The Prospective Association between Early Life Growth and Breast Density in Young Adult Women.

Breast density is a strong intermediate endpoint to investigate the association between early-life exposures and breast cancer risk. This study investigates the association between early-life growth and breast density in young adult women measured using Optical Breast Spectroscopy (OBS) and Dual X-ray Absorptiometry (DXA). OBS measurements were obtained for 536 female Raine Cohort Study participants at ages 27-28, with 268 completing DXA measurements. Participants with three or more height and weight measurements from ages 8 to 22 were used to generate linear growth curves for height, weight and body mass index (BMI) using SITAR modelling. Three growth parameters (size, velocity and timing) were examined for association with breast density measures, adjusting for potential confounders. Women who reached their peak height rapidly (velocity) and later in adolescence (timing) had lower OBS-breast density. Overall, women who were taller (size) had higher OBS-breast density. For weight, women who grew quickly (velocity) and later in adolescence (timing) had higher absolute DXA-breast density. Overall, weight (size) was also inversely associated with absolute DXA-breast density, as was BMI. These findings provide new evidence that adolescent growth is associated with breast density measures in young adult women, suggesting potential mediation pathways for breast cancer risk in later life.

Do parent-reported early indicators predict later developmental language disorder? A Raine Study investigation.

BACKGROUND: Developmental language disorder (DLD) is one of the most common neurodevelopmental conditions. Due to variable rates of language growth in children under 5 years, the early identification of children with DLD is challenging. Early indicators are often outlined by speech pathology regulatory bodies and other developmental services as evidence to empower caregivers in the early identification of DLD. AIMS: To test the predictive relationship between parent-reported early indicators and the likelihood of children meeting diagnostic criteria for DLD at 10 years of age as determined by standardized assessment measures in a population-based sample. METHODS: Data were leveraged from the prospective Raine Study (n = 1626 second-generation children: n = 104 with DLD; n = 1522 without DLD). These data were transformed into 11 predictor variables that reflect well-established early indicators of DLD from birth to 3 years, including if the child does not smile or interact with others, does not babble, makes only a few sounds, does not understand what others say, says only a few words, says words that are not easily understood, and does not combine words or put words together to make sentences. Family history (mother and father) of speech and language difficulties were also included as variables. Regression analyses were planned to explore the predictive relationship between this set of early indicator variables and likelihood of meeting DLD diagnostic criteria at 10 years. RESULTS: No single parent-reported indicator uniquely accounted for a significant proportion of children with DLD at 10 years of age. Further analyses, including bivariate analyses testing the predictive power of a cumulative risk index of combined predictors (odds ratio (OR) = 0.95, confidence interval (CI) = 0.85-1.09, p = 0.447) and the moderating effect of sex (OR = 0.89, CI = 0.59-1.32, p = 0.563) were also non-significant. CONCLUSIONS: Parent reports of early indicators of DLD are well-intentioned and widely used. However, data from the Raine Study cohort suggest potential retrospective reporting bias in previous studies. We note that missing data for some indicators may have influenced the results. Implications for the impact of using early indicators as evidence to inform early identification of DLD are discussed. WHAT THIS PAPER ADDS: What is already known on the subject DLD is a relatively common childhood condition; however, children with DLD are under-identified and under-served. Individual variability in early childhood makes identification of children at risk of DLD challenging. A range of 'red flags' in communication development are promoted through speech pathology regulatory bodies and developmental services to assist parents to identify if their child should access services. What this paper adds to the existing knowledge No one parent-reported early indicator, family history or a cumulation of indicators predicted DLD at 10 years in the Raine study. Sex (specifically, being male) did not moderate an increased risk of DLD at 10 years in the Raine study. Previous studies reporting on clinical samples may be at risk of retrospective reporting bias. What are the potential or actual clinical implications of this work? The broad dissemination and use of 'red flags' is well-intentioned; however, demonstrating 'red flags' alone may not reliably identify those who are at later risk of DLD. Findings from the literature suggest that parent concern may be complemented with assessment of linguistic behaviours to increase the likelihood of identifying those who at risk of DLD. Approaches to identification and assessment should be considered alongside evaluation of functional impact to inform participation-based interventions.

Gender non-conformity in childhood and adolescence and mental health through to adulthood: a longitudinal cohort study, 1995-2018.

