Bylaws of the COnsortium of METabolomics Studies (COMETS)

I. Mission

The COMETS Mission is to promote collaborations among prospective cohort studies that follow participants for a range of outcomes and perform metabolomic profiling of individuals. COMETS aims to facilitate an open exchange of ideas, knowledge, and results to accelerate a shared goal of studying the metabolomic profiles associated with chronic disease phenotypes (e.g., heart disease, diabetes, cancer).

Within the scope defined by its Mission, the objectives of COMETS are to:

  1. Provide a framework to foster international collaborations among studies sharing common objectives;
  2. Provide a forum for the discussion, development, and pursuit of new collaborative studies and research directions;
  3. Support the development of early career researchers; and
  4. Advance the knowledge of the metabolome to improve our understanding of prediction of disease etiology, diagnosis, and prognosis.

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II. Membership Eligibility Criteria

Cohort eligibility criteria

At present, eligibility is restricted to cohorts with measured metabolomic profiles in blood using either mass-spectrometry or nuclear magnetic resonance in at least 100 participants with follow-up for disease incidence. As the technology advances and the COMETS consortium matures, this stipulation is open to modification.  Membership is granted upon majority vote of the SC which includes steering committee membership for the lead investigator.

Consortium membership falls under the 4 categories below. Individuals who are interested in Consortium membership and are not members of the Steering Committee will follow the guidelines and eligibility under associate and affiliate membership. Consortium members are eligible to propose investigations to the SC for approval.

Steering Committee (SC) Member

SC members are the primary representatives of the participating cohort studies (one per cohort) are entitled to vote, SC members participate in WGs and can become WG chairs. Membership is effective upon notification and confirmation of acceptance of the cohort application by the current SC.

Associate Member

Associate members are investigators who are affiliated with a COMETS cohort working in the field of metabolomics. Membership requires a nomination by a SC member and is effective upon acceptance by the SC. Associate members are required to maintain active participation in at least one WG and may become WG chairs.

Affiliate Member

Affiliate members can be either predoctoral or postdoctoral fellows or trainees who are part of a team led by either an SC or Consortium Member. They may lead or co-lead a project sponsored by an SC or Consortium Member and are eligible to transition to Member status upon transition to an independent research position. Affiliate members have no voting rights or eligibility for the SC.

Non-Affiliate Member

Non-affiliate membership is available to non-affiliated methodologic experts and requires nomination by a SC member. Members are further required to maintain active participation in at least one WG and may become WG chairs. Investigators who are interested in membership require a nomination by a SC member. Membership is effective upon acceptance by the SC.

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III. Chair, Vice-Chair, and Secretary


The Chair is a member of the Steering Committee (SC) and provides leadership to the members of the consortium. He/she is responsible for chairing the meetings and conference calls of the SC after developing the agenda in consultation with the Vice-Chair. Additionally, the Chair is responsible for assuring that action items and tasks identified during SC meetings and conference calls are completed in a timely fashion. Finally, the Chair also serves ex officio as a member of Working Groups (WGs) and attends WG meetings when invited.


The Vice-Chair is a member of the SC, and he/she works closely with the Chair to develop SC meeting and conference call agendas. The Vice-Chair also performs other responsibilities as assigned by the SC. Finally, the Vice-Chair also serves ex officio as a member of WGs and can optionally attend WG meetings when invited. The Vice-Chair performs Chair responsibilities (see above) when the Chair cannot be available. The Vice-Chair automatically assumes the duties of the Chair if the Chair becomes indisposed.


The Secretary is a member of the SC. He/she maintains records of the SC and ensures effective management of consortium records, manages the minutes of SC and member meetings, and ensures that the minutes are distributed to the SC and members (as determined by the SC) shortly after each meeting. Additionally, the Secretary is sufficiently familiar with consortium policies to note applicability during meetings.

Term Length

The term of the Chair, Vice-Chair, and Secretary will be for the duration of 1 year and is renewable for a total duration of 3 years. (Terms can be nonconsecutive.)

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IV. Working Group (WG) Policies

WG Definition and Activities

COMETS research will take place primarily within COMETS WGs. WGs consist of COMETS investigators, fellows, and other researchers interested in a particular research topic.

WG activities include:

  1. Evaluating gaps in the literature and research needs for the topic of interest;
  2. Standardizing exposure/endpoint data across cohorts as needed for a particular project;
  3. Coordinating/conducting the analysis and evaluating the findings;
  4. Planning and drafting the manuscripts;
  5. Determining authorship based on the COMETS authorship policy and specific circumstances of the WG; and
  6. Determining whether additional follow-up work or studies are needed, such as in confirmation samples.

