Race and Performance

[Guest guest]

I have seen this article somewhere before and it, as it has this

time, left me wondering if there is any true deciding genetic factor

for performance? One power sport with a lower black turn out rate is

olympic lifting, though powerlifting seems to have some outstanding

black competitors. Strongman competitions also seem White,

especially northern European, dominated. Yet, as noted in the

article, other explosive power sports, like sprinting, are Black

dominated. Bodybuilding as well has a stong Black profile. Are we

left shaking our heads for a true definitive answer?

Any correlation with intelligence is weak at best, and perhaps

irrelevant when discussing sports performance. What about attributes

like passion, desire, dedication, perserverence, all the qualities it

takes to make an athlete, despite how " genetically gifted " they might

be. Would Jordan be considered the greatest without pushing

himself as hard as possible? Even Kenyen runners don't just one day

decide " hey, I feel like running 25 miles today for the first time. "

Maybe a correlation between training commitment and body/mind

education should be made.

Chip Conrad

Sacramento, CA

----------------

Mcsiff@a... wrote:

<I cannot recall whether or not this article has been cited earlier,

so my apologies if it is old news to you. It offers a broad overview of

that Race and Performance topic which we were discussing recently.

-----------------------------

WHY BLACK WILL BEAT WHITE AT THE OLYMPICS

Kenan Malik Monday 18th September 2000

<http://www.newstatesman.co.uk/200009180009.htm>

Yes, nature does help to explain African sporting success. If you

think that's racist, your idea of race is wrong.

By Kenan Malik

Next Saturday afternoon, in less time than it has taken me to type

this sentence, the fastest man at the Olympics will take the 100m gold

medal. That man may be the pre-Olympic favourite, the American Maurice Greene.

It may be Trinidad and Tobago's Ato Boldon. It may even be Britain's Dwain

Chambers, who has run in to impressive form in the past few weeks. But

whoever it is, of one thing we can be certain: he will be black. The last time a

white athlete ever appeared in a final, Jimmy was still in the

White House. Over the past decade, the ten-second barrier in the 100m has been

broken 200 times - but not once by a white athlete. Nor is it just at the 100m

that white runners are so noticeably absent. Every men's world record at

every commonly run track distance from 100m to the marathon now belongs

to a runner of African descent. .........

......For Entine, such physiological and biomechanical differences

demonstrate the natural superiority of black athletes. For Entine's critics, on

the

other hand, the very search for such differences betrays a racist

outlook. " I don't think it matters what the biological conclusions are, " argues

the

former footballer Garth Crooks. " It forges a distinction between black and

white athletes which is unhealthy, unhelpful and untrue. " According to

the prestigious scientific journal Nature, " the danger that interracial

comparisons will be inhibited by considerations of political

correctness is less serious than that interracial studies will be wrongly used " .

These critics are responding to a long history of racism in which

black athletic superiority has often been seen as evidence of

intellectual backwardness. " The Negro excels in the events he does because he

is

closer to the primitive than the white man, " claimed Dean Cromwell, the head

coach to the US team at the 1936 Berlin Olympics. " It was not long ago that

his ability to sprint and jump was a life-and-death matter to him in

the jungle. "

Today, too, scientific racists, such as the Canadian psychologist,

J Philippe Rushton, argue that there is a trade-off between brain and brawn,

and that black athletic superiority has been purchased at the price of lower

intelligence. In The Faster Race, Rushton argued that Asian and

white children are born with bigger heads than black infants. Hence, he

said, Asian and white women have a bigger pelvic girdle than do black women. A

smaller pelvis, Rushton claimed, is better suited to running. Ergo, Asians

and whites are brainier, blacks more athletic.

Such claims may seem deeply offensive, but that is no reason to

ignore science or censor data. The debate about differences in sporting

ability is part of a wider debate about the meaning of new knowledge regarding

genetic diversity. Channel 4's The Difference links racial variation in

physical attributes to racial variation in intelligence. The final programme

in the series is largely given over to Murray, the co-author of

The Bell Curve, to argue that black people are naturally less intelligent

that whites and Asians. Liberals who refuse to engage in the debate about

natural difference are simply leaving the terrain open to the likes of

Rushton, Murray and Entine.

The real problem with the " blacks are born to run " thesis is not

that it is politically incorrect, but that it is factually incorrect. The most

basic difficulty with it is its confusion of racial and population

differences. Different population groups are clearly physically distinct. The

Masai of Kenya tend to be taller and longer limbed than the stocky, short-

limbed Inuit in the Arctic, because the body forms of both have been shaped by

natural selection to suit their particular environments. But that there are

physical differences between human groups does not mean that such

differences can be reduced to racial distinctions, nor need they necessarily

have a

consequence in human endeavour, whether that be sport or IQ tests.

It is certainly possible to divide humanity into a number of races,

as we conventionally do, according to skin colour and body form. However,

it is also possible to do it many other ways - using, for instance, blood

group, lactose tolerance, sickle cell, or any other genetic trait.

Genetically, each would be as valid a criterion as skin colour. The distribution

of

one physical or genetic characteristic - say, skin colour - is not

necessarily the same as that of another - such as blood group. The current

division of the world into black, white, Asian and oriental races is, in other

words, as rooted in social convention as in genetics.

Entine rejects such criticisms as mere " semantics " , but his own

argument shows why it is not so. According to Entine, East Africans are

naturally superior at endurance sports, West Africans at sprinting and

jumping, and " whites fall somewhere in the middle " .

