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Discover the most talked about and latest scientific content & concepts.

Concept: Family

286

Disadvantaged social environments are associated with adverse health outcomes. This has been attributed, in part, to chronic stress. Telomere length (TL) has been used as a biomarker of chronic stress: TL is shorter in adults in a variety of contexts, including disadvantaged social standing and depression. We use data from 40, 9-y-old boys participating in the Fragile Families and Child Wellbeing Study to extend this observation to African American children. We report that exposure to disadvantaged environments is associated with reduced TL by age 9 y. We document significant associations between low income, low maternal education, unstable family structure, and harsh parenting and TL. These effects were moderated by genetic variants in serotonergic and dopaminergic pathways. Consistent with the differential susceptibility hypothesis, subjects with the highest genetic sensitivity scores had the shortest TL when exposed to disadvantaged social environments and the longest TL when exposed to advantaged environments.

Concepts: Family, Scientific method, Sociology, Child, Telomere, Magnetic susceptibility, The Fragile, Highly sensitive person

211

Little is known about how factors within the general family environment are associated with weight and related behaviors among adolescents/young adults.

Concepts: Family

180

Studies have suggested that number of siblings and birth order is associated with obesity. However, studies combining these exposures are needed. This study aimed at investigating obesity in children and young adults in regard to different combinations of family size and birth order.

Concepts: Family, Biology, Obesity, Child, Childhood, Cultural studies, Childhood obesity, Sibling

177

Rural development initiatives across the developing world are designed to improve community well-being and livelihoods. However they may also have unforeseen consequences, in some cases placing further demands on stretched public services. In this paper we use data from a longitudinal study of five Ethiopian villages to investigate the impact of a recent rural development initiative, installing village-level water taps, on rural to urban migration of young adults. Our previous research has identified that tap stands dramatically reduced child mortality, but were also associated with increased fertility. We demonstrate that the installation of taps is associated with increased rural-urban migration of young adults (15-30 years) over a 15 year period (15.5% migrate out, n = 1912 from 1280 rural households). Young adults with access to this rural development intervention had three times the relative risk of migrating to urban centres compared to those without the development. We also identify that family dynamics, specifically sibling competition for limited household resources (e.g. food, heritable land and marriage opportunities), are key to understanding the timing of out-migration. Birth of a younger sibling doubled the odds of out-migration and starting married life reduced it. Rural out-migration appears to be a response to increasing rural resource scarcity, principally competition for agricultural land. Strategies for livelihood diversification include education and off-farm casual wage-labour. However, jobs and services are limited in urban centres, few migrants send large cash remittances back to their families, and most return to their villages within one year without advanced qualifications. One benefit for returning migrants may be through enhanced social prestige and mate-acquisition on return to rural areas. These findings have wide implications for current understanding of the processes which initiate rural-to-urban migration and transitions to low fertility, as well as for the design and implementation of development intervention across the rural and urban developing world.

Concepts: Family, Demography, Population, City, Urban area, Human migration, Urbanization, Rural economics

173

Offspring survival can often depend on successful communication with parents about their state of need. Theory suggests that offspring will be less likely to honestly signal their need when they experience greater competition from either a greater number of nestmates or less-related nestmates. We found support for this hypothesis with a comparative analysis, examining data from across 60 species of birds. We found that offspring are less honest about their level of need when (i) they face competition from current siblings; (ii) their parents are likely to breed again, and so they are in competition with future siblings; and (iii) parental divorce or death means that they are likely to be less related to future siblings. More generally, these patterns highlight the sensitivity of communication systems to conflict between signaler and receiver while also suggesting that when there is little conflict, natural selection favors the honest.

