Browsing by Author "Silio, Margarita"

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    Associations of Low Vitamin D and Elevated Parathyroid Hormone Concentrations With Bone Mineral Density in Perinatally HIV-Infected Children
    (Wolters Kluwer, 2017-09-01) Jacobson, Denise L.; Stephensen, Charles B.; Miller, Tracie L.; Patel, Kunjal; Chen, Janet S.; Van Dyke, Russell B.; Mirza, Ayesha; Schuster, Gertrud U.; Hazra, Rohan; Ellis, Angela; Brummel, Sean S.; Geffner, Mitchell E.; Silio, Margarita; Spector, Stephen A.; DiMeglio, Linda A.; Pediatrics, School of Medicine
    BACKGROUND: Perinatally HIV-infected (PHIV) children have, on average, lower bone mineral density (BMD) than perinatally HIV-exposed uninfected (PHEU) and healthy children. Low 25-hydroxy vitamin D [25(OH)D] and elevated parathyroid hormone (PTH) concentrations may lead to suboptimal bone accrual. METHODS: PHIV and PHEU children in the Pediatric HIV/AIDS Cohort Study had total body (TB) and lumbar spine (LS) BMD and bone mineral content (BMC) measured by dual-energy x-ray absorptiometry; BMD z-scores (BMDz) were calculated for age and sex. Low 25(OH)D was defined as ≤20 ng/mL and high PTH as >65 pg/mL. We fit linear regression models to estimate the average adjusted differences in BMD/BMC by 25(OH)D and PTH status and log binomial models to determine adjusted prevalence ratios of low 25(OH)D and high PTH in PHIV relative to PHEU children. RESULTS: PHIV children (n = 412) were older (13.0 vs. 10.8 years) and more often black (76% vs. 64%) than PHEU (n = 207). Among PHIV, children with low 25(OH)D had lower TB-BMDz [SD, -0.38; 95% confidence interval (CI), -0.60 to -0.16] and TB-BMC (SD, -59.1 g; 95% CI, -108.3 to -9.8); high PTH accompanied by low 25(OH)D was associated with lower TB-BMDz. Among PHEU, children with low 25(OH)D had lower TB-BMDz (SD, -0.34; 95% CI, -0.64 to -0.03). Prevalence of low 25(OH)D was similar by HIV status (adjusted prevalence ratio, 1.00; 95% CI, 0.81 to 1.24). High PTH was 3.17 (95% CI, 1.25 to 8.06) times more likely in PHIV children. CONCLUSIONS: PHIV and PHEU children with low 25(OH)D may have lower BMD. Vitamin D supplementation trials during critical periods of bone accrual are needed.
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    Changes in insulin sensitivity over time and associated factors in HIV-infected adolescents
    (Lippincott, Williams & Wilkins, 2018-03-13) Geffner, Mitchell E.; Patel, Kunjal; Jacobson, Denise L.; Wu, Julia; Miller, Tracie L.; Hazra, Rohan; Gerschenson, Mariana; Sharma, Tanvi; Silio, Margarita; Jao, Jennifer; Takemoto, Jody K.; Van Dyke, Russell B.; Dimeglio, Linda A.; Pediatric HIV/AIDS Cohort Study (PHACS); Pediatrics, School of Medicine
    OBJECTIVE: To compare prevalence of insulin resistance between perinatally HIV-infected (PHIV+) and perinatally HIV-exposed, but uninfected adolescents (PHEU), determine incidence of and contributory factors to new and resolved cases of insulin resistance in PHIV+, and evaluate glucose metabolism. DESIGN: Cross-sectional design for comparison of prevalence among PHIV+ and PHEU. Longitudinal design for incidence and resolution of insulin resistance among PHIV+ at risk for these outcomes. METHODS: The source population was adolescents from pediatric HIV clinics in the United States and Puerto Rico participating in the Pediatric HIV/AIDS Cohort Study, an ongoing prospective cohort study designed to evaluate impact of HIV infection and its treatment on multiple domains in preadolescents and adolescents. Insulin resistance was assessed by homeostatic model assessment of insulin resistance. Those with incident insulin resistance underwent 2-h oral glucose tolerance test and HbA1c. Baseline demographic, metabolic, and HIV-specific variables were evaluated for association with incident or resolved insulin resistance. RESULTS: Unadjusted prevalence of insulin resistance in PHIV+ was 27.3 versus 34.1% in PHEU. After adjustment for Tanner stage, age, sex, and race/ethnicity, there was no significant difference between groups. Factors positively associated with developing insulin resistance included female sex, higher BMI z score, and higher waist circumference; those associated with resolving insulin resistance included male sex and lower BMI z score. CONCLUSION: Prevalence of insulin resistance in PHIV+ and PHEU was substantially higher than that reported in HIV-uninfected nonoverweight youth, but similar to that in HIV-uninfected obese youth. Factors associated with incident or resolved insulin resistance among PHIV+ were similar to those reported in HIV-negative obese youth. However, a contributory role of HIV infection and/or its treatment to the incident risk of insulin resistance cannot be excluded.