BACKGROUND: Few studies have examined associations between gender non-conformity (GNC) in childhood or adolescence and mental health outcomes later in life. This study examined associations between (1) GNC and mental health over multiple time points in childhood and adolescence, and (2) GNC in childhood and/or adolescence and mental health in adulthood. METHOD: Second generation participants from the Raine Study, a longitudinal cohort from Perth, Western Australia. Data were collected between 1995 and 2018, comprising seven waves: ages 5 (N = 2236), 8 (N = 2140), 10 (N = 2048), 14 (N = 1864), 17 (N = 1726), 22 (N = 1236) and 27 (N = 1190) years. History of GNC, v. absence of this history, was based on responses to item 110 from the Child Behaviour Checklist (CBCL)/Youth Self Report (YSR) ('wishes to be of opposite sex'). The CBCL/YSR were used to measure internalising and externalising symptoms. Items 18 ('deliberate self-harm [DSH] or attempts suicide') and 91 ('talks/thinks about killing self') were used as measures of suicidal ideation (SI) and DSH. For adults, Depression, Anxiety and Stress Subscales and Kessler Psychological Distress Scale assessed mental health. RESULTS: Child and adolescent GNC was associated with elevated internalising and externalising behaviours and increased odds of DSH. A history of GNC was also associated with vulnerability for severe psychological distress in adulthood in some symptom scales. CONCLUSION: GNC over the child and adolescent period is associated with significant emotional and behavioural difficulties, and psychological distress. A history of GNC in childhood and/or adolescence also predicts poorer mental health in adulthood on multiple symptom domains.

Neurodevelopmental outcomes in children after prenatal marijuana exposure.

BACKGROUND: The effect of prenatal marijuana exposure (PME) on child neurodevelopment remains poorly understood. Prior studies have demonstrated inconsistent results. OBJECTIVES: This study evaluated the association between PME and neuropsychological test scores in late childhood and early adulthood, accounting for a wide range of parental characteristics. METHODS: This study evaluated participants from the Raine Study, a cohort of 2868 children born between 1989 and 1992. Children whose mothers provided information on marijuana use during pregnancy were included. The primary outcome was the Clinical Evaluation of Language Fundamentals (CELF) at age 10. Secondary outcomes included the Peabody Picture Vocabulary Test (PPVT), Child Behaviour Checklist (CBCL), McCarron Assessment of Neuromuscular Development (MAND), Coloured Progressive Matrices (CPM), Symbol Digit Modality Test (SDMT) and Autism Spectrum Quotient (AQ) scores. Exposed and unexposed children were matched by propensity score using optimal full matching. Missing covariate data were imputed using multiple imputation. Inverse probability of censoring weighting (IPCW) was used to adjust for missing outcome data. Linear regression within matched sets, adjusted by IPCW, evaluated score differences between exposed and unexposed children. As a secondary analysis, modified Poisson regression, adjusted by match weights and IPCW, evaluated the risk of clinical deficit in each outcome following PME. RESULTS: Of the 2804 children in this cohort, 285 (10.2%) had PME. After optimal full matching and IPCW, exposed children scored similarly on CELF Total (-0.33 points, 95% confidence interval [CI] -4.71, 4.05), Receptive (+0.65 points, 95% CI -4.08, 5.38) or Expressive (-0.53 points, 95% CI -5.07, 4.02). PME was not associated with secondary outcomes or risks of clinical deficit in any neuropsychological assessments. CONCLUSIONS: After adjusting for sociodemographic and clinical covariates, PME was not associated with worse neuropsychological test scores at age 10 or autistic traits at 19-20.

How we measure language skills of children at scale: A call to move beyond domain-specific tests as a proxy for language.

PURPOSE: The aim of this research note is to encourage child language researchers and clinicians to give careful consideration to the use of domain-specific tests as a proxy for language; particularly in the context of large-scale studies and for the identification of language disorder in clinical practice. METHOD: We report on data leveraged through the prospective Raine Study cohort. Participants included 1626 children aged 10 years (n = 104 with developmental language disorder [DLD] and n = 1522 without DLD). We assessed the predictive utility of common language measures including subtests of a standardised omnibus language assessment, non-verbal intelligence, and a domain-specific receptive vocabulary test. RESULT: Children with DLD performed within the average range on a measure of non-verbal intelligence (z = -0.86) and receptive vocabulary (z = -0.38), as well as two out of the six subtests on the omnibus language assessment (zs > -1.50). The magnitude of the predictive relationship between language assessments and the likelihood of a child meeting criteria for DLD at 10 years was assessed using a logistic regression model, which was significant: χ2(8) = 16.91, p = 0.031. Semantic Relationships (OR = 1.13, CI = 1.04 - 1.23, p = .004), Formulated Sentences (OR = 1.07, CI = 1.01 - 1.13, p = .028), Recalling Sentences (OR = 1.20, CI = 1.15 - 1.26, p < .001), and Sentence Assembly (OR = 1.17, CI = 1.07 - 1.30, p = .001) were significant predictors of DLD. CONCLUSION: Domain-specific language assessments, particularly those testing receptive vocabulary, may overestimate the language ability of children with DLD. Caution is urged when using such tests by clinicians and researchers, especially those measuring language skills of children at scale. Future directions for measuring the functional impact of DLD are presented.

