Mental and physical health changes around transitions into unpaid caregiving in the UK: a longitudinal, propensity score analysis

BACKGROUND

The health of unpaid caregivers is poorer, on average, than in non-caregivers. There has been little focus on how health changes when becoming a caregiver and whether this varies by age, gender, and caregiving intensity. We aimed to investigate the mental and physical health changes involved with becoming a caregiver and whether these associations varied by gender, caregiving intensity, or age.

METHODS

This study used data from the UK Household Longitudinal Study (2009-20) to examine mental and physical health changes around the transition to becoming a caregiver in adults aged 16 years and older. We included adults with information on care, complete covariates needed for matching, and at least one measure of health before or after becoming a caregiver (or matched non-caregiver). Health was measured via General Health Questionnaire-12 (GHQ-12, psychological distress) and 12-item Short Form Survey (SF-12, physical and mental functioning). We applied piecewise growth curve modelling with propensity score matching to model trajectories of mental and physical health for caregivers and matched non-caregivers. Analyses were stratified by age group, gender, and caregiving intensity.

FINDINGS

Sample sizes varied from 3025 (GHQ-12 analyses in early adulthood) to 5785 (SF-12 analyses in early mid-adulthood). Psychological distress increased during transition to caregiving for all ages, particularly in those younger than 64 years, those providing care for 20 h or more per week, and for someone living within the household. Mental health functioning worsened during caregiving transition for those aged 30-64 years, those providing 20 h or more per week, and for those caring for someone within the household. Physical health functioning did not change but there was evidence of lower levels of functioning before caregiving. Changes in mental and physical health upon transition to caregiving did not differ by gender.

INTERPRETATION

Our findings highlight the importance of early identification of and support for caregivers, including younger caregivers. This is important to break the cycle of caregiving and future care need. Health services staff, including general practitioners and hospital discharge teams, are well positioned for early identification of caregivers. We also encourage particular support for the mental health of caregivers and particularly those who become caregivers at a younger age.

FUNDING

The UK Economic and Social Research Council.

Investigating the factorial structure and measurement invariance of the parent-reported strengths and difficulties questionnaire at 11 years of age from the UK Millennium Cohort Study

The strengths and difficulties questionnaire (SDQ) consist of five sub-scales that have been used to measure internalising and externalising symptoms in children, typically by combining sum scores of two sub-scales each, and pro-social behaviours. However, the different possible factorial structures that represent these symptoms have not been formally tested in a nationally representative sample of UK children. In addition, it is necessary to assess whether the SDQ is interpreted similarly across subgroups of the population. Exploratory and confirmatory factor analysis were used to test three competing structures for the parent-reported SDQ collected at age 11, the start of adolescence, in the UK Millennium Cohort Study (n = 11,519), and measurement invariance was assessed according to sex and a measure of deprivation of the area in which households lived. Internal consistency using ordinal alpha, internal convergent validity and external discriminant validity using average variance explained (AVE), and predictive validity were assessed. A five-factor model and a model with two second-order factors for internalising and externalising symptoms had better model fit than a three-factor model. For both structures, invariance was demonstrated across sex and area-level deprivation. AVE scores for the five-factor model indicated that peer and emotional problems factors were measuring a similar construct, as were the hyperactivity and conduct factors. In the second-order model, AVE scores indicated internalising and externalising symptoms were distinct constructs. A second-order model with two factors for internalising and externalising symptoms is appropriate for use in a cohort of UK children born in 2001/02, and our finding of invariance across sex and area-level deprivation indicate that the SDQ can be used in analysis investigating differences in symptoms across subgroups of the population.

Inequalities in associations between young adult caregiving and social relationships: Evidence from the UK Household Longitudinal Study

INTRODUCTION

Young adult caregivers (aged 16-29 years) are an important but underrecognized group of informal caregivers. There is some evidence suggesting that young adult caregivers have fewer social relationships. However, this research has been largely cross-sectional in design or restricted to caregivers, providing no comparison with noncaregivers. Further, there is little evidence on whether and to what extent there are inequalities in associations between young adult caregiving and social relationships by gender, age, caregiving intensity, or household income.

METHODS

Using five waves of data on 3-4000 young adults aged 16-29 from the UK Household Longitudinal Study, we investigated associations between becoming a young adult caregiver and subsequent social relationships (number of close friends and participation in organized social activities) in the short-term (1-2 years after caregiving initiation) and longer-term (4-5 years later). We also assessed differences by gender, age, household income, and caregiving intensity.

