Perception of lactose intolerance impairs health-related quality of life.

BACKGROUND/OBJECTIVES: Chronic conditions impair perception of well-being. Malabsorption of lactose is the most frequent form of malabsorption and manifests as lactose intolerance. There is a lack of information regarding their impact on self-perception of health. The objective of this study is to determine the subjective impact of self-reported lactose intolerance or objective lactose malabsorption on patient health by using a patient-reported outcome to measure health-related quality of life (HRQOL) and modification of lactose-containing food diet. SUBJECTS/METHODS: A 3-year prospective, cross-sectional study was performed in patients referred for a lactose hydrogen breath test. Patients were asked about their subjective opinion relative to their lactose tolerance and completed a validated, specific questionnaire to determine symptoms of intolerance during habitual consumption of dairy. A 50-g lactose breath test was then performed. Patients were grouped as absorbers vs malabsorbers and tolerant vs intolerants. RESULTS: A total of 580 patients were included (median age 30 years, 419 female). Overall, 324 patients (56%) considered themselves lactose intolerant and that perception was associated with avoidance of dairy consumption (55% vs only 9% of self-defined tolerants). Self-perception of intolerance was associated with lower HRQOL scores (median, 60 vs 70, P<0.01). In contrast, lactose objective malabsorption was not clearly associated with dairy avoidance (41% of malabsorbers avoided dairy vs 31% of absorbers). However, HRQOL scores were also significantly lower in malabsorbers than in absorbers (60 vs 70 respectively, P<0.001). CONCLUSIONS: Subjective perception of lactose intolerance affects the decision to avoid dairy even more than objective malabsorption. However, both self-perception of lactose intolerance and objective lactose malabsorption are associated with poorer perceived quality of life.

Influence of colectomy on hydrogen excretion in breath.

INTRODUCTION: Hydrogen breath test is the most commonly used method to analyze carbohydrate absorption and diagnose carbohydrate malabsorption. The result of the H(2) breath test is influenced by different factors, which are mostly related to quantitative or qualitative aspects of colonic flora. A scarcely studied variable is the effect of colonic anatomical integrity on H(2) excretion in breath. PURPOSE: The present study aims to determine whether loss of colonic integrity reduces H(2) excretion capacity after an oral load of an unabsorbable carbohydrate. METHODS: An observational study was conducted in three patient groups: controls with preserved colon, patients with partial colectomy, and patients with complete colectomy and ileostomy. H(2) concentration in breath was measured by gas chromatography every 10 min for 3 h after oral lactulose administration. RESULTS: Twenty-two patients with partial colectomy, 18 controls with preserved colon, and seven patients with ileostomy were included. H(2) excretion after lactulose did not differ between patients with partial colectomy and controls (basal excretion = 8.5 vs 4 ppm; delta increase = 50.0 vs 47.5 ppm; area under the curve = 4,480.0 vs 4,710.5 ppm/min). In contrast, H(2) excretion was significantly lower in the ileostomy group. CONCLUSIONS: Partial colectomy does not influence the capacity for H(2) excretion after oral unabsorbable carbohydrate administration.

Development, validation, and applicability of a symptoms questionnaire for lactose malabsorption screening.

UNLABELLED: Lactase deficiency has a high prevalence worldwide. Thus, a valid symptom scale would be a useful tool for identifying patients with lactose malabsorption. OBJECTIVE: To develop, validate, and apply a symptoms questionnaire on lactose malabsorption to identify lactose malabsorbers diagnosed with the gold-standard hydrogen breath test. METHODS: In the first part of the study, 292 patients completed a questionnaire at the end of a 50-g lactose breath test. The questionnaire included five items (diarrhea, abdominal cramping, vomiting, audible bowel sounds, and flatulence or gas) scored on a 10-cm visual analogue scale. In the second part of the study, 171 patients completed the questionnaire twice: first, according to their opinion when consuming dairy products at home and second, after a 50-g lactose breath test. Patients were grouped as absorbers or malabsorbers according to the result of the breath test. RESULTS: Diarrhea, abdominal cramping, and flatulence were scored significantly higher in malabsorbers than in absorbers. Total score of the symptomatic questionnaire was significantly higher in malabsorbers (17.5 versus 3.0, P<0.01). According to receiver operator characteristics (ROC) analysis, the most discriminant cut-off of the total score to identify lactose malabsorption was 6.5 (sensitivity 0.75, specificity 0.67). In 58 malabsorbers the effect size of the questionnaire to determine sensitivity to change was 1.32. In the second part of the study, scoring of the home questionnaire was higher than after the lactose-breath test. The lactose malabsorbers rate was higher according to the home questionnaire than after the lactose breath test (72% versus 52%). The home questionnaire had excellent sensitivity (0.82) but low specificity (0.35). CONCLUSION: We developed and validated a five-item symptoms questionnaire for lactose malabsorption. This is a valid test that permits patients with a total score lower than 7 to be excluded from future studies.