WGs also help initiate, prepare, and refine COMETS Publication and Presentation (P&P) Proposals (see next section), and ensure that proposals have been circulated to WG members for discussion and revision. Once P&P Proposals have been completed, the WG chair will be responsible for forwarding them to the COMETS Secretary for dissemination to the SC.

For manuscripts, WG members ensure that any necessary disclaimers, reviews, and approvals on behalf of the parent studies take place as required. These approvals should occur within 1 month of the completion of the final draft, unless extenuating circumstances are documented.

Process for Establishing WGs

To initiate a new WG, an investigator should complete the new working group application form.  This form will ask the investigator to provide his or her name, a name for the group, and a working draft of the mission and objectives of that group.  This form is different from that of the P&P proposal, which outlines the details of one particular project.  In many cases, we anticipate that the WG and P&P forms will be completed concurrently, at the initiation of a specific research project.

WGs are then discussed by the SC and established by consensus.  After this cohorts may—if interested—select one or two representatives to participate on behalf of the cohort. Cohorts may join individual research projects and be entitled to appropriate authorship without having a cohort representative as a member of the WG, although cohorts should have a defined point person to contact for questions about data and other issues.

In some instances, an investigator may wish to submit a P&P Proposal on a topic for which no appropriate WG has yet been created by the SC. In these instances, the investigator may form his/her own team and should contact the SC to recommend the names of COMETS collaborators to join that team. When the P+P Proposal is submitted, the SC can then establish the team as a WG.

Upon establishing a WG, the SC appoints a Coordinator to convene the first WG conference call or meeting. At this first session, the WG may select its own Chair or Co-Chairs to arrange, coordinate, and run the meetings and calls. The Chair or Co-Chairs may or may not be the Coordinator originally identified by the SC.

WG Membership

Membership within a WG is to be determined by the WG itself, based on consensus and with additional input from the SC. Membership will include COMETS investigators, fellows, or other researchers—and also may include members of institutions that are not represented within the consortium, contingent upon approval by the SC.

COMETS P&P Proposals

Membership within a WG is to be determined by the WG itself, based on consensus and with additional input from the SC. Membership will include COMETS investigators, fellows, or other researchers—and also may include members of institutions that are not represented within the consortium, contingent upon approval by the SC.

P&P Proposals are first submitted by an investigator to a specific WG (if no appropriate group exists, the investigator can form his/her own team, per “Process for Establishing WGs” above). The P&P Proposal will describe the proposed analysis, specific outcomes, name(s) of lead investigator(s), and the proposed timeline. Proposals should be narrow in scope and highly focused. The WG will discuss and help refine the proposal.

The P&P Proposal is next submitted to the SC, which will determine whether the proposal is unique—i.e., not duplicative of other COMETS efforts—and whether the proposal is appropriately narrow in scope. If yes, the proposal will be approved, cohorts will be permitted to “opt in” to the project, and the SC will circulate the proposal to all COMETS members for participation in the analysis. If no, the SC will elaborate upon why the proposal was not approved, and investigators will be given a chance to respond.

For approved proposals, each cohort that “opts in” will designate an investigator to be the primary representative for his or her cohort. The primary cohort representative will inform the lead investigator on the P&P Proposal that he/she is the designated representative for the project.

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V. Principles for Analyses Based on Aggregate Results Sharing

Overall Guiding Principles

A major goal of COMETS is to produce jointly coordinated, multicohort, high-impact publications describing relationships between metabolites and diseases (e.g., diabetes, cardiovascular disease, cancer), and other biological constructs (e.g., aging, genetics). Publications will be initiated and produced by COMETS project WGs and many, though not necessarily all, analyses will be done through aggregate results sharing. Aggregate results sharing is a process in which data analysis occurs separately within each participating cohort, then the results are shared so that they can be meta-analyzed. Aggregate results do not include participant-specific data; separate agreements would be needed for sharing of participant-specific data.

These guidelines establish agreed-upon protocols meant to encourage investigators to conduct their research in the spirit of collaboration and trust.

Definition and Timing of Opt-in for Manuscripts

Cohorts will share aggregate results within a set time window (e.g. a 1 week period), and the guidelines for “Opt-in” depend on whether data sharing has occurred.  These guidelines do not preclude cohorts from publishing their own study-specific data although cohorts should communicate any related plans to the WG.  A table below summarizes the major points, with greater detail provided below.