RESULTS

Overall, those who became young adult caregivers, and particularly those providing 5+ h/week, reported fewer friends in the short- but not longer-term. No associations were observed between young adult caregiving and participation in organized social activities. Also, there was no evidence of differences by gender, age, income, or caregiving hours.

CONCLUSIONS

Becoming a young adult caregiver is associated with a reduction in number of close friends, particularly in the short-term. Given the importance of practical and emotional support provided by friends, the early identification of young adult caregivers and greater population awareness of caring in young adulthood may help to mitigate the effects on social relationships.

Mediating mechanisms of the relationship between exposure to deprivation and threat during childhood and adolescent psychopathology: evidence from the Millennium Cohort Study

The key aim of our study was to examine pathways from exposure to childhood adversities (i.e., deprivation and threat) to adolescent psychopathology. The assessed mediating mechanisms included cognitive ability and emotion regulation, as proposed by the Dimensional Model of Adversity and Psychopathology (DMAP). The study comprised participants from the nationally representative Millennium Cohort Study. Latent scores for deprivation and threat were derived using confirmatory factor analysis from indicators collected when participants were at age of 9 months, 3 and 5 years. Cognitive ability was measured using the Verbal Similarities subscale of the British Ability Scales II at age 11, and emotion regulation was measured using emotion dysregulation subscale of the Child Social Behavioural Questionnaire at age 7. Psychopathology, defined as psychological distress, was assessed using the Kessler 6 scale at age 17. We conducted causal mediation analysis adjusting for multiple confounding factors. We did not find total effect of either exposure to deprivation or threat on psychological distress, but we did find significant indirect effects of exposure to deprivation on psychological distress via cognitive ability (- 0.11, 95% CI - 0.20 to - 0.05) and emotion regulation (0.03, 0.02 to 0.12), and exposure to threat on psychological distress via cognitive ability (- 0.04, - 0.07 to - 0.01) and emotion regulation (0.09, 0.03 to 0.15). The lack of associations between deprivation or threat and psychological distress may be due to reporting bias or developmental period of psychopathology. Results of mediation analysis partially support the DMAP but indicate limited benefits to reduce adolescent psychological distress by targeting cognitive ability or emotion regulation to those exposed to childhood adversities.

Testing lifecourse theories characterising associations between maternal depression and offspring depression in emerging adulthood: the Avon Longitudinal Study of Parents and Children

BACKGROUND

Maternal depression is a major determinant of offspring mental health. Yet, little is understood about how the duration and timing of maternal depression shapes youth risk for depressive symptoms, which if understood could inform when best to intervene. This study aimed to determine how the timing and duration of maternal depression was related to offspring depression in emerging adulthood, and if these associations varied by sex.

METHODS

We analysed data from the Avon Longitudinal Study of Parents and Children (a prenatal cohort in the Avon area of England, 1991-2003), n = 3,301. We applied the structured lifecourse modelling approach to maternal depression (assessed at 13 points from prenatal period to adolescence) and emerging adult depressive symptoms (age 21). Lifecourse models assessed were accumulation (sum of timepoints when maternal depression was reported), sensitive periods (each period assessed as one during which maternal depression has a stronger effect) and instability (frequent fluctuations in maternal depression).

RESULTS

Female adolescents (n = 2,132) had higher SMFQ scores (mean = 6.15, SD = 5.90) than males (n = 1,169, mean = 4.87, SD = 4.82). Maternal depression was most common in the infancy period (21.2% males; 21.4% females). For males, accumulation was the most appropriate lifecourse model; for each additional period of maternal depression, depressive symptoms in emerging adulthood increased by 0.11 (95% CI: 0.07, 0.15, one-sided p value ≤ .001). For females, exposure to maternal depression was associated with increasing depressive symptoms in emerging adulthood, with the largest effect in mid-childhood (increase of 0.27 units, 95% CI 0.03-0.50, p = .015 for difference between mid-childhood and other time-periods) and a smaller, equal effect at all other time-periods (increase of 0.07 units per time-period, 95% CI: 0.03-0.12, p = .002).

CONCLUSIONS

This study highlights the importance of ongoing maternal depression for the development of depression in offspring through to emerging adulthood. Because long-term exposure to maternal depression was particularly important, early interventions are warranted.

