Body Mass Index VCDE Small Group Lynne Wilkens, Lewis Frey, Mary Cooper, Brian Davis, Mike Keller, Daniela Smith 3/22/2007

Issues for Consideration  Focus: Harmonize/Reuse existing caDSR content, CDE, DEC, VD Calculated BMI Value of a person Capture pre-calculated BMI components, height and weight Provide CDE for describing source of height and weight values  Specificity: Different formulas for international customary and metric units Provide guidance for UML model development  Out of Scope: Interpretation of BMI BMI for Age (Interpretation of BMI for children and teens)

Proposed Components for Standardization  Person Body Mass Index – Weight in kg divided by height in meters, squared  Person Weight  Person Height  Unit of Measure – For person weight and height  Source of Information – Valid values = Measured, Self-report, etc.

Recommendation Details Person Body Mass Index Value Person Body Mass Index Public ID v1.0 Object = Person (C25190) Property = Body Mass Index (C16358) Definition: The body fat an individual is carrying based upon the ratio of weight to height. Reused from SPOREs Body Mass Index Value Public ID v2.0 Representation Term: Value (C25712) Qualifier = Body Mass Index (C16358) Definition: A calculated numerical quantity that represents the body fat an individual is carrying based upon the ratio of weight to height. Data Type = Number Max length = 4 Decimal place = 1 Unit of measure = kg/m2 Reused from SPOREs Person Body Mass Index Value Public ID v3.0 Definition: A calculated numerical quantity that represents the body fat an individual is carrying based upon the ratio of weight to height. [Explanatory comment: Also known as Quetelet Index.] Reused from SPOREs

Recommendation Details Body Mass Index Value Number Data Element Derivation Details Body Mass Index Value Number Derivation Type: Calculated Rule: weight/[height]^2 for metric units Method: The ratio of weight in kilograms to height in meters squared. If weight and height are given in the international customary units of pounds and inches, respectively, these components must be converted to metric units in order to compute BMI. Convert weight in pounds to weight in kilograms, height in inches to height in meters, and then compute BMI based on the metric units. Note that one decimal place of accuracy is desired for BMI, which requires that weight and height in metric units be stored to at least three decimal places of accuracy. Convert weight in pounds to weight in kilograms by multiplying by the conversion factor Convert height in inches to height in meters by multiplying by the conversion factor Component Data Elements: 1.Person Weight Value ( v4.0) 2.Person Height Value ( v4.0)

Calculation Algorithm  Body Mass Index (BMI) = ratio of weight in kilograms to height in meters squared  Weight and Height collected in International Customary Units (pounds and inches, respectively), convert to metric units for computation of BMI  Options: 1.Computation of BMI directly from metric units Compute BMI as the ratio of weight in kilograms to height in meters squared. 2. Computation of BMI via conversion of weight and height to metric units Convert weight in pounds to weight in kilograms, height in inches to height in meters, and then compute BMI based on the metric units. One decimal place of accuracy for BMI requires weight and height in metric units be stored to at least three decimal places of accuracy. Convert weight in pounds to weight in kilograms – multiply by NIST conversion factor x Convert height in inches to height in meters- multiply by NIST conversion factor 2.54 x Use method 1 to calculate BMI. 3.Computation of BMI directly from international customary units Compute the ratio weight in pounds to height in inches, squared. Convert this ratio to BMI - multiply by NIST conversion factor x 10 2.

Recommendations Person Weight Value Person Weight Public ID v4.0 Object = Person (C25190) Property = Weight (C25208) Definition: The vertical force exerted by the mass of an individual as a result of gravity. Reused from CCR Weight Value Public ID v2.0 Representation = Value (C25712) Definition: The numerical result of the determination of the vertical force exerted by the mass of an individual as a result of gravity. Data Type = Number Max Length = 7 (xxx.xxx) Decimal place = 3 Reused from DCP Person Weight Value Public ID v4.0 Definition: The number that describes the vertical force exerted by the mass of an individual as a result of gravity. Reused from DCP

Recommendations Person Weight Unit of Measure UCUM Code Person Weight Unit of Measure Public ID v1.0 Object = Person (C25190) Property = Unit of Measure (C25709) Prop. Qualifier = Weight (C25208) Definition: A named quantity in terms of which other quantities are measured or specified for the vertical force exerted by the mass of an individual as a result of gravity. Weight UCUM Code New value domain Representation = Code (C25162) Qualifier = Unified Code for Units of Measure (C53403) Qualifier = Weight (C25208) Definition: The Unified Code for Units of Measure symbols that represent a determinate amount or quantity used as the standard of measurement for the vertical force exerted by the mass of an individual as a result of gravity. Data Type = Character Max Length = 10 Permissible Values: g, kg, [lb_av], [oz_av] Person Weight Unit of Measure UCUM Code Public ID Definition: The Unified Code for Units of Measure symbols that represent a determinate amount or quantity used as the standard of measurement for the vertical force exerted by the mass of an individual as a result of gravity.

