Non-parental Childcare During Early Childhood and Problem Behaviour Trajectories from Ages 5 to 14 Years

Using data from the nationally representative Millennium Cohort Study, this study examined the association between age of starting and weekly hours in formal childcare between birth and 5 years with internalising and externalising behaviour trajectories from ages 5 to 14 years in England (N = 6194 children). Associations were analysed using multilevel general linear regression models, with adjustment for socio-economic position, maternal mental health, demographics, and child temperament. Later entry was associated with more internalising behaviours at age 14 years. Children who spent > 40 h per week in childcare between birth and 3 years displayed more externalising behaviour at 5 years than children who did not attend childcare. Controlling for socio-economic position and parental mental health attenuated findings.

Trends in childhood body mass index between 1936 and 2011 showed that underweight remained more common than obesity among 398 970 Danish school children

AIM

To examine trends in all body mass index (BMI) groups in children from 1936 to 2011.

METHODS

We included 197 694 girls and 201 276 boys from the Copenhagen School Health Records Register, born between 1930 and 1996, with longitudinal weight and height measurements (6-14 years). Using International Obesity Task Force criteria, BMI was classified as underweight, normal-weight, overweight and obesity. Sex- and age-specific prevalences were calculated.

RESULTS

From the 1930s, the prevalence of underweight was stable until a small increase occurred from 1950 to 1970s, and thereafter it declined into the early 2000s. Using 7-year-olds as an example, underweight changed from 10% to 7% in girls and from 9% to 6% in boys during the study period. The prevalence of overweight plateaued from 1950 to 1970s and then steeply increased from 1970s onwards and in 1990-2000s 15% girls and 11% boys at 7 years had overweight. The prevalence of obesity particularly increased from 1980s onwards and in 1990-2000s 5% girls and 4% boys at 7 years had obesity. These trends slightly differed by age.

CONCLUSION

Among Danish schoolchildren, the prevalence of underweight was greater than overweight until the 1980s and greater than obesity throughout the period. Thus, monitoring the prevalence of childhood underweight remains an important public health issue.

Greater variability in judgements of the value of novel ideas

Understanding the factors that hinder support for creative ideas is important because creative ideas fuel innovation-a goal prioritized across the arts, sciences and business. Here we document one obstacle faced by creative ideas: as ideas become more novel-that is, they depart more from existing norms and standards-disagreement grows about their potential value. Specifically, across multiple contexts, using both experimental methods (four studies, total n = 1,801) and analyses of archival data, we find that there is more variability in judgements of the value of more novel (versus less novel) ideas. We also find that people interpret greater variability in others' judgements about an idea's value as a signal of risk, reducing their willingness to invest in the idea. Our findings show that consensus about an idea's worth diminishes the newer it is, highlighting one reason creative ideas may fail to gain traction in the social world.

Associations between diabetes status and grip strength trajectory sub-groups in adulthood: findings from over 16 years of follow-up in the MRC National Survey of Health and Development

BACKGROUND

Cross-sectional studies suggest a relationship between diabetes status and weaker grip strength (GS) in adulthood and limited evidence from longitudinal studies has focussed on the association with average change in GS. We aimed to investigate whether diabetes status was related to membership of distinct GS trajectories in mid-to-late adulthood in 2,263 participants in the Medical Research Council National Survey of Health and Development.

METHODS

Grip strength (kg) was measured at 53, 60-64 and 69 years. Pre-/diabetes was defined at 53 years based on HbA1c > 5.6% and/or doctor-diagnosis of diabetes. Sex-specific latent class trajectory models were developed and multinomial logistic regression was used to investigate the association between pre-/diabetes status and membership into GS trajectory classes.

RESULTS

For both males and females, a 3-class solution ('High', 'Intermediate', 'Low') provided the best representation of the GS data and the most plausible solution. There was no evidence that pre-/diabetes status was associated with class membership in either sex: e.g., adjusted odds ratios of being in the 'Low' class (vs. 'High') for males with pre-/diabetes (vs. no-diabetes) was 1.07 (95% CI:0.45,2.55).

CONCLUSION

Using a flexible data-driven approach to identify GS trajectories between 53 and 69 years, we observed three distinct GS trajectories, all declining, in both sexes. There was no association between pre-/diabetes status at 53 years and membership into these GS trajectories. Understanding the diabetes status-GS trajectories association is vital to ascertain the consequences that projected increases in pre-/diabetes prevalence's are likely to have.

Dietary supplementation with milk lipids leads to suppression of developmental and behavioral phenotypes of hyperexcitable Drosophila mutants

Dietary modifications often have a profound impact on the penetrance and expressivity of neurological phenotypes that are caused by genetic defects. Our previous studies in Drosophila melanogaster revealed that seizure-like phenotypes of gain-of-function voltage-gated sodium (Na_v) channel mutants (para^Shu, para^bss1, and para^GEFS+), as well as other seizure-prone "bang-sensitive" mutants (eas and sda), were drastically suppressed by supplementation of a standard diet with milk whey. In the current study we sought to determine which components of milk whey are responsible for the diet-dependent suppression of their hyperexcitable phenotypes. Our systematic analysis reveals that supplementing the diet with a modest amount of milk lipids (0.26% w/v) mimics the effects of milk whey. We further found that a minor milk lipid component, α-linolenic acid, contributed to the diet-dependent suppression of adult para^Shu phenotypes. Given that lipid supplementation during the larval stages effectively suppressed adult para^Shu phenotypes, dietary lipids likely modify neural development to compensate for the defects caused by the mutations. Consistent with this notion, lipid feeding fully rescued abnormal dendrite development of class IV sensory neurons in para^Shu larvae. Overall, our findings demonstrate that milk lipids are sufficient to ameliorate hyperexcitable phenotypes in Drosophila mutants, providing a foundation for future investigation of the molecular and cellular mechanisms by which dietary lipids modify genetically induced abnormalities in neural development, physiology, and behavior.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Reaching racial/ethnic and sexual and gender minorities with HIV prevention information via social marketing

The Pre-exposure Prophylaxis, Data to Care, Implementation, and Evaluation (PrIDE) multi-site demonstration project utilized a cluster evaluation approach and identified six funding recipients that evaluated similar media evaluation questions (Baltimore, Los Angeles County, Lousiana, Michigan, New York City, and Virginia). All of the evaluated social marketing campaigns were developed in collaboration with health department staff, external marketing firms, and community advisory boards (CAB) aiming to produce changes in PrEP outcomes by reaching racial/ethnic and sexual and gender minorities. Jurisdictions demonstrated changes in PrEP awareness, knowledge, willingness to take PrEP, and/or PrEP literacy following initiation of the campaigns. In data from four sites, PrEP awareness significantly increased from 72 % at baseline to 86 % at mid-project, and to 90 % post-campaigns. The campaigns illustrate the importance of partnerships and stakeholder engagement, audience segmentation, and intentional evaluation planning. As PrEP services mature, evaluating PrEP demand and PrEP use resulting from campaigns, will be necessary. Also, future campaigns for racial/ethnic and sexual and gender minorities should identify the best channels to reach each group based on their input, disaggregate data by priority group, and determine campaign effectiveness.

