breath hydrogen test. The challenge was either lactose solution (1 g/kg) or cow's milk (10 ml/kg). Overall, 68% of the children showed a significant increase in breath hydrogen following the lactose challenge while only 17% showed an increase after the cow's milk challenge and 13% after both challenges. The number of malabsorbers increased significantly (p less than 0.001) with age and no associated gastrointestinal symptoms or signs were found in any of the children following the challenges, suggesting a gradual and partial loss of intestinal lactase activity. We conclude that the prevalence of lactose malabsorption in Hong Kong children is very high using the standard lactose tolerance test but when a more realistic amount of lactose and a natural medium such as a glass of milk is used as the challenge, the number of malabsorbers becomes small and clinically insignificant.

Background. Nontyphoidal Salmonella infection is a common cause for acute bacterial gastroenteritis in children in China. There have been no reports of the prevalence of lactose intolerance or food allergies in children with nontyphoidal Salmonella infection. The aim of this study was to characterize nontyphoidal Salmonella gastroenteritis in a tertiary children’s hospital and evaluate clinical presentation, lactose intolerance, and food allergies in children with prolonged nontyphoidal Salmonella gastroenteritis. Methods. A retrospective case-series analysis was carried out in a tertiary children’s hospital in Guangzhou, China. We included all infants and children who were diagnosed with nontyphoidal Salmonella gastroenteritis between 1 January 2014 and 31 December 2016. Patients’ clinical features, feeding patterns, laboratory tests, and treatment outcomes were reviewed. Results. A total of 142 infants and children were diagnosed with nontyphoidal Salmonella gastroenteritis. 52.1% of cases occurred in infants ≤ 12 months of age and the majority (89.4%) in children younger than 3 years old. The most common symptoms were diarrhea (100%), fever (62%), and vomiting (18.3%). Salmonella Typhimurium was the predominant serotype, accounting for 82.4%. 91.5% of patients were treated with antibiotics. Forty-one (28.9%) and 9 (6.3%) children improved with a lactose-free diet and hypoallergenic formula, respectively, when diarrhea persisted for more than a week. Conclusions. Salmonella Typhimurium was the predominant serotype. Most patients with nontyphoidal Salmonella gastroenteritis were younger than 3 years old. Lactose intolerance occurred frequently in children with nontyphoidal Salmonella gastroenteritis and dietary modification should be considered when diarrhea is persistent and prolonged. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the reasons for the Chinese's aversion to milk. Several topics are also discussed in the article including the definition of hypolactasia and lactose absorption, the emergence of adult lactose absorbers, and the barrier to the adoption of milk and dairy products in the Chinese diet. It mentions that the occurrence of hypolactasia is genetically controlled. In any abundant prehistoric population there would have been a few individuals who, through mutation or inheritance, had retained the ability to digest lactose as adults.