Post-proposal but pre-data sharing Post-data sharing
  1. For cohorts that opted-in to a proposal, new collaborations with other consortia on the topic are discouraged
  2. Cohorts that opt-in can still opt-out at any time before data sharing
  1. Each WG determines whether results sent after the data-sharing date will continue to be accepted
  2. After data sharing, cohorts may no longer opt-out
  3. In some cases, investigators may be finalizing their own manuscripts even as data analysis proceeds on the same topic within COMETS.  We acknowledge the right of each study to publish independently, but request that investigators do not “cherry-pick” findings from COMETS analyses when reporting individual study results.

Post-proposal but pre-data sharing

  1. The decision to “opt in” to an analysis occurs after submission of the P&P Proposal. The “opt-in” represents a commitment to collaborate only with the COMETS WG and no other consortia-based groups for the analysis described in the P&P proposal.
  2. Cohort representatives have the option to “opt out” any time before formal distribution of shared results (see Primary Results Distribution, below).  Prior to distribution of shared results, the lead investigator will prepare a detailed data analysis plan that is reviewed by WG members. The plan will include a timeline and target dates for: completing analyses, sharing aggregate results, conducting additional analyses, and submitting the manuscript to a journal. As a rule of thumb, if all data are present, analyses should be completed within 1 year, but this is subject to negotiation with cohort representatives. The lead investigator will work with each participating cohort’s representative to determine reasonable deadlines for completion of analyses. This plan also will identify an analyst(s) who will meta-analyze the shared data using a method that is mutually agreed upon. This analyst could be the lead investigator or another investigator.

Post data-sharing

  1. Sometimes, a few of the participating cohorts may—for various reasons and/or despite their best efforts—be unable to complete their metabolomics analyses on time. To ensure timely publication, WGs may determine that data sharing and preliminary meta-analysis can occur between two or more participating cohorts before the other cohorts are ready. Whether results submitted after the prearranged date for data sharing will be accepted for the manuscript is at the discretion of the WG.
  2. After the first occurrence of formal sharing of aggregate results, no cohort that has “opted in” may then “opt out” of the manuscript.
  3. Investigators who receive or otherwise learn of the aggregate results for COMETS should not use these data to “cherry pick” findings within their own ongoing studies.  Such cherry-picking might include, for example, deliberately analyzing or reporting on only one particular metabolite or endpoint in an individual-study, while knowing already that it will be supported by a future consortium-based paper.

Primary Results Distribution (Prior to Publication)

  1. Cohort-specific aggregate results will be submitted to the lead investigator or analyst via a secure website. Results will be submitted in a standard format agreed upon in advance by the lead investigator and cohort representatives. All sharing of results will occur within a prespecified time frame, e.g., a particular 72-hour period. The shared files will include a complete listing of aggregate association results for all metabolites present within the data set and appropriate documentation (as determined by the lead investigator).
  2. The analyst will then meta-analyze the shared aggregate results and distribute the meta-analysis results to the WG and cohort representatives. WG members and cohort representatives may use the meta-analysis results to compare with other data sets and/or guide other research studies. The individual investigator(s) agree(s), however, to communicate with the rest of the COMETS WG and the COMETS SC about actionable results, such as if the investigator plans to send additional samples for metabolomics analysis based on the shared aggregate results. If interesting results emerge from a combination of external and COMETS meta-analysis data, the same policies should be followed as if results arose entirely from the COMETS data.
  3. Submission of prepublication results, such as in an abstract or grant application, must be agreed upon by all cohort representatives and be consistent with the initial P&P Proposal. The results and draft abstract should be submitted to cohort representatives at least 7 days in advance of the abstract guideline.
  4. Secondary distribution of unpublished COMETS aggregate results to investigators or other persons who have not explicitly “opted in” to the P&P Proposal may occur only after approval by the WG and confirmation by the COMETS SC. In general, such secondary distribution will be discouraged until after the relevant manuscript has been accepted for publication.
  5. Communication. All involved investigators/cohort representatives agree to keep the other investigators in the COMETS WG informed about additional analyses and follow-up experiment plans. Specifically, participating investigators agree at a minimum to communicate with each other at the following times:
    • When action is taken by an individual COMETS investigator (for example, analyzing new samples) based on shared meta-analysis results.
    • When an analysis is complete (with some degree of confidence) for follow-up metabolomics analysis from shared meta-analysis results.
    • When data used in a COMETS manuscript are proposed for use in other collaborations (e.g., other meta-analyses). The timeline for publication of data from additional collaborations must be agreed upon by WG consensus.
  6. Any sharing of aggregate results not stipulated in this Principles document is not allowed unless the issue is brought to the COMETS SC for discussion and approval.
  7. The consortium expects that the data will be used for legitimate research purposes and requests that users of the data acknowledge the appropriate consortium investigators for their work.