Changes over time in latent patterns of childhood-to-adulthood BMI development in Great Britain: evidence from three cohorts born in 1946, 1958, and 1970

BACKGROUND

Most studies on secular trends in body mass index (BMI) are cross-sectional and the few longitudinal studies have typically only investigated changes over time in mean BMI trajectories. We aimed to describe how the evolution of the obesity epidemic in Great Britain reflects shifts in the proportion of the population demonstrating different latent patterns of childhood-to-adulthood BMI development.

METHODS

We used pooled serial BMI data from 25,655 participants in three British cohorts: the 1946 National Survey of Health and Development (NSHD), 1958 National Child Development Study (NCDS), and 1970 British Cohort Study (BCS). Sex-specific growth mixture models captured latent patterns of BMI development between 11 and 42 years. The classes were characterised in terms of their birth cohort composition.

RESULTS

The best models had four classes, broadly similar for both sexes. The 'lowest' class (57% of males; 47% of females) represents the normal weight sub-population, the 'middle' class (16%; 15%) represents the sub-population who likely develop overweight in early/mid-adulthood, and the 'highest' class (6%; 9%) represents those who likely develop obesity in early/mid-adulthood. The remaining class (21%; 29%) reflects a sub-population with rapidly 'increasing' BMI between 11 and 42 years. Both sexes in the 1958 NCDS had greater odds of being in the 'highest' class compared to their peers in the 1946 NSHD but did not have greater odds of being in the 'increasing' class. Conversely, males and females in the 1970 BCS had 2.78 (2.15, 3.60) and 1.87 (1.53, 2.28), respectively, times higher odds of being in the 'increasing' class.

CONCLUSIONS

Our results suggest that the obesity epidemic in Great Britain reflects not only an upward shift in BMI trajectories but also a more recent increase in the number of individuals demonstrating more rapid weight gain, from normal weight to overweight, across the second, third, and fourth decades of life.

Prevalence and spatial distribution of Coxiella burnetii seropositivity in northern Australian beef cattle adjusted for diagnostic test uncertainty

Q fever is a zoonotic disease caused by infection with Coxiella burnetii transmitted from animals including, but not limited to, cattle, sheep and goats. The infection in cattle is typically sub-clinical with some evidence suggesting associated reproductive loss. There is currently limited data on the true prevalence and distribution of coxiellosis in beef cattle across northern Australia. During this study, 2,012 sera samples from beef cattle managed on commercial farms located in Queensland and the Northern Territory were tested using an indirect immunofluorescent assay (IFA) for serological evidence of IgG antibodies against C. burnetii. Bayesian latent class models were used to estimate the true prevalence, adjusted for diagnostic test sensitivity and specificity and incorporating the hierarchical structure of the cattle within farms and regions. In this study, cattle in the Northern Territory had lower estimated true prevalence than cattle within most regions of Queensland with the exception of south-east Queensland. Results from this study have described the geographic distribution and estimated the true prevalence of antibodies to C. burnetii in a sample of extensively managed beef cattle located across the tropical grazing regions of northern Australia.

Effects of medicine ball mass on the intensity of 90°/90° plyometric throwing exercise

OBJECTIVES

To quantify the effects of medicine ball mass (1 kg, 1.5 kg, 2 kg) on the intensity of 90°/90° plyometric throwing exercise.

STUDY DESIGN

Controlled laboratory study.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Fifteen physically active collegiate aged men.

MAIN OUTCOME MEASURES

Kinematics of the upper extremity were collected during completion of eight to ten repetitions of 90°/90° plyometric throwing exercise with three different mass medicine balls. Four parameters, medicine ball release and contact momentum, time-to-rebound, and contact time, were computed for each selected repetition and used for statistical analysis.

RESULTS

Ball mass did not significantly influence time-to-rebound (P = .718) and had a small (less than 0.05s) effect on ball contact time (P = .039). Ball release momentum was significantly greater (P < .001, 67-123% greater) than ball contact momentum. Medicine ball mass significantly increased both ball release (34-35%) and ball contact (45-67%) momentum however the effect was significantly greater for ball release momentum (P = .005).

CONCLUSIONS

These results document the effects of increasing medicine ball mass during 90°/90° plyometric throwing exercise and provide evidence for designing upper extremity plyometric training programs. Based on ball contact momentum being less than ball release momentum, as well as ball mass having greater influence on ball release velocity, we suggest that 90°/90° plyometric throwing exercise is a safe exercise.

Framework for developing a national surgical, obstetric and anaesthesia plan

Background

Emergency and essential surgical, obstetric and anaesthesia (SOA) care are now recognized components of universal health coverage, necessary for a functional health system. To improve surgical care at a national level, strategic planning addressing the six domains of a surgical system is needed. This paper details a process for development of a national surgical, obstetric and anaesthesia plan (NSOAP) based on the experiences of frontline providers, Ministry of Health officials, WHO leaders, and consultants.

Methods

Development of a NSOAP involves eight key steps: Ministry support and ownership; situation analysis and baseline assessments; stakeholder engagement and priority setting; drafting and validation; monitoring and evaluation; costing; governance; and implementation. Drafting a NSOAP involves defining the current gaps in care, synthesizing and prioritizing solutions, and providing an implementation and monitoring plan with a projected cost for the six domains of a surgical system: infrastructure, service delivery, workforce, information management, finance and governance.

Results

To date, four countries have completed NSOAPs and 23 more have committed to development. Lessons learned from these previous NSOAP processes are described in detail.

