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Tobago, Trinidad and Tobago

Barbour K.E.,University of Pittsburgh | Zmuda J.M.,University of Pittsburgh | Horwitz M.J.,University of Pittsburgh | Strotmeyer E.S.,University of Pittsburgh | And 7 more authors.
Osteoporosis International | Year: 2011

Summary: We examined the association of serum 25-hydroxyvitamin D [25(OH)D] with indices of bone quality in older men. Positive associations for 25(OH)D and bone mineral density, content, cortical thickness, and axial and polar strength strain indices were observed among Caucasians; however, among men of African descent findings were either null or negative. Introduction: There are limited data on serum 25(OH)D and bone measures in men of African ancestry. To better understand racial differences in vitamin D status and bone health, a cross-sectional study among 446 Caucasian men in the US and 496 men of African ancestry in Tobago (age ≥ 65 years) was conducted. Methods: Serum 25(OH)D (liquid chromatography and tandem mass spectrometry) was measured, and peripheral quantitative computed tomography scans were administered. Bone measures estimated included trabecular and cortical volumetric bone mineral density (vBMD), bone mineral content (BMC), bone geometry (cross-sectional area and cortical thickness), and polar and axial strength strain indices (SSIp and SSIx). Results: Men of African ancestry had higher 25(OH)D than Caucasians (34.7 vs. 27.6 ng/ml, p < 0.01). Among Caucasians, 25(OH)D was positively (p trend < 0.05) associated with cortical vBMD, total BMC, cortical thickness, SSIp, and SSIx at the distal radius after adjustment for potential confounders. Similar patterns were observed at the distal tibia. In contrast, in men of African ancestry, there was an inverse association (p trend < 0.05) between 25(OH)D and the cross-sectional area, and SSIx. Race modified (p for interaction < 0.05) the association between 25(OH)D and total BMC, cross-sectional area, SSIp, SSIx, and trabecular vBMD of the radius. In men of African ancestry, there was evidence of a threshold effect (at approximately 18 ng/ml) for 25(OH)D on tibial total BMC and cortical thickness. Conclusions: More studies are needed to better comprehend these race differences for 25(OH)D and bone density, geometry, and indices of bone strength. © 2010 International Osteoporosis Foundation and National Osteoporosis Foundation.

Kuipers A.L.,University of Pittsburgh | Zmuda J.M.,University of Pittsburgh | Patrick A.L.,Tobago Health Studies Office | Ge Y.,University of North Carolina at Charlotte | And 2 more authors.
Osteoporosis International | Year: 2014

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors. Introduction: The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence. Methods: Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia. Results: Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P < 0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45-0.92). Conclusions: Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification. © 2013 International Osteoporosis Foundation and National Osteoporosis Foundation.

Henning J.D.,University of Pittsburgh | Bunker C.H.,University of Pittsburgh | Patrick A.L.,Tobago Health Studies Office | Jenkins F.J.,University of Pittsburgh
Prostate | Year: 2016

Background The Caribbean island of Tobago, which is 97% African ancestry, has one of the highest rates of prostate cancer in the world. We have previously reported that human herpesvirus 8 (HHV-8) infection is significantly associated with prostate cancer in Tobago. In this study, we extend those results testing the hypothesis that HHV-8 seropositive Tobagonian men have a chronic HHV-8 infection in their prostates that is associated with increased inflammation. Methods Prostate sections were screened by immunohistochemistry for the expression of HHV-8 proteins K8.1 and LANA-1 and for presence of B cells (CD20) and macrophages (CD68). Results HHV-8 antigen expression representing lytic and latent infections was seen in 73.9% of prostates from HHV-8 seropositive subjects. Latent infections were seen predominantly in glandular epithelia whereas lytic gene expression was seen mainly in macrophages in prostate stroma. Macrophage infiltrates were significantly increased in sections expressing HHV-8 proteins. Conclusion HHV-8 establishes a chronic latent infection in the prostate, which is associated with an increased macrophage infiltrate. Prostate 76:735-743, 2016. © 2016 Wiley Periodicals, Inc.

Forrest K.Y.Z.,Slippery Rock University | Bunker C.H.,University of Pittsburgh | Sheu Y.,University of Pittsburgh | Wheeler V.W.,Tobago Health Studies Office | And 2 more authors.
Age and Ageing | Year: 2012

Background: muscle strength is essential for physical functions and an indicator of morbidity and mortality in older adults. Among the factors associated with muscle strength loss with age, ethnicity has been shown to play an important role. Objective: to examine the patterns and correlates of muscle strength change with age in a population-based cohort of middle-aged and older Afro-Caribbean men. Methods: handgrip strength and body composition were measured in 1,710 Afro-Caribbean men. Data were also collected for demographic variables, medical history and lifestyle behaviours. Results: the age range of the study population was 29-89 years. Grip strength increased below age 50 years, and decreased after age 50 years over 4.5-year follow-up. The average loss in grip strength was 2.2% (0.49% per year) for ages 50 years or older and 3.8% (0.64% per year) for ages 65 years or older. The significant independent predictors of grip strength loss included older age, a greater body mass index, lower initial arm lean mass and greater loss of arm lean mass. Conclusion: Afro-Caribbean men experience a significant decline in muscle strength with advanced age. The major independent factors associated with strength loss were similar to other ethnic groups, including age, body weight and lean mass. © The Author 2012. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved.

Sheu Y.,University of Pittsburgh | Cauley J.A.,University of Pittsburgh | Wheeler V.W.,Tobago Health Studies Office | Patrick A.L.,Tobago Health Studies Office | And 4 more authors.
Osteoporosis International | Year: 2011

Summary: We compared rates of BMD decline in older men of diverse ethnic backgroud. The rate of bone loss was statistically equivalent between men of African and Caucasian descent. Introduction: Race differences in peak bone mineral density (BMD) are well established, but the magnitude of bone loss among non-white men has not been well characterized. Our objective was to compare and contrast the rates of decline in BMD with aging among older men of different race/ethnic groups. Methods: The rate of decline in hip BMD was measured by dual-energy X-ray absorptiometry (Hologic QDR-4500 W) with an average follow-up of 4.6 years in 3,869 Caucasian, 138 African American, 145 Asian, and 334 Afro-Caribbean men aged≥65 years (Mean ages: 73±5, 70±4, 72±5, 71±5 years, respectively). Results: The annual rate of decline in BMD at the femoral neck was -0.32%, -0.42%, -0.09%, and -0.44%/year for Caucasian, African American, Asian, and Afro-Caribbean men, respectively (p<0.05 for Caucasian versus Asian). Although men of African ancestry have higher peak BMD than Caucasians, rates of decline in BMD with aging appear to be statistically equivalent in our study. In contrast, Asian men experienced a slower rate of decline in BMD compared with Caucasians and African Americans. Conclusion: More studies are needed to better define the natural history of and factors associated with bone loss among non-white men. © 2010 International Osteoporosis Foundation and National Osteoporosis Foundation.

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