Family adversity and health characteristics associated with intimate partner violence in children and parents presenting to health care: a population-based birth cohort study in England

BACKGROUND

Little is known about the clinical characteristics of children and parents affected by intimate partner violence (IPV) presenting in health-care settings. We examined the associations between family adversities, health characteristics, and IPV in children and parents using linked electronic health records (EHRs) from primary and secondary care between 1 year before and 2 years after birth (the first 1000 days). We compared parental health problems in in children and parents with and without recorded IPV.

METHODS

We developed a population-based birth cohort of children and parents (aged 14-60 years) in England, comprising linked EHRs from mother-child pairs (with no identified father) and mother-father-child triads. We followed the cohort across general practices (Clinical Practice Research Datalink GOLD), emergency departments, outpatient visits, hospital admissions, and mortality records. Family adversities included 33 clinical indicators of parental mental health problems, parental substance misuse, adverse family environments, and high-risk child maltreatment-related presentations. Parental health problems included 12 common comorbidities, ranging from diabetes and cardiovascular diseases to chronic pain or digestive diseases. We used adjusted and weighted logistic-regression models to estimate the probability of IPV (per 100 children and parents) associated with each adversity, and period prevalences of parental health problems associated with IPV.

FINDINGS

We included 129 948 children and parents, comprising 95 290 (73·3%) mother-father-child triads and 34 658 (26·7%) mother-child pairs only between April 1, 2007, and Jan 29, 2020. An estimated 2689 (2·1%) of 129 948 children and parents (95% CI 2·0-2·3) had recorded IPV and 54 758 (41·2%; 41·5-42·2) had any family adversity between 1 year before and 2 years after birth. All family adversities were significantly associated with IPV. Most parents and children with IPV had recorded adversities (1612 [60·0%] of 2689) before their first IPV recording. The probability of IPV was 0·6 per 100 children and parents (95% CI 0·5-0·6) with no adversity, increasing to 4·4 per 100 children per parents (4·2-4·7) with one adversity, and up to 15·1 per 100 parents and children (13·6-16·5) with three of more adversities. Mothers with IPV had a significantly higher prevalence of both physical (73·4% vs 63·1%, odds ratio [OR] 1·6, 95% CI 1·4-1·8) and mental health problems (58·4% vs 22·2%, OR 4·9, 4·4-5·5) than mothers without IPV. Fathers with IPV had a higher prevalence of mental health problems (17·8% vs 7·1%, OR 2·8, 2·4-3·2) and similar prevalences of physical health problems than those without IPV (29·6% vs 32·4%, OR 0·9, 0·8-1·0).

INTERPRETATION

Two in five of the children and parents presenting to health care had recorded parental mental health problems, parental substance misuse, adverse family environments, or high-risk presentations of maltreatment in the first 1000 days. One in 22 children and parents with family adversity also had recorded IPV before age 2 years. Primary and secondary care staff should safely ask about IPV when parents or children present with family adversity or health problems associated with IPV, and respond appropriately.

FUNDING

NIHR Policy Research Programme.

Does providing informal care in young adulthood impact educational attainment and employment in the UK?

Most research on the effects of caring has focused on older spouses or working-age carers providing care for older people, but providing care in early adulthood may have longer-term consequences, given the importance of this life stage for educational and employment transitions. This study aims to investigate the impact of informal care in early adulthood on educational attainment and employment in the UK and to test whether these associations differ by gender or socio-economic circumstances. Data are from young adults (age 16-29 at first interview, n = 27,209) in the UK Household Longitudinal Study wave 1 (2009/11) to wave 10 (2018/2020). Carers are those who provide informal care either inside or outside the household. We also considered six additional aspects of caring, including weekly hours spent caring, number of people cared for, relationship to care recipient, place of care, age at which caring is first observed, and duration of care. Cox regression was used to analyse the association between caring and educational qualifications and employment transitions. We found that young adult carers were less likely to obtain a university degree and enter employment compared to young adults who did not provide care. In terms of care characteristics, weekly hours spent caring were negatively associated with the likelihood of obtaining a university degree qualification and being employed. Providing care after full-time education age negatively influenced employment entry, but having a university degree buffered the negative influence of providing care on entering employment. The influence on unemployment may be stronger for female carers than for male carers. Our results highlight the importance of supporting the needs of young adults who are providing informal care while making key life course transitions.

Adverse childhood experiences and the development of multimorbidity across adulthood-a national 70-year cohort study

AIM

To examine impact of adverse childhood experiences (ACE) on rates and development of multimorbidity across three decades in adulthood.