Conclusion

There is global movement to address the burden of surgical disease, improving quality and access to SOA care. The development of a strategic plan to address gaps across the SOA system systematically is a critical first step to ensuring countrywide scale‐up of surgical system‐strengthening activities.

At what age do normal weight Canadian children become overweight adults? Differences according to sex and metric

BACKGROUND

The prevalence of overweight and obesity doubles between adolescence and young adulthood; however, the exact age, and appropriate metric to use to identify when overweight develops is still debated.

AIM

To examine the age of onset of overweight by sex and four metrics: body mass index (BMI), fat mass (%FM), waist circumference (WC) and waist-to-height ratio (WHtR).

SUBJECTS AND METHODS

Between 1991 and 2017, serial measures of body composition were taken on 237 (108 males) individuals (aged 8-40 years of age). Hierarchical random effects models were used to develop growth curves. Curves were compared to BMI, %FM and WC overweight age- and sex-specific cut-points.

RESULTS

In males, the BMI growth curve crossed the cut-point at 22.0 years, compared to 23.5 and 26.5 years for WHtR and %FM, respectively; WC cut-off was not reached until 36 years. In females, the BMI growth curve crossed the overweight cut-point at 21.5 years, compared to 14.2 years for %FM and 21.9 and 27.5 years for WC and WHtR, respectively.

CONCLUSION

In summary, overweight onset occurs during young adulthood with the exception of WC in males. BMI in males and %FM in females were the metrics identifying overweight the earliest.

Body size trajectories and cardio-metabolic resilience to obesity

Individuals with obesity do not represent a single homogenous group in terms of cardio‐metabolic health prospects. The concept of metabolically healthy obesity is a crude way of capturing this heterogeneity and has resulted in a plethora of research linking to future outcomes to show that it is not a benign condition. By contrast, very few studies have looked back in time and modelled the life course processes and exposures that explain the heterogeneity in cardio‐metabolic health and morbidity and mortality risk among people with the same body mass index (BMI) (or waist circumference or percentage body fat). The aim of the Medical Research Council New Investigator Research Grant (MR/P023347/1) ‘Body size trajectories and cardio‐metabolic resilience to obesity in three United Kingdom birth cohorts’ is to reveal the body size trajectories, pubertal development patterns and other factors (e.g. early‐life adversity) that might attenuate the positive associations of adulthood obesity makers (e.g. BMI) with cardio‐metabolic disease risk factors and other outcomes, thereby providing some degree of protection against the adverse effects of obesity. This work builds on the Principle Investigator's previous research as part of the Cohort and Longitudinal Studies Enhancement Resources initiative and focuses on secondary data analysis in the nationally representative UK birth cohort studies (initiated in 1946, 1958 and 1970), which have life course body size and exposure data and a biomedical sweep in adulthood. The grant will provide novel evidence on the life course processes and exposures that lead to some people developing a cardio‐metabolic complication or disease or dying while other people with the same BMI do not. This paper details the grant's scientific rationale, research objectives and potential impact.

A Bilateral Comparison of the Underlying Mechanics Contributing to the Seated Single-Arm Shot-Put Functional Performance Test

CONTEXT

Functional performance tests (FPTs) are tools used to assess dynamic muscle strength and power. In contrast to the lower extremity, fewer FPTs are available for the upper extremity. The seated single-arm shot put test has the potential to fill the void in upper extremity FPTs; however, the underlying mechanics have not been examined and, therefore, the validity of bilateral comparisons is unknown.

OBJECTIVE

To examine the effects of upper extremity dominance and medicine-ball mass on the underlying mechanics of the seated single-arm shot put.

DESIGN

Crossover study.

SETTING

Biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Fifteen women (age = 23.6 ± 2.1 years, height = 1.65 ± .07 m, mass = 68.1 ± 11.7 kg) and 15 men (age = 24.3 ± 4.0 years, height = 1.80 ± 0.06 m, mass = 88.1 ± 16.4 kg), all healthy and physically active.

INTERVENTION(S)

Seated single-arm shot-put trials using the dominant and nondominant limbs were completed using three 0.114-m-diameter medicine-ball loads (1 kg, 2 kg, 3 kg).

MAIN OUTCOME MEASURE(S)

Customized touch-sensitive gloves, synchronized with kinematic data of the hands, signaled ball release, so that release height, release angle, and peak anterior and vertical velocity could be quantified for each trial. In addition, the horizontal range from release to first floor impact was recorded.

RESULTS

The dominant-limb horizontal ranges were 7% to 11% greater ( P < .001) than for the nondominant limb for each of the 3 ball masses. No bilateral release-height or -angle differences were revealed ( P ≥ .063). Release velocities were 7.6% greater for the dominant limb than the nondominant limb ( P = .001).

CONCLUSIONS

Our results support the use of the seated single-arm shot put test as a way to compare bilateral upper extremity functional performance. The near-identical release heights and angles between the dominant and nondominant limbs support the interpretation of measured bilateral horizontal-range differences as reflecting underlying strength and power differences.

The positive association of infant weight gain with adulthood body mass index has strengthened over time in the Fels Longitudinal Study

BACKGROUND

Infant weight gain is positively related to adulthood body mass index (BMI), but it is unknown whether or not this association is stronger for individuals born during (compared with before) the obesity epidemic.

OBJECTIVES

The aim of the study was to examine how the infant weight gain-adulthood BMI association might have changed across successive birth year cohorts spanning most of the 20th century.

METHODS

The sample comprised 346 participants in the Fels Longitudinal Study. Confounder-adjusted regression models were used to test the associations of conditional weight-for-length Z-score, capturing weight change between ages 0-2 years, with young adulthood BMI and blood pressure, including cohort [1933-1949 {N = 137}, 1950-1969 {N = 108}, 1970-1997 {N = 101}] as an effect modifier.

RESULTS

Conditional weight-for-length Z-score was positively related to adulthood BMI, but there was significant effect modification by birth year cohort such that the association was over two times stronger in the 1970-1997 cohort (β 2.31; 95% confidence interval 1.59, 3.03) compared with the 1933-1949 (0.98; 0.31, 1.65) and 1950-1969 (0.87; 0.21, 1.54) cohorts. A similar pattern was found for systolic blood pressure.

CONCLUSIONS

The infant weight gain-adulthood BMI association was over two times stronger among a cohort born during the obesity epidemic era compared with cohorts born earlier in the 20th century.

