OBJECTIVES: This study examined whether networks of drug-injecting and sexual relationships among drug injectors are associated with individual human immunodeficiency virus (HIV) serostatus and with behavioral likelihood of future infection. METHODS: A cross-sectional survey of 767 drug injectors in New York City was performed with chain-referral and linking procedures to measure large-scale (sociometric) risk networks. Graph-theoretic algebraic techniques were used to detect 92 connected components (drug injectors linked to each other directly or through others) and a 105-member 2-core within a large connected component of 230 members. RESULTS: Drug injectors in the 2-core of the large component were more likely than others to be infected with HIV. Seronegative 2-core members engaged in a wide range of high-risk behaviors, including engaging in risk behaviors with infected drug injectors. CONCLUSIONS: Sociometric risk networks seem to be pathways along which HIV travels in drug-injecting peer groups. The cores of large components can be centers of high-risk behaviors and can become pockets of HIV infection. Preventing HIV from reaching the cores of large components may be crucial in preventing widespread HIV epidemics.

Background Anorexia nervosa (AN) is prevalent in adolescents and is associated with decreased bone mineral accrual at a time critical for optimizing bone mass. Low bone mineral density (BMD) in AN is a consequence of nutritional and hormonal alterations, including hypogonadism and low estradiol levels. Effective therapeutic strategies to improve BMD in adolescents with AN have not been identified. Specifically, high estrogen doses given as an oral contraceptive do not improve BMD. The impact of physiological estrogen doses that mimic puberty on BMD has not been examined. Subjects and Methods We enrolled 110 girls with AN and 40 normal-weight controls (C) 12–18y of similar maturity. Subjects were studied for 18 months. Mature AN [bone age (BA) ≥15 y; n=96] were randomized to transdermal 100mcg 17β-estradiol (with cyclic progesterone) or placebo for 18m. Immature AN (BA <15y; n=14) were randomized to incremental low dose oral ethinyl-estradiol (3.75mcg daily from 0–6m, 7.5mcg from 6–12m, 11.25mcg from 12–18m) to mimic pubertal estrogen increases, or placebo for the 18m duration. Results All BMD measures assessed by dual energy x-ray absorptiometry (DXA) were lower in AN than C. At baseline, AN randomized to estrogen (AN E+) did not differ from those randomized to placebo (AN E−) for age, maturity, height, BMI, amenorrhea duration and BMD parameters. Spine and hip BMD Z-scores increased over time in the AN E+ compared with AN E− group, even after controlling for baseline age and weight. Conclusion Physiological estradiol replacement increases spine and hip BMD in girls with AN.

Adiponectin contributes significantly to the variability of bone density, and insulin contributes to bone turnover markers in adolescent girls.

Even short-term weight gain with menstrual recovery is associated with a stabilization of BMD measures.

OBJECTIVE-We hypothesized that, despite increased activity, bone density would be low in athletes with amenorrhea, compared with athletes with eumenorrhea and control subjects, because of associated hypogonadism and would be associated with a decrease in bone formation and increases in bone-resorption markers.METHODS-In a cross-sectional study, we examined bone-density measures (spine, hip, and whole body) and body composition by using dual-energy radiograph absorptiometry and assessed fasting levels of insulin-like growth factor I and bone-turnover markers (N-terminal propeptied of type 1 procollagen and N-telopeptide) in 21 athletes with amenorrhea, 18 athletes with eumenorrhea, and 18 control subjects. Subjects were 12 to 18 years of age and of comparable chronologic and bone age.RESULTS-Athletes with amenorrhea had lower bone-density z scores at the spine and whole body, compared with athletes with eumenorrhea and control subjects, and lower hip z scores, compared with athletes with eumenorrhea. Lean mass did not differ between groups. However, athletes with amenorrhea had lower BMI z scores than did athletes with eumenorrhea and lower insulin-like growth factor I levels than did control subjects. Levels of both markers of bone turnover were lower in athletes with amenorrhea than in control subjects. BMI z scores, lean mass, insulin-like growth factor I levels, and diagnostic category were important independent predictors of bone mineral density z scores.CONCLUSIONS-Although they showed no significant differences in lean mass, compared with athletes with eumenorrhea and control subjects, athletes with amenorrhea had lower bone density at the spine and whole body. Insulin-like growth factor I levels, body-composition parameters, and menstrual status were important predictors of bone density. Follow-up studies are necessary to Copyright © 2008 by the American Academy of Pediatrics. All rights reserved.Address correspondence to Madhusmita Misra, MD, MPH, Massachusetts General Hospital, Neuroendocrine Unit, BUL 457, 55 Fruit St, Boston, MA 02114. mmisra@partners.org. The authors have indicated they have no financial relationships relevant to this article to disclose.Drs Christo and Prabhakaran contributed equally to this work. NIH Public Access Author ManuscriptPediatrics. Author manuscript; available in PMC 2011 November 4. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript determine whether amenorrhea in athletes adversely affects the rate of bone mass accrual and therefore peak bone mass. Keywordsadolescents; athletes; bone density; bone-turnover markers; insulin-like growth factor I Amenorrhea has been reported to occur in 23.5% of high school athletes, 1 although the prevalence may vary depending on the type, intensity, and duration of exercise, as well as the athlete's nutritional status. [1][2][3][4] In particular, activities such as gymnastics, running track, ballet, diving, swimming, and cheerleading are common among high school girls, require a thin physique, and are as...