But if East and West Africans are at either end of a genetic

spectrum of athletic ability, why consider them to be part of a single race,

and one that is distinct from whites? Only because, conventionally, we use skin

colour as the criterion of racial difference.

To understand why genetic notions of population difference are at

odds with social ideas of race, consider the Australian athlete

Freeman. Freeman, an Aborigine, is the hottest Australian athlete, and a good

tip for

the 400m Olympic gold. Because of their skin colour, Aborigines are often

bracketed with sub-Saharan Africans as a " black " race.

Racial scientists have often argued that Australian Aborigines and

black Africans are the two most primitive races in the world. Since

Freeman's rise to prominence, there has been much speculation that Aborigines,

like black Africans, are natural athletes. Genetically, however, there is no

population in the world more distinct from those of sub-Saharan Africa than

Australian Aborigines. Freeman is genetically closer to white athletes such as

Britain's Merry than to black athletes such as America's n

. Here, as in so much else, appearances can be deceptive.

Not only are genetic notions of population differences distinct

from political concepts of race, but the physiology of human differences

is not easy to interpret in sporting terms. Jon Entine suggests that West

Africans have relatively slender calves compared to whites, and that this

helps their sprinting ability. It is difficult to see how, because muscle power

increases with cross-sectional area; smaller calves should make it harder,

not easier, to excel in explosive sprinting events.

Indeed, slender calves are the main biological reason given for the

feeble presence of African Americans in ice hockey. Yet the same attribute

is seen as enhancing their performance on the track.

It is true that athletes of West African descent living in North

America, Western Europe and the Caribbean dominate many sports. But

contemporary West Africans do not. This is the opposite of what one should

expect if

athletic ability were predominantly determined by genetics.

In the United States, considerable intermixing between black and

white has meant that the African American population embodies, on average,

roughly 30 per cent of genes from populations of European descent. Hence,

African Americans should be poorer athletes than West Africans. The reverse

is true.

What all this suggests is that the relationship between sport,

culture and genetics is much more complex than either liberal anti-racists or

conservatives such as Entine and Murray will allow. Athletic talent

is at least in part inherited, and there are undoubted genetic

differences between regional populations. Nor should we dismiss the possibility

that

West Africans and Kenyans have a genetic advantage when it comes to

sprinting or long-distance running.

There is no reason to assume that all populations have physical

characteristics equally suited to every athletic activity. But are

blacks naturally better athletes than whites? Not necessarily. After all,

how many African Pygmies have you ever seen climbing on to the winners'

rostrum? .........>

[Guest guest]

Mel, Although I've familiar with some of Gould's material and

books, it's important to point out that many scientists in the area

disagree with Gould's sentiments and from my understanding (correct if

I'm wrong) he also represents the minority position in this area. Others

who work in this area may wish to comment. As I stated previously, I

think many individuals (particularly within the left-liberal

political spectrum like Gould who considers himself a Marxist) for

moral and philosophical reasons find that any research suggesting a

genetic component wrt differences in athletic capacities between

individuals, racial sub-groups (however, ill-defined), etc. not only

questionable but repugnant.

[i have met Gould and politically and philosophically I do not see

eye to eye with him. However, his conclusions are by no means

unique to him, as you will see if you browse through our archives. His

concern is that genetics and race are being confused and that is exactly

what everyone is doing in trying to rebut his argument. I have no hesitation

in stating that I also find any attempts to prove racial superiority or

inferiority in any field of endeavour repugnant and counterproductive, be

it in sport, science or anything else. There are far better things to do with

science and our intelligence. Mel Siff]

Again while one may understand such sentiments I think the evidence for a

genetic component wrt athletic ability exists. Here is some research suggesting

a genetic component to athletic ability:

[Neither Gould nor I disagree with this. We are trying to stress that there is

a

major difference between 'race' and genetics. Of course, there are certain

genetic

attributes like height, muscle fibre types, metabolic differences and so forth

which can offer physical advantages, but these are not necessarily a function of

skin-colour-defined 'race', where homogeneity of race is a myth. I am very

aware

of the following papers, especially since I studied material on ACE inhibitors

after

my cardiac bypass surgery, but I came across nothing there which showed any

correlation between some specific gene in Black athletes which explained their

performance in the sprints. Did you? Mel Siff]

1. Myostatin gene and muscle hypertrophy potential:

http://www.ultimate-exercise.com/

(look at articles " brave new world " )

http://www.pnas.org/cgi/content/full/95/25/14938

2. ACE gene and athletic potential:

-------------------------------------------------

http://www.nature.com/cgi-taf/DynaPage.taf?

file=/nature/journal/v393/n6682/full/393221a0_fs.html

-------------------------------------------------

J Appl Physiol 1999 Oct;87(4):1313-6

Human angiotensin I-converting enzyme gene and endurance performance.

Myerson S, Hemingway H, Budget R, J, Humphries S, Montgomery H.

Human physical performance is strongly influenced by genetic factors.