Development of an indirect ELISA for detection of antibody to wobbly possum disease virus in archival sera of Australian brushtail possums (Trichosurus vulpecula) in New Zealand

AIMS

To develop an indirect ELISA based on recombinant nucleocapsid (rN) protein of wobbly possum disease (WPD) virus for investigation of the presence of WPD virus in Australian brushtail possums (Trichosurus vulpecula) in New Zealand.

METHODS

Pre- and post-infection sera (n=15 and 16, respectively) obtained from a previous experimental challenge study were used for ELISA development. Sera were characterised as positive or negative for antibody to WPD virus based on western-blot using WPD virus rN protein as antigen. An additional 215 archival serum samples, collected between 2000-2016 from five different regions of New Zealand, were also tested using the ELISA. Bayesian modelling of corrected optical density at 450 nm (OD₄₅₀) results from the ELISA was used to obtain estimates of receiver operating characteristic (ROC) curves to establish cut-off values for the ELISA, and to estimate the prevalence of antibody to WPD virus.

RESULTS

Western blot analysis showed 5/14 (36%) pre-infection sera and 11/11 (100%) post-infection sera from experimentally infected possums were positive for antibodies to WPD virus. Bayesian estimates of the ROC curves established cut-off values of OD₄₅₀≥0.41 for samples positive, and OD₄₅₀<0.28 for samples negative for antibody to WPD virus, for sera diluted 1:100 for the ELISA. Based on the model, the estimated proportion of samples with antibodies to WPD virus was 0.30 (95% probability interval=0.196-0.418). Of the 230 archival serum samples tested using the ELISA, 48 (20.9%) were positive for antibody to WPD virus, 155 (67.4%) were negative and 27 (11.7%) equivocal, using the established cut-off values. The proportion of samples positive for WPD virus antibody differed between geographical regions (p<0.001).

CONCLUSION

The results suggested that WPD virus or a related virus has circulated among possums in New Zealand with differences in the proportion of antibody-positive samples from different geographical regions. Antibodies to WPD virus did not seem to protect possums from disease following experimental infection, as one third of possums from the previous challenge study showed evidence of pre-existing antibody at the time of challenge. These results provide further support for existence of different pathotypes of WPD virus, but the exact determinants of protection against WPD and epidemiology of infection in various regions of New Zealand remain to be established.

CLINICAL RELEVANCE

Availability of the indirect ELISA for detection of WPD virus antibody will facilitate prospective epidemiological investigation of WPD virus circulation in wild possum populations in New Zealand.

Life course factors associated with metabolically healthy obesity: a protocol for the systematic review of longitudinal studies

BACKGROUND

There is heterogeneity among obese individuals, as some appear to have healthier metabolic profiles and decreased health risks. These individuals are defined as metabolically healthy obese (MHO), whilst those with unhealthy metabolic profiles are defined as metabolically unhealthy obese (MUO). To date, most research on MHO has been cross-sectional or focused on disease prognosis. However, longitudinal studies are required to provide greater insight into the life course factors that contribute to the development of MHO. This study aims to systematically review longitudinal studies investigating the association between life course exposures and future MHO status.

METHODS

Electronic databases (MEDLINE, SCOPUS, and Web of Science) will be searched using a trialled search strategy. Studies will be included following a double-screening process according to inclusion criteria to assess eligibility. Studies eligible for inclusion will include those that have a longitudinal observational design where a life course exposure occurred or was measured at least 1 year before the outcome, investigate a human study population, are published in English after 1956, and investigate the association between ≥ 1 life course exposure and ≥ 1 outcome that reflects a measure of cardiometabolic resilience to obesity. Accepted life course exposures will include body size, body composition, pubertal development, smoking, diet, physical activity, sedentary behaviour, and psychosocial stress. The primary measure of cardiometabolic resilience to obesity will be MHO as an outcome (at follow-up). Studies investigating the development of cardiometabolic risk factors in an obese group without specifying MHO will also be accepted, such as the development of the metabolic syndrome (MetS) in an obese group. Key results of included studies will be tabulated, and a narrative synthesis will be conducted.

DISCUSSION

This will be the first systematic review to summarise the literature on the life course correlates of MHO. Importantly, it may highlight which modifiable lifestyle factors could be targeted to delay the onset of cardiometabolic complications among the obese.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017057992.

Two synthetic compounds containing chromium in different valency states

Two compounds, one an apatite and the other a perovskite, have been synthesized by sintering mixtures containing CaO and Cr2O3, and CaO, Cr2O3, and Fe2O3 respectively. The apatite formed by partial oxidation of the Cr2O3 and subsequent pick-up of moisture from the atmosphere, to give Ca5(CrO4)3OH. The perov-skite formed as a non-stoicheiometric compound Ca4(Fe,Cr)4O11 by partial oxidation of the Cr2O3 during firing. Lattice parameters and interplanar spacings are given for the two structures.

The Role of the Primary Romantic Relationship in HIV Care Engagement Outcomes Among Young HIV-Positive Black Men Who Have Sex with Men

The primary romantic relationship plays a fundamental role in health maintenance, but little is known about its role in HIV care engagement among young Black men who have sex with men (MSM) living with HIV. We examined how HIV care engagement outcomes (i.e., having a primary healthcare provider, receiving HIV treatment, taking antiretroviral medication, and medication adherence) vary by partnership status (single vs. concordant-positive vs. discordant) in a sample of young Black MSM living with HIV. Results showed mixed findings. Partnership status was significantly associated with HIV care engagement, even after adjusting for individual, social, and structural factors. While partnered men were consistently more likely than their single counterparts to have a regular healthcare provider, to receive recent treatment, and to have ever taken antiretroviral medication, they were less likely to report currently receiving antiretroviral therapy. Moreover, men with a discordant partner reported better adherence compared to men with a concordant or no partner. The association between partnership status and HIV care engagement outcomes was not consistent across the stages of the HIV Care Continuum, highlighting the complexity in how and why young Black men living with HIV engage in HIV healthcare. Given the social context of HIV disease management, more research is needed to explicate underlying mechanisms involved in HIV care and treatment that differ by relational factors for young Black MSM living with HIV.

