Longitudinal Examination of Which Married Young Women Use Contraception to Delay a First Pregnancy in Bihar and Uttar Pradesh, India

Early marriage and childbearing put young women and their babies at risk of poor health and well-being. This study uses two rounds of longitudinal data from young women ages 15–19 in 2015–2016 and followed in 2018–2019 to determine factors associated with contraceptive use before a first pregnancy among young, married women in Bihar and Uttar Pradesh, India. Discrete time hazard models were used to analyze time to first use starting from the month of marriage. Overall, use of contraception prior to a first pregnancy was low in this sample (between 12 to 20% used before a first pregnancy). Young women who reported that someone discussed the importance of delaying a first birth at the time of marriage were significantly more likely to have used a method of family planning (FP) before a first pregnancy than those who did not receive this information. Further, women who discussed FP with their husband before a first pregnancy were more likely to use contraception. Finally, among recently married young women, those who experienced pressure to have a child were less likely to use before a first pregnancy. As young women recognize the advantages of delaying a first birth and adopt FP to meet their needs, social norms around early childbearing will slowly adjust and early use to delay a first pregnancy will become more normative

The genetic architecture of the human cerebral cortex

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 306 nominally genome-wide significant loci (P < 5 × 10−8) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 299 loci for which replication data were available, 241 loci influencing surface area and 14 influencing thickness remained significant after replication, with 199 loci passing multiple testing correction (P < 8.3 × 10−10; 187 influencing surface area and 12 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation (rG = −0.32, SE = 0.05, P = 6.5 × 10−12), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 10 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Subcortical volumes across the lifespan: data from 18,605 healthy individuals aged 3-90 years

Age has a major effect on brain volume. However, the normative studies available are constrained by small sample sizes, restricted age coverage and significant methodological variability. These limitations introduce inconsistencies and may obscure or distort the lifespan trajectories of brain morphometry. In response, we capitalized on the resources of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium to examine age-related trajectories inferred from cross-sectional measures of the ventricles, the basal ganglia (caudate, putamen, pallidum, and nucleus accumbens), the thalamus, hippocampus and amygdala using magnetic resonance imaging data obtained from 18,605 individuals aged 3-90 years. All subcortical structure volumes were at their maximum value early in life. The volume of the basal ganglia showed a monotonic negative association with age thereafter; there was no significant association between age and the volumes of the thalamus, amygdala and the hippocampus (with some degree of decline in thalamus) until the sixth decade of life after which they also showed a steep negative association with age. The lateral ventricles showed continuous enlargement throughout the lifespan. Age was positively associated with inter-individual variability in the hippocampus and amygdala and the lateral ventricles. These results were robust to potential confounders and could be used to examine the functional significance of deviations from typical age-related morphometric patterns.Education and Child Studie

Perceptions of peer contraceptive use and its influence on contraceptive method use and choice among young women and men in Kenya: a quantitative cross-sectional study

Plain language summary In Kenya, about 15% of women age 15-19 have already had a birth and approximately one third of these women did not want to have a child at that time. Yet about 45% of sexually active women ages 15-24 report that they currently use family planning (FP). Among young people, friends and peers are an important influence on behaviors. This study focused on a representative sample from Kenya of female and male youth (ages 15-24) who ever had sex. Men and women were asked questions about use of FP, if they think their peers use FP and about characteristics such as age and education. The results showed that young women and men who believed their peers use FP were more likely to use FP themselves. Also, young men and women who believed that peers use FP were more likely to use condoms than not use any FP and more likely to use condoms than to use another modern method of FP. Young women who thought their peers use were more likely to use another modern method (not including condoms) than to be a nonuser of FP. Programs targeting young people should include information on a range of FP methods and aim to include groups of peers and encourage open discussion.Background Prior research has established that an individual's social environment may influence his or her reproductive behaviors, yet less is known about peer influence on contraceptive use among young people (ages 15-24). In Kenya, the site of this study, 15% of adolescents ages 15-19 have begun childbearing and 45% of sexually active young women report current use of a modern contraceptive method. This highlights the need to better understand what factors influence young people to use contraception. The objective of this study is to explore the relationship between the perception of peers' use of contraceptives and contraceptive use and method choice among young men and women in Kenya. Methods This study utilizes a nationally representative sample of women and men aged 15-24 years from the 2018 and 2019 cross sectional Shujaaz State of the Kenyan Youth annual surveys. Among the sample of sexually experienced young people (59%), multivariable multinomial logistic regression was used to explore the association between the perception of peers' use of contraceptives and the respondent's contraceptive method choice: non-user, condom use or use of any other modern method. Results are presented separately for young men and young women. Results Our results show that sexually experienced young men and women who perceive that their peers are using contraceptives are more likely to report current use of condoms compared to being a nonuser (RRR = 2.12, p < 0.001, RRR = 2.59, p < 0.001, respectively); they are also more likely to use condoms than another modern method of contraception (RRR = 2.13, p = 0.034, RRR = 1.71, p = 0.014, respectively). Young women are more likely to use another modern method (not including condoms) than be a nonuser when they perceive that their peers' use contraceptives (RRR = 1.51, p = 0.020). Conclusions The results of this study highlight the important role of peer influence on young people's contraceptive choices. These findings can be used to develop programs that encourage behavior change communication activities in Kenya that focus on normalizing use of a full range of contraceptive methods among peer groups of sexually experienced young people

Dose response of the 16p11.2 distal copy number variant on intracranial volume and basal ganglia

Contains fulltext : 225428.pdf (publisher's version ) (Open Access)Carriers of large recurrent copy number variants (CNVs) have a higher risk of developing neurodevelopmental disorders. The 16p11.2 distal CNV predisposes carriers to e.g., autism spectrum disorder and schizophrenia. We compared subcortical brain volumes of 12 16p11.2 distal deletion and 12 duplication carriers to 6882 non-carriers from the large-scale brain Magnetic Resonance Imaging collaboration, ENIGMA-CNV. After stringent CNV calling procedures, and standardized FreeSurfer image analysis, we found negative dose-response associations with copy number on intracranial volume and on regional caudate, pallidum and putamen volumes (β = -0.71 to -1.37; P < 0.0005). In an independent sample, consistent results were obtained, with significant effects in the pallidum (β = -0.95, P = 0.0042). The two data sets combined showed significant negative dose-response for the accumbens, caudate, pallidum, putamen and ICV (P = 0.0032, 8.9 × 10(-6), 1.7 × 10(-)(9), 3.5 × 10(-12) and 1.0 × 10(-4), respectively). Full scale IQ was lower in both deletion and duplication carriers compared to non-carriers. This is the first brain MRI study of the impact of the 16p11.2 distal CNV, and we demonstrate a specific effect on subcortical brain structures, suggesting a neuropathological pattern underlying the neurodevelopmental syndromes