Childhood sleep health and epigenetic age acceleration in late adolescence: Cross-sectional and longitudinal analyses.

AIM: Investigate if childhood measures of sleep health are associated with epigenetic age acceleration in late adolescence. METHODS: Parent-reported sleep trajectories from age 5 to 17, self-reported sleep problems at age 17, and six measures of epigenetic age acceleration at age 17 were studied in 1192 young Australians from the Raine Study Gen2. RESULTS: There was no evidence for a relationship between the parent-reported sleep trajectories and epigenetic age acceleration (p ≥ 0.17). There was a positive cross-sectional relationship between self-reported sleep problem score and intrinsic epigenetic age acceleration at age 17 (b = 0.14, p = 0.04), which was attenuated after controlling for depressive symptom score at the same age (b = 0.08, p = 0.34). Follow-up analyses suggested this finding may represent greater overtiredness and intrinsic epigenetic age acceleration in adolescents with higher depressive symptoms. CONCLUSION: There was no evidence for a relationship between self- or parent-reported sleep health and epigenetic age acceleration in late adolescence after adjusting for depressive symptoms. Mental health should be considered as a potential confounding variable in future research on sleep and epigenetic age acceleration, particularly if subjective measures of sleep are used.

Longitudinal effects of prenatal exposure to plastic-derived chemicals and their metabolites on asthma and lung function from childhood into adulthood.

BACKGROUND AND OBJECTIVE: Environmental exposure to phthalates and bisphenol A (BPA), chemicals used in the production of plastics, may increase risk for asthma and allergies. However, little is known about the long-term effects of early life exposure to these compounds. We investigated if prenatal exposure to these compounds was associated with asthma, allergy and lung function outcomes from early childhood into adulthood in a cohort study. METHODS: Maternal serum samples collected from 846 pregnant women in the Raine Study were assayed for BPA and phthalate metabolites. The children of these women were followed up at 5, 13 and 22 years where spirometry and respiratory questionnaires were conducted to determine asthma and allergy status. Lung function trajectories were derived from longitudinal spirometry measurements. Multinomial logistic regression and weighted quantile sum regression was used to test associations of individual and chemical mixtures with asthma phenotypes and lung function trajectories. RESULTS: Effects of prenatal BPA and phthalates on asthma phenotypes were seen in male offspring, where BPA was associated with increased risk for persistent asthma, while mono-iso-butyl phthalate and mono-iso-decyl phthalate was associated with increased risk for adult asthma. Prenatal BPA had no effect on lung function trajectories, but prenatal phthalate exposure was associated with improved lung function. CONCLUSION: Prenatal BPA exposure was associated with increased likelihood of persistent asthma in males, while prenatal phthalate exposure was associated with increased likelihood of adult asthma in males. Results suggest that prenatal exposure to prenatal BPA and phthalates affect asthma risk, particularly in males, however lung function was not adversely affected.

Applying the 4Ps of social marketing to retain and engage participants in longitudinal cohort studies: generation 2 Raine study participant perspectives.

BACKGROUND: Investigations of participant retention in longitudinal health and medical research, document  strategies that work best but overlook social marketing's capacity to influence participant retention. After applying the social marketing framework: the idea that determining what longitudinal participants 'buy' (product), at what cost (price), in what location (place) and through which communication channels (promotion),  this paper  aims to inform and enhance retention efforts. METHODS: This qualitative study was conducted through in-depth interviews with participants from the Raine Study that began in Western Australia in 1989. The Generation 2 participants, initially enrolled into the Raine Study as babies by their parents (Generation 1), are now young adults invited to attend follow-up studies and tests every few years. Our study defined 'active' participants (n = 17) as those who agreed to attend their 27 year follow-up, and 'inactive' (n = 12) participants as those who had attended neither of the past two follow-ups (22 and 27 years). RESULTS: Raine Study participants experienced core, actual and augmented product benefits. Inactive participants focused on the costs (price) associated with participation, and were more likely to suggest tele-health (place) strategies to overcome barriers to follow-up attendance. Both active and inactive participants found professional processes and friendly staff made the Raine Study environment appealing, suggested that social media (promotion) was underutilised, and offered novel ideas to enhance engagement. CONCLUSIONS: Social marketing can support the development of differentiated strategies addressing the unique needs and wants of active and inactive participants. Sophisticated cohort segmentation can reach participants in a more meaningful way, reinforce the study 'brand' and guard against attrition.