Concepts: Family, Natural selection, Parent, Signal, Sibling, Offspring, Parental investment, Divorce

173

BACKGROUND: Successful cancer prevention policies and programming for youth must be based on a solid understanding of youth’s conceptualization of cancer and cancer prevention. Accordingly, a qualitative study examining youth’s perspectives of cancer and its prevention was undertaken. Not surprisingly, smoking (i.e., tobacco cigarette smoking) was one of the dominant lines of discourse in the youth’s narratives. This paper reports findings of how youth conceptualize smoking with attention to their perspectives on parental and family-related smoking issues and experiences. METHODS: Seventy-five Canadian youth ranging in age from 11–19 years participated in the study. Six of the 75 youth had a history of smoking and 29 had parents with a history of smoking. Youth were involved in traditional ethnographic methods of interviewing and photovoice. Data analysis involved multiple levels of analysis congruent with ethnography. RESULTS: Youth’s perspectives of parents and other family members' cigarette smoking around them was salient as represented by the theme: It’s not fair. Youth struggled to make sense of why parents would smoke around their children and perceived their smoking as an unjust act. The theme was supported by four subthemes: 1) parenting the parent about the dangers of smoking; 2) the good/bad parent; 3) distancing family relationships; and 4) the prisoner. Instead of being talked to about smoking it was more common for youth to share stories of talking to their parents about the dangers of smoking. Parents who did not smoke were seen by youth as the good parent, as opposed to the bad parent who smoked. Smoking was an agent that altered relationships with parents and other family members. Youth who lived in homes where they were exposed to cigarette smoke felt like a trapped prisoner. CONCLUSIONS: Further research is needed to investigate youth’s perceptions about parental cigarette smoking as well as possible linkages between youth exposed to second hand smoke in their home environment and emotional and lifestyle-related health difficulties. Results emphasize the relational impact of smoking when developing anti-tobacco and cancer prevention campaigns. Recognizing the potential toll that second-hand smoke can have on youth’s emotional well-being, health care professionals are encouraged to give youth positive messages in coping with their parents' smoking behaviour.

Concepts: Family, Lung cancer, Smoking, Tobacco, Tobacco smoking, Passive smoking, Cigarette, Parent

171

BACKGROUND: Numerous studies have documented a profound reduction in alcohol use among pregnant women, whereas research on expectant fathers has been scarce. The aim of this study was to measure changes in alcohol consumption from before pregnancy to 17 weeks in gestation for mothers and fathers, differentiating between parents with and without any previous children, and to measure how level and change in alcohol consumption into early pregnancy was associated with relationship satisfaction. METHODS: The data collection was conducted as part of the Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health. This cohort now includes 108 000 children, 90 700 mothers and 71 500 fathers recruited from 1999 to 2008. The present study comprises 82 362 couples. Alcohol consumption was assessed using a questionnaire including items about usual drinking frequency, quantities, and number of occasions with heavy episodic drinking (HED). Relationship satisfaction was measured by five items scored on a Likert agreement scale. RESULTS: The findings indicate that both mothers and fathers reduce their drinking significantly during pregnancy. Reduction was apparent for all three measures of alcohol consumption. First-time fathers reduced their alcohol consumption more than experienced fathers, from initially higher levels. The gap between the fathers and their pregnant partner was greater for first-time parents compared to parents with previous children. Drinking pre-pregnancy and relationship satisfaction during pregnancy were weakly related within each partner, whereas no association across partners was observed. CONCLUSIONS: Both expectant mothers and fathers changed their alcohol consumption patterns when expecting a child. Almost all mothers stopped drinking, whereas fathers reduced their drinking to a considerable degree. Relationship satisfaction was only slightly related to their drinking patterns. The findings may have important policy implications, mainly with regard to developing alcohol preventive strategies.

