Purpose

Social environment and family context exert substantial influence on adolescent sexual behaviors. These influences are especially important to examine in countries undergoing rapid demographic and social change. This study employs unique, intergenerational and longitudinal data (1998-2009) to examine the effects of parental, peer, and household influences on sexual initiation among young adults in Cebu, Philippines.

Methods

Intergenerational and longitudinal cohort data from the 1998 Cebu Longitudinal Health and Nutrition Survey (CLHNS) are analyzed to examine the effects of household, peer, family, and young adults' sexual attitudes on age at first sex by 2009 among young men and women. Gender-stratified Cox proportional hazards models and Cox regression models are used to model time to first sex.

Results

Household, family, peer, and individual characteristics have disparate influences on sexual initiation among Filipino boys and girls. Boys' sexual initiation was positively associated with urbanicity, household wealth, and the presence of a family member working abroad, whereas for girls, these variables had no significant effects. Unique effects were also found for girls-mother's education was negatively associated, and girls' number of siblings was positively associated, with higher hazards of sex. Additionally, the effects of some variables on the occurrence of first sex differed across time, indicating that boys and girls may be differentially influenced by contextual characteristics across adolescence.

Conclusions

Amid substantial sociodemographic changes and persistence of traditional gender norms, this study highlights the importance of examining the unique influences and intersections of gender and context on sexual initiation in the Philippines.

Objective

To identify sociodemographic characteristics and factors involved in Tibetan women's decisions to deliver at the Tibetan Birth and Training Center (TBTC) in rural western China.

Methods

In the present mixed-methods study, a random sample of married women who delivered at the TBTC between June 2011 and June 2012 were surveyed. Additionally, four focus group discussions were conducted among married women living in the TBTC catchment area. Descriptive analyses were conducted, and dominant themes were identified.

Results

In focus group discussions, women (n=33) reported that improved roads and transportation meant that access to health facilities was easier than in the past. Although some of the 114 survey participants voiced negative perceptions of healthcare facilities and providers, 99 (86.8%) indicated that they chose to deliver at the TBTC because they preferred to have a doctor present. Most women (75 [65.8%]) said their mother/mother-in-law made the final decision about delivery location. Women valued logistic and cultural aspects of the TBTC, and 108 (94.7%) said that they would recommend the TBTC to a friend.

Conclusion

Study participants preferred delivery care that combines safety and comfort. The findings highlight avenues for further promotion of facility delivery among populations with lower rates of skilled deliveries.

Background

Increasing skilled birth attendance at delivery is key to reducing maternal mortality, particularly among marginalized populations. Despite China's successful rollout of a national policy to promote facility deliveries, challenges remain among rural and ethnic minority populations. In response, a Tibetan Birth and Training Center (TBTC) was constructed in 2010 to provide high-quality obstetric care in a home-like environment to a predominantly Tibetan population in Tso-ngon (Qinghai) province in western China to improve maternal care in the region. This study examines if and how first users of the TBTC differ from women in the broader community, and how this information may inform subsequent maternal health care interventions in this area.

Methods

Trained, Tibetan interviewers administered a face-to-face, quantitative questionnaire to two groups of married, Tibetan women: women who had delivered at the TBTC between June 2011-June 2012 (n = 114) and a non-equivalent comparison group of women from the same communities who had delivered in the last two years, but not at the TBTC (n = 108). Chi-squared and ANOVA tests were conducted to detect differences between the samples.

Results

There were no significant differences between the samples in education or income; however, women from the TBTC sample were significantly younger (25.55 vs. 28.16 years; p < 0.001) and had fewer children (1.54 vs. 1.70; p = 0.05). Items measuring maternity health care-seeking and perceived importance of health facility amenities indicated minimal differences between the samples. However, as compared to the community sample, the TBTC sample had a greater proportion of women who reported having the final say regarding where to deliver (26% vs. 14%; p = 0.02) and having a friend or family member who delivered at home (50% vs. 28%; p < 0.001).

Conclusions

Findings did not support the hypothesis that the TBTC attracts lower-income, less-educated women. Minimal differences in women's characteristics and perceptions regarding delivery care between the two samples suggest that the TBTC is serving a broad cross-section of women. Differences between the samples with respect to delivery care decision-making and desire for skilled birth care underscore areas that may be further explored and supported in subsequent efforts to promote facility delivery in this population, and similar populations, of women.

We revisit a novel causal model published in Demography by Hicks et al. (2018), designed to assess whether exposure to neighborhood disadvantage over time affects children's reading and math skills. Here, we provide corrected and new results. Reconsideration of the model in the original article raised concerns about bias due to exposure-induced confounding (i.e., past exposures directly affecting future exposures) and true state dependence (i.e., past exposures affecting confounders of future exposures). Through simulation, we show that our originally proposed propensity function approach displays modest bias due to exposure-induced confounding but no bias from true state dependence. We suggest a correction based on residualized values and show that this new approach corrects for the observed bias. We contrast this revised method with other causal modeling approaches using simulation. Finally, we reproduce the substantive models from Hicks et al. (2018) using the new residuals-based adjustment procedure. With the correction, our findings are essentially identical to those reported originally. We end with some conclusions regarding approaches to causal modeling.

Objective

To identify sociodemographic characteristics and factors involved in Tibetan women's decisions to deliver at the Tibetan Birth and Training Center (TBTC) in rural western China.

Methods

In the present mixed-methods study, a random sample of married women who delivered at the TBTC between June 2011 and June 2012 were surveyed. Additionally, four focus group discussions were conducted among married women living in the TBTC catchment area. Descriptive analyses were conducted, and dominant themes were identified.