The prevalence of and potential risk factors for Developmental Language Disorder at 10 years in the Raine Study.

AIM: This study sought to determine the prevalence of Developmental Language Disorder (DLD) in Australian school-aged children and associated potential risk factors for DLD at 10 years. METHODS: This study used a cross-sectional design to estimate the prevalence of DLD in Generation 2 of the prospective Raine Study. Participants included 1626 children aged 10 years with available language data. Primary outcomes included variables matching diagnostic criteria for DLD. Associations of other potential prenatal and environmental variables were analysed as secondary outcomes. RESULTS: The prevalence of DLD in this sample was 6.4% (n = 104) at 10 years. This sub-cohort comprised 33.7% (n = 35) with expressive language deficits, 20.2% (n = 21) with receptive language deficits, and 46.2% (n = 48) with receptive-expressive deficits. No significant difference in sex distribution was observed (52.9% male, p = 0.799). Children who were exposed to smoke in utero at 18 weeks gestation were at increased risk of DLD at 10 years (OR = 2.56, CI = 1.23-5.35, p = 0.012). CONCLUSIONS: DLD is a relatively prevalent condition in Australian children, even when assessed in middle childhood years. These findings can inform future research priorities, and public health and educational policy which account for the associations with potential risk factors.

Prevalence and Risk Factors of Myopia in Young Adults: Review of Findings From the Raine Study.

Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15-16 years old. Thus, most studies on myopia have centered on children. Data on the refractive error profile in young adulthood - a time in life when myopia is thought to have stabilized and refractive error is unaffected by age-related pathology such as cataract - are limited. The Raine Study has been following a community-based cohort of young adults representative of the general Western Australia population since their prenatal periods in 1989-1991, with eye examinations performed when participants were 20 and 28 years old. At 20 years old, prevalence of myopia in the cohort was 25.8%. Using long-term trajectory of serum vitamin D levels and conjunctival ultraviolet autofluorescence (CUVAF) area to objectively quantify sun exposure, the Raine Study confirmed a negative relationship between time spent outdoors and myopia prevalence. However, prospective studies are required to determine the amount of CUVAF area or serum vitamin D levels associated with time duration. Combining data from the Raine Study and several other cohorts, Mendelian randomization studies have confirmed a link between myopia and a genetic predisposition toward higher education. Several novel potential associations of myopia or ocular biometry were investigated, including fetal growth trajectory, which was found to be significantly associated with corneal curvature at 20 years. By age 28, myopia prevalence had increased to 33.2%. Between 20 and 28 years old, myopia progressed and axial length elongated, on average, by -0.041D/year and 0.02 mm/year, respectively. Smaller CUVAF area at follow-up, female sex, and parental myopia were significant risk factors for myopia incidence and progression between 20 and 28 years. Given the limited research in young adults, further investigations are warranted to confirm the Raine Study findings, as well as identify novel genetic or environmental factors of myopia incidence and progression in this age group.

Prenatal tobacco and alcohol exposures and the risk of anxiety symptoms in young adulthood: A population-based cohort study.

BACKGROUND: Epidemiological studies have linked prenatal tobacco and alcohol exposures to internalizing behaviours in children and adolescents with inconsistent findings. Dearth of epidemiological studies have investigated the associations with the risk of experiencing symptoms of anxiety in young adulthood. METHODS: Study participants (N = 1190) were from the Raine Study, a population-based prospective birth cohort based in Perth, Western Australia. Data on prenatal tobacco and alcohol exposures were available for the first and third trimesters of pregnancy. Experiencing symptoms of anxiety in young adulthood at age 20 years was measured by a short form of the Depression Anxiety Stress Scale (DASS 21). Relative risk (RR) of experiencing symptoms of anxiety in young adulthood for prenatal tobacco and alcohol exposures were estimated with log binomial regression. RESULTS: After adjusting for potential confounders, we observed increased risks of experiencing symptoms of anxiety in young adults exposed to prenatal tobacco in the first trimester [RR = 1.52, 95% CI: 1.12-2.06, p-value < 0.01] and third trimester [RR = 1.53, 95% CI: 1.10-2.13, p-value  = 0.02]. However, we found insufficient statistical evidence for an association between first trimester [RR = 1.01, 95% CI: 0.76-1.22, p-value = 0.90] and third trimester [RR = 1.03, 95% CI: 0.80-1.34, p-value = 0.91] prenatal exposure to alcohol and the risk of experiencing symptoms of anxiety in young adults. There was a dose response association between prenatal tobacco exposure and increasing anxiety symptoms in offspring. CONCLUSION: The findings of this study suggest that an association between prenatal tobacco exposure and risk of anxiety symptoms remains apparent into young adulthood.

