William Aiken

There is something very special about the people of the Caribbean. Of the 35 or so men in the world who belong to the elite club of having run the men's 100 metres sprint in under 10 seconds, six (Asafa Powell, Donald Quarrie, Raymond Stewart, Ben Johnson, Linford Christie and Donovan Bailey) were born in Jamaica.

Another five of these men are from other Caribbean countries and the remainder are largely African-Americans (18), four West Africans (Frankie Fredericks, Francis Obikwelu, Olusoju Fasuba and Aziz Zakari), one Briton (Dwain Chambers) and one Australian whose mother interestingly is an aborigine. On a per capita basis, the Caribbean is disproportionately endowed with athletic sprinting ability as it is with prostate cancer.

Trinidad and Tobago makes for some interesting observations. A much higher prostate cancer incidence and mortality has been documented in Afro-Trinidadians compared to Indo-Trinidadians although they share the same environment, notwithstanding cultural/religious differences and perhaps differences in socioeconomic status which may serve as confounding factors (associations that may provide alternative explanations to observed differences) to race.

All four of Trinidad's famous sprinters are primarily of African descent. Indeed, Trinidad's relatively small sub-population of African descent has produced more successful sprinters than the entire billion-plus population of the Indian subcontinent. Is this due primarily to inherent differences in racial abilities, or is it due to areas of focus by different racial groups or are the two interrelated? Interestingly, the incidence of prostate cancer in India is extremely low at 7.4 men per 100,000 per year.

Sprinting prowess seems to mirror prostate cancer incidence or prevalence very well as is well demonstrated by Jamaica's example.

Anabolic steroid

It is well known that athletes take anabolic steroids to unfairly enhance athletic performance. Anabolic steroids undoubtedly can make a sprinter run faster, and we have seen many infamous examples of this over the years. Testosterone, the naturally occurring prototypical anabolic steroid when inhibited or its primary source, the testicles, removed in someone with advanced prostate cancer, will cause the cancer to shrink. The corollary of this is that testosterone is needed for prostate cancer to develop in the first place.

Unwittingly, giving someone who has prostate cancer testosterone is analogous to throwing gasoline on an open fire. Evidence is contradictory, but some studies demonstrate that blacks have 15 per cent higher testosterone levels compared to Caucasians. Even more importantly, the testosterone receptor in blacks is more responsive to testosterone and its active derivative dihydrotestosterone. Could Afro-Caribbean people and African-Americans in general and Jamaicans in particular have higher testosterone responsiveness than native West Africans, and could this be an effect of selection pressures induced by the middle passage?

History and biology

Known risk factors for prostate cancer include male gender, age, family history and black ethnicity. However, when prostate cancer incidence in West African blacks is compared to that in blacks in places such as Jamaica, Trinidad and the United States, it is seen to be much lower. Again, is this a result of the middle passage or the influence of different environmental exposures, or both?

Could history and biology be intersecting at the cross roads of the transatlantic slave trade ? I again posit that race is not the main issue at hand. It is the influence and importance of the transatlantic slave trade which, by its selection pressure, has focused or concentrated inherent abilities or biologic traits of displaced Africans and their descendants which are testosterone-responsive and were undoubtedly essential for survival, and which now interplay with our current environment.

Dr. William Aiken is the head of Urology at the University Hospital of the West Indies and president of the Jamaica Urological Society; email: yourhealth@gleanerjm.com.