William Aiken

Admixture and Population Stratification in African Caribbean Populations

Throughout biomedical research, there is growing interest in the use of ancestry informative markers (AIMs) to deconstruct racial categories into useful variables. Studies on recently admixed populations have shown significant population substructure due to differences in individual ancestry; however, few studies have examined Caribbean populations. Here we used a panel of 28 AIMs to examine the genetic ancestry of 298 individuals of African descent from the Caribbean islands of Jamaica, St. Thomas and Barbados. Differences in global admixture were observed, with Barbados having the highest level of West African ancestry (89.6%± 2.0) and the lowest levels of European (10.2%± 2.2) and Native American ancestry (0.2%± 2.0), while Jamaica possessed the highest levels of European (12.4%± 3.5) and Native American ancestry (3.2%± 3.1). St. Thomas, USVI had ancestry levels quite similar to African Americans in continental U.S. (86.8%± 2.2 West African, 10.6%± 2.3 European, and 2.6%± 2.1 Native American). Significant substructure was observed in the islands of Jamaica and St. Thomas but not Barbados (K=1), indicating that differences in population substructure exist across these three Caribbean islands. These differences likely stem from diverse colonial and historical experiences, and subsequent evolutionary processes. Most importantly, these differences may have significant ramifications for case‐control studies of complex disease in Caribbean populations.

Pathological outcome and biochemical recurrence‐free survival after radical prostatectomy in African‐American, Afro‐Caribbean (Jamaican) and Caucasian‐American men: an international comparison

Whats known on the subject? and What does the study add?

8q24 risk alleles in West African and Caribbean men

Multiple genetic studies have confirmed associations of 8q24 variants with susceptibility to prostate cancer (CaP). However, the magnitude of risk conferred in men living in West Africa is unknown.

Both serum 25-hydroxyvitamin D and calcium levels may increase the risk of incident prostate cancer in Caribbean men of African ancestry

Circulating 25‐hydroxyvitamin D [25(OH)D] concentrations have been associated with both higher and lower risk of prostate cancer (PCa), whereas elevated levels of circulating calcium has been related to higher risks. However, there are few studies that account for effects of both calcium and 25(OH)D concentrations on incident PCa in a black population. We examined these relationships in a case–control study of men 40–80 years old with newly diagnosed, histologically confirmed PCa in Jamaica, a tropical country. Mean serum calcium concentrations was higher among cases (2.32 ± 0.19 mmol/L) than controls, (2.27 ± 0.30 mmol/L) (P = 0.023) however, there were no differences in 25(OH)D by cancer status (cases, 33.67 ± 12.71 ng/mL; controls (32.25 ± 12.59 ng/mL). Serum calcium was not correlated with 25(OH)D (partial correlation: r, 0.06; P = 0.287). Multivariable‐adjusted models showed a positive linear relationship between PCa and serum calcium (OR, 1.12; CI, 1.00–1.25 per 0.1 nmol/L). Serum 25(OH)D concentration also showed a positive association with PCa (OR, 1.23; CI, 1.01–1.49 per 10 ng/mL). The odds of PCa in men with serum 25(OH)D tertile 2 was OR, 2.18; CI, 1.04–4.43 and OR, 2.47 CI, 1.20–4.90 for tertile 3 (Ptrend = 0.013). Dietary intakes of calcium showed no relationship with PCa. Despite the strong relationship between serum calcium and vitamin D the mechanism by which each affects prostate cancer risk in men of African ancestry needs additional investigation.