In Utero Exposure to Smoking and Alcohol, and Passive Smoking during Childhood: Effect on the Retinal Nerve Fibre Layer in Young Adulthood.

PURPOSE: In utero exposure to cigarette smoke has been suggested to result in thinner retinal nerve fibre layer (RNFL). However, the potential cofounding effects of in utero alcohol exposure and passive smoking during childhood had not been considered. We explored RNFL thickness in young adults in relation to these early life factors. METHODS: In 1989-1991, pregnant women completed questionnaires on their current smoking and alcohol drinking patterns. Following the birth of their offspring, information on household smokers was obtained between the 1- and 13-year follow-ups. At the 20-year follow-up, these offspring underwent an eye examination including optical coherence tomography imaging of the RNFL. RESULTS: Participants (n = 1,287) were 19-22 years old at time of eye examination. Most participants (77%) had no in utero exposure to cigarette smoke; 1.3% were initially exposed but not after 18 weeks' gestation, while 21% had continual in utero smoking exposure. Half of the mothers never consumed alcohol or only consumed alcohol once during their pregnancies. After correcting for potential confounders, including in utero alcohel exposure and childhood passive smoking, participants who had continued in utero exposure to >10 cigarettes/day and ≤10 cigarettes/day had thinner RNFLs by 6.6 (95% confidence interval [CI] = 4.4-8.7) and 3.7 µm (95%[CI] = 2.3-5.5), respectively, than those with no exposure (p < .001). In utero alcohol exposure and childhood passive smoking were not significantly associated with RNFL thickness after accounting for in utero exposure to smoking. CONCLUSIONS: In utero exposure to cigarette smoke is associated with thinner RFNL in young adulthood, independent of other early life environmental factors.

Adiposity associated DNA methylation signatures in adolescents are related to leptin and perinatal factors.

Epigenetics links perinatal influences with later obesity. We identifed differentially methylated CpG (dmCpG) loci measured at 17 years associated with concurrent adiposity measures and examined whether these were associated with hsCRP, adipokines, and early life environmental factors. Genome-wide DNA methylation from 1192 Raine Study participants at 17 years, identified 29 dmCpGs (Bonferroni corrected p < 1.06E-07) associated with body mass index (BMI), 10 with waist circumference (WC) and 9 with subcutaneous fat thickness. DmCpGs within Ras Association (RalGDS/AF-6), Pleckstrin Homology Domains 1 (RAPH1), Musashi RNA-Binding Protein 2 (MSI2), and solute carrier family 25 member 10 (SLC25A10) are associated with both BMI and WC. Validation by pyrosequencing confirmed these associations and showed that MSI2 , SLC25A10 , and RAPH1 methylation was positively associated with serum leptin. These were  also associated with the early environment; MSI2 methylation (ß = 0.81, p = 0.0004) was associated with pregnancy maternal smoking, SLC25A10 (CpG2 ß = 0.12, p = 0.002) with pre- and early pregnancy BMI, and RAPH1 (ß = -1.49, p = 0.036) with gestational weight gain. Adjusting for perinatal factors, methylation of the dmCpGs within MSI2, RAPH1, and SLC25A10 independently predicted BMI, accounting for 24% of variance. MSI2 methylation was additionally associated with BMI over time (17 years old ß = 0.026, p = 0.0025; 20 years old ß = 0.027, p = 0.0029) and between generations (mother ß = 0.044, p = 7.5e-04). Overall findings suggest that DNA methylation in MSI2, RAPH1, and SLC25A10 in blood may be robust markers, mediating through early life factors.

Associations of 12-year sleep behaviour trajectories from childhood to adolescence with myopia and ocular biometry during young adulthood.

