The NTP Office of Health Assessment and Translation (OHAT) develops literature-based evaluations to reach conclusions about potential human health hazards and to examine the state of the science. In 2012, OHAT began exploring and developing an approach for implementation of systematic review methodology to carry out these evaluations (Birnbaum et al. 2013). The output from an evaluation can vary including, but not limited to: NTP Monograph, state-of-the-science workshop report, or peer-reviewed journal publication. All evaluations follow a similar process, the OHAT Evaluation Process, with opportunities for external scientific, public, and interagency input.
See the Systematic Review Fact Sheet to learn more about the systematic review process.
The “Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration” provides standard operating procedures for the implementation of systematic review in OHAT evaluations. The standard operating procedures are based on (1) lessons learned from developing protocols for two case studies for implementing systematic review, (2) consideration of public comments received on systematic review during the past two years, and (3) discussions with experts at other organizations and agencies working on applying methods of systematic review to environmental health and toxicology. The handbook is a living document and will be updated as methodological practices are refined and evaluated and strategies are identified that improve the reliability, ease, and efficiency of conducting systematic reviews.
The handbook for conducting systematic reviews presents OHAT’s tool for assessing study quality, or “risk of bias.” The tool applies a parallel approach to the evaluation of risk of bias for human and non-human animal studies to facilitate consideration of potential bias across evidence streams with common terminology and “domains” or areas of bias. The risk-of-bias domains and questions for experimental animal studies are based on established guidance for experimental human studies (randomized clinical trials). Detailed instructions for response are provided in the OHAT tool. The risk-of-bias rating tool will be refined and updated as practices evolve and empirical evidence is developed to support risk of bias elements. OHAT is currently refining the OHAT tool to assess potential bias for in vitro or mechanistic studies.
Systematic review and evidence integration for literature-based environmental health science assessments.
Rooney AA, Boyles AL, Wolfe MS, Bucher JR, Thayer KA. Environ Health Perspect. 2014 Jul;122(7):711-8. doi: 10.1289/ehp.1307972. Epub 2014 Apr 18.
Intersection of Systematic Review Methodology with the NIH Reproducibility Initiative.
Thayer KA, Wolfe MS, Rooney AA, Boyles AL, Bucher JR, Birnbaum LS.
Environ Health Perspect. 2014 Jul 1;122(7):A176-7. doi: 10.1289/ehp.1408671. No abstract available.
Implementing systematic review at the National Toxicology Program: status and next steps.
Birnbaum LS, Thayer KA, Bucher JR, Wolfe MS.
Environ Health Perspect. 2013 Apr;121(4):A108-9. doi: 10.1289/ehp.1306711. No abstract available.
The timeline below shows NTP activities associated with the development of the OHAT approach for systematic review. For more information about the activities, please see the “Events and Activities” webpage.
The Draft OHAT Approach for Systematic Review and Evidence Integration for Literature-based Health Assessments – February 2013 (“Draft OHAT Approach – February 2013”) provides a seven-step framework for conducting evaluations using principles of systematic review. The Draft OHAT Approach – February 2013 reflects consideration of input from a working group of the NTP Board of Scientific Counselors (BSC), the BSC, and the public (see for information, presentations, and minutes from the June 21-22 and December 11, 2012 meetings). This framework for conducting evaluations integrates within the OHAT Evaluation Process and includes multiple opportunities for external scientific, public, and interagency input.
NTP held a public webinar on September 26, 2013 from 1:00 – 4:00 p.m. EDT to gain additional clarity on issues raised in public comments. For each topic covered, there was a brief presentation by OHAT staff and then the opportunity for discussion in a question and answer session. The webinar also included a general discussion period for any additional comments or questions from the attendees.
Individuals interested in receiving updates on this project are encouraged to register to the NTP Listserv.