Evidence Report/Technology Assessment Number 192 Lactose Intolerance and Health Prepared for: Agency for Healthcare Research and Quality U.S. Department of Health and Human Services 540 Gaither Road Rockville, MD 20850 www.ahrq.gov Contract No. HHSA 290-2007-10064-I Prepared by: Minnesota Evidence-based Practice Center, Minneapolis, MN Investigators Timothy J. Wilt, M.D., M.P.H. Aasma Shaukat, M.D., M.P.H. Tatyana Shamliyan, M.D., M.S. Brent C. Taylor, Ph.D., M.P.H. Roderick MacDonald, M.S. James Tacklind, B.S. Indulis Rutks, B.S. Sarah Jane Schwarzenberg, M.D. Robert L. Kane, M.D. Michael Levitt, M.D. AHRQ Publication No. 10-E004 February 2010 This report is based on research conducted by the Minnesota Evidence-based Practice Center (EPC) under contract to the Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Contract No. HHSA 290-2007-10064-I). The findings and conclusions in this document are those of the authors, who are responsible for its content, and do not necessarily represent the views of AHRQ. No statement in this report should be construed as an official position of AHRQ or of the U.S. Department of Health and Human Services. The information in this report is intended to help clinicians, employers, policymakers, and others make informed decisions about the provision of health care services. This report is intended as a reference and not as a substitute for clinical judgment. This report may be used, in whole or in part, as the basis for the development of clinical practice guidelines and other quality enhancement tools, or as a basis for reimbursement and coverage policies. AHRQ or U.S. Department of Health and Human Services endorsement of such derivative products may not be stated or implied. This document is in the public domain and may be used and reprinted without permission except those copyrighted materials noted for which further reproduction is prohibited without the specific permission of copyright holders. Suggested Citation: Wilt TJ, Shaukat A, Shamliyan T, Taylor BC, MacDonald R, Tacklind J, Rutks I, Schwarzenberg SJ, Kane RL, and Levitt M. Lactose Intolerance and Health. No. 192 (Prepared by the Minnesota Evidence-based Practice Center under Contract No. HHSA 290-2007-10064-I.) AHRQ Publication No. 10-E004. Rockville, MD. Agency for Healthcare Research and Quality. February 2010. No investigators have any affiliations or financial involvement (e.g., employment, consultancies, honoraria, stock options, expert testimony, grants or patents received or pending, or royalties) that conflict with material presented in this report. ii Preface The Agency for Healthcare Research and Quality (AHRQ), through its Evidence-Based Practice Centers (EPCs), sponsors the development of evidence reports and technology assessments to assist public- and private-sector organizations in their efforts to improve the quality of health care in the United States. This report was requested by the Office of Medical Applications of Research (OMAR) at the National Institutes of Health (NIH). The reports and assessments provide organizations with comprehensive, science-based information on common, costly medical conditions, and new health care technologies. The EPCs systematically review the relevant scientific literature on topics assigned to them by AHRQ and conduct additional analyses when appropriate prior to developing their reports and assessments. To bring the broadest range of experts into the development of evidence reports and health technology assessments, AHRQ encourages the EPCs to form partnerships and enter into collaborations with other medical and research organizations. The EPCs work with these partner organizations to ensure that the evidence reports and technology assessments they produce will become building blocks for health care quality improvement projects throughout the Nation. The reports undergo peer review prior to their release. AHRQ expects that the EPC evidence reports and technology assessments will inform individual health plans, providers, and purchasers as well as the health care system as a whole by providing important information to help improve health care quality. We welcome written comments on this evidence report. They may be sent to the Task Order Officer named below at: Agency for Healthcare Research and Quality, 540 Gaither Road, Rockville, MD 20850, or by email to [email protected]. Carolyn M. Clancy, M.D. Jean Slutsky, P.A., M.S.P.H. Director Director, Center for Outcomes and Evidence Agency for Healthcare Research and Quality Agency for Healthcare Research and Quality Beth A. Collins Sharp, R.N., Ph.D. Stephanie Chang, M.D., M.P.H. Director, EPC Program EPC Program Task Order Officer Agency for Healthcare Research and Quality Agency for Healthcare Research and Quality Jennifer Croswell, M.D., M.P.H. Susanne