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Guideline Summary
Guideline Title
NIH Consensus Development Conference statement on lactose intolerance and health.
Bibliographic Source(s)
Suchy FJ, Brannon PM, Carpenter TO, Fernandez JR, Gilsanz V, Gould JB, Hui SL, Lupton JR, Mennella J, Miller NJ, Osganian SK, Sellmeyer DE, Wolf MA. NIH Consensus Development Conference Statement on lactose intolerance and health. NIH Consens State Sci Statements. 2010 Feb 22-24;27(2):1-27. PubMed External Web Site Policy
Guideline Status

This is the current release of the guideline.

Scope

Disease/Condition(s)
  • Lactose intolerance
  • Lactose malabsorption

Note: Lactose intolerance is defined as the onset of gastrointestinal symptoms (diarrhea, abdominal pain, flatulence, and/or bloating) following a blinded, single-dose challenge of ingested lactose by an individual with lactose malabsorption, which are not observed when the person ingests an indistinguishable placebo.

Guideline Category
Counseling
Management
Clinical Specialty
Family Practice
Gastroenterology
Internal Medicine
Nutrition
Pediatrics
Intended Users
Advanced Practice Nurses
Dietitians
Nurses
Patients
Physician Assistants
Physicians
Public Health Departments
Guideline Objective(s)

To provide healthcare providers, patients, and the general public with a responsible assessment of currently available data on lactose intolerance and health

Target Population

Children (4 years of age and older), adolescents, and adults with symptoms of lactose malabsorption and/or lactose intolerance (LI)

Note: The guideline developers included observations that examined prevalence, symptoms, and outcomes of LI in different age, gender, racial, and ethnic groups. They excluded populations with other gastrointestinal disorders, including individuals diagnosed with irritable bowel syndrome (IBS), inflammatory or infectious bowel diseases, or milk allergies. They excluded children younger than 4 years of age.

Interventions and Practices Considered

Management

  1. Evidence-based dietary approaches with and without dairy foods and supplementation strategies that ensure adequate consumption of calcium and vitamin D
  2. Educational programs and behavioral approaches
Major Outcomes Considered
  • Prevalence of lactose intolerance (LI)
  • Adverse health outcomes of dairy exclusion, including fracture and osteoporosis
  • Gastrointestinal symptoms
  • Disease specific and overall quality of life

Methodology

Methods Used to Collect/Select the Evidence
Searches of Electronic Databases
Description of Methods Used to Collect/Select the Evidence

Note from the National Guideline Clearinghouse (NGC): A systematic review of the literature was prepared by the Minnesota Evidence-based Practice Center (EPC) for the Agency for Healthcare Research and Quality (AHRQ) for use by the National Institutes of Health (NIH) (see the "Availability of Companion Documents" field).

Methods

The guideline developers searched several databases including MEDLINE® via PubMed® and via Ovid, the Cochrane Library of randomized controlled clinical trials, BIOSIS Previews®, Biological Abstracts®, Global Health, Food Science and Technology Abstracts®, and Commonwealth Agricultural Bureau International databases, to find studies published in English between 1967 and November 2009. They included observations that examined prevalence, symptoms, and outcomes of lactose intolerance (LI) in different age, gender, racial, and ethnic groups. They excluded populations with other gastrointestinal disorders, including individuals diagnosed with irritable bowel syndrome (IBS), inflammatory or infectious bowel diseases, or milk allergies. They excluded children younger than 4 years of age.

General Inclusion Criteria

The guideline developers included original observational studies that examined prevalence, symptoms, and outcomes in different age, gender, racial, and ethnic groups; published in the English language; randomized controlled clinical trials (RCTs) that examined different treatment options or doses of lactose loads in patients with LI or lactose malabsorption (LM); and large observational studies in individuals with LI, LM, lactase nonpersistence, or reduced dairy intake that performed at least one strategy to reduce bias. The search was limited to studies published from 1967 to November 2009. The EPC staff excluded studies that were published in non English languages and small case reports or descriptive case series with less than 100 subjects unless there are no reliable data from other higher quality studies. Because this report is to be used for a U.S. NIH Consensus Conference report, U.S. based population studies were emphasized. Refer to the Evidence Report (see the "Availability of Companion Documents" field) for additional information.

Number of Source Documents

Included Studies: n = 160 references*

  • Question (Q) 1 (prevalence) = 54 references
  • Q 2 (outcomes) = 67 references
  • Q 3 (daily intake) = 28 references
  • Q 4 (management) = 40 references

*The total number of included references is not a sum of eligible references for each question because of overlapping eligibility.