A variation in the structure of the human angiotensin I-converting

enzyme (ACE) gene has been reported in which the insertion (I)

variant is associated with lower ACE levels than the deletion (D)

gene. We have previously reported that the I variant was associated

with improved endurance performance in high-altitude mountaineers and

British Army recruits. We now examine this genotype distribution in

91 British Olympic-standard runners (79 Caucasians). DNA was

extracted from the buccal cells contained in 10 ml of saline

mouthwash donated by the subjects, and the I and D variants of the

ACE gene were identified by PCR amplification of the polymorphic

region. There was an increasing frequency of the I allele with

distance run [0.35, 0.53, and 0.62 for </=200 m (n = 20), 400-3,000 m

(n = 37), and >/=5,000 m (n = 34), respectively; P = 0.009 for linear

trend]. Among 404 Olympic-standard athletes from 19 other mixed

sporting disciplines (in which endurance performance was not

necessarily a key factor), the I allele did not differ significantly

from that found in control subjects: 0.50 vs. 0.49 (P = 0.526). These

results support a positive association of the I allele with elite

endurance performance.

--------------------------------------------------

http://jap.physiology.org/cgi/content/full/87/4/1313

--------------------------------------------------

Eur J Appl Physiol 2000 May;82(1-2):117-20

Genetic variation in the renin-angiotensin system and athletic

performance.

Alvarez R, Terrados N, Ortolano R, Iglesias-Cubero G, Reguero JR,

Batalla A, Cortina A, Fernandez- B, C, Braga S,

Alvarez V, Coto E.

The D allele at the angiotensin-I-converting enzyme (ACE)-

insertion/deletion polymorphism has been associated with an increased

risk of developing several pathological processes, such as coronary

heart disease and ventricular hypertrophy. Individuals with the DD

genotype show a significantly increased left-ventricular mass in

response to physical training, compared to the II genotype (which

would be associated with the lowest plasma ACE levels) and the ID

genotype. The II genotype has been linked to a greater anabolic

response. In accordance with a role for ACE in the response to

rigorous physical training, a higher frequency of the I allele has

been reported to exist among elite rowers and high-altitude

mountaineers. Sixty elite (professional) athletes (25 cyclists, 20

long-distance runners, and 15 handball players), and 400 healthy

controls were genotyped for the DNA polymorphisms of the ACE,

angiotensinogen (Ang) and angiotensin receptor type 1 (AT1) genes.

Plasma ACE levels showed a strong correlation with the I/D genotype

in our population. The I-allele occurred at a significantly higher

frequency in athletes compared to controls (P = 0.0009). Gene and

genotype frequencies for the Ang and AT1 polymorphisms did not differ

between athletes and controls. Since the frequency of the ACE I

allele was significantly increased among our elite athletes, we

conclude that the ACE polymorphism represents a genetic factor that

contributes to the development of an elite athlete.

---------------------------------------------------

Hum Genet 1998 Jul;103(1):48-50

Elite endurance athletes and the ACE I allele--the role of genes in

athletic performance.

Gayagay G, Yu B, Hambly B, Boston T, Hahn A, Celermajer DS, Trent RJ.

Genetic markers that might contribute to the making of an elite

athlete have not been identified. Potential candidate genes might be

found in the renin-angiotensin pathway, which plays a key role in the

regulation of both cardiac and vascular physiology. In this study,

DNA polymorphisms derived from the angiotensin converting enzyme

(ACE), the angiotensin type 1 receptor (AT1) and the angiotensin type

2 receptor (AT2) were studied in 64 Australian national rowers.

Compared with a normal population, the rowers had an excess of the

ACE I allele (P<0.02) and the ACE II genotype (P=0.03). The ACE I

allele is a genetic marker that might be associated with athletic

excellence. It is proposed that the underlying mechanism relates to a

healthier cardiovascular system.

-------------------------------------------------

Gus Karageorgos

Toronto, Canada

[Guest guest]

Race and genetics are related, for all blacks share the same gene for black

skin.

[Are we to assume that this includes Black Indians, Black Arabs, Black

Aborigines,

Black Polynesians and so forth, so that this common gene may also be somehow

related to athletic prowess in some sports? Mel Siff]

I think the fact that blacks have different bone lengths and different

calve attachments can have a lot to do with running and jumping. I think we

all agree that different races evolved over time and each has had to evolve

to suit the environment. If we take dogs, we don't say that all dogs are

equal to running and mental ability. I don't know what the problem is with

there being differences between different races abilities. We know that race

exists, and there have been some interracial mixing, but that is the

exception and not the rule. I think we haven't seem much research on race has

to do with the political correctness of this topic. All the scientists and

psychologists who show differences between races are immediately called

racist and chased into a hole. I think once we stop being so hypersensitive

about the subject we can then get to the bottom of the argument.

[Yes, let us pay attention to the science involved, namely the relationship

between

genetics and performance, and not 'race' and performance. Nobody objects to

that,

especially since we are one day going to use that knowledge to genetically

manipulate

genes to enhance performance. Some folk may even choose to manipulate skin

colour

for personal reasons and this will really upset the applecart! Mel Siff]

Bob Forney

Bay Area California

>

> [This has nothing to do with 'race', but with genetics, and this is the

> point that Gould, Keino,

> myself and many others are making. Others have pointed out that there is

> as much intragroup

> variation as there is intergroup variation and that comparisons based upon

> small samples

> of large groups can be very misleading. Browse through those past articles

> by Dr Owen and

> others for more material on this issue. Mel Siff]

>

> Kurland

> Chicago

>

[Guest guest]

< Others have pointed out that there is as much intragroup

variation as there is intergroup variation and that comparisons based upon

small samples of large groups can be very misleading. Browse through those past

articles by Dr Owen and others for more material on this issue. Mel

Siff >

This is provably false - if there was as much intragroup variation as

intergroup variation, then the group would not excel. There is less, which

is not to say zero.

