Hypertension in a Brazilian Urban Slum Population

Low- and middle-income countries account for the majority of hypertension disease burden. However, little is known about the distribution of this illness within subpopulations of these countries, particularly among those who live in urban informal settlements. A cross-sectional hypertension survey was conducted in 2003 among 5649 adult residents of a slum settlement in the city of Salvador, Brazil. Hypertension was defined as either an elevated arterial systolic (≥140 mmHg) or diastolic (≥90 mmHg) blood pressure. Sex-specific multivariable models of systolic blood pressure were constructed to identify factors associated with elevated blood pressure. The prevalence of hypertension in the population 18 years and older was 21 % (1162/5649). Men had 1.2 times the risk of hypertension compared with women (95 % confidence intervals (CI), 1.05, 1.36). Increasing age and lack of any schooling, particularly for women, were also significantly associated with elevated blood pressure (p < 0.05). There was also a direct association between men who were black and an elevated blood pressure. Among those who were hypertensive, 65.5 % were aware of their condition, and only 36.3 % of those aware were actively using anti-hypertensive medications. Men were less likely to be aware of their diagnosis or to use medications (p < 0.01 for both) than women. The prevalence of hypertension in this slum community was lower than reported frequencies in the non-slum population of Brazil and Salvador, yet both disease awareness and treatment frequency were low. Further research on hypertension and other chronic non-communicable diseases in slum populations is urgently needed to guide prevention and treatment efforts in this growing population.     

Could associations between breastfeeding and insulin‐like growth factors underlie associations of breastfeeding with adult chronic disease? The Avon Longitudinal Study of Parents and Children

Objective The influence of infant feeding method (breast/formula) on growth factor levels could underlie associations of breastfeeding with childhood growth and risk factors for cardiovascular disease. We investigated associations of having been breastfed with serum IGF‐I and IGFBP‐3 in childhood. Methods Prospective birth cohort study (subsample of the Avon Longitudinal Study of Parents and Children, UK) based on 871 children born in 1991/1992 who underwent clinical follow‐up and blood tests at age 7–8 years. A total of 488 (56%) children had complete data. Results In children with complete data, the age‐ and sex‐standardized IGF‐I levels of those who were partially or exclusively breastfed were 6·1 and 13·8 ng/ml higher, respectively, than those who were never breastfed (increase in IGF‐I levels per category of breastfeeding exclusivity: 7·1 ng/ml; 95% CI: 0·3–13·9; P = 0·04). In models also controlling for birthweight, gestational age, mother's age, and socioeconomic and dietary factors, the breastfeeding–IGF‐I association was attenuated (regression coefficient: 3·3 ng/ml; ?4·2–10·7; P = 0·4); further adjustment for IGFBP‐3 made little difference (regression coefficient: 4·1 ng/ml; ?2·8–10·9; P = 0·2). There was little evidence for an association between breastfeeding and IGFBP‐3 or the molar ratio IGF‐I/IGFBP‐3. Conclusions The positive association between breastfeeding and IGF‐I could be due to residual confounding or to chance. Nevertheless, the magnitude of the fully adjusted effect estimate and the novelty of the association suggest that larger studies should now be conducted to confirm or refute the hypothesis that variations in IGF‐I by infant feeding mode explain associations of breastfeeding with health in later life.     