METHODS

Sample: Participants from the 1946 National Survey of Health and Development, who attended the age 36 assessment in 1982 and follow-up assessments (ages 43, 53, 63, 69; N = 3,264, 51% males). Prospectively collected data on nine ACEs was grouped into (i) psychosocial, (ii) parental health and (iii) childhood health. For each group, we calculated cumulative ACE scores, categorised into 0, 1 and ≥2 ACEs. Multimorbidity was estimated as the total score of 18 health disorders.Serial cross-sectional linear regression was used to estimate associations between grouped ACEs and multimorbidity during follow-up. Longitudinal analysis of ACE-associated changes in multimorbidity trajectories across follow-up was estimated using linear mixed-effects modelling for ACE groups (adjusted for sex and childhood socioeconomic circumstances).

FINDINGS

Accumulation of psychosocial and childhood health ACEs were associated with progressively higher multimorbidity scores throughout follow-up. For example, those with ≥2 psychosocial ACEs experienced 0.20(95% CI 0.07, 0.34) more disorders at age 36 than those with none, rising to 0.61(0.18, 1.04) disorders at age 69.All three grouped ACEs were associated with greater rates of accumulation and higher multimorbidity trajectories across adulthood. For example, individuals with ≥2 psychosocial ACEs developed 0.13(-0.09, 0.34) more disorders between ages 36 and 43, 0.29(0.06, 0.52) disorders between ages 53 and 63, and 0.30(0.09, 0.52) disorders between ages 63 and 69 compared with no psychosocial ACEs.

INTERPRETATIONS

ACEs are associated with widening inequalities in multimorbidity development in adulthood and early old age. Public health policies should aim to reduce these disparities through individual and population-level interventions.

Association of Interparental Violence and Maternal Depression With Depression Among Adolescents at the Population and Individual Level

Importance

Parental intimate partner violence (IPV) and maternal depression are associated with increased risk of depression in children at the population level. However, it is not known whether having information about these experiences can accurately identify individual children at higher risk of depression.

Objective

To examine the extent to which experiencing parental IPV and/or maternal depression before age 12 years is associated with depression at age 18 years at the population and individual level.

Design, Setting, and Participants

This cohort study used data from the Avon Longitudinal Study of Parents and Children, a UK population-based birth cohort, which initially recruited pregnant mothers with estimated due dates in 1991 and 1992. Data used in this study were collected from 1991 to 2009. Data analysis was performed from February to March 2022.

Exposures

Mother-reported parental IPV was assessed on 8 occasions (child age, 1-11 years). Maternal depression was assessed via the Edinburgh Postnatal Depression Scale or by the mother taking medication for depression, as reported by the mother on 8 occasions (child age, 2-12 years).

Main Outcomes and Measures

Depressive symptoms were measured with the Short Mood and Feelings Questionnaire (SMFQ) and Clinical Interview Schedule-Revised (CIS-R) when the child was aged 18 years. Binary indicators of a case of depression were derived the cutoff point of 11 points or above for the SMFQ and 12 points or above for the CIS-R.

Results

The study included 5029 children (2862 girls [56.9%]; 2167 boys [43.1%]) with a measure of depressive symptoms at age 18 years. IPV only was associated with a 24% (adjusted risk ratio, 1.24; 95% CI, 0.97-1.59) higher risk of depression at age 18 years, exposure to maternal depression only was associated with a 35% (adjusted risk ratio, 1.35; 95% CI, 1.11-1.64) higher risk, and exposure to both IPV and maternal depression was associated with a 68% (adjusted risk ratio, 1.68; 95% CI, 1.34-2.10) higher risk. At the individual level, the area under the receiver operating characteristic curve was 0.58 (95% CI, 0.55-0.60) for depression according to the SMFQ and 0.59 (95% CI, 0.55-0.62) for the CIS-R, indicating a 58% to 59% probability (ie, 8%-9% above chance) that a random participant with depression at age 18 years had been exposed to IPV and/or maternal depression compared with a random participant who did not have depression.

Conclusions and Relevance

In this cohort study, parental IPV and maternal depression were associated with depression in adolescence at the population level. However, estimation of an individual developing depression in adolescence based only on information about IPV or maternal depression is poor. Screening children for maternal depression and IPV to target interventions to prevent adolescent depression will fail to identify many children who might benefit and may unnecessarily target many others who do not develop depression.