A Comparison of Four Different Methods of Fixation of Osteochondral Fragments

Fixation methods for osteochondral shell grafts were studied using replace-ment of a femoral trochlear autograft in rabbits as the model. Twenty skeletally mature rabbits were divided into four groups with five rabbits in each. The articular cartilage of the femoral trochlea, including 2.0 mm of subchondral bone, was removed using a sagittal bone saw. The grafts were immediately reattached using either small Kirschner pins (K-pins), polydioxanone pins (PDP), polydioxanone suture (PDS), or polymethylmethacrylate (PMMA) cement. Six months postoperatively the rabbits were killed and the graft sites compared to the contralateral control using radiography, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Mild degenerative joint changes were evident radio-graphically in all of the operated joints. Articular surface defects at the graft sites were common and included small craters and erosions; a few had larger areas devoid of cartilage. Defects associated with the pin entrance sites were common in the K-pin and PD P groups. The PDS group had the least number of animals with articular surface defects. Safranin-O staining was complete in the PDS group, partial or complete in the K-pin and PD P groups, and partial in all of the joints in the PMM A group. H & E preparations of the cartilage sections were graded from 1 (normal cartilage) to 5 (multiple fissures, severe degradation). The PDS group had a mean (SD) score of 1.8 (0.8), the PD P group 2.4 (1.1), the K-pin group 2.5 (1.3), and the PMM A group 4.6 (0.6). The scores for the PMM A group were significantly greater then the scores for the other groups (p <0.05). The mean (SD) for radioactive counts per minute/mg tissue in treated graft sites as a percent of control was PDS: 130 (83); PDP : 115 (14); K-pins: 92 (42); PMMA : 91 (29). The relative percentages for radioactive uptake were not significantly different (P >0.05). Graft fixation using PDS, PDP, or K-pins was technically easy to perform and the results were generally satisfactory. Fixation using PMM A was technically demanding and histological evidence of moderate to severe cartilage degradation was present in all treated joints.

Femoral trochlear autografts in rabbits were used to study fixation methods for osteochondral graft fragments. Six months after the operations the graft sites were evaluated using radiographs, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Grafts stabilized using polydioxanone suture had the least number of articular surface defects and the most complete Safranin-O staining.

Generation and characterization of new alleles of quiver (qvr) that encodes an extracellular modulator of the Shaker potassium channel

Our earlier genetic screen uncovered a paraquat-sensitive leg-shaking mutant quiver¹ (qvr¹), whose gene product interacts with the Shaker (Sh) K⁺ channel. We also mapped the qvr locus to EY04063 and noticed altered day-night activity patterns in these mutants. Such circadian behavioral defects were independently reported by another group, who employed the qvr¹ allele we supplied them, and attributed the extreme restless phenotype of EY04063 to the qvr gene. However, their report adopted a new noncanonical gene name sleepless (sss) for qvr. In addition to qvr¹ and qvr^EY, our continuous effort since the early 2000s generated a number of novel recessive qvr alleles, including ethyl methanesulfonate (EMS)-induced mutations qvr² and qvr³, and P-element excision lines qvr^ip6 (imprecise jumpout), qvr^rv7, and qvr^rv9 (revertants) derived from qvr^EY. Distinct from the original intron-located qvr¹ allele that generates abnormal-sized mRNAs, qvr², and qvr³ had their lesion sites in exons 6 and 7, respectively, producing nearly normal-sized mRNA products. A set of RNA-editing sites are nearby the lesion sites of qvr³ and qvr^EY on exon 7. Except for the revertants, all qvr alleles display a clear ether-induced leg-shaking phenotype just like Sh, and weakened climbing abilities to varying degrees. Unlike Sh, all shaking qvr alleles (except for qvr^f01257) displayed a unique activity-dependent enhancement in excitatory junction potentials (EJPs) at larval neuromuscular junctions (NMJs) at very low stimulus frequencies, with qvr^EY displaying the largest EJP and more significant NMJ overgrowth than other alleles. Our detailed characterization of a collection of qvr alleles helps to establish links between novel molecular lesions and different behavioral and physiological consequences, revealing how modifications of the qvr gene lead to a wide spectrum of phenotypes, including neuromuscular hyperexcitability, defective motor ability and activity-rest cycles.

Gene-environment interplay in depressive symptoms: moderation by age, sex, and physical illness

BACKGROUND

Numerous factors influence late-life depressive symptoms in adults, many not thoroughly characterized. We addressed whether genetic and environmental influences on depressive symptoms differed by age, sex, and physical illness.

METHOD

The analysis sample included 24 436 twins aged 40-90 years drawn from the Interplay of Genes and Environment across Multiple Studies (IGEMS) Consortium. Biometric analyses tested age, sex, and physical illness moderation of genetic and environmental variance in depressive symptoms.

RESULTS

Women reported greater depressive symptoms than men. After age 60, there was an accelerating increase in depressive symptom scores with age, but this did not appreciably affect genetic and environmental variances. Overlap in genetic influences between physical illness and depressive symptoms was greater in men than in women. Additionally, in men extent of overlap was greater with worse physical illness (the genetic correlation ranged from near 0.00 for the least physical illness to nearly 0.60 with physical illness 2 s.d. above the mean). For men and women, the same environmental factors that influenced depressive symptoms also influenced physical illness.

CONCLUSIONS

Findings suggested that genetic factors play a larger part in the association between depressive symptoms and physical illness for men than for women. For both sexes, across all ages, physical illness may similarly trigger social and health limitations that contribute to depressive symptoms.

Heart rate and VO2 responses to treadmill running with body weight support using the GlideTrak™

BACKGROUND/OBJECTIVE

The heart rate (HR) and metabolic (VO2) responses to treadmill running using the GlideTrak™ body weight support system have not been reported. The purpose of this study was to compare the submaximal and maximal HR and VO2 responses to normal-weight treadmill running (TMR) to treadmill running with body weight support provided by the GlideTrak™ (GTR).

METHODS

Twenty participants (11 males; 9 females) 18 to 26 years of age voluntarily participated in this study. Each participant completed two exercise tests in each mode of running: a maximal graded exercise test to compare maximal HR and VO2 values and a submaximal exercise test to compare the HR-VO2 relationship.

RESULTS

Maximal HR and VO2 values were significantly (p < 0.001) lower during GTR (183.4 ± 9.1 bpm, 38.1 ± 7.2 mL kg-1 min-1) compared to TMR (194.3 ± 8.6 bpm, 49.5 ± 8.9 kg-1 min-1). There was a significant difference in the HR-VO2 relationship between GTR and TMR. Compared to TMR, exercising at a HR of 140 bpm resulted in a VO2 that was 4.0 mL kg-1 min-1 lower during GTR. At the VO2 associated with a HR of 140 bpm during TMR, the HR during GTR was 16 bpm higher. During GTR at intensities of exercise up to an RER of 1.0, only 8 participants achieved vigorous intensities of aerobic exercise defined as 64-90% of VO2max.