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VI. Authorship Policy

General Principles

The approach to authorship will be inclusive rather than exclusive, although authors should meet the criteria proposed by the International Committee of Medical Journal Editors (ICMJE) (Annals of Int Med 1988;258-304). The ICMJE specified that authorship credit should be limited to those who contribute substantially to all of the following:

  • Conception and design, or acquisition of data, or analysis and interpretation of data;
  • Drafting the article or revising it critically for important intellectual content; and
  • Final approval of the version to be published.

For each project, authorship is agreed upon as it is initiated and revisited during the manuscript stage to ensure that it reflects this agreement and policy prior to submission.

Authorship Guidelines and Policies

General Format for Authorship: Writing group lead(s), data coauthors in alphabetical order, Writing Group senior author(s)

The author list will begin with the members of the writing team (except the senior author(s)). All other researchers (in alphabetical order) who meet the criteria for authorship will be listed after the writing team. The last author(s) will be the senior researcher(s) responsible for that particular manuscript/project.

Writing Group

Manuscripts typically will be led by a writing group that consists of a small number of consortium members, e.g., 5–12 people. When proposals that are submitted to the SC by an investigator are approved, the SC will circulate them to all consortium members for participation in the study and in the writing group. The person who submitted the proposal will assemble the writing group from among those who express interest, spreading membership across cohorts as much as possible. All writing team members are expected to advise on data analysis, assist in interpreting results, and provide in-depth reading and feedback on drafts prior to circulation to the whole group.

Members of this group rightfully will claim slots at the front (“junior” authors) and back end (“senior” authors) of the paper, with the specific location determined by contribution and by internal discussion among the members. In general, the following definitions should be considered when determining these key authorship slots:

  • Lead Author(s): These are the researcher(s) on the writing team who will take primary responsibility for data analysis and writing, and will be considered first authors. These researchers usually are determined by the senior author, and generally should be from a different institution than that of the senior author.
  • Senior Author(s): These are the researcher(s) who submitted the proposal or are mentors of the person who submitted the proposal. Their role is to edit the paper and accept full responsibility for its content.
  • Other Writing Group Member(s): These are the researcher(s) who comprised part of the writing team but who do not meet the definitions of a lead or senior author. The order of authorship for these members will be determined based on their contribution to the writing team, but should be grouped either toward the front (just after the leads) or at the end (just before the senior authors), as appropriate.

Other important authorship principles for the writing team include:

  • All consortium members, including members who are not contributing primary data, are eligible to participate in writing groups.
  • Either the lead or senior investigator will serve as the corresponding author. Multiple corresponding authorship is encouraged.
  • Junior investigators are encouraged to lead projects and, as such, lead in authorship.
  • Multiple co-first and co-last authors are permitted to recognize equal efforts and contributions among writing group members. If the journal permits it, the writing group and co-first or co-last authors should be specified in a footnote.
  • If major imbalances appear between cohorts, and if these imbalances do not fairly reflect the level of contribution, the authorship lists will be negotiated with the SC.
  • Cohort representatives are not required to participate in a writing group to be a coauthor (see Data Coauthors, below).

Data Coauthors
Members of groups that conduct individual projects that contribute data to a collaborative project will be recognized as coauthors. (Preference should be given to the person who facilitated the analysis, responded to questions, and reviewed the work as it progressed—at the discretion of the project Principal Investigator [PI]).

We propose that each cohort contribute two coauthors. Participating consortia, such as EPIC, COMBI-BIO, and UCLEB, will be permitted to negotiate for a greater number of coauthorships. Consortium or WG members who contributed greatly to the research may be included as well, as appropriate.

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VII. General Expectations

The consortium is for the exchange of ideas, knowledge, and data/aggregate results in metabolomics studies.  To maintain this focus on scientific collaboration, members will not use the consortium as a vehicle to sell or promote products or services.

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