[Not true - as Oti and others have pointed out, many members of a given group

may not even

take part in a given sport or that sport may not even be practised or practised

as seriously by

different groups. Moreover, the groups being discussed are hardly homogeneous.

Much of this

discussion has been assuming that race is the only variable involved, with all

other factors being

held constant (ceteris paribus). On this basis, how does one accurately define

" race " as a discrete

group insofar as it relates to what we are discussing? Mel Siff]

Kurland

Chicago

[Guest guest]

> I'll admit that " practice makes perfect " in the true sense of the

> adage, but to deny there exists genetic advantages by certain

> individual is plain ludicrous.

> Surely these people can't deny that certain distinct inate physical

> traits/attributes like fiber typing, limb and forelimb length

> etc " aid " in one's

> ability to develop into a champion? Or am I completely missing the

> point? I

> think that all of this is just " scientific do-goodism " and that

> liberalism is

> invading into the realm of empiricism once again.

The issue is not that traits like fiber typing, skeletal build etc.

are not essential in determining sporting performance. The issue is

also not that physical variations exist between individuals which

lead to disparities in performance. The influence of genetics on

sporting performance is undeniable and undisputed.

What is being questioned is the assertion that specific *races* are

innately better at athletic activities than other races. There are

many arguments against such an assertion, but they broadly break down

into three categories:

1. The concept of " race " is difficult, if not impossible to quantify.

Much reference is made for instance of African Americans, whereas US

blacks are not even a homogeneous group let alone racially " pure " --

the past two centuries have ensured that there is a very significant

Caucasian complement to their West African ancestry.

2. There is no scientific evidence that one " race " posseses genetic

advantages. No study has conclusively shown, for example, that

African Americans have more fast twitch fiber on average than

Caucasian Americans. The key word here is " on average " .

3. Socio-economic (e.g. nutrition, standard of living, training

facilities, commercial support etc.) and cultural factors (role

models, community expectations, national sport preferences etc.) are

the primary contributing factors to the relative successes of

different groups in different sports.

Arguments that assert that certain races are better than others in

sports usually rely on one argument:

1. In sport X in country Y, there are a disproportionate number of

people of race Z who excel in that sport. Therefore race Z must have

innately superior athletics abilities.

For some unfathomable reason, this attitude is especially prevalent

among my US friends and acquaintances, and to a lesser degree among

Brits. A number of my closest friends are from former East Bloc and

Near East countries, and they do not share this attitude at all.

Elliott Oti

The Netherlands

[Guest guest]

> to do with sprinting abilities. They make up about 10% of the

>population of

> the US, yet they completely dominate this sport in the US. They

> make up a

> very small percentage of the world's population, yet they

> completely dominate

> sprinting on the world level. The top 20 asian sprinters in the

> world can't

> come close to the performance of many black sprinters who are

> nowhere near

> the top 10, let alone the very top.

Yet the fact is also that the Japanese sprint record (100m, 10.00s,

Keiji Ito) is faster than the national sprint records of all West

African countries except Ghana and Nigeria.

The fact is, West Africans don't dominate sprinting. Black US

sprinters and sprinters of Carribean extract do. But there is nothing

racially " pure " about black US sprinters --judging from their skin

colour, Maurice Greene and Jon Drummond are closer to mulatto than to

classic black.

The fact that all men's track records from the 100m to the 10,000m

are held by people of African descent, is often touted as proof of

their athletics superiority.

Less mention is made of the fact that all women's track records with

the sole exception of the 100m and 200m, are held by women who are

NOT of African descent.

> That is an issue that needs to be considered. I don't think that

> being

> concerned about divisiveness will lead anyone to the truth. It

> smacks of

> taking ideology over evidence.

The only ideology I see, is the ideology that genetically

identifiable and separable races exist (and specifically, the US-

centric notion of separate black and white races).

In the US it was the case (and still is, to some extent), that a

person was classified as " colored " even if the proportion of African

ancestry was minor. Hence terms like mulatto, quadroons and

octoroons. Tiger Woods, for instance, is called " black " even though

he is only one-quarter of African-American descent. (For some reason

he is not called " Chinese " , even though he is also of 25% Chinese

descent. I guess that would spoil the myth).

The US is probably one of the most racially heterogeneous countries

in the world, with a lot of intermixture between races. Yet local

ideology clings to the idea of separate, genetically distinguishable

races. I think not.

Elliott Oti

The Netherlands.

[Guest guest]

This discussion has been temporarily closed, since almost all contributions

are repeating what was written several months ago on the same topic, albeit

in different words. However, if anyone has any genuine research information

on the relationship between specific genes and specific types of human or

animal performance, that sort of material will be welcomed because of its far

more objective nature.

Many thanks to all who took the time to contribute to discuss this

controversial issue.

Dr Mel C Siff

Denver, USA

[Guest guest]

Mel Siff wrote:

<I came across nothing there which showed any

correlation between some specific gene in Black athletes which

explained their performance in the sprints. Did you? >

Elliott Oti wrote:

<No study has conclusively shown, for example, that

African Americans have more fast twitch fiber on average than

Caucasian Americans. The key word here is " on average " . >

I thought I would post some of the studies done by a few researchers in this

area.

