The STROBE-Vet statement checklist.

Item / STROBE-Vetrecommendation / Page #
TitleandAbstract / 1 / (a) Indicatethatthestudywasanobservationalstudyand, ifapplicable, useacommonstudydesignterm
(b) Indicatewhythestudywasconducted, thedesign, theresults, thelimitations, andtherelevanceofthefindings
Background/rationale / 2 / Explainthescientificbackgroundandrationalefortheinvestigationbeingreported
Objectives / 3 / (a) Statespecificobjectives, includinganyprimaryorsecondaryprespecifiedhypothesesortheirabsence
(b) Ensurethattheleveloforganizationaisclearforeachobjectiveandhypothesis
Studydesign / 4 / Presentkeyelementsofstudydesignearlyinthepaper
Setting / 5 / (a) Describethesetting, locations, andrelevantdates, includingperiodsofrecruitment, exposure, follow-up, anddatacollection
(b) Ifapplicable, includeinformationateachleveloforganization
Participantsb / 6 / (a) Describetheeligibilitycriteriafortheowners/managersandfortheanimals, ateachrelevantleveloforganization
(b) Describethesourcesandmethodsofselectionfortheowners/managersandfortheanimals, ateachrelevantleveloforganization
(c) Describethemethodoffollow-up
(d) Formatchedstudies, describematchingcriteriaandthenumberofmatchedindividualspersubject (e.g., numberofcontrolspercase)
Variables / 7 / (a) Clearlydefinealloutcomes, exposures, predictors, potentialconfounders, andeffectmodifiers. Ifapplicable, givediagnosticcriteria
(b) Describetheleveloforganizationatwhicheachvariablewasmeasured
(c) Forhypothesis-drivenstudies, theputativecausal-structureamongvariablesshouldbedescribed (adiagramisstronglyencouraged)
Datasources/measurement / 8* / (a) Foreachvariableofinterest, givesourcesofdataanddetailsofmethodsofassessment (measurement). Ifapplicable, describecomparabilityofassessmentmethodsamonggroupsandovertime
(b) Ifaquestionnairewasusedtocollectdata, describeitsdevelopment, validation, andadministration
(c) Describewhetherornotindividualsinvolvedindatacollectionwereblinded, whenapplicable
(d) Describeanyeffortstoassesstheaccuracyofthedata (includingmethodsusedfor “datacleaning” inprimaryresearch, ormethodsusedforvalidatingsecondarydata)
Bias / 9 / Describeanyeffortstoaddresspotentialsourcesofbiasduetoconfounding, selection, orinformationbias
Studysize / 10 / (a) Describehowthestudysizewasarrivedatforeachrelevantleveloforganization
(b) Describehownon-independenceofmeasurementswasincorporatedintosample-sizeconsiderations, ifapplicable
(c) Ifaformalsample-sizecalculationwasused, describetheparameters, assumptions, andmethodsthatwereused, includingajustificationfortheeffectsizeselected
Quantitativevariables / 11 / Explainhowquantitativevariableswerehandledintheanalyses. Ifapplicable, describewhichgroupingswerechosen, andwhy
Statisticalmethods / 12 / (a) Describeallstatisticalmethodsforeachobjective, atalevelofdetailsufficientforaknowledgeablereadertoreplicatethemethods. Includeadescriptionoftheapproachestovariableselection, controlofconfounding, andmethodsusedtocontrolfornon-independenceofobservations
(b) Describetherationaleforexaminingsubgroupsandinteractionsandthemethodsused
(c) Explainhowmissingdatawereaddressed
(d) Ifapplicable, describetheanalyticalapproachtolosstofollow-up, matching, complexsampling, andmultiplicityofanalyses
(e) Describeanymethodsusedtoassesstherobustnessoftheanalyses (e.g., sensitivityanalysesorquantitativebiasassessment)
Participants / 13* / (a) Reportthenumbersofowners/managersandanimalsateachstageofstudyandateachrelevantleveloforganization - e.g., numberseligible, includedinthestudy, completingfollow-up, andanalyzed
(b) Givereasonsfornon-participationateachstageandateachrelevantleveloforganization
(c) Consideruseofaflowdiagramand/oradiagramoftheorganizationalstructure
Descriptivedataonexposuresandpotentialconfounders / 14* / (a) Givecharacteristicsofstudyparticipants (e.g., demographic, clinical, social) andinformationonexposuresandpotentialconfoundersbygroupandleveloforganization, ifapplicable
(b) Indicatenumberofparticipantswithmissingdataforeachvariableofinterestandatallrelevantlevelsoforganization
(c) Summarizefollow-uptime (e.g., averageandtotalamount), ifappropriatetothestudydesign
Outcomedata / 15* / (a) Reportoutcomesasappropriateforthestudydesignandsummarizeatallrelevantlevelsoforganization
(b) Forproportionsandrates, reportthenumeratoranddenominator
(c) Forcontinuousoutcomes, reportthenumberofobservationsandameasureofvariability
Mainresults / 16 / (a) Giveunadjustedestimatesand, ifapplicable, adjustedestimatesandtheirprecision (e.g., 95% confidenceinterval). Makeclearwhichconfoundersandinteractionswereadjusted. Reportallrelevantparametersthatwerepartofthemodel
(b) Reportcategoryboundarieswhencontinuousvariableswerecategorized
(c) Ifrelevant, considertranslatingestimatesofrelativeriskintoabsoluteriskforameaningfultimeperiod
Otheranalyses / 17 / Reportotheranalysesdone,suchassensitivity/robustnessanalysisandanalysisofsubgroups
Keyresults / 18 / Summarizekeyresultswithreferencetostudyobjectives
StrengthsandLimitations / 19 / Discussstrengthsandlimitationsofthestudy, takingintoaccountsourcesofpotentialbiasorimprecision. Discussbothdirectionandmagnitudeofanypotentialbias
Interpretation / 20 / Giveacautiousoverallinterpretationofresultsconsideringobjectives, limitations, multiplicityofanalyses, resultsfromsimilarstudies, andotherrelevantevidence
Generalizability / 21 / Discussthegeneralizability (externalvalidity) ofthestudyresults
FundingTransparency / 22 / (a) Funding- Givethesourceoffundingandtheroleofthefundersforthepresentstudyand, ifapplicable, fortheoriginalstudyonwhichthepresentarticleisbased
(b) Conflictsofinterest-Describeanyconflictsofinterest, orlackthereof, foreachauthor
(c) Describetheauthors’ roles- Provisionofanauthors’ declarationoftransparencyisrecommended
(d) Ethicalapproval- Includeinformationonethicalapprovalforuseofanimalandhumansubjects
(e) Qualitystandards-Describeanyqualitystandardsusedintheconductoftheresearch

a Level of organization recognizes that observational studies in veterinary research often deal with repeated measures (within an animal or herd) or animals that are maintained in groups (such as pens and herds); thus, the observations are not statistically independent. This non-independence has profound implications for the design, analysis, and results of these studies.

b The word “participant” is used in the STROBE statement. However, for the veterinary version, it is understood that “participant” should be addressed for both the animal owner/manager and for the animals themselves.

*Give such information separately for cases and controls in case-control studies and, if applicable, for exposed and unexposed groups in cohort and cross-sectional studies.