Current state of prostate cancer treatment in Jamaica

Prostate cancer is the commonest cancer in Jamaica as well as the leading cause of cancer-related deaths. One report suggested that Jamaica has the highest incidence rate of prostate cancer in the world, with an age-standardised rate of 304/100,000 per year. The Caribbean region is reported to have the highest mortality rate of prostate cancer worldwide. Prostate cancer accounts for a large portion of the clinical practice for health-care practitioners in Jamaica. The Jamaica Urological Society is a professional body comprising 19 urologists in Jamaica who provide most of the care for men with prostate cancer in collaboration with medical oncologists, radiation oncologists, and a palliative care physician. The health-care system is structured in two tiers in Jamaica: public and private. The urologist-to-patient ratio is high, and this limits adequate urological care. Screening for prostate cancer is not a national policy in Jamaica. However, the Jamaica Urological Society and the Jamaica Cancer Society work synergistically to promote screening as well as to provide patient education for prostate cancer. Adequate treatment for localised prostate cancer is available in Jamaica in the forms of active surveillance, nerve-sparing radical retropubic prostatectomy, external beam radiation, and brachytherapy. However, there is a geographic maldistribution of centres that provide prostate cancer treatment, which leads to treatment delays. Also, there is difficulty in affording some treatment options in the private health-care sectors. Androgen deprivation therapy is available for treatment of locally advanced and metastatic prostate cancer and is subsidised through a programme called the National Health Fund. Second-line hormonal agents and chemotherapeutic agents are available but are costly to most of the population. The infrastructure for treatment of prostate cancer in Jamaica is good, but it requires additional technological advances as well as additional specialist services.

Bone mineral density in Jamaican men on androgen deprivation therapy for prostate cancer

BackgroundAndrogen deprivation therapy (ADT) has been reported to reduce the bone mineral density (BMD) in men with prostate cancer (CaP). However, Afro-Caribbeans are under-represented in most studies. The aim was to determine the effect of androgen deprivation therapy (ADT) on the bone mineral density (BMD) of men with prostate cancer in Jamaica.MethodsThe study consisted of 346 Jamaican men, over 40 years of age: 133 ADT treated CaP cases (group 1), 43 hormone-naïve CaP controls (group 2) and 170 hormone naïve controls without CaP (group 3). Exclusion criteria included metastatic disease, bisphosphonate therapy or metabolic disease affecting BMD. BMD was measured with a calcaneal ultrasound and expressed in S.D. units relative to young adult men (T score), according to the World Health Organization definition. Patient weight, height and BMI were assessed.ResultsMean ± sd, age of patients in group 1 (75± 7.4 yrs) was significantly greater than groups 2 and 3 (67 ± 8.1 yrs; 65±12.0 yrs). There was no significant difference in weight and BMI between the 3 groups. . The types of ADT (% of cases, median duration in months with IQR) included LHRH (Luteinizing hormone releasing hormone) analogues (28.6%, 17.9, IQR 20.4), oestrogens (9.8%, 60.5, IQR 45.6) anti-androgens (11.3%, 3.3, IQR 15.2) and orchiectomy (15.7%, 43.4, IQR 63.9). Unadjusted t score of group 1, mean ± sd, (-1.6± 1.5) was significantly less than group 2 (-0.9±1.1) and group 3 (-0.7±1.4), p <0.001. Ninety three (69.9%), 20 (45%) and 75 (42%) of patients in groups 1, 2 and 3 respectively were classified as either osteopenic or osteoporotic (p<0.001). Adjusting for age, there was a significant difference in t scores between groups 1 and 2 as well as between groups 1 and 3 (p<0.001). Compared with oestrogen therapy and adjusting for duration of therapy, the odds of low bone mineral density (osteopenia or osteoporosis) with LHRH analogue was 4.5 (95%CI, 14.3 to 3.4); with anti-androgens was 5.9 (95%CI, 32.7 to 5); with orchiectomy was 7.3 (95%CI, 30 to 5.8) and multiple drugs was 9.2 ((95%CI, 31 to 7.1).ConclusionsADT is associated with lower BMD in Jamaican men on hormonal therapy for prostate cancer.

Bilateral complete ureteral duplication with calculi obstructing both limbs of left double ureter.