I'm hoping that Dr. Siff will allow this post through so that others who may not

have

come across the material may see why some researchers do believe that

there may be a ethnic/racial(however, ill-defined) relationship to

particular athletic abilities, just as there arguably is with certain

disease states.

[Mel Siff: I am allowing this post through because it draws upon scientific

research, even

though all of the research is, as Gus states, based upon a very ill-defined

superficial

racial or ethnic classification, rather than any analysis of genetic markers.

No comparison

is made between the characteristics and performances of very young children,

pre-adolescents

or twins within racial groups - nor is any attempt made to control for

environmental factors

such as childhood activities and nutrition.

In the South African research, presented in Item 5 (Endurance ability and East

African Heritage),

it is noteworthy that the Caucasian subjects often did not include various elite

athletes, such as

Bruce Fordyce, who were never defeated by Black runners in ultramarathon events

(especially

the renowned Comrades marathon). In other words, the samples used may not have

been free

from certain bias.

In fact, only two Black men have ever won the Comrades Marathon since it began

in 1921, and no

black woman has ever won the women's event since it began in1975. Even if we

take account of the

apartheid years which made competition very difficult for or Black colleagues,

only two Black athletes

have ever won the Comrades in some 20 years. Interestingly, during the past

five years, the

event has been won by Russian or Eastern European runners, even though many

hundreds of Black

athletes compete annually. Does this somehow suggest that 'Black' athletes may

not be genetically

suited to ultra-endurance events? I think not.

Enough said! While all of this research is interesting and suggestive, it does

not yet permit us

to specifically identify which factor or factors currently determine why so many

Black

athletes excel in sprint type activities and marathon races, but not

ultramarathons. With the

rapid growth of genetic research which is accompanying the Human Genome project,

it will be very

interesting to see the first research which examines the presence of specific

genes or genetic

variations which may relate to certain types of motor and metabolic proficiency.

Until then,

there are simply too many uncontrolled variables to allow scientists to make any

definitive

conclusions about correlations between 'race' and performance. ]

--------------------------------------------

1. Fiber-type Differences:

---------------------------------------------

J Appl Physiol 1986 Nov;61(5):1758-61

Skeletal muscle characteristics in sedentary black and Caucasian

males.

Ama PF, Simoneau JA, Boulay MR, Serresse O, Theriault G, Bouchard C.

Twenty-three male Black African and 23 male Caucasian subjects,

ascertained as sedentary, participated in this study designed to

determine whether there were differences in skeletal muscle

histochemical and biochemical characteristics between racial groups.

Muscle fiber type proportions (I, IIa, and IIb), fiber areas and

activities of several enzyme markers of different energy metabolic

pathways were determined from a biopsy of the vastus lateralis.

Results indicated that Caucasians had a higher percent type I (8%, P

less than 0.01) and a lower percent type IIa (6.7%, P less than 0.05)

fiber proportions than Africans. No significant differences were

observed between the two racial groups in the type IIb fiber

proportion or in the three fiber type areas. Enzymes catalyzing

reactions in phosphagenic [creatine kinase (CK)] and glycolytic

[hexokinase (HK), phosphofructokinase (PFK), and lactate

dehydrogenase (LDH)] metabolic pathways had significantly higher

activities (about 30-40%) in the Black African group than in the

Caucasian group (P less than 0.01). No significant difference was

noted in the activities of oxidative enzymes [malate dehydrogenase

(MDH), oxoglutarate dehydrogenase (OGDH), and 3-hydroxyacyl-CoA

dehydrogenase (HADH)]. Consequently, the PFK/OGDH ratio was

significantly elevated in Africans (P less than 0.05). The racial

differences observed between Africans and Caucasians in fiber type

proportion and enzyme activities of the phosphagenic and glycolytic

metabolic pathways may well result from inherited variation. These

data suggest that sedentary male Black individuals are, in terms of

skeletal muscle characteristics, well endowed for sport events of

short duration.

-----------------------------------------------

2. ACE differences:

-----------------------------------------------

Am J Med Sci 2000 Jul;320(1):18-23

Elevated mortality rates from circulatory disease in African American

men and women of Los Angeles County, California--a possible genetic

susceptibility?

SO, Coetzee GA, Ross RK, Yu MC, BE.

OBJECTIVE: Reports of higher mortality in African Americans have

often focused on socioeconomic differences. Such differences do not

explain the excess mortality in African Americans compared with

Hispanics in Los Angeles County. We suggest the existence of genetic

factors to explain at least some of the differences in mortality

risk. METHODS: We compared the mortality rates from circulatory

diseases in African American and Hispanic adults of Los Angeles

County for 1988 to 1992 with the frequency of the angiotensin-

converting enzyme (ACE) genotype. RESULTS: African American adults 45

to 74 years old had a 2-fold higher overall mortality rate than

Hispanics. The largest differences were seen for hypertensive disease

and cardiomyopathy in men; the most striking differences were seen in

the youngest age group. Rates were lower in women than in men, but

African American women also showed substantial excess compared with

Hispanics. ACE genotype also showed a significant difference between

the Hispanic and African American population; the latter had a

significantly higher prevalence of the DD genotype, which is

associated with a higher level of circulating enzyme, and lower

prevalence of the II genotype, which is associated with a lower

enzyme level.

CONCLUSION: African American adults aged 45 to 74 years

in Los Angeles County have a substantial excess mortality from

hypertensive diseases compared with a similar Hispanic population.

