Racial/ethnic differences in male pattern baldness

[Vulpix]

Someone at Skadi brought my attention to this interesting blog entry:

Racial/ethnic differences in male pattern baldness




The following entry from Polak showed up in my feed reader, though Polak seems to have removed it from his site.

Recent positive selection and male pattern baldness

[This study] shows that recent selection has apparently pushed up the risk of baldness in Europeans, although obviously it's a lot more complex than that. The authors focus on the HapMap cohorts (Chinese, Japanese, Yoruba from Nigeria and Utah European Americans), which is a bit of a shame, because it would've been great to see the results for a variety of European groups. By the way, no subscription or payment is required for this one...

Axel M. Hillmer et al, Recent positive selection of a human androgen receptor/ectodysplasin A2 receptor haplotype and its relationship to male pattern baldness, Human Genetics, Published online: 17 April 2009, doi: 10.1007/s00439-009-0668-z

I'm not terribly interested in quantitative differences here, but some qualitative ethnic differences in hairlines jump out at the observant. The straight-across hairline can add a vaguely disturbing note to already less-than-aesthetic Jewish physiognomies.

More:

The Mediterranean or Latin development of pattern baldness involves recession of the frontal hairline and the development of vertex baldness. These two regions of hair loss expand and coalesce into the extensive type V pattern.

The Semitic (Jewish, Arabian) presentation of pattern alopecia involves progressive recession of the frontal hairline but there is no associated thinning on the vertex according to Ebling.

The Nordic presentation with a central lock of surviving hair was noted by Norwood in the development of his classification system. Ebling suggested the five stage system for Nordic races as shown below.

Also see this book chapter:

Human balding occurs in several patterns. These sometimes occur together or separately and occur at different frequencies. Some noteworthy patterns are: (A) Double point, forehead recession, widow’s peak; (B) Monk’s spot (usually A and B occur together; they are common in many European countries); (C) Line-of-march, common in the Mediterranean countries (e.g., Albert Einstein); (D) Single point forehead recession, common among Orientals (e.g., Mao Tse-tung).

References (from the first site linked above):

* Norwood OT. Male pattern baldness: classification and incidence. South Med J. 1975 Nov;68(11):1359-65.
* Hamilton JB. Patterned loss of hair in man: types and incidence. Ana N Y Acad Dermatol 1951:53;708-28
* Camacho F, Montagna W. Trichology. Diseases of the pilosebaceous follicle. S. Karger Publishers Inc. Farmington, USA. 1998. ISBN: 3-8055-6672-7
* Norwood OT. Hair Transplant Surgery. Charles C Thomas Publishers, Springfield IL, USA, 1973. ISBN 0-398-02892-3

[Freomæg]

Interesting. These days I'm curious about the more subtle physical indicators of race: Waviness and density of hair, baldness, body hair etc. So this is a welcome thread.

[Vargtand]

d: ˙˙˙uǝddɐɥ ʇuoʍ ʇı ʎllnɟǝdoɥ os ʇǝʎ pǝʇɹɐʇs ʇou ǝʌɐɥ ı llǝʍ `plɐq ƃuıʇʇǝƃ ˙˙˙sǝıɹɹoʍ ʇsǝƃƃıq ʎɯ ɟo ǝuo

[Tabiti]

No bald men in my family as far as I know.

[Rainraven]

d: ˙˙˙uǝddɐɥ ʇuoʍ ʇı ʎllnɟǝdoɥ os ʇǝʎ pǝʇɹɐʇs ʇou ǝʌɐɥ ı llǝʍ `plɐq ƃuıʇʇǝƃ ˙˙˙sǝıɹɹoʍ ʇsǝƃƃıq ʎɯ ɟo ǝuo

I think you deserve it for typing upside down

I'm more scared of this!

[Gooding]

My Dad started going bald in his early thirties and he still has quite a bit of hair left, my mother's father never went bald and I'm a couple of years older than my Dad when he started to lose his hair and I've still got a full head of hair. Baldness is not a concern of mine right now.

[Lenny]

Baldness is one of those things very hard to select for, it seems to me. Being that it passes through the female line. Or so is my understanding.

I wonder how it began and the relative frequencies of baldness across groups.

[Vargtand]

Baldness is one of those things very hard to select for, it seems to me. Being that it passes through the female line. Or so is my understanding.

I wonder how it began and the relative frequencies of baldness across groups.

Once I read an article that purposed that much like the gorilla males develop an elongated forehead as sign of social status or some such, from there pattern baldness was interlinked, I can't really remember what it said exactly but it was drawing parallels to characteristics of other maturing primates.

[Lenny]

much like the gorilla males develop an elongated forehead as sign of social status or some such, from there pattern baldness was interlinked

But baldness passes thru the female in humans!

[Agrippa]

Baldness/Alopecia being linked to a genetically determined sensitiveness to a product of the male hormon circle.

Traits can also survive if they have no significant negative effect - remember, its not necessary for a trait to be positive to survive, its enough to bring not too much damage, disadvantages to the carrier. Obviously baldness from 30's on f.e. is not such a bad impact, that it would bring death to a bloodline over a short time span, thats for sure.

There might have been positive effects, like a higher forehead, more mature looking face or something like that, but thats all speculation.