Methods Used to Assess the Quality and Strength of the Evidence
Weighting According to a Rating Scheme (Scheme Given)
Rating Scheme for the Strength of the Evidence

Assessment of Methodological Quality of Individual Studies

  • Well designed and conducted (good; low risk of bias). A study that adheres mostly to the commonly held concepts of high quality, including the following: a formal randomized controlled study; clear description of the population, setting, interventions, and comparison groups; appropriate measurement of outcomes; appropriate statistical and analytic methods and reporting; no reporting errors; low dropout rate; and clear reporting of dropouts.
  • Fair. These studies are susceptible to some bias, but it is not sufficient to invalidate the results. They do not meet all the criteria required for a rating of good quality because they have some deficiencies, but no flaw is likely to cause major bias. The study may be missing information, making it difficult to assess limitations and potential problems.
  • Poor (high risk of bias). These studies have significant flaws that imply biases of various types that may invalidate the results. They have serious errors in design, analysis, or reporting; large amounts of missing information; or discrepancies in reporting.

Grading the Evidence for Each Key Question

Assess Study Quality and Strength of Evidence

Overall Ranking of Evidence

High - High confidence that the evidence reflects the true effect. Further research is very unlikely to change our confidence in the estimate of effect.

Moderate - Moderate confidence that the evidence reflects the true effect. Further research may change the confidence in the estimate of effect and may change the estimate.

Low - Low confidence that the evidence reflects the true effect. Further research is likely to change the confidence in the estimate of effect and is likely to change the estimate.

Insufficient - Evidence either is unavailable or does not permit a conclusion.

Methods Used to Analyze the Evidence
Review of Published Meta-Analyses
Systematic Review with Evidence Tables
Description of the Methods Used to Analyze the Evidence

Note from the National Guideline Clearinghouse (NGC): A systematic review of the literature was prepared by the Minnesota Evidence-based Practice Center (EPC) for the Agency for Healthcare Research and Quality (AHRQ) for use by the National Institutes of Health (NIH) (see the "Availability of Companion Documents" field).

Assessment of Methodological Quality of Individual Studies

Each article was read by one extractor and was included for further review if the article either appeared to meet the inclusion criteria or if inclusion was uncertain. In cases where inclusion was not obvious, additional review by a senior investigator occurred.

The guideline developers rated the quality of studies according to recommendations from the Methods Guide for Comparative Effectiveness Reviews (see "Availability of Companion Documents" field). See the "Rating Scheme for the Strength of the Evidence" field for ratings of the quality of individual studies.

External validity (applicability) was assessed according to the Methods Guide for Comparative Effectiveness Reviews.

Data Synthesis

Evidence was summarized into summary tables with qualitative analysis of the results for prevalence of lactose intolerance (LI) by subgroups for Key Question 1. Evidence-Based Practice Center (EPC) staff did not pool results for Key Question 1. They attempted to calculate odds ratio with 95 percent confidence interval (CI) or absolute risk differences from the reported number of events in randomized controlled trials (RCTs) as well as the number needed to treat to achieve one event of the outcome if the data are homogeneous enough to permit pooling. All additional calculations were performed at 95 percent confidence levels.

Minimum difference in continuous variables was calculated from the reported sample size, means, and standard deviations. Crude odds ratios were calculated from the reported number of subjects with and without outcomes among compared categories of exposure. Calculations were performed using STATA software, SAS 9.2, and Meta-analyst software at the 95 percent confidence level.

Attributable risk was calculated as the outcome events rate in patients exposed to different clinical interventions. The number needed to treat to prevent one symptomatic event was calculated as the reciprocal to the absolute risk differences in rates of outcomes events in the active and control groups: 1/(control group event rate - treatment group event rate). EPC staff did not pool data related to Key Questions 1 or 2.

For Key Questions 3 and 4 if symptoms associated with lactose malabsorption (abdominal pain and frequency of diarrhea) data were appropriate for pooling, they were analyzed using RevMan 5.0 software using a random effects model. Standardized mean differences (symptom effect sizes) were calculated with the generic inverse variance method due to the crossover study design of the trials.

Grading the Evidence for Each Key Question

Assess Study Quality and Strength of Evidence

On the basis of the quality checklist(s) developed for articles relevant to the various key questions, a quality score was assigned to each article. EPC staff used methods for assessing study quality and strength of evidence according to the Methods Guide for Comparative Effectiveness Reviews (see "Availability of Companion Documents") that is conceptually similar to the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system of evidence rating. Specifically, four domains were assessed: risk of bias, consistency, directness, and precision. When appropriate, dose response association, presence of confounders that would diminish an observed effect, strength of association, and publication were also included.

See the "Rating Scheme for the Strength of the Evidence" field for the quality of evidence grading for primary outcomes across studies.