CONCLUSION

Exercising with the GlideTrak™ body weight support system may not provide the same cardiorespiratory training stimulus as normal-weight treadmill running.

Spirituality/religiosity, substance use, and HIV testing among young black men who have sex with men

BACKGROUND

Spirituality and religiosity may serve as both a resource and a barrier to HIV prevention with young black men who have sex with men (YBMSM). We examined indices of spirituality/religiosity as correlates of binge drinking, stimulant use, and recent HIV testing in a sample of YBMSM.

METHODS

From 2011-2013, annual venue-based surveys of sexually active YBMSM ages 18-29 were conducted in Dallas and Houston, Texas. Binge drinking and stimulant use were assessed in the past two months. Participants recently tested for HIV (i.e., within the past six months) were compared to those without recent HIV testing (i.e., never tested or tested more than six months ago).

RESULTS

Among the 1565 HIV-negative or HIV-unknown YBMSM enrolled, more engagement in spiritual and religious activities was associated with greater odds of reporting stimulant use (Adjusted Odds Ratio [AOR]=1.20; 95% CI=1.04-1.40) while higher spiritual coping was associated with lower odds of reporting stimulant use (AOR=0.66; 95% CI=0.56-0.78). Binge drinking was independently associated with 29% lower odds of recent HIV testing (AOR=0.71; 95% CI=0.55-0.92), but lower odds of binge drinking did not mediate the association of engagement in spiritual and religious activities with 27% greater odds of recent HIV testing (AOR=1.27; 95% CI=1.11-1.46).

CONCLUSIONS

Among YBMSM, culturally tailored approaches addressing spirituality/religiosity could support prevention of stimulant use and increase HIV testing. In particular, expanded efforts are needed to promote HIV testing in binge drinkers.

Is infant body mass index associated with adulthood body composition trajectories? An exploratory analysis

BACKGROUND

Infant body mass index (BMI) is increasingly used as a marker of obesity risk based on its association with young-adulthood BMI.

OBJECTIVES

The aim of this study is to test the association of infant BMI with young-adulthood fat mass and fat-free mass, and how this association changes during advancing adulthood.

METHODS

Body mass index Z-score at age 9 months was measured in 350 White, non-Hispanic Fels Longitudinal Study participants. This exposure was entered into multilevel models to test its association with trajectories describing 2665 BMI observations and 1388 observations of fat mass index (FMI, kg m^-2 ) and fat-free mass index (FFMI, kg m^-2 ) between ages 20 and 60 years.

RESULTS

Partitioning young-adulthood BMI into its fat and fat-free components, infant BMI Z-score was associated with FFMI (β = 0.745; 95% confidence interval = 0.367 to 1.124) but not FMI (0.528; -0.055 to 1.110) at age 20 years. Greater infant BMI Z-score was associated with slower age-related increases in all outcomes, such that (looking at 10-year intervals) only FFMI at age 30 years was related to infant BMI Z-score (0.338; 0.119, 0.557).

CONCLUSIONS

Focus on infant BMI reduction for adulthood obesity prevention warrants caution as high infant BMI values are associated with greater lean mass, which is protective against ageing changes.

Electromagnetic Metal Forming

Some results of an experimental and theoretical investigation of the dynamic forming of thin-walled tubes and flat circular diaphragms by the electromagnetic metal forming process are given. The paper is divided into two parts.

Part 1—The magnetic forming process is described and its use as a production technique is discussed. The process is a high strain-rate technique suitable for forming relatively light gauge material; the forces causing deformation result from the interaction of the current in specially constructed coils and the resulting eddy currents induced in the workpiece. The source of energy is a capacitor bank which can be discharged rapidly through the work-coil. The experiments described were performed using a specially constructed 16 kj discharge unit. The method of constructing work-coils and the failures experienced with these coils in service are described.

Thin-walled copper and aluminium tubes were expanded by means of internal solenoidal work-coils of various lengths. The strain distribution and forming efficiency is presented, together with results showing the variation of process efficiency with changes in the primary circuit parameters. The strain distribution for a circular aluminium alloy diaphragm bulged by means of a flat spiral coil is given.

Typical primary current waveforms are given and the changes in waveform and discharge current frequency due to different workpiece materials and changes in primary circuit parameters are indicated.

Part 2—An attempt is made to determine theoretically the forces acting on one of the aluminium alloy tubes expanded and described in the work of Part 1. The currents in the work-coil and workpiece are calculated using the experimentally determined current waveform and the calculated value of workpiece inductance. A rudimentary method is developed for relating pressure on the workpiece to the primary and secondary currents and, using this, the radial motion of the tube is predicted. Although the analysis involves the use of a number of simplifications and approximations, the theoretical results obtained are of the same magnitude as would be expected by reference to other high-rate forming processes.

Risk Behaviors and Testing History of African American MSM: Implications for Prevention

OBJECTIVES

Knowledge of HIV status is an important step in prevention efforts especially for at risk populations like MSM. CDC recommends that MSM be tested at least annually. There is a limited information on the demographics and risk behaviors of MSM who never tested or test infrequently. This study examined the demographic characteristics, risk behaviors, and HIV status of African American MSM who reported never previously testing for HIV, testing > 12 months prior, or testing within the last 12 months from a testing evaluation study in Washington, D.C.

METHODS

Eligibility requirements were: 18-64 years old; Black/African American; biologically male; and self-reported oral and/or anal sex with a man in the past six months. Descriptive statistics and logistic regression analyses were used.

RESULTS

Men who never tested had greater odds of being 25-34 years old, identifying as bisexual or heterosexual and reporting condomless sex with female and male partners. In the multivariate model, men who never tested or tested > 12 months prior to the study had a greater likelihood of having a BS degree, and being age 35 or over. Being newly identified as HIV-positive was associated with never testing and testing > 12 months prior, but was significant in the multivariate model only for never testing.

CONCLUSION

Results suggest prevention strategies should target risk behaviors rather than orientation and engage older men. Future studies should identify factors associated with risky sexual behaviors for men who never test or test infrequently in order to inform prevention interventions.