Poverty from fetal life onward and child brain morphology

Poverty is a risk factor for impaired child development, an association possibly mediated by brain morphology. Previous studies lacked prospective poverty assessments during pregnancy and did not stratify by majority/minority status. We investigated the association of household poverty from fetal life forward with brain morphological differences at age 10 years, in 2166 mother-child dyads. Overall, the results showed no associations between any poverty exposure early in life and brain volumes. However, there was the evidence of timing effects: children exposed to poverty in utero had smaller amygdala volumes (B =  - 0.18, 95%CI - 0.30; - 0.07, pFDR-adjusted = 0.009). There were also differences in associations by majority/minority status (cerebral white matter: p for interaction = 0.04). Dutch children exposed to childhood poverty showed smaller cerebral white matter volumes than their control (B =  - 0.26, 95%CI - 0.45; - 0.06, pFDR-adjusted = 0.035). This association was not observed in the minority population (B =  - 0.05, 95%CI - 0.23; 0.12, pFDR-adjusted = 0.542). The smaller cerebral white matter volume mediated the association between childhood poverty and poorer school performance in Dutch children. Our findings point to the importance of poverty exposure in the fetal period and suggest different mechanisms and vulnerabilities across majority/minority groups.

Childhood adversity and cardiometabolic biomarkers in mid-adulthood in the 1958 British birth cohort

Studies that have examined associations between adverse childhood experiences (ACEs) and cardiometabolic biomarkers in adulthood are limited as they mainly focus on childhood maltreatment. This study aimed to examine the association between a range of prospectively and retrospectively reported ACEs and cardiometabolic biomarkers in mid-adulthood. Multiply-imputed data on 8511 participants from the National Child Development Study (1958 British birth cohort) were used. ACEs were prospectively reported at ages 7, 11 and 16, and retrospectively reported at age 33/44/45. Cardiometabolic outcomes assessed at age 44/45 included glycated haemoglobin (HbA1c), cholesterol (total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL)), triglycerides, blood pressure (systolic and diastolic), body mass index, waist circumference and metabolic syndrome. Parental separation/divorce, physical neglect, emotional neglect and psychological abuse were associated with lower HDL cholesterol. Parental offending and physical neglect were associated with higher triglyceride concentrations. Parental offending was also associated with increased HbA1c. Exposure to 2+ (vs. 0) prospective ACEs was associated with lower HDL cholesterol. All these associations were after adjustment for sex and multiple early life factors. To conclude, several individual ACEs are associated with poorer cardiometabolic risk factor profiles in mid-adulthood. Furthermore, exposure to two or more prospective ACEs is associated with lower HDL cholesterol concentrations in mid-adulthood.

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Parental separation/divorce in childhood is associated with lower high-density lipoprotein cholesterol in mid-adulthood.

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Physical neglect in childhood is associated with poorer lipid profiles in mid-adulthood.

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Psychological abuse in childhood is associated with lower high-density lipoprotein cholesterol in mid-adulthood.

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Parental offending in childhood is associated with higher triglycerides and glycated haemoglobin in mid-adulthood.

Measuring Positive Childhood Experiences: Testing the Structural and Predictive Validity of the Health Outcomes From Positive Experiences (HOPE) Framework

OBJECTIVE

Positive childhood experiences (PCEs), that occur within secure and nurturing social environments, are fundamental to healthy physical, social-emotional, and cognitive development. However, reliable measures of these experiences are not yet widely available. We used data from the Longitudinal Study of Australian Children (LSAC) to empirically represent and psychometrically evaluate 3 primary domains of PCEs defined within the Health Outcomes from Positive Experiences (HOPE) framework, specifically: 1) nurturing and supportive relationships; 2) safe and protective environments and; 3) constructive social engagement and connectedness.

METHODS

LSAC is a nationally representative cohort that has followed young Australians from birth since 2004. LSAC data were used to represent the 3 primary HOPE-PCEs domains (birth to 11 years) across 4 inter-related PCEs constructs: 1) positive parenting, 2) trusting and supportive relationships, 3) supportive neighborhood and home learning environments, and 4) social engagement and enjoyment. Confirmatory factor analysis was used to test the proposed 4-factor structure. Predictive validity was examined through associations with mental health problems and academic difficulties at 14 to 15 years.

RESULTS

The 4-factor structure was supported by empirical data at each time point. Higher exposure to PCEs across each domain was associated with lower reporting of mental health problems (β = -0.20 to -2.05) and academic difficulties (β = -0.01 to -0.13) in adolescence.