Methods Used to Formulate the Recommendations
Expert Consensus (Consensus Development Conference)
Description of Methods Used to Formulate the Recommendations

The Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Office of Medical Applications of Research of the National Institutes of Health convened a Consensus Development Conference on February 22-24, 2010 to assess the available scientific evidence related to five questions.

A non-Department of Health and Human Services, nonadvocate 14-member panel represented the fields of internal medicine, pediatrics, pediatric endocrinology, gastroenterology, hepatology, neonatology and perinatology, geriatrics, radiology, maternal and fetal nutrition, vitamin and mineral metabolism, nutritional sciences, bone health, preventive medicine, biopsychology, biostatistics, statistical genetics, epidemiology, and a public representative.

At the conference, the invited panel experts presented information relevant to these questions:

  1. What is the prevalence of lactose intolerance, and how does this prevalence differ by race, ethnicity, and age?
  2. What are the health outcomes of dairy exclusion diets?
  3. What amount of daily lactose intake is tolerable in subjects with diagnosed lactose intolerance?
  4. What strategies are effective in managing individuals with diagnosed lactose intolerance?
  5. What are the future research needs for understanding and managing lactose intolerance?

A systematic evidence review, prepared under contract with the Agency for Healthcare Research and Quality, was summarized; the systematic evidence review (available at http://www.ahrq.gov/clinic/tp/lactinttp.htm External Web Site Policy) emphasizes randomized controlled trials with health outcomes as their endpoints. Conference participants also provided oral and written comments in response to the conference questions, and the panel considered all of this evidence when preparing the consensus statement.

The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was presented on the final day of the conference and circulated to the audience for comment. The panel released a revised statement later that day at http://consensus.nih.gov External Web Site Policy.

Rating Scheme for the Strength of the Recommendations

Not applicable

Cost Analysis

A formal cost analysis was not performed and published cost analyses were not reviewed.

Method of Guideline Validation
External Peer Review
Internal Peer Review
Description of Method of Guideline Validation

To bring the broadest range of experts into the development of evidence reports and health technology assessments, the Agency for Health Research Quality (AHRQ) encourages the Evidence-Based Practice Centers (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.

Recommendations

Major Recommendations

Conclusions

  • Lactose intolerance is a real and important clinical syndrome, but its true prevalence is not known.
  • The majority of people with lactose malabsorption do not have clinical lactose intolerance. Many individuals who think they are lactose intolerant are not lactose malabsorbers.
  • Many individuals with real or perceived lactose intolerance avoid dairy and ingest inadequate amounts of calcium and vitamin D, which may predispose them to decreased bone accrual, osteoporosis, and other adverse health outcomes. In most cases, individuals do not need to eliminate dairy consumption completely.
  • Evidence-based dietary approaches with and without dairy foods and supplementation strategies are needed to ensure appropriate consumption of calcium and other nutrients in lactose-intolerant individuals.
  • Educational programs and behavioral approaches for individuals and their healthcare providers should be developed and validated to improve the nutrition and symptoms of individuals with lactose intolerance and dairy avoidance.
Clinical Algorithm(s)

None provided

Evidence Supporting the Recommendations

Type of Evidence Supporting the Recommendations

The type of supporting evidence is not specifically stated for each recommendation.

Benefits/Harms of Implementing the Guideline Recommendations

Potential Benefits

Better understanding of currently available data on lactose intolerance and health

Potential Harms

Not stated

Qualifying Statements

Qualifying Statements
  • The statement reflects the panel's assessment of medical knowledge available at the time the statement was written. Thus, it provides a "snapshot in time" of the state of knowledge on the conference topic. When reading the statement, keep in mind that new knowledge is inevitably accumulating through medical research, and that the information provided is not a substitute for professional medical care or advice.
  • This statement is an independent report of the panel and is not a policy statement of the National Institutes of Health (NIH) or the Federal Government.

Implementation of the Guideline

Description of Implementation Strategy

An implementation strategy was not provided.

Institute of Medicine (IOM) National Healthcare Quality Report Categories

IOM Care Need
Living with Illness
IOM Domain
Effectiveness
Patient-centeredness

Identifying Information and Availability

Bibliographic Source(s)
Suchy FJ, Brannon PM, Carpenter TO, Fernandez JR, Gilsanz V, Gould JB, Hui SL, Lupton JR, Mennella J, Miller NJ, Osganian SK, Sellmeyer DE, Wolf MA. NIH Consensus Development Conference Statement on lactose intolerance and health. NIH Consens State Sci Statements. 2010 Feb 22-24;27(2):1-27. PubMed External Web Site Policy
Adaptation

Not applicable: The guideline was not adapted from another source.