Results

In focus group discussions, women (n=33) reported that improved roads and transportation meant that access to health facilities was easier than in the past. Although some of the 114 survey participants voiced negative perceptions of healthcare facilities and providers, 99 (86.8%) indicated that they chose to deliver at the TBTC because they preferred to have a doctor present. Most women (75 [65.8%]) said their mother/mother-in-law made the final decision about delivery location. Women valued logistic and cultural aspects of the TBTC, and 108 (94.7%) said that they would recommend the TBTC to a friend.

Conclusion

Study participants preferred delivery care that combines safety and comfort. The findings highlight avenues for further promotion of facility delivery among populations with lower rates of skilled deliveries.

Prior research has suggested that children living in a disadvantaged neighborhood have lower achievement test scores, but these studies typically have not estimated causal effects that account for neighborhood choice. Recent studies used propensity score methods to account for the endogeneity of neighborhood exposures, comparing disadvantaged and nondisadvantaged neighborhoods. We develop an alternative propensity function approach in which cumulative neighborhood effects are modeled as a continuous treatment variable. This approach offers several advantages. We use our approach to examine the cumulative effects of neighborhood disadvantage on reading and math test scores in Los Angeles. Our substantive results indicate that recency of exposure to disadvantaged neighborhoods may be more important than average exposure for children's test scores. We conclude that studies of child development should consider both average cumulative neighborhood exposure and the timing of this exposure.

Here we present the results of the NSF-funded Workshop on Topology, which met on June 11 and 12 in Miami Beach,Florida. This report identifies important problems involving both computation and topology

Osteoprotegerin (OPG) is involved in bone homeostasis and tumor cell survival. Circulating OPG levels are also important biomarkers of various clinical traits, such as cancers and atherosclerosis. OPG levels were measured in serum or in plasma. In a meta-analysis of genome-wide association studies in up to 10 336 individuals from European and Asian origin, we discovered that variants >100 kb upstream of the TNFRSF11B gene encoding OPG and another new locus on chromosome 17q11.2 were significantly associated with OPG variation. We also identified a suggestive locus on chromosome 14q21.2 associated with the trait. Moreover, we estimated that over half of the heritability of OPG levels could be explained by all variants examined in our study. Our findings provide further insight into the genetic regulation of circulating OPG levels.

Rheumatoid arthritis (RA) and osteoporosis (OP) are two comorbid complex inflammatory conditions with evidence of shared genetic background and causal relationships. We aimed to clarify the genetic architecture underlying RA and various OP phenotypes while additionally considering an inflammatory component, C-reactive protein (CRP). Genome-wide association study summary statistics were acquired from the GEnetic Factors for OSteoporosis Consortium, Cohorts for Heart and Aging Research Consortium and UK Biobank. Mendelian randomization (MR) was used to detect the presence of causal relationships. Colocalization analysis was performed to determine shared genetic variants between CRP and OP phenotypes. Analysis of pleiotropy between traits owing to shared causal single nucleotide polymorphisms (SNPs) was performed using PL eiotropic A nalysis under CO mposite null hypothesis (PLACO). MR analysis was suggestive of horizontal pleiotropy between RA and OP traits. RA was a significant causal risk factor for CRP (β = 0.027, 95% confidence interval = 0.016-0.038). There was no evidence of CRP→OP causal relationship, but horizontal pleiotropy was apparent. Colocalization established shared genomic regions between CRP and OP, including GCKR and SERPINA1 genes. Pleiotropy arising from shared causal SNPs revealed through the colocalization analysis was all confirmed by PLACO. These genes were found to be involved in the same molecular function 'protein binding' (GO:0005515) associated with RA, OP and CRP. We identified three major components explaining the epidemiological relationship among RA, OP and inflammation: (1) Pleiotropy explains a portion of the shared genetic relationship between RA and OP, albeit polygenically; (2) RA contributes to CRP elevation and (3) CRP, which is influenced by RA, demonstrated pleiotropy with OP.

The growth hormone/insulin-like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF-related proteins including IGF-I and IGF-binding protein-3 (IGFBP-3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes, and cancer. Through genomewide association study of up to 30 884 adults of European ancestry from 21 studies, we confirmed and extended the list of previously identified loci associated with circulating IGF-I and IGFBP-3 concentrations (IGF1, IGFBP3, GCKR, TNS3, GHSR, FOXO3, ASXL2, NUBP2/IGFALS, SORCS2, and CELSR2). Significant sex interactions, which were characterized by different genotype-phenotype associations between men and women, were found only for associations of IGFBP-3 concentrations with SNPs at the loci IGFBP3 and SORCS2. Analyses of SNPs, gene expression, and protein levels suggested that interplay between IGFBP3 and genes within the NUBP2 locus (IGFALS and HAGH) may affect circulating IGF-I and IGFBP-3 concentrations. The IGF-I-decreasing allele of SNP rs934073, which is an eQTL of ASXL2, was associated with lower adiposity and higher likelihood of survival beyond 90 years. The known longevity-associated variant rs2153960 (FOXO3) was observed to be a genomewide significant SNP for IGF-I concentrations. Bioinformatics analysis suggested enrichment of putative regulatory elements among these IGF-I- and IGFBP-3-associated loci, particularly of rs646776 at CELSR2. In conclusion, this study identified several loci associated with circulating IGF-I and IGFBP-3 concentrations and provides clues to the potential role of the IGF axis in mediating effects of known (FOXO3) and novel (ASXL2) longevity-associated loci.