Highlights • First report of complete ureteral duplication with stones obstructing both limbs.• Ureters are smaller and contained terminally within common adventitial sheath.• Small and unyielding ureters make ureteroscopic intubation and passage difficult.• Pre-stenting improves ureteral compliance and causes passive dilation of ureter.• Recommend routine pre-stenting in this scenario to improve ureteroscopic access.

Accessory renal arteries in a Caribbean population: a computed tomography based study

IntroductionThe commonest variation to the classic anatomic description of renal arterial supply is the presence of accessory renal arteries. The incidence varies widely according to ethnicity. There is no data on the prevalence of these anomalies in persons of Caribbean ethnicity.MethodsAll CT scans done over two years from July 1, 2010 to June 30, 2012 were retrospectively evaluated. The anatomy of the renal arterial supply was reported from these studies and the anatomy of accessory renal arteries was documented.ResultsThere were 302 CT scans evaluated and accessory renal arteries were present in 109/302 (36.1%) CT scans, 95% confidence interval 30.6%, 41.4%. There were 71/309 (23.5%) patients with accessory arteries on the left and 54/309 (17.9%) had them on the right (p 0.087). Of these, 16 (14.7%) patients had bilateral accessory renal arteries present. The most common origin for the accessory arteries was the abdominal aorta in 108 (99.1%) cases and in 1 case the accessory artery arose from the coeliac trunk. There were 80 left sided accessory renal arteries: 17 (21.3%) upper polar and 27 (33.8%) lower polar arteries. Of 62 right sided accessory arteries, 14 (22.6%) were upper polar and 26 (42%) were lower polar arteries.ConclusionThis is the first population-based report of anatomic anomalies in renal arterial supply in a Caribbean population. These are important findings that may affect vascular and urologic procedures on persons of Caribbean ethnicity.

Impact of the National Health Fund policy on hormone treatment for prostate cancer in Jamaica

OBJECTIVE To compare the proportion of patients choosing surgical versus medical castration to treat prostate cancer, before and after the National Health Fund (NHF) of Jamaica began to subsidize hormone therapy. METHODS A retrospective review was performed at the University Hospital of the West Indies (UHWI), Jamaica. The pathology database at UHWI was searched to identify patients who had prostate biopsies between January 2000 and December 2007. These were combined with records of biopsies at external institutions. Medical records of all patients with positive prostate biopsies were reviewed to determine if they had received androgen deprivation therapy (ADT). Patients were classified as having had surgical castration (bilateral orchiectomy) or medical castration. Chi-square statistics were used to determine the difference in proportions between those choosing medical versus surgical castration before and after March 2005, when the NHF began offering subsidies for ADT drugs. RESULTS Of the 1,529 prostate biopsies performed during the study period, 680 (44.0%) cases of prostate cancer were diagnosed. Of these, 458 patients underwent ADT and had complete records available for analysis. The mean patient age was 72 years. During the entire study period, surgical castration was performed in 265 patients (58.0%) and medical castration in 193 (42.0%). A greater proportion of orchiectomies were performed before March 2005, rather than after (P < 0.001). Estrogens were the most common method of medical castration used before the NHF subsidy became available (62.0%); while luteinizing hormone-releasing hormone analogues (38.0%) and antiandrogens (36.5%) were most often chosen afterwards. CONCLUSIONS Surgical castration was more common than medical castration before March 2005. After the NHF began to subsidize the cost of drugs for hormone therapy, medical castration was chosen more often. Increased access to drugs for hormone therapy has changed treatment patterns in Jamaica.

Ovarian Dermoid Cyst Causing Distal Ureteral Obstruction.

A case of a 45-year old woman with an ovarian dermoid cyst causing ureteric colic secondary to distal ureteral obstruction is reported. The dermoid cyst was observed on computed tomography to be adjacent to and compressing the distal left ureter and this was confirmed at surgical exploration. Following oophorectomy, the patients symptoms completely resolved and the excised ovarian cyst was confirmed on pathological evaluation to be a dermoid cyst. This appears to be the first reported case of ureteral obstruction caused by an ovarian dermoid cyst in the English medical literature.