Date Released
2010 Feb
Guideline Developer(s)
National Institutes of Health (NIH) State-of-the-Science Panel - Independent Expert Panel
Source(s) of Funding

United States Government

Guideline Committee

Consensus Development Panel

Composition of Group That Authored the Guideline

Panel Members: Frederick J. Suchy, M.D. (Panel and Conference Chairperson), Professor of Pediatrics, Chief of Pediatric Hepatology, Jack and Lucy Clark Department of Pediatrics, Mount Sinai School of Medicine of New York University, Mount Sinai Kravis Children's Hospital, New York, New York; Patsy M. Brannon, Ph.D., R.D., Professor, Division of Nutritional Sciences, Cornell University, Ithaca, New York; Thomas O. Carpenter, M.D., Professor, Department of Pediatrics, Director, Yale Center for X-Linked Hypophosphatemia, Yale School of Medicine, New Haven, Connecticut; Jose R. Fernandez, Ph.D., Associate Professor, Department of Nutrition Sciences, The University of Alabama at Birmingham, Birmingham, Alabama; Vicente Gilsanz, M.D., Ph.D., Director, Children's Imaging Research Program, Children's Hospital Los Angeles, Professor of Radiology, Pediatrics and Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California; Jeffrey B. Gould, M.D., M.P.H., Robert L. Hess Professor in Pediatrics-Neonatology, Stanford University School of Medicine, Stanford, California; Karen Hall, M.D., Ph.D., Clinical Associate Professor, Department of Internal Medicine, University of Michigan Medical School, Research Scientist, Geriatric Research, Education, and Clinical Center (GRECC), Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan; Siu L. Hui, Ph.D., Professor, Department of Medicine, Division of Biostatistics, Senior Biostatistician, Center for Aging Research, Indiana University School of Medicine, Senior Scientist, Regenstrief Institute, Indianapolis, Indiana; Joanne Lupton, Ph.D., Distinguished Professor, William W. Allen Endowed Chair in Human Nutrition, Department of Nutrition and Food Science, Texas A&M University, College Station, Texas; Julie Mennella, Ph.D., Member, Monell Chemical Senses Center, Philadelphia, Pennsylvania; Natalie J. Miller, Graduate Student, Combined Veterinary Medicine (VMD) and Ph.D. Program, School of Veterinary Medicine, University of Pennsylvania, Co-founder, Cares4Pets, Philadelphia, Pennsylvania; Stavroula Kalis Osganian, M.D., Sc.D., M.P.H., Assistant Professor, Harvard University, Director, Clinical Research Program, Children's Hospital Boston, Boston, Massachusetts, Deborah E. Sellmeyer, M.D., Associate Professor of Medicine, Director, Metabolic Bone Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland; Marshall A. Wolf, M.D., Professor of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts

Financial Disclosures/Conflicts of Interest

All of the panelists who participated in this conference and contributed to the writing of this statement were identified as having no financial or scientific conflict of interest, and all signed forms attesting to this fact. Unlike the expert speakers who present scientific data at the conference, the individuals invited to participate on National Institutes of Health (NIH) Consensus and State-of-the-Science Panels are reviewed prior to selection to ensure that they are not proponents of an advocacy position with regard to the topic and are not identified with research that could be used to answer the conference questions.

Guideline Status

This is the current release of the guideline.

Guideline Availability

Electronic copies: Available from the National Institutes of Health (NIH) Consensus Development Conference Program Web site External Web Site Policy.

Print copies: NIH Consensus Statements, State-of-the-Science Statements, and related materials are available by visiting http://consensus.nih.gov External Web Site Policy; by calling toll free 888-644-2667; or by emailing consensus@mail.nih.gov. Written requests can be mailed to the NIH Consensus Development Program Information Center, P.O. Box 2577, Kensington, MD 20891. When ordering copies of this statement, please reference item number 2010-00121-STMT.

Availability of Companion Documents

The following are available:

  • Lactose intolerance and health. Evidence report/technology assessment. AHRQ Publication No. 192. Rockville (MD): Agency for Healthcare Research and Quality. 2010 Feb. Available from the AHRQ Web site External Web Site Policy.
  • Methods guide for comparative effectiveness reviews. AHRQ Publication No. 10(11)-EHC063-EF. Rockville (MD): Agency for Healthcare Research and Quality. 2011 Mar. Available from the AHRQ Web site External Web Site Policy.
Patient Resources

None available

NGC Status

This NGC summary was completed by ECRI Institute on April 7, 2011. The information was verified by the guideline developer on May 24, 2011.

Copyright Statement

No copyright restrictions apply.

Disclaimer

NGC Disclaimer

The National Guideline Clearinghouseâ„¢ (NGC) does not develop, produce, approve, or endorse the guidelines represented on this site.

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