The frequency of the ACE DD genotype was higher in African Americans

than in Hispanics. These studies may indirectly support the

possibility of a genetic contribution to the excess hypertensive

disease mortality in African Americans.

-----------------------------------------------

3. Body and Bone Mass Differences:

-----------------------------------------------

Ethn Health 1996 Dec;1(4):337-47

Ethnic differences in body composition and their relation to health

and disease in women.

Gasperino J.

Differences in body composition between black and white women have

been well established. Black women have more bone and muscle mass,

but less fat, as a percentage of body weight, than white women, after

controlling for ethnic differences in age, body weight, and height.

In addition, black women have more upper-body fat than white women.

These ethnic differences in body composition appear to be associated

with disease risk in women. The greater skeletal and muscle mass in

black compared to white women appears to protect them from

osteoporosis. The relationship between fat distribution and

cardiovascular disease also appears to be influenced by ethnicity.

This review has two purposes: (1) To examine previous research

investigating ethnic differences in body composition between black

and white women; and (2) To demonstrate the relationship between body

composition and disease in women as a function of ethnicity.

-----------------------------------------------

Am J Clin Nutr 2000 Jun;71(6):1392-402

Measures of body composition in blacks and whites: a comparative

review.

Wagner DR, Heyward VH.

Biological differences exist in the body composition of blacks and

whites. We reviewed literature on the differences and similarities

between the 2 races relative to fat-free body mass (water, mineral,

and protein), fat patterning, and body dimensions and proportions. In

general, blacks have a greater bone mineral density and body protein

content than do whites, resulting in a greater fat-free body density.

Additionally, there are racial differences in the distribution of

subcutaneous fat and the length of the limbs relative to the trunk.

The possibility that these differences are a result of ethnicity

rather than of race is also examined. Because most equations that

predict relative body fat were derived from predominantly white

samples, biological variation between the races in these body-

composition indexes has practical significance. Systematic error can

result in the inaccurate estimation of the relative body fat of

blacks, and therefore of definitions of obesity, if these inherent

differences are ignored.

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J Appl Physiol 1984 Jun;56(6):1647-9

Density of lean body mass is greater in blacks than in whites.

Schutte JE, Townsend EJ, Hugg J, Shoup RF, Malina RM, Blomqvist CG.

Previous studies have reported that Blacks have 10-20% more bone

mineral than Whites of the same height. Theoretically, this should

mean that the lean body mass of Blacks is denser than that of Whites,

such that formulas for calculating lean body mass from density in

Whites will overestimate the lean body mass (and thus underestimate

fatness) in Blacks. To determine if the lean body mass of Blacks is

indeed denser than that of Whites, we measured density, total body

water, and anthropometric dimensions in 19 white and 15 black male

college students. The black and white cohorts were nearly identical

in height, weight, and total body water. Among the Whites there was

no significant difference between the observed density and that

predicted from anthropometry, nor were there any significant

differences between the dimensions of body composition calculated

from total body water and from observed density. Among the Blacks,

however, the observed density was significantly greater than that

predicted from anthropometry, and the lean body mass calculated from

observed density was significantly greater than that calculated from

total body water. These results are consistent with the hypothesis

that the lean body mass of the Blacks is denser than that of the

Whites. Separate formulas should therefore be used for converting

density to body composition. Based on our data, the correct formula

for Blacks is: %fat = 100 X [(4.374/density) - 3.928]. This formula

indicates a lean body density of 1.113 g/cm3 in Blacks compared with

1.100 in Whites.

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4. Hormonal differences:

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J Clin Endocrinol Metab 1995 Aug;80(8):2291-7

Greater secretion of growth hormone in black than in white men:

possible factor in greater bone mineral density--a clinical research

center study.

NM, Renault J, Willi S, Veldhuis JD, Pandey JP, Gordon L, Key

LL, Bell NH.

To determine why blacks have a higher bone mineral density (BMD) and

lower incidence of osteoporosis and fractures than whites, we

investigated whether the secretion of GH is higher in black than in

white men. Measurements of GH were obtained at 20-min intervals over

24 h and analyzed by deconvolution. BMD was determined by dual energy

x-ray absorptiometry in 16 normal black and 17 normal white men, aged

20-40 yr. The 24-h integrated GH concentration 942 +/- 174 vs. 602 +/-

104 micrograms/L; P = 0.0495) and GH secretory burst amplitude (0.499

+/- 0.163 vs. 0.169 +/- 0.027 micrograms/L.min; P = 0.0482) were

higher in black than in white men. GH burst frequency, half-duration,

mass, and half-life were not different in the 2 groups. The serum 17

beta-estradiol level (162 +/- 12 vs. 108 +/- 11 pmol/L; P = 0.0011)

was higher, and the serum insulin-like growth factor-binding protein

3 level (2.2 +/- 0.1 vs. 2.8 +/- 0.1 microgram/mL; P = 0.0001) was

lower in black than in white men. BMD values for total body (1.22 +/-

0.02 vs. 1.14 +/- 0.02 g/cm2; P = 0.0041), forearm (0.69 +/- 0.01 vs.

0.66 +/- 0.01 g/cm2; P = 0.0211), trochanter (0.91 +/- 0.03 vs. 0.77

+/- 0.03 g/cm2; P = 0.0003), and femoral neck (1.08 +/- 0.03 vs. 0.93

+/- 0.03 g/cm2; P = 0.0007) were higher in black than in white men.