Using Super-Imposition by Translation And Rotation (SITAR) to relate pubertal growth to bone health in later life: the Medical Research Council (MRC) National Survey of Health and Development

Background: To explore associations between pubertal growth and later bone health in a cohort with infrequent measurements, using another cohort with more frequent measurements to support the modelling, data from the Medical Research Council (MRC) National Survey of Health and Development (2–26 years, 4901/30 004 subjects/measurements) and the Avon Longitudinal Study of Parents And Children (ALSPAC) (5–20 years) (10 896/74 120) were related to National Survey of Health and Development (NSHD) bone health outcomes at 60–64 years.

Methods: NSHD data were analysed using Super-Imposition by Translation And Rotation (SITAR) growth curve analysis, either alone or jointly with ALSPAC data. Improved estimation of pubertal growth parameters of size, tempo and velocity was assessed by changes in model fit and correlations with contemporary measures of pubertal timing. Bone outcomes of radius [trabecular volumetric bone mineral density (vBMD) and diaphysis cross-sectional area (CSA)] were regressed on the SITAR parameters, adjusted for current body size.

Results: The NSHD SITAR parameters were better estimated in conjunction with ALSPAC, i.e. more strongly correlated with pubertal timing. Trabecular vBMD was associated with early height tempo, whereas diaphysis CSA was related to weight size, early tempo and slow velocity, the bone outcomes being around 15% higher for the better vs worse growth pattern.

Conclusions: By pooling NSHD and ALSPAC data, SITAR more accurately summarized pubertal growth and weight gain in NSHD, and in turn demonstrated notable associations between pubertal timing and later bone outcomes. These associations give insight into the importance of the pubertal period for future skeletal health and osteoporosis risk.

Distribution of bisphenol A in the neuroendocrine organs of female rats

The distribution of 14C-bisphenol A (BPA) in plasma and neuroendocrine organs was determined in Fischer 344 female rats following three oral doses (0.1, 10 or 100 mg/kg). Plasma and tissue maximum concentrations (Cmax) were reached within 15-30 min of dosing. Plasma areas-under-the-curve (AUC) ranged from 0.06 to 53.9 mg-h/mL. The AUCs of the pituitary gland and uterus/gonads were 16-21% higher than that of plasma. The AUCs of hypothalamus and the rest of the brain were 43.7% and 77% of the plasma AUCs, respectively. In the brain tissue, the exposure increased linearly with the oral dose, as the dose was increased from 0.1 to 10 and 100 mg/kg; the exposure in the brain relative to the plasma increased by factors of 1, 1.19 and 1.24. This indicates that the brain barrier systems do not limit the access of the lipophilic BPA to the brain. The increases of the uterus/gonads relative to the plasma were 1, 1.07 and 1.04. Tissue partitioning was also examined in vitro by the uptake of 14C-BPA. The BPA tissue/blood partition coefficients were as follows: heart, 7.5; liver, 6.1; kidney, 6.4; fat, 3.6; muscle, 2.6; breast, 3.6; ovaries, 9.1; uterus, 5.9; stomach, 5.1; and small intestine, 6.7. The tissue/cerebrospinal fluid partition coefficients were as follows: pituitary gland, 12.8; brain stem, 6.1; cerebellum, 6.4; hippocampus, 7.1; hypothalamus, 6.1; frontal cortex, 4.9; and caudate nucleus, 6.8.

A randomized trial comparing standard outcomes in two treatment models for substance users with tuberculosis

SETTING

Chicago Department of Public Health (CDPH), TB Control Program.

OBJECTIVES

To compare anti-tuberculosis treatment outcomes using two different types of directly observed therapy (DOT) outreach workers.

METHODS

Substance users diagnosed with TB from October 1996 to July 2000 were randomized to DOT administered by either 1) CDPH personnel (standard arm) or 2) previous substance-using human immunodeficiency virus/acquired immune-deficiency syndrome outreach workers (enhanced arm). Treatment completion was physician-determined, and adherence was estimated based on risk of missed DOT appointments.

RESULTS

Of 94 patients, 46 were randomized to the standard and 48 to the enhanced arm. The standard arm had a significantly higher risk of non-completion of treatment (39% vs. 15%, RR 2.7, 95%CI 1.2-5.8), and a significantly higher risk of missing DOT appointments (RR 2.6, 95%CI 1.4-4.8). For both outcomes, housing instability was a significant predictor in multivariate analyses.

CONCLUSIONS

TB treatment completion and adherence among substance users was improved by the enhanced intervention; the familiarity of enhanced-arm DOT workers with the patients' social norms due to their own previous substance use may have made them more effective. Successful DOT in hard-to-reach populations may require strategies that directly address the population's circumstances and utilize DOT workers who are intimately familiar with patients' life situations.

Small-for-gestational age and large-for-gestational age thresholds to predict infants at risk of adverse delivery and neonatal outcomes: are current charts adequate? An observational study from the Born in Bradford cohort

OBJECTIVES

Construct an ethnic-specific chart and compare the prediction of adverse outcomes using this chart with the clinically recommended UK-WHO and customised birth weight charts using cut-offs for small-for-gestational age (SGA: birth weight <10th centile) and large-for-gestational age (LGA: birth weight >90th centile).

DESIGN

Prospective cohort study.

SETTING

Born in Bradford (BiB) study, UK.

PARTICIPANTS

3980 White British and 4448 Pakistani infants with complete data for gestational age, birth weight, ethnicity, maternal height, weight and parity.

MAIN OUTCOME MEASURES

Prevalence of SGA and LGA, using the three charts and indicators of diagnostic utility (sensitivity, specificity and area under the receiver operating characteristic (AUROC)) of these chart-specific cut-offs to predict delivery and neonatal outcomes and a composite outcome.

RESULTS

In White British and Pakistani infants, the prevalence of SGA and LGA differed depending on the chart used. Increased risk of SGA was observed when using the UK-WHO and customised charts as opposed to the ethnic-specific chart, while the opposite was apparent when classifying LGA infants. However, the predictive utility of all three charts to identify adverse clinical outcomes was poor, with only the prediction of shoulder dystocia achieving an AUROC>0.62 on all three charts.

