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Thinking Thinking Systematically about Systematically about Nature and Nurture:Nature and Nurture:

Part II – Race and BonesPart II – Race and Bones

Anne Fausto-Sterling, Brown UniversityAnne Fausto-Sterling, Brown University

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Medical Folklore: Relative Risk for Medical Folklore: Relative Risk for Bone DiseaseBone Disease

White and Asian womenWhite and Asian women

>Hispanic women>Hispanic women

>White and Asian men>White and Asian men

= African American women= African American women

>African American men>African American men

Source: National Osteoporosis Foundation and the Source: National Osteoporosis Foundation and the National Institutes of HealthNational Institutes of Health

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Science-Health Policy: a confusing Science-Health Policy: a confusing messagemessage

““the fact that osteoporosis and fragility the fact that osteoporosis and fragility fractures are often mistakenly viewed fractures are often mistakenly viewed by both the public and health care by both the public and health care practitioners as only being a problem practitioners as only being a problem for older White women…may delay and for older White women…may delay and even prevent treatment in men and even prevent treatment in men and minority women…” minority women…”

US Surgeon General’s report : US Surgeon General’s report : Bone Health and Bone Health and Osteoporosis (2004)Osteoporosis (2004)

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Typological Thinking: historyTypological Thinking: history

1818thth and 19 and 19thth Century Hierarchies Century Hierarchies Brain sizeBrain size Skull shapesSkull shapes Pain thresholdsPain thresholds Developmental and evolutionary sequenceDevelopmental and evolutionary sequence

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Race in Contemporary Medicine: Race in Contemporary Medicine: Bodies out of ContextBodies out of Context

Lung function correctionLung function correction ““race specific” pharmaceuticals race specific” pharmaceuticals Body mass index and obesityBody mass index and obesityAge at menarcheAge at menarcheDiabetesDiabetes

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What is Race?What is Race?

1999: Institute of Medicine agrees with 1999: Institute of Medicine agrees with American Anthropologists that race is a American Anthropologists that race is a social but not a biological conceptsocial but not a biological concept

Post 2000 Editorials in Post 2000 Editorials in Nature GeneticsNature Genetics, , JAMAJAMA, , NEJMNEJM insist researchers should insist researchers should define race and explain why it is a relevant define race and explain why it is a relevant variablevariable

Competing contemporary views of RaceCompeting contemporary views of Race

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Current Debates in the Medical Current Debates in the Medical LiteratureLiterature

Race neutralRace neutralGeographical ancestryGeographical ancestrySelf identification using census categoriesSelf identification using census categories

But…But…

Census categories are a socio-political Census categories are a socio-political constructionconstruction

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The common race categories are The common race categories are unscientificunscientific

Breadth: each has important historical, Breadth: each has important historical, cultural and genetic substructure cultural and genetic substructure

Populations are on the move—skin Populations are on the move—skin color is a poor marker of current color is a poor marker of current populationspopulations E.g. more recent African immigrants now E.g. more recent African immigrants now

in the US than descendants of those from in the US than descendants of those from the middle passagethe middle passage

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““Real” differences are contextual-1Real” differences are contextual-1

(e.g. Taaffe et al, 2003): (sex/race diffs in bmd and X-sect. (e.g. Taaffe et al, 2003): (sex/race diffs in bmd and X-sect. geometry of femur mid-shaft in older adults)geometry of femur mid-shaft in older adults)

Males 4.3% higher vol. b.d. than females (no racial diff.)Males 4.3% higher vol. b.d. than females (no racial diff.) Even when factored in diffs in smoking, medication, Even when factored in diffs in smoking, medication,

physical activity, height and weightphysical activity, height and weight Males had greater cortical, medullary, areas of femur Males had greater cortical, medullary, areas of femur

shaft and no race difference between menshaft and no race difference between men Black women had 4.3% greater total, and 5.7% greater Black women had 4.3% greater total, and 5.7% greater

cortical areas than white womencortical areas than white women These differences disappeared if they corrected for total These differences disappeared if they corrected for total

bone lengthbone length

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““Real” differences are contextual-IIReal” differences are contextual-II

Taafe et al: “Thus racial differences in Taafe et al: “Thus racial differences in volumetric density and geometry are likely volumetric density and geometry are likely dependent on the composition of the bone, dependent on the composition of the bone, whether an apparent or true density whether an apparent or true density measurement is obtained as well as the measurement is obtained as well as the skeletal site assessed and age of the skeletal site assessed and age of the population.”population.”

Composition: depends on diet, physiology Composition: depends on diet, physiology developmental history of use and disusedevelopmental history of use and disuse

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What do Genes Have to What do Genes Have to do With It?do With It?

Genes are Genes are mediatorsmediators, not causal agents, not causal agents Genes Genes translatetranslate experience into molecular experience into molecular

and cellular changeand cellular change In mice over 30 genes affect bone In mice over 30 genes affect bone

development either positively or negativelydevelopment either positively or negatively Probably at least that many in humansProbably at least that many in humans ConclusionConclusion: individual genetic make-up : individual genetic make-up

relevant to bone structure and density but relevant to bone structure and density but effects can only be calculated in context of effects can only be calculated in context of mechanical experience, environment and mechanical experience, environment and cultural habitscultural habits

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Source: West-Eberhard, Mary Jane. Developmental Plasticity and Evolution, Oxford University Press: 2003.

Chewing bones makes Chewing bones makes crested hyena skullscrested hyena skulls

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Race is a poor category for Race is a poor category for analysis of complex health issues*analysis of complex health issues*

““genetic, anthropological, medical and genetic, anthropological, medical and epidemiological definitions and uses are not epidemiological definitions and uses are not analytically congruent in theory or practice”.analytically congruent in theory or practice”.

Assessment of race is unreliableAssessment of race is unreliable Race is an invalid concept for genetic studiesRace is an invalid concept for genetic studies Does not facilitate development of useful Does not facilitate development of useful

mechanistic hypothesesmechanistic hypotheses Typological view overemphasizes and Typological view overemphasizes and

inappropriately divides biological factors inappropriately divides biological factors from social and environmental componentsfrom social and environmental components

--Shields et al, 2005--Shields et al, 2005

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Analytical and treatment goalsAnalytical and treatment goals

Combine knowledge of personal history Combine knowledge of personal history (past and current nutrition, physical (past and current nutrition, physical

activity, geographical location, activity, geographical location, geographic history, etc.) with an geographic history, etc.) with an analysis of key components of analysis of key components of individual biology to devise a individual biology to devise a

particularized bone health planparticularized bone health plan

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Racial Science is Bad Science Racial Science is Bad Science

Biological race is not a useful variable Biological race is not a useful variable although skin color (vitamin D) or although skin color (vitamin D) or genotype might begenotype might be

Sociological race might correlate with Sociological race might correlate with particular cultural practices, economic particular cultural practices, economic status, types of physical activity, etc., status, types of physical activity, etc., but why not study these instead of an but why not study these instead of an imperfect stand-inimperfect stand-in

Stop using macro-ethnic categoriesStop using macro-ethnic categories

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Nature

Culture

M.C. Escher