Thus, serum 17 beta-estradiol level, GH secretion, and BMD values for

the total body, forearm, trochanter, and femoral neck are greater in

black than in white men. As estrogen is known to increase GH

secretion and GH to increase bone mass, increases in circulating 17

beta-estradiol may contribute to the higher GH secretion and bone

mass in black men.

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J Natl Cancer Inst 1986 Jan;76(1):45-8

Serum testosterone levels in healthy young black and white men.

Ross R, Bernstein L, Judd H, Hanisch R, Pike M, B.

Blacks in the United States have the highest prostate cancer rate in

the world and nearly twice that of whites in the United States. The

2:1 black-to-white ratio in prostate cancer rates is already apparent

at age 45 years, the age at which the earliest prostate cancer cases

occur. This finding suggests that the factor(s) responsible for the

difference in rates occurs, or first occurs, early in life.

Testosterone has been hypothesized to play a role in the etiology of

prostate cancer, because testosterone and its metabolite,

dihydrotestosterone, are the principal trophic hormones that regulate

growth and function of epithelial prostate tissue. This report gives

the results of assays of circulating steroid hormone levels in white

and black college students in Los Angeles, CA. Mean testosterone

levels in blacks were 19% higher than in whites, and free

testosterone levels were 21% higher. Both these differences were

statistically significant. Adjustment by analysis of covariance for

time of sampling, age, weight, alcohol use, cigarette smoking, and

use of prescription drugs somewhat reduced the differences. After

these adjustments were made, blacks had a 15% higher testosterone

level and a 13% higher free testosterone level. A 15% difference in

circulating testosterone levels could readily explain a twofold

difference in prostate cancer risk.

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5. Endurance ability and East African Heritage:

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J Appl Physiol 1999 Mar;86(3):915-23

African runners exhibit greater fatigue resistance, lower lactate

accumulation, and higher oxidative enzyme activity.

Weston AR, Karamizrak O, A, Noakes TD, Myburgh KH.

Nine African and eight Caucasian 10-km runners resident at sea level

volunteered. Maximal O2 consumption and peak treadmill velocity (PTV)

were measured by using a progressive test, and fatigue resistance

[time to fatigue (TTF)] was measured by using a newly developed high-

intensity running test: 5 min at 72, 80, and 88% of individual PTV

followed by 92% PTV to exhaustion. Skeletal muscle enzyme activities

were determined in 12 runners and 12 sedentary control subjects. In a

comparison of African and Caucasian runners, mean 10-km race time,

maximal O2 consumption, and PTV were similar. In African runners, TTF

was 21% longer (P < 0.01), plasma lactate accumulation after 5 min at

88% PTV was 38% lower (P < 0.05), and citrate synthase activity was

50% higher (27.9 +/- 7.5 vs. 18.6 +/- 2.1 micromol. g wet wt-1. min-

1, P = 0.02). Africans accumulated lactate at a slower rate with

increasing exercise intensity (P < 0.05). Among the entire group of

runners, a higher citrate synthase activity was associated with a

longer TTF (r = 0.70, P < 0.05), a lower plasma lactate accumulation

(r = -0.73, P = 0.01), and a lower respiratory exchange ratio (r = -

0.63, P < 0.05). We conclude that the African and Caucasian runners

in the present study differed with respect to oxidative enzyme

activity, rate of lactate accumulation, and their ability to sustain

high-intensity endurance exercise.

The full article can be found at:

<http://jap.physiology.org/cgi/content/full/86/3/915>

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J Appl Physiol 1993 Oct;75(4):1822-7

Superior fatigue resistance of elite black South African distance

runners.

Coetzer P, Noakes TD, B, Lambert MI, Bosch AN, Wiggins T,

Dennis SC.

Black athletes currently dominate long-distance running events in

South Africa. In an attempt to explain an apparently superior running

ability of black South African athletes at distances > 3 km, we

compared physiological measurements in the fastest 9 white and 11

black South African middle-to long-distance runners. Whereas both

groups ran at a similar percentage of maximal O2 uptake (%VO2max)

over 1.65-5 km, the %VO2max sustained by black athletes was greater

than that of white athletes at distances > 5 km (P < 0.001). Although

both groups had similar training volumes, black athletes reported

that they completed more exercise at > 80% VO2max (36 +/- 18 vs. 14

+/- 7%: P < 0.005). When corrections were made for the black

athletes' smaller body mass, their superior ability to sustain a high

%VO2max could not be explained by any differences in VO2max, maximal

ventilation, or submaximal running economy. Superior distance running

performance of the black athletes was not due to a greater (+/- 50%)

percentage of type I fibers but was associated with lower blood

lactate concentrations during exercise. Time to fatigue during

repetitive isometric muscle contractions was also longer in black

runners (169 +/- 65 vs. 97 +/- 69 s; P < 0.05), but whether this

observation explains the superior endurance or was due to the lower

peak muscle strength (46.3 +/- 10.3 vs. 67.5 +/- 18.0 Nm/l lean thigh

volume; P < 0.01) remains to be established.

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Eur J Appl Physiol Occup Physiol 1990;61(1-2):68-72

Physiological differences between black and white runners during a

treadmill marathon.

Bosch AN, Goslin BR, Noakes TD, Dennis SC.