Recommendations Person Height Value Person Height Public ID v4.0 Object = Person (C25190) Property = Height (C25347) Definition: The vertical distance from the base to the top of an individual. Reused from CCR Height Value Public ID v2.0 Representation = Value (C25712) Definition: The numerical result of the determination of the vertical distance of an individual. Data Type = Number Max Length = 7 (xxx.xxx) Decimal place = 3 Reused from DCP Person Height Value Public ID v4.0 Definition: The number that describes the vertical distance of an individual. Reused from DCP

Recommendations Person Height Unit of Measure UCUM Code Person Height Unit of Measure Public ID Object = Person (C25190) Property = Unit of Measure (C25709) P.Qualifier = Height (C25347) Definition: A named quantity in terms of which other quantities are measured or specified for the vertical distance from the base to the top of an individual. Height UCUM Code Public ID Representation = Code (C25162) Qualifier = Unified Code for Units of Measure (C53403) Qualifier = Height (C25347) Definition: The Unified Code for Units of Measure symbols that represent a determinate amount or quantity used as the standard of measurement for the vertical size of an individual person. Data Type = Character Max Length = 10 Permissible Values: m, cm, [in_i], [ft_i] Person Height Unit of Measure UCUM Code New CDE Definition: The Unified Code for Units of Measure symbols that represent a determinate amount or quantity used as the standard of measurement for the Vertical size of an individual person.

Recommendations Person Information Source Text Type Person Information Source New or version Object = Person (C25190) Property = Source (C25683) P.Qualifier = Information (C48191) Definition: The origination of knowledge about an individual that has been gathered or received by communication. Reused from PS&CC Information Source Text Type Representation = Type (C25284) Qualifier = Information Qualifier = Source Qualifier = Type Definition: A subdivision of a particular kind of knowledge that has been gathered or received by communication. Data Type = Character Max Length = 20 Reused from PS&CC Person Information Source Text Type Definition: A subdivision of a particular kind of knowledge about an individual that has been gathered or received by communication. Reused from PS&CC Permissible Values Estimated Measured Reported by proxy Self-reported

Recommendations Template [Object Class] Body Mass Index Value Template [Object Class] BMI Value Object Class = Any Property = Body Mass Index (C16358) Definition: When there is a need to capture body mass index with an Object Class other than Person, this template may be used to create descriptive data elements. Template [Object Class] Body Mass Index Value Definition: When there is a need to capture body mass index with an Object Class other than Person, this template may be used to create descriptive data elements. Body Mass Index Value Public ID v2.0 Representation Term: Value (C25712) Qualifier = Body Mass Index (C16358) Definition: A calculated numerical quantity that represents the body fat an individual is carrying based upon the ratio of weight to height. Data Type = Number Max length = 4 Decimal place = 1 Unit of measure = kg/m2 Reused from SPOREs

Suggested UML Guidance  Goal is to provide reusable/searchable metadata for manual and automated curation methods  Standardize CDEs from existing caDSR content.  Three acceptable UML models shown, in order of preference.  Preference #1: UML model to fit proposed standard CDEs  Preference #2: Use standard attribute and value domain if alternate class name is necessary  Preference #3: Use standardized concept in Class or attribute name and standard value domain

UML Model Guidance (Preference #1) Person Body Mass Index Value Person Height Value Person Weight Value Person Height Unit of Measure UCUM Code Person Weight Unit of Measure UCUM Code Person Information Source Text Type Use Standard CDEs Person - bodyMassIndex - height - weight - heightUnitOfMeasure - weightUnitOfMeasure - informationSource UML Model

UML Model Guidance (Preference #2) Include 2 Classes in a model, with any Class name and attribute bodyMassIndex (C16358). Map attribute to Value Domain Body Mass Index Value (Public ID ). Template [Object Class] Body Mass Index Value Object Class - bodyMassIndex (C16358) Person -height -weight -heightUnitOfMeasure -weightUnitOfMeasure -informationSource Person Height Value Person Weight Value Person Height Unit of Measure UCUM Code Person Weight Unit of Measure UCUM Code Person Information Source Text Type UML Model Use Template CDE to create new CDE from existing (Slide 12) Reuse CDEs

UML Model Guidance (Preference #3) Include 2 Classes in a model, using Body Mass Index (C16358) as the Class name and value (C25712) as the attribute. Map attribute to Value Domain Body Mass Index Value (Public ID ). Body Mass Index Value* *Curated for naming Best Practice - Uses standard VD Body Mass Index - value Person -height -weight -heightUnitOfMeasure -weightUnitOfMeasure -informationSource Person Height Value Person Weight Value Person Height Unit of Measure UCUM Code Person Weight Unit of Measure UCUM Code Person Information Source Text Type UML Model UML Loader Created CDE Reuse CDEs 0,1

Summary  Standardizing existing CDEs meets needs of Forms curation and UML modeling community for harmonization and reuse.  UML modeling guidance allows flexibility in creation of projects that represent legacy and future data modeling approaches.  Algorithm for conversion of height and weight and calculation of BMI is included in Specification documentation.  Questions/comments?  VCDE WS Vote to adopt/distribute for caBIG community review.