Olkkola, M.Ed., M.P.A. Acting Director Senior Advisor, Consensus Development Program Consensus Development Program Office of Medical Applications of Research Office of Medical Applications of Research National Institutes of Health National Institutes of Health iii Acknowledgments We wish to thank the librarian, Judith Stanke, for her contributions to the literature search, Marilyn Eells for her outstanding work in the preparation and text editing of this report; Stephanie Chang, M.D., AHRQ Task Order Officer, for her patience and guidance; our Technical Expert Panel members for their helpful recommendations, and the reviewers for their comments and suggestions. iv Structured Abstract Objectives: We systematically reviewed evidence to determine lactose intolerance (LI) prevalence, bone health after dairy-exclusion diets, tolerable dose of lactose in subjects with diagnosed LI, and management. Data Sources: We searched multiple electronic databases for original studies published in English from 1967-November 2009. Review Methods: We extracted patient and study characteristics using author’s definitions of LI and lactose malabsorption. We compared outcomes in relation to diagnostic tests, including lactose challenge, intestinal biopsies of lactase enzyme levels, genetic tests, and symptoms. Fractures, bone mineral content (BMC) and bone mineral density (BMD) were compared in categories of lactose intake. Reported symptoms, lactose dose and formulation, timing of lactose ingestion, and co-ingested food were analyzed in association with tolerability of lactose. Symptoms were compared after administration of probiotics, enzyme replacements, lactose- reduced milk and increasing lactose load. Results: Prevalence was reported in 54 primarily nonpopulation based studies (15 from the United States). Studies did not directly assess LI and subjects were highly selected. LI magnitude was very low in children and remained low into adulthood among individuals of Northern European descent. For African American, Hispanic, Asian, and American Indian populations LI rates may be 50 percent higher in late childhood and adulthood. Small doses of lactose were well tolerated in most populations. Low level evidence from 55 observational studies of 223,336 subjects indicated that low milk consumers may have increased fracture risk. Strength and significance varied depended on exposure definitions. Low level evidence from randomized controlled trials (RCTs) of children (seven RCTs) and adult women (two RCTs) with low lactose intake indicated that dairy interventions may improve BMC in select populations. Most individuals with LI can tolerate up to 12 grams of lactose, though symptoms became more prominent at doses above 12 grams and appreciable after 24 grams of lactose; 50 grams induced symptoms in the vast majority. A daily divided dose of 24 grams was generally tolerated. We found insufficient evidence that use of lactose reduced solution/milk, with lactose content of 0-2 grams, compared to a lactose dose of greater than 12 grams, reduced symptoms of lactose intolerance. Evidence was insufficient for probiotics (eight RCTs), colonic adaptation (two RCTs) or varying lactose doses (three RCTs) or other agents (one RCT). Inclusion criteria, interventions, and outcomes were variable. Yogurt and probiotic types studied were variable and results either showed no difference in symptom scores or small differences in symptoms that may be of low clinical relevance. Conclusions: There are race and age differences in LI prevalence. Evidence is insufficient to accurately assess U.S. population prevalence of LI. Children with low lactose intake may have beneficial bone outcomes from dairy interventions. There was evidence that most individuals with presumed LI or LM can tolerate 12-15 grams of lactose (approximately 1 cup of milk). There was insufficient evidence regarding effectiveness for all evaluated agents. Additional research is needed to determine LI treatment effectiveness. v Contents Executive Summary.......................................................................................................................1 Evidence Report.........................................................................................................................17 Chapter 1. Introduction ...............................................................................................................19 Lactase Deficiency.................................................................................................................20 Lactose Malabsorption...........................................................................................................21 Lactose Intolerance ................................................................................................................21