CONCLUSIONS

Despite being recommended in national clinical guidelines, the UK-WHO and customised birth weight charts perform poorly at identifying infants at risk of adverse neonatal outcomes. Being small or large may increase the risk of an adverse outcome; however, size alone is not sensitive or specific enough with current detection to be useful. However, a significant amount of missing data for some of the outcomes may have limited the power needed to determine true associations.

Risk for transmission of Naegleria fowleri from solid organ transplantation

Primary amebic meningoencephalitis (PAM) caused by the free-living ameba (FLA) Naegleria fowleri is a rare but rapidly fatal disease of the central nervous system (CNS) affecting predominantly young, previously healthy persons. No effective chemotherapeutic prophylaxis or treatment has been identified. Recently, three transplant-associated clusters of encephalitis caused by another FLA, Balamuthia mandrillaris, have occurred, prompting questions regarding the suitability of extra-CNS solid organ transplantation from donors with PAM. During 1995-2012, 21 transplant recipients of solid organs donated by five patients with fatal cases of PAM were reported in the United States. None of the recipients developed PAM, and several recipients tested negative for N. fowleri by serology. However, historical PAM case reports and animal experiments with N. fowleri, combined with new postmortem findings from four patients with PAM, suggest that extra-CNS dissemination of N. fowleri can occur and might pose a risk for disease transmission via transplantation. The risks of transplantation with an organ possibly harboring N. fowleri should be carefully weighed for each individual recipient against the potentially greater risk of delaying transplantation while waiting for another suitable organ. In this article, we present a case series and review existing data to inform such risk assessments.

Abstract P3-06-11: Disease and treatment characteristics of a large insured female population with advanced or metastatic breast cancer by receipt of HER2-targeted agents

This retrospective administrative claims study of women diagnosed with advanced or metastatic breast cancer (BC) compared clinical histories and BC treatment by receipt of HER2- targeted agents (2TA), disease stage, and age group.

Women ≥ 18 years, diagnosed with stage III or IV BC were selected from the 2008-2012 Truven Health MarketScan databases using ICD-9-CM codes on non-diagnostic medical claims corresponding to BC and local or distant metastases; date of first metastasis was the index date. Patients were followed until the earliest of end of enrollment, inpatient death or 12/31/2012. Those with &lt;12 months continuous enrollment (CE) or non-BC primary cancers pre-index, or HIV or pregnancy anytime were excluded. 2TA was defined as ≥1 medical or pharmacy claim for trastuzumab or lapatinib in the pre- or post-index periods. Study cohorts were women ± 2TA use, 2TA users with stage III and IV BC, and 2TA users age 18-44, 45-64, or 65+ at index. Index demographics, pre-index BC and clinical histories, and post-index BC treatments were compared using t-tests, one-way ANOVA, and chi-square statistics.

Of 30,660 eligible women, 14.4% received 2TA at sometime. Compared to non-2TA patients those with 2TA were younger (mean (SD) age 55 (11) vs. 59 (13) years; p≤0.001) and had significantly lower comorbidity burden. While pre-index BC was similar (48% each), 2TA patients had higher rates of pre-index BC surgery (20% vs. 17%), adjuvant/neoadjuvent chemotherapy (74% vs. 53%), radiation treatment (12% vs. 10%), and lower non-2TA biologics use (0% vs. 3%), all p&lt;0.005. Of the 2TA cohort with pre-index BC, 58% used 2TA pre-index. Also among 2TA patients, 57% had Stage III BC at index and 18% were 18-44, 68% 45-64 and 15% 65+. Pre-index BC diagnosis differed by index BC stage (30% III vs. 73% IV) and increased with age (44% 18-44, 48% 45-64, 54% 65+), both p&lt;0.001.

Of those with ≥ 3 months CE post-index, 2TA users had higher rates, p&lt;0.001 of BC surgery (53% vs. 47%), radiation (65% vs. 54%) and non-2TA antineoplastic treatment (AT: 89% vs. 83%), compared to non-2TA patients. Of those treated, 2TA users had a higher rate of chemotherapy use (85% vs. 58%), but lower use rates of hormone therapy (56% vs. 78%) and non-2TA biologics (5% vs. 8%), all p&lt;0.001. Receipt of post-index BC surgery was greater among 2TA stage III than stage IV patients (78% vs. 19%) and decreased with age (62% 18-44, 53% 45-64, 42% 65+), both p&lt;0.001. Post-index, stage III 2TA patients were more likely (p&lt;0.001) to have radiation therapy (72% vs. 56%), use 2TA agents post-index (97% vs. 91%), and other AT (92% vs. 84%) compared to stage IV 2TA patients. Radiation declined in the 2TA cohort post-index with increasing age (70%, 65%, 61%, p&lt;0.001). 2TA and AT use also declined with increasing age but these did not reach statistical significance.

Receipt of 2TA (vs. non-2TA) was significantly associated with younger age and receipt of pre- and post- BC treatments. Clinical history and BC treatment differences between these cohorts partly reflect differential treatment patterns of HER2- positive and HER2- negative BC patients. Treatment characteristics for the 2TA cohort differ by disease stage and age group.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-06-11.

Genetic amplification and the individualization of the parent-child relationship across adolescence

BACKGROUND

Many psychological traits become increasingly influenced by genetic factors throughout development, including several that might intuitively be seen as purely environmental characteristics. One such trait is the parent-child relationship, which is associated with a variety of socially significant outcomes, including mental health and criminal behavior. Genetic factors have been shown to partially underlie some of these associations, but the changing role of genetic influence over time remains poorly understood.

METHOD

Over 1000 participants in a longitudinal twin study were assessed at three points across adolescence with a self-report measure regarding the levels of warmth and conflict in their relationships with their parents. These reports were analyzed with a biometric growth curve model to identify changes in genetic and environmental influences over time.

RESULTS

Genetic influence on the child-reported relationship with parent increased throughout adolescence, while the relationship's quality deteriorated. The increase in genetic influence resulted primarily from a positive association between genetic factors responsible for the initial relationship and those involved in change in the relationship over time. By contrast, environmental factors relating to change were negatively related to those involved in the initial relationship.

CONCLUSIONS

The increasing genetic influence seems to be due to early genetic influences having greater freedom of expression over time whereas environmental circumstances were decreasingly important to variance in the parent-child relationship. We infer that the parent-child relationship may become increasingly influenced by the particular characteristics of the child (many of which are genetically influenced), gradually displacing the effects of parental or societal ideas of child rearing.