PURPOSE: Cross-sectional studies have variably reported that poor sleep quality may be associated with myopia in children. Longitudinal data, collected over the ages when myopia develops and progresses, could provide new insights into the sleep-myopia paradigm. This study tested the hypothesis that 12-year trajectories of sleep behaviour from childhood to adolescence is associated with myopia during young adulthood. METHODS: At the 5-, 8-, 10-, 14- and 17-year follow-ups of the longitudinal Raine Study, which has been following a cohort since their birth in 1989-1992, participants' parents/guardians completed the Child Behaviour Checklist questionnaire (CBCL), which collected information on their child's sleep behaviour and quality. The CBCL includes six questions measuring sleep behaviour, which parents rated as 0 = not true, 1 = somewhat/sometimes true, or 2 = very/often true. Scores were summed at each follow-up to form a composite "sleep behaviour score". Latent Class Growth Analysis (LCGA) was used to classify participants according to their 12-year trajectory of sleep behaviour. At the 20-year follow-up, an eye examination was performed which included cycloplegic autorefraction and axial length measurement. RESULTS: The LCGA identified three clusters of participants based on their trajectory of sleep behaviour: those with minimal' (43.6% of the total Raine Study sample), 'declining' (48.9%), or 'persistent' (7.5%) sleep problems. A total of 1194 participants had ophthalmic data and longitudinal sleep data available for analysis (47.2% female, 85.6% Caucasian). No significant differences were observed in regards to age, sex, ethnicity or ocular parameters between trajectory groups. Unadjusted and fully adjusted analyses demonstrated that sleep problem behaviour was not significantly associated with changes in refractive error, axial length or corneal radius. CONCLUSIONS: Our findings do not support the hypothesis that there is an association between sleep behaviour and myopia. Future longitudinal studies should explore sleep trajectory data pre- and post-myopia diagnosis to confirm our results.

The anticipatory response to stress and symptoms of depression and anxiety in early adulthood.

BACKGROUND: Whilst cortisol reactivity has been associated with depression and anxiety disorders, research examining cortisol reactivity with early symptoms of these conditions in males and females is limited. METHODS: At age 18, 748 males and females from Gen2 of the Raine Study were assessed for their salivary cortisol response to a psychosocial stressor using the Trier Social Stress Test (TSST). Participants later completed the Depression Anxiety Stress Scale (DASS-21) at age 20 which was used as the outcome measure in regression models. RESULTS: We found differences in DASS-21 across TSST responder categories in females but not males. Female reactive-responders (RR) and non-responders (NR) had increased symptoms of depression and anxiety compared to anticipatory-responders (AR). AR were associated with the lowest symptomology in females. We found limited evidence for an association between salivary cortisol summary measures (CBL, CMAX, CMIN, CRANGE, AUCG and AUCR) and depression/anxiety symptoms at age 20. CONCLUSIONS: This study sheds new light on adaptive and maladaptive physiological responses to psychosocial stress in terms of depression and anxiety symptoms. These preliminary findings indicate the pattern of response to a psychosocial stressor may contribute to individual vulnerability for stress-related diseases in a sex-specific manner.

Only one fifth of young Australian adults have beliefs about medical imaging for low back pain that align with current evidence: A cross-sectional study.

BACKGROUND: Patients' perceptions/expectations may be a factor behind medical imaging referral rates. Few studies have investigated the beliefs that might drive expectations of medical imaging. OBJECTIVES: This study examined whether beliefs of young Australian adults with and without impactful low back pain (LBP) concerning medical scans for LBP align with current evidence. It also investigated if these beliefs were associated with clinical factors (history of impactful LBP, history of previous medical scans, LBP-related disability and the presence of leg pain) or sociodemographic factors (sex, education, income). DESIGN: Cross-sectional observational study. METHODS: 78 participants from the Raine Study with a history of impactful LBP and 85 participants with no history of impactful LBP completed a study-specific questionnaire with five statements concerning beliefs about medical imaging for LBP. All statements were not aligned with current evidence about the use of medical imaging in LBP management. RESULTS: Only 15-21% (n = 24-34) of the participants held beliefs that were aligned with current evidence. Participants with a university education had slightly more aligned beliefs compared to those whose highest education was completing secondary school. There was no difference in the beliefs of participants based on their history of impactful LBP, or other clinical or sociodemographic factors. CONCLUSION: As beliefs are likely to drive care-seeking behavior, it is notable that most participants' views about the role of medical imaging for LBP were not aligned with current evidence. Therefore, this suggests a need for community education, especially for those with lower education.

Prenatal tobacco exposure and the risk of conduct disorder symptoms in offspring at the age of 14 years: Findings from the Raine Study.