CONCLUSIONS

The 4 LSAC-based HOPE-PCEs have sufficient internal coherence and predictive validity to offer a potentially useful way of conceptualizing and measuring PCEs in future cohort studies and intervention trials aiming to enhance the understanding of, and mitigate the negative impacts of, adverse childhood experiences.

The Clustering of Adverse Childhood Experiences in the Avon Longitudinal Study of Parents and Children: Are Gender and Poverty Important?

Previous research has demonstrated a graded relationship between the number of Adverse Childhood Experiences reported (an ACE score) and child outcomes. However, ACE scores lack specificity and ignore the patterning of adversities, which are informative for interventions. The aim of the present study was to explore the clustering of ACEs and whether this clustering differs by gender or is predicted by poverty. Data on 8,572 participants of the Avon Longitudinal Study of Parents and Children (ALSPAC) were used. ALSPAC is a regionally representative prenatal cohort of children born between 1991 and 1992 in the Avon region of South-West England. ACEs included parental divorce, death of a close family member, interparental violence, parental mental health problems, parental alcohol misuse, parental drug use, parental convictions, and sexual, emotional, and physical abuse, between birth and 19 years. Latent class analysis was used to derive ACE clusters and associations between poverty, gender, and the derived classes tested using multinomial logistic regression. Five latent classes were identified: "Low ACEs" (55%), "Parental separation and mother's mental health problems" (18%), "Parental mental health problems, convictions and separation" (15%), "Abuse and mental health problems" (6%), and "Poly adversity" (6%). Death of a close family member and sexual abuse did not cluster with other adversities. The clustering did not differ by gender. Poverty was strongly related to both individual ACEs and clusters. These findings demonstrate that ACEs cluster in specific patterns and that poverty is strongly related to this. Therefore, reducing child poverty might be one strategy for reducing ACEs.

Associations between Adverse Childhood Experiences and the novel inflammatory marker glycoprotein acetyls in two generations of the Avon Longitudinal Study of Parents and Children birth cohort

BACKGROUND

Adverse childhood experiences (ACEs) are associated with increased risk of non-communicable diseases in adulthood, potentially mediated by chronic low-grade inflammation. Glycoprotein acetyls (GlycA) is a marker of chronic and cumulative inflammation. We investigated associations between ACEs and GlycA at different ages, in two generations of the population-based Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort.

METHODS

ALSPAC offspring's total ACE scores were generated for two age periods using prospectively collected data: 0-7y and 0-17y. GlycA was measured using high-resolution proton nuclear magnetic resonance at mean ages 8y, 18y, and 24y. Sample sizes ranged from: n = 5116 (8y) to n = 3085 (24y). ALSPAC mothers (n = 4634) retrospectively reported ACEs experienced before age 18y and GlycA was assessed at mean age 49y. We used multivariable linear regression to estimate associations between ACEs (total ACE score and individual ACEs) and subsequent GlycA in both samples, adjusting for key confounders.

RESULTS

Mean GlycA levels were similar in offspring and mothers and over time. In offspring, there was no evidence that ACEs (total score or individual ACE) were associated with GlycA at age 8y or 18y, or 24y after adjustment for maternal age at birth and parity, maternal marital status, household occupational social class, maternal education, maternal smoking, own ethnicity, sex, and age in months. In mothers, there was evidence of a positive association between the total ACE score and GlycA at age 49y (adjusted mean difference 0.007 mmol/L; 95%CI: 0.003, 0.01). Emotional neglect was the only individual ACE associated with higher GlycA after adjusting for confounders and other ACEs.

CONCLUSION

Results suggest the association between ACEs and GlycA may emerge in middle age. Future research should explore the extent to which inflammation in adulthood mediates well-documented associations between ACEs and adverse health outcomes in later life.

How is the distribution of psychological distress changing over time? Who is driving these changes? Analysis of the 1958 and 1970 British birth cohorts

AIMS

The main objective of this study was to investigate distributional shifts underlying observed age and cohort differences in mean levels of psychological distress in the 1958 and 1970 British birth cohorts.

METHODS

This study used data from the 1958 and 1970 British birth cohorts (n = 24,707). Psychological distress was measured by the Malaise Inventory at ages 23, 33, 42 and 50 in the 1958 cohort and 26, 34, 42 and 46-48 in the 1970 cohort.