Concepts: Family, Alcohol, Pregnancy, Childbirth, Embryo, Uterus, Parent, Mother

169

OBJECTIVE: To identify reasons why eligible families are not accessing free ‘Healthy Start’ vitamin supplementation (providing vitamins A, C and D) in England. DESIGN: Qualitative study using in-depth interviews. SETTING: 13 primary care trusts in England. PARTICIPANTS: Purposive sample of 15 Healthy Start coordinators, 50 frontline health and children’s professionals and 107 parents. RESULTS: Vitamin take-up was low across all research sites, reported as below 10% of eligible beneficiaries for free vitamins. Reasons identified by both parents and professionals included (1) poor accessibility of vitamins, (2) low promotion of the scheme by health professionals, (3) a lack of awareness among eligible families, and (4) low motivation among mothers to take vitamins for themselves during pregnancy or for children under 4 years old. CONCLUSIONS: Low uptake rates can be explained by poor accessibility of vitamins and lack of awareness and motivation to take vitamin supplements among eligible families. Universal provision (at least for pregnant women) and better training for health professionals are identified as potential solutions worthy of further research and evaluation.

Concepts: Family, Pregnancy, Nutrition, Vitamin, Dietary supplement, Educational psychology, Folic acid, Mother

169

Next-generation sequencing is revolutionizing genomic analysis, but this analysis can be compromised by high rates of missing true variants. To develop a robust statistical method capable of identifying variants that would otherwise not be called, we conducted sequence data simulations and both whole-genome and targeted sequencing data analysis of 28 families. Our method (Family-Based Sequencing Program, FamSeq) integrates Mendelian transmission information and raw sequencing reads. Sequence analysis using FamSeq reduced the number of false negative variants by 14-33% as assessed by HapMap sample genotype confirmation. In a large family affected with Wilms tumor, 84% of variants uniquely identified by FamSeq were confirmed by Sanger sequencing. In children with early-onset neurodevelopmental disorders from 26 families, de novo variant calls in disease candidate genes were corrected by FamSeq as Mendelian variants, and the number of uniquely identified variants in affected individuals increased proportionally as additional family members were included in the analysis. To gain insight into maximizing variant detection, we studied factors impacting actual improvements of family-based calling, including pedigree structure, allele frequency (common vs. rare variants), prior settings of minor allele frequency, sequence signal-to-noise ratio, and coverage depth (∼20× to >200×). These data will help guide the design, analysis, and interpretation of family-based sequencing studies to improve the ability to identify new disease-associated genes.

Concepts: Family, Gene, Genetics, Allele, Evolution, Classical genetics, Data, Sequence

169

Although the concept of genomic selection relies on linkage disequilibrium (LD) between quantitative trait loci and markers, reliability of genomic predictions is strongly influenced by family relationships. In this study, we investigated the effects of LD and family relationships on reliability of genomic predictions and the potential of deterministic formulas to predict reliability using population parameters in populations with complex family structures. Five groups of selection candidates were simulated taking different information sources from the reference population into account: 1) allele frequencies; 2) LD pattern; 3) haplotypes; 4) haploid chromosomes; 5) individuals from the reference population, thereby having real family relationships with reference individuals. Reliabilities were predicted using genomic relationships among 529 reference individuals and their relationships with selection candidates and with a deterministic formula where the number of effective chromosome segments (M(e)) was estimated based on genomic and additive relationship matrices for each scenario. At a heritability of 0.6, reliabilities based on genomic relationships were 0.002±0.0001 (allele frequencies), 0.015±0.001 (LD pattern), 0.018±0.001 (haplotypes), 0.100±0.008 (haploid chromosomes) and 0.318±0.077 (family relationships). At a heritability of 0.1, relative differences among groups were similar. For all scenarios, reliabilities were similar to predictions with a deterministic formula using estimated M(e). So, reliabilities can be predicted accurately using empirically estimated M(e) and level of relationship with reference individuals has a much higher effect on the reliability than linkage disequilibrium per se. Furthermore, accumulated length of shared haplotypes is more important in determining the reliability of genomic prediction than the individual shared haplotype length.

Concepts: Family, Scientific method, Gene, Genetics, Prediction, Futurology, Genetic genealogy, Linkage disequilibrium