Evolution and diversity of copy number variation in the great ape lineage

Copy number variation (CNV) contributes to disease and has restructured the genomes of great apes. The diversity and rate of this process, however, have not been extensively explored among great ape lineages. We analyzed 97 deeply sequenced great ape and human genomes and estimate 16% (469 Mb) of the hominid genome has been affected by recent CNV. We identify a comprehensive set of fixed gene deletions (n = 340) and duplications (n = 405) as well as >13.5 Mb of sequence that has been specifically lost on the human lineage. We compared the diversity and rates of copy number and single nucleotide variation across the hominid phylogeny. We find that CNV diversity partially correlates with single nucleotide diversity (r² = 0.5) and recapitulates the phylogeny of apes with few exceptions. Duplications significantly outpace deletions (2.8-fold). The load of segregating duplications remains significantly higher in bonobos, Western chimpanzees, and Sumatran orangutans—populations that have experienced recent genetic bottlenecks (P = 0.0014, 0.02, and 0.0088, respectively). The rate of fixed deletion has been more clocklike with the exception of the chimpanzee lineage, where we observe a twofold increase in the chimpanzee–bonobo ancestor (P = 4.79 × 10⁻⁹) and increased deletion load among Western chimpanzees (P = 0.002). The latter includes the first genomic disorder in a chimpanzee with features resembling Smith-Magenis syndrome mediated by a chimpanzee-specific increase in segmental duplication complexity. We hypothesize that demographic effects, such as bottlenecks, have contributed to larger and more gene-rich segments being deleted in the chimpanzee lineage and that this effect, more generally, may account for episodic bursts in CNV during hominid evolution.Sequence and assembly of great ape reference genomes have consistently revealed that copy number variation (CNV) affects more base pairs than single nucleotide variation (SNV) (Cheng et al. 2005; The Chimpanzee Sequencing and Analysis Consortium 2005; Locke et al. 2011). Segmental duplications, in particular, have disproportionately affected the African great ape (human, chimpanzee, and gorilla) lineages, where they appear to have accumulated at an accelerated rate (Cheng et al. 2005; Marques-Bonet et al. 2009). This has led to speculation that differences in fixation and copy number polymorphism may have contributed to the phenotypic “plasticity” and species-specific differences between humans and great apes (Olson 1999; Varki et al. 2008). While there is some evidence that fixed deletions and duplications contribute to morphological differences between humans and great apes (McLean et al. 2011; Charrier et al. 2012; Dennis et al. 2012), a comprehensive assessment of these differences at the level of the genome has not yet been performed. Previous studies of CNV have been predominated by array comparative genomic hybridization (CGH) experiments (Fortna et al. 2004; Perry et al. 2006; Dumas et al. 2007; Gazave et al. 2011; Locke et al. 2011), which provide limited size resolution, are imprecise in absolute copy number differences, and are biased by probes derived from the human reference genome. Comparisons of reference genomes have been complicated by assessments of a single individual and distinguishing CNVs from assembly errors (The Chimpanzee Sequencing and Analysis Consortium 2005; Locke et al. 2011; Ventura et al. 2011; Prüfer et al. 2012). Here, we compare the evolution and diversity of deletions, duplications, and SNVs in 97 great ape individuals sequenced to high coverage (median ∼25×) (Prado-Martinez et al. 2013). The set includes multiple individuals from the four great ape genera, including Bornean and Sumatran orangutans, each of the four recognized chimpanzee subspecies, bonobos, and both Eastern and Western gorillas, in addition to 10 diverse humans and a high-coverage archaic Denisovan individual. This data set provides unprecedented genome-wide resolution to interrogate multiple forms of genetic variation and a unique opportunity to directly compare mutational processes and patterns of diversity in great apes.     

Efficacy and safety of stavudine plus didanosine in asymptomatic HIV-infected children with plasma HIV RNA below 50,000 copies per milliliter

Abstract

BACKGROUND: Simple antiretroviral drug combinations might provide a comparable benefit to standard triple regimens in patients with mild HIV disease, because poor adherence and toxicities often compromise the sustained benefit of the latest triple regimens, especially when protease inhibitors are used. Bad adherence is the main cause of virological failure in HIV-positive children. The activity and safety of a double combination of nucleosides with high genetic barrier for resistance (stavudine plus didanosine) was assessed in children with nonadvanced HIV disease. METHOD: From February 1998 to March 1999, 16 children were enrolled in six Spanish hospitals in a trial in which didanosine (180 mg/m²/day) and stavudine (2 mg/Kg/day) were administered for 48 weeks to asymptomatic naive children with plasma HIV RNA below 50,000 copies/mL and CD4 counts above 15%. Genotypic resistance to nucleoside analogues was examined at baseline and at the end of the study. RESULTS: At baseline, median age was 6.5 years (range, 2-14). The absolute and percentage mean CD4 counts were 864 and 32%, respectively (z score: -0.48 and -1.1). Mean plasma viral load was 4.05 log. No clinical events occurred during the 1-year study period. Minor side effects were recorded in two thirds of children, although none led to drug discontinuation. Lipoatrophy was not recognized in any of the participants. Plasma HIV RNA below 400 copies/mL was reached by 43% and 44% of patients at 24 and 48 weeks, respectively. The z score for absolute and percentage CD4 count increased significantly at 48 weeks (+0.63 and +0.97, respectively) in respect to baseline (p < .05). Resistance mutations linked to didanosine (L74V or M184V) or stavudine (V75T) were not recognized and neither were multinucleoside resistant genotypes (151 complex or 69 inserts). However, four children developed AZT-like mutations T215Y and/or M41L. CONCLUSION: Treatment with a dual combination of didanosine plus stavudine in naive children with nonadvanced HIV disease is safe and provides a satisfactory virological outcome at 1 year. Toxicity and drug resistance seem to occur rarely when this combination is used, which allows good adherence and spares other future treatment options.