To determine why black distance runners currently out-perform white

distance runners in South Africa, we measured maximum oxygen

consumption (VO2max), maximum workload during a VO2max test (Lmax),

ventilation threshold (VThr), running economy, inspiratory

ventilation (VI), tidal volume (VT), breathing frequency (f) and

respiratory exchange ratio (RER) in sub-elite black and white runners

matched for best standard 42.2 km marathon times. During maximal

treadmill testing, the black runners achieved a significantly lower

(P less than 0.05) Lmax (17 km h-1, 2% grade, vs 17 km h-1, 4% grade)

and VI max (6.21 vs 6.82 l kg-2/3 min-1), which was the result of a

lower VT (101 vs 119 ml kg-2/3 breath-1) as fmax was the same in both

groups. The lower VT in the black runners was probably due to their

smaller body size. The VThr occurred at a higher percentage VO2max in

black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2%

respectively) but there were no differences in the VO2max. However,

during a 42.2-km marathon run on a treadmill, the black athletes ran

at the higher percentage VO2max (76%, SD 7.9% vs 68%, SD 5.3%), RER

(0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min-1, SD 11 vs 47

breaths min-1, SD 10), and at lower VT (78 ml kg-2/3 breath-1, SD 15

vs 85 ml kg-2/3 breath-1, SD 19). The combination of higher f and

lower VT resulted in an identical VI.

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Scand J Med Sci Sports 1995 Aug;5(4):209-21

Aerobic exercise capacity at sea level and at altitude in Kenyan

boys, junior and senior runners compared with Scandinavian runners.

Saltin B, Larsen H, Terrados N, Bangsbo J, Bak T, Kim CK, Svedenhag

J, Rolf CJ.

The aim of this study was to characterize Kenyan runners in regard to

their oxygen uptake and blood and ammonia responses when running.

Untrained Kenyan boys (14.2 +/- 0.2 years) and Scandinavian runners

were included for comparison. The studies were performed at altitude

(approximately 2.000 m.a.s.l.) and, for several Kenyan and

Scandinavian runners, at sea level as well.

At altitude sedentary adolescent Kenyan boys had a mean maximal oxygen uptake

(VO2max) of

47 (44-51) ml.kg-1.min-1, whereas similarly aged boys regularly

walking or running but not training for competition reached above 62

(58-71) ml.kg-1.min-1 in VO2max. Kenyan runners in active training

had 68 +/- 1.4 ml.kg-1.min-1 at altitude and 79.9 +/- 1.4 ml.kg-1.min-

1 at sea level, with individuals reaching 85 ml.kg-1.min-1. The best

Scandinavian runners were not significantly different from the Kenyan

runners in VO2max both at altitude and at sea level, but none of the

Scandinavians reached as high individual values as observed for some

Kenyan runners. The running efficiency, determined as the oxygen cost

at a given running speed, was less in the Kenyan runners, and the

difference became more pronounced when body weight was expressed in

ml.kg-0.75 min-1. Blood lactate concentration was in general lower in

the Kenyan than in the Scandinavian runners, and the Kenyans also had

extremely low ammonia accumulation in the blood even at very high

exercise intensities. It is concluded that it is the physical

activity during childhood, combined with intense training as

teenagers that brings about the high VO2max observed in some Kenyan

runners. Their high aerobic capacity, as well as their good running

economy, makes them such superior runners. In addition, their low

blood lactate and ammonia accumulation in blood when running may also

be contributing factors.

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Scand J Med Sci Sports 1995 Aug;5(4):222-30

Morphology, enzyme activities and buffer capacity in leg muscles of

Kenyan and Scandinavian runners.

Saltin B, Kim CK, Terrados N, Larsen H, Svedenhag J, Rolf CJ.

The study comprises data on 12 Scandinavian runners who had either

trained for two weeks in Kenya (n = 6; approximately 2000 meters

above sea level (m.a.s.l.)) or in Portugal (n = 6; sea level (s.l.))

and on 13 Kenyan runners (9 junior and 4 senior) living and training

at approximately 2000 m.a.s.l. Muscle biopsies were taken before and

after the training camps in the Scandinavian runners and once on the

Kenyan runners from the vastus lateralis (v.l.) and the gastrocnemius

muscles.

Muscle fiber size and composition were similar in the

various groups (4.6-5.1 X 10(3) microns2; ST approximately 60-70%;

FTa 30-40%; FTb < 6.0%) with a tendency for some more (approximately

5%) FTa fibers in the gastrocnemius muscle. Mean number of

capillaries in v.l. varies between 405-493 cap.(mm2)-1, 2.0-2.7

cap.fiber-1, and 4.4-6.2 cap around the various fiber types, with the

Kenyan seniors having the highest and the Kenyan juniors the lowest

values. All runners had 10-20% more capillaries in their

gastrocnemius muscle. Similar levels for citrate synthase (CS)

activity were found in the v.l. of the Kenyan seniors and

Scandinavian runners, whereas the Kenyan juniors were 10-15% lower.

The 3- hydroxyacyl-CoA-dehydrogenase (HAD) activity was 20% higher in

the Kenyan than in the Scandinavian runners. In the gastrocnemius

muscle, both enzyme activities were 20-50% higher in Scandinavian and

Kenyan runners. The ratio for lactate dehydrogenase (LDH) isoform1-2

and isoform4-5 was increased when training at altitude due to a

lowering of LDH4-5 and became close to what was observed in the

Kenyan runners.

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Gus Karageorgos

Toronto, Canada