RESULTS

The shifts in the distribution across age appear to be mainly due to changing proportion of those with moderate symptoms, except for midlife (age 42-50) when we observed polarisation in distress- an increase in proportions of people with no symptoms and multiple symptoms. The elevated levels of distress in the 1970 cohort, compared with the 1958 cohort, appeared to be due to an increase in the proportion of individuals with both moderate and high symptoms. For instance, at age 33/34 42.3% endorsed at least two symptoms in the 1970 cohort vs 24.7% in 1958, resulting in a shift in the entire distribution of distress towards the more severe end of the spectrum.

CONCLUSIONS

Our study demonstrates the importance of studying not only mean levels of distress over time, but also the underlying shifts in its distribution. Due to the large dispersion of distress scores at any given measurement occasion, understanding the underlying distribution provides a more complete picture of population trends.

Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and narrative synthesis

BACKGROUND

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI), a measure of weight for height, has been extensively reviewed in children, showing consistent associations between disadvantaged SEP and higher BMI in high-income countries (HICs) and lower BMI in middle-income countries (MICs). Fat mass (FM), a more accurate measure of adiposity, and fat-free mass (FFM) are not captured by BMI, but have been shown to track from childhood to adulthood, and be important for cardiovascular health and functional outcomes in later life. It is not clear whether body composition is associated with SEP. We systematically reviewed the association between SEP and body composition in childhood.

METHODS

A systematic review was carried out following PRISMA guidelines. The protocol was pre-registered with PROSPERO (CRD42019119937). Original studies in the English language, which examined the association between SEP and body composition in childhood, were included. An electronic search of three databases was conducted. Two independent reviewers carried out screening, data extraction and quality assessment. Due to heterogeneity in results, a narrative synthesis was conducted. Heterogeneity in findings according to SEP, sex, body composition measure and country income level was investigated.

RESULTS

50 papers were included, the majority from HICs. No papers were from low-income countries. Disadvantage in childhood was associated with greater FM and lower FFM in HICs, but with lower FM and lower FFM in MICs. When measures of FFM indexed to height were used there was no evidence of associations with SEP. In HICs, more studies reported associations between disadvantaged SEP and higher FM among girls comparative to boys.

CONCLUSIONS

Inequalities in FM are evident in HICs and, in the opposite direction, in MICs and follow similar trends to inequalities for BMI. Inequalities in height are likely important in understanding inequalities in FFM.

Area-level and family-level socioeconomic position and body composition trajectories: longitudinal analysis of the UK Millennium Cohort Study

BACKGROUND

Inequalities in the trajectories of body composition in childhood and adolescence have been infrequently studied. Despite the importance of environmental factors in obesity development, little research has looked at area-level socioeconomic position, independent of family socioeconomic position. We aimed to assess how inequalities in body composition develop with age.

METHODS

The Millennium Cohort Study is a longitudinal study of 19 243 families who had a child born between 2000 and 2002 in the UK. Multilevel growth curve models were applied to examine change in fat mass index (FMI), fat free mass index (FFMI; using the Benn index), and fat mass to fat free mass ratio (FM:FFM), measured using Bioelectrical Impedance Analysis, from ages 7 years to 17 years by the Index of Multiple Deprivation (IMD) and household income at baseline.

FINDINGS

Inequalities in FMI and FM:FFM ratio are evident at age 7 years and widen with age. At age 17 years, adolescents in the most disadvantaged IMD group had FMI 0·57 kg/mB (B=Benn parameter; 95% CI 0·43 to 0·70) higher and FM:FFM ratio 0·037 (95% CI 0·026 to 0·047) higher compared with the most advantaged group. Disadvantaged socioeconomic position is associated with higher FFMI but is reversed in adolescence after adjustment for FMI. Inequalities were greater in girls at age 7 years (mean FMI 0·22 kg/mB; 95% CI 0·13 to 0·32) compared with boys of the same age (0·05 kg/mB; -0·04 to 0·15, p=0·3), but widen fastest in boys, especially for FMI, in which there was over an 11 times increase in the inequality from age 7 years of 0·05kg/mB (95% CI -0·04 to 0·15) to 0·62 kg/mB at 17 years (0·42 to 0·82). Inequalities for the IMD were similar to income, and persisted at age 17 years independent of family socioeconomic position.

INTERPRETATION

Childhood and adolescence is an important period to address inequalities in body composition, as they emerge and widen. Policies should consider FFM as well as FM, and inequalities in the environment.

FUNDING

Medical Research Council, Economic and Social Research Council.