Context:Adolescents with anorexia nervosa (AN) have low areal bone mineral density (aBMD) at both cortical and trabecular sites, and recent data show impaired trabecular microarchitecture independent of aBMD. However, data are lacking regarding both cortical microarchitecture and bone strength assessment by finite element analysis (FEA) in adolescents with AN. Because microarchitectural abnormalities and FEA may predict fracture risk independent of aBMD, these data are important to obtain. Objective: Our objective was to compare both cortical and trabecular bone microarchitecture and FEA estimates of bone strength in adolescent girls with AN vs normal-weight controls.Design, Setting, and Subjects: We conducted a cross-sectional study at a clinical research center that included 44 adolescent girls (21 with AN and 23 normal-weight controls) 14 to 22 years old. Main Outcome Measures:We evaluated 1) aBMD (dual-energy x-ray absorptiometry) at the distal radius, lumbar spine, and hip, 2) cortical and trabecular microarchitecture at the ultradistal radius (high-resolution peripheral quantitative computed tomography), and 3) FEA-derived estimates of failure load at the ultradistal radius.Results: aBMD was lower in girls with AN vs controls at the lumbar spine and hip but not at the distal radius. Girls with AN had lower total (P Ͻ .0001) and trabecular volumetric BMD (P ϭ .02) and higher cortical porosity (P ϭ .03) and trabecular separation (P ϭ .04). Despite comparable total crosssectional area, trabecular area was higher in girls with AN (P ϭ .04), and cortical area and thickness were lower (P ϭ .002 and .02, respectively). FEA-estimated failure load was lower in girls with AN (P ϭ .004), even after controlling for distal radius aBMD. Conclusions:Both cortical and trabecular microarchitecture are altered in adolescent girls with AN. FEA-estimated failure load is decreased, indicative of reduced bone strength. The finding of reduced cortical bone area in girls with AN is consistent with impaired cortical bone formation at the endosteum as a mechanism underlying these findings. (J Clin Endocrinol Metab 98:

In a cross-sectional study of 174 new injecting drug users (IDUs) in New York City who had injected for < or = 6 years, we examined whether those who both share syringes and have personal risk networks that include high-risk injectors are particularly likely to be infected with HIV. Subjects were street recruited between July 1991 and January 1993, were interviewed about their risk behaviors in the prior 2 years and their personal risk networks with other IDUs in the prior 30 days, and were tested for HIV; 20% were HIV seropositive. Among those who both shared syringes and had a personal risk network member who injected more than once a day, 40% were HIV seropositive (versus 14% for others, p < 0.001). In simultaneous multiple logistic regression, the interaction of both sharing syringes and having a personal risk network member who injected more than once a day remained independently and significantly associated with being HIV seropositive (OR, 3.57; 95% CI, 1.22, 10.43; p < 0.020), along with Latino race/ethnicity and exchanging sex for money or drugs. These findings suggest that the combination of sharing syringes with having a high-risk personal network is a risk factor for HIV infection among new IDUs. Studies of risk factors for HIV infection among new IDUs and interventions to reduce the spread of HIV among them should focus on their risk networks as well as their risk behaviors.

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