BACKGROUND: Emerging epidemiological evidence suggests that offspring born to mothers who smoked tobacco during pregnancy may have elevated risk of developing conduct disorder (CD) symptoms. We examined associations between maternal and paternal tobacco smoking during pregnancy and CD symptoms in offspring at the age of 14 years. METHODS: We obtained data from the Raine Study, a multi-generational cohort study based in Western Australia. DSM-oriented scale of the Child Behavior Checklist (CBCL) was used to measure CD symptoms in offspring. Negative binomial regression was used to estimate the rate ratio (risks) (RR) of CD symptoms in offspring. We also produced the E-values to investigate the extent of unmeasured confounding. Paternal smoking during pregnancy was used as a proxy for environmental tobacco smoke exposure. RESULTS: Complete data were available for 1747 mother-offspring and 1711 father-offspring pairs. After adjusting for potential confounders, we found elevated risks (rates) of CD symptoms in offspring born to mothers smoking tobacco during the first trimester [RR 1.52 (95 % CI: 1.24-1.87)], third trimester [RR 1.36 (95 % CI: 1.09-1.69)] and during both trimesters of pregnancy [RR 1.50 (95 % CI: 1.19-1.90)]. The rates of CD symptoms in offspring increased with the level of exposure to maternal smoking during pregnancy. However, we noted insufficient statistical evidence for an association between paternal smoking during pregnancy and CD symptoms in offspring. CONCLUSION: The associations we found for maternal but not paternal smoking may suggest a biological mechanism for intrauterine tobacco exposure on the risk of CD symptoms in offspring. Early interventions assisting pregnant mothers to quit tobacco smoking, or avoid smoking initiation, have potential to contribute health benefits to both mothers and their offspring.

Insight into the longitudinal relationship between chronic subclinical inflammation and obesity from adolescence to early adulthood: a dual trajectory analysis.

OBJECTIVES AND DESIGN: This study aimed to understand the longitudinal relationship between C-reactive protein (CRP) and body mass index (BMI) from adolescence to early adulthood. METHODS: CRP and BMI were collected from participants of the Raine Study Gen2 at 14-, 17-, 20- and 22-year follow-ups (n = 1312). A dual trajectory analysis was conducted to assess the association between CRP and BMI trajectories, providing conditional probabilities of membership of CRP trajectory membership given BMI trajectory membership. Best model fit was assessed by systematically fitting two to eight trajectory groups with linear and quadratic terms and comparing models according to the Bayesian Information Criterion statistic. RESULTS: The three CRP trajectories were; "stable-low" (71.0%), "low-to-high" (13.8%) and "stable-high" (15.2%). Participants in a "high-increasing" BMI trajectory had a higher probability of being in the "stable-high" CRP trajectory (60.4% of participants). In contrast, individuals in the "medium-increasing" BMI trajectory did not have a significantly increased probability of being in the "stable-high" CRP trajectory. CONCLUSIONS: These findings support that chronic sub-clinical inflammation is present through adolescence into early adulthood in some individuals. Targeting chronic sub-clinical inflammation though obesity prevention strategies may be important for improving future health outcomes.

Prenatal exposure to maternal stressful life events and earlier age at menarche: the Raine Study.