Maternal and Paternal Distress in Early Childhood and Child Adiposity Trajectories: Evidence from the Millennium Cohort Study

OBJECTIVE

The current study investigated associations between mothers' and fathers' distress reported in early childhood (at ages 9 months and 3 years) and childhood adiposity trajectories from ages 5 to 14 years.

METHODS

Linear mixed-effects models were undertaken in the Millennium Cohort Study. Self-reported maternal and paternal distress was measured at ages 9 months and 3 years. BMI and fat mass index (FMI) were modeled from ages 5 to 14 years, adjusting for socioeconomic and child characteristics and stratifying by child sex.

RESULTS

Maternal distress reported at 9 months was associated with steeper increases in BMI and FMI trajectories for girls (BMI: β = 0.06; 95% CI: 0.01 to 0.11; FMI: β = 0.04; 95% CI: 0.00 to 0.08). Paternal distress reported at 9 months was associated with steeper increases in BMI and FMI for both girls (BMI: β = 0.06; 95% CI: 0.00 to 0.12, FMI: β = 0.05; 95% CI: -0.02 to 0.10) and boys (BMI: β = 0.09; 95% CI:  0.03 to 0.15, FMI: β = 0.06; 95% CI: 0.01 to 0.10). Maternal "moderate" distress at 3 years was associated with steeper BMI and FMI trajectories for girls only (BMI: β = 0.08; 95% CI: 0.03 to 0.12, FMI; β = 0.06; 95% CI: 0.02 to 0.10).

CONCLUSIONS

Maternal and paternal distress experienced in early childhood, particularly during infancy, was associated with steeper adiposity trajectories for children from ages 5 to 14 years.

Adverse childhood experiences and trajectories of internalizing, externalizing, and prosocial behaviors from childhood to adolescence

BACKGROUND

Adverse childhood experiences (ACEs) predict poorer mental health across the life course but most of the extant research has employed ACE scores or individual adversities using retrospective data.

OBJECTIVES

To study the impact of ACEs on later mental health using not only ACEs scores and individual ACEs, but also latent class analysis (LCA), which respects the clustering of adversities.

PARTICIPANTS AND SETTING

8823 members from the UK Millennium Cohort Study.

METHODS

We investigated the impact of prospectively reported ACEs on mental health trajectories derived using the Strengths and Difficulties Questionnaire at age 3, 5, 7, 11 and 14. Associations between LCA-derived ACE clusters, ACE scores, individual ACEs and mental health trajectories were tested using linear mixed effects models.

RESULTS

With statistical significance set at 5% level, ACE scores showed a graded association with internalizing (ACE score of 1: β = 0.057; ACE score of 2: β = 0.108; ACE score of 3: β = 0.202), externalizing (ACE score of 1: β = 0.142; ACE score of 2: β = 0.299; ACE score of 3: β = 0.415) and prosocial behaviors (ACE score of 1: β=-0.019; ACE score of 2: β=-0.042; ACE score of 3: β=-0.059). Harsh parenting and physical punishment were particularly strongly associated with externalizing (β = 0.270 and β = 0.256) and negatively associated with prosocial behaviors (β=-0.046 and β=-0.058). Parental discord and parental depression showed the strongest associations with internalizing problems (β = 0.125 and β = 0.113). LCA did not discriminate ACE clusters in this dataset.

CONCLUSIONS

ACEs have an important impact on mental health from childhood to adolescence. ACEs score approach yielded useful results, which were further enhanced by exploring individual ACEs.

Adverse childhood experiences and early life inflammation in the Avon longitudinal study of parents and children

BACKGROUND

Adverse childhood experiences (ACEs) have been associated with poorer health across the life course. Previous studies have used cumulative risk scores (ACE scores) or individual ACEs but these two approaches have important shortcomings. ACE scores assume that each adversity is equally important for the outcome of interest and the single adversity approach assumes that ACEs do not co-occur. Latent class analysis (LCA) is an alternative approach to operationalising ACEs data, identifying groups of people co-reporting similar ACEs. Here we apply these three approaches for ACEs operationalisation with inflammation in childhood with the aim of identifying particular ACEs or ACE combinations that are particularly associated with higher inflammation in early life.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) we compare ACE scores, single adversities and LCA-derived ACE clusters in their relationships with Interleukin-6 at age 9 (n = 4935) and C-Reactive Protein (CRP) at age 9 (n = 4887). ACEs included were parental separation/divorce, parental alcohol