Prevalence of Lactose Intolerance in Chile: A Double-Blind Placebo Study

Abstract

Background and Study Aims: Lactase non-persistence (LNP), or primary hypolactasia, is a genetic condition that mediates lactose malabsorption and can cause lactose intolerance. Here we report the prevalence of lactose intolerance in a double-blind placebo study. Methods: The LCT C>T_-13910 variant was genotyped by RT-PCR in 121 volunteers and lactose malabsorption was assessed using the hydrogen breath test (HBT) after consuming 25 g of lactose. Lactose intolerance was assessed by scoring symptoms (SS) using a standardized questionnaire following challenge with a lactose solution or saccharose placebo. Results: The LNP genotype was observed in 57% of the volunteers, among whom 87% were HBT(+). In the HBT(+) group the median SS was 9 and in the HBT(-) group the median SS was 3 (p < 0.001). No difference was observed in the SS when both groups were challenged with the placebo. The most common symptoms included audible bowel sounds, abdominal pain and meteorism. In the ROC curve analysis, an SS ≥6 demonstrated 72% sensitivity and 81% specificity for predicting a positive HBT. To estimate prevalence, lactose intolerance was defined as the presence of an SS ≥6 points after subtracting the placebo effect and 34% of the study population met this definition. Conclusions: The LNP genotype was present in more than half of subjects evaluated and the observed prevalence of lactose intolerance was 34%.

The effects of the DDS-1 strain of lactobacillus on symptomatic relief for lactose intolerance - a randomized, double-blind, placebo-controlled, crossover clinical trial

“…The lactose challenge was used to determine eligibility during screening; subjects were included if they had a symptom score of 10 or more during an in-clinic lactose challenge test where lactose was dissolved in water and consumed. Lactose at 25 g per dose, which is equivalent to 480 ml of milk, was used in this study instead of the usual 50 g per dose for the lactose HBT [ 44 ] because it more closely reflects the average amount of milk consumed by the population [ 7 ].…”

Concordance between Lactose Quick Test, hydrogen‐methane breath test and genotyping for the diagnosis of lactose malabsorption in children

“…In our study, 35% of patients had LP‐related genotype. In Chile, several publications have shown a prevalence of LP‐related genotype in general population between 40% and 57%, and only 10% in Chilean Amerindian population, being the C>T ‐13910 SNP the main determinant of LP/LNP in our population . The usefulness of the genetic test for determination of the LP/LNP phenotype has the main difficulty that concordance between genetics and phenotype depends on age.…”

Blinded Oral Challenges with Lactose and Placebo Accurately Diagnose Lactose Intolerance: A Real-Life Study

“…Blinded testing could represent the ideal method for unmasking the correlation between self-reported symptoms of LI and the objective findings of lactose malabsorption in clinical practice. However, until now, only one study analyzed the prevalence of LI in a young, healthy cohort of subjects using this approach [ 10 ].…”