STUDY QUESTION: Is there an association between prenatal exposure to stressful life events and age at menarche, and does childhood BMI mediate this association? SUMMARY ANSWER: Girls exposed to prenatal stress had a slightly earlier age at menarche, but this association did not show a dose-response effect and was not mediated by childhood offspring BMI. WHAT IS ALREADY KNOWN: Prenatal stress may impact on reproductive function in females including age at menarche, but human data are very limited. High childhood BMI is known to be associated with earlier age at menarche. Only one small study has measured the association between maternal stress and age at menarche and reported that childhood BMI mediated the association between maternal stress and earlier age at menarche. However, neither maternal stress nor age at menarche was prospectively recorded and the study was limited to 31 mother-daughter pairs. STUDY DESIGN, SIZE, DURATION: The Raine Study is a large prospective population-based pregnancy cohort study (n = 1414 mother-daughter pairs) continuously followed from prenatal life through to adolescence. In the present study, we examined the association between exposure to maternal stressful life events during early, late and total gestation and age at menarche in offspring using 753 mother-daughter pairs with complete case information. PARTICIPANTS/MATERIALS, SETTING, METHODS: Mothers prospectively reported stressful life events during pregnancy at 18 and 34 weeks using a standardized 10-point questionnaire. Exact date of menarche was assessed using a purpose-designed questionnaire at 8, 10, 14 and 17 years of age. Complete information on exposure, outcome and confounding variables was obtained from 753 mothers-daughter pairs. Multivariate linear regression complete case analysis was used to examine associations between maternal stressful life event exposure and age at menarche. Potential selection bias was evaluated using multiple imputations (50 datasets). The mediating effects of offspring childhood BMI (ages 5, 8, or 10 years) on these associations were measured in separate sub-analyses. MAIN RESULTS AND ROLE OF CHANCE: Most (580/753, 77%) daughters were exposed to at least one prenatal stressful life event. Exposure to maternal stressful life events during the entire pregnancy was associated with a non-linear earlier age at menarche. Exposure to one event and two or more psychological stressful events was associated with a 3.5 and 1.7-month earlier onset of puberty, respectively when compared to the reference group with no exposure maternal stressful life events. The estimates from multiple imputation with 50 datasets were comparable with complete case analysis confirming the existence of an underlying effect. No separate significant effects were observed for exposure during early or late gestation. The association between prenatal stressful events and age at menarche was not mediated by childhood BMI in the offspring. LIMITATIONS, REASONS FOR CAUTION: Stressful life events may have affected pregnant women in different ways and self-perceived maternal stress severity may have provided a more precise estimate of gestational psychological stress. The observed non-linear U-shape of the association between maternal psychological stress and age at menarche did not reflect a dose-response. This suggests that the first exposure to prenatal stress exerts a greater effect on fetal reproductive development. A potential mechanism is via dramatic initial activation of the hypothalamic-pituitary-adrenal (HPA) axis following the first stressful life event which is greater than that observed following subsequent exposure to two or more maternal stressful life events. Whilst we adjusted for a priori chosen confounders, we cannot exclude residual confounding or confounding by factors we did not include. Maternal age at menarche was not available so the effects of familial history/genetics could not be assessed. There was a large loss due to the number of girls with no information on date of menarche and missing confounder information implying risk of selection bias and multiple imputation analyses did not fully exclude this risk (similar direction but slightly weaker estimate magnitude). WIDER IMPLICATIONS OF THE FINDINGS: Menarche is a sentinel reproductive event and earlier age at menarche carries implications for psychological, social and reproductive health and for long-term risk of common non-communicable diseases. Understanding the factors regulating age at menarche has extensive health implications. This is the first population-based cohort study in humans to demonstrate that prenatal psychological stress might directly modify age at menarche. STUDY FUNDING/COMPETING INTEREST(S): Dr. Bräuner and Trine Koch's salaries were supported by Doctor Sofus Carl Emil Friis and spouse Olga Doris Friis foundation, The Danish Cancer Society (Kræftens Bekæmpelse, RP15468, R204-A12636, Denmark) and The Danish Health Foundation (Helsefonden, F-22181-23, Denmark). Martha Hickey was funded by NHMRC Practitioner Fellowships. The funding bodies played no role in the design, collection, analysis, or interpretation of data; in the writing of the manuscript; or in the decision to submit the manuscript for publication. Dr. Hart has received personal fees in his function as the Medical Director of Fertility Specialists of Western Australia and received educational sponsorship grants from MSD, Merck-Serono and from Ferring Pharmaceuticals. Dr Hart has also received personal fees from Shareholders in Western IVF outside the submitted work. TRIAL REGISTRATION NUMBER: NA.

Prenatal exposure to maternal, but not paternal, tobacco smoking is associated with smoking in adolescence.

BACKGROUND: Mounting epidemiological evidence suggests an association between prenatal tobacco exposure and an increased risk of tobacco smoking in offspring. However, it is uncertain whether the association is due to the intrauterine or shared environmental exposures. METHODS: Study participants were from the Raine Study, a prospective birth cohort study based in Perth, Western Australia (N = 2730). Tobacco smoking in adolescents, at age 17 years, was measured using a self-reported questionnaire. Log-binomial regression was used to estimate the relative risks (RRs) of tobacco smoking in offspring exposed to maternal prenatal tobacco use during the first and third trimesters of pregnancy. We have also calculated the E-values to investigate the potential effect of unmeasured confounding. Paternal smoking during pregnancy was used as a negative control for comparison. RESULTS: A total of 1210 mothers-offspring pairs were included in the final analysis. After controlling for potential confounders, we found increased risks of tobacco smoking in offspring exposed to maternal prenatal tobacco use during the first trimester [RR 1.50 (95% CI: 1.13-1.97)] (E-value for point estimate = 2.37) and during both trimesters of pregnancy [RR 1.41 (95% CI: 1.03-1.89)] (E-value for point estimate = 2.17). However, we found insufficient statistical evidence for an association between paternal smoking during pregnancy and risk of tobacco smoking in offspring [RR 1.18 (95% CI: 0.84-1.67)]. CONCLUSION: Maternal prenatal tobacco exposure was associated with an increased risk of tobacco smoking in offspring at the age of 17 years. Tobacco smoking cessation at the early stages of gestation may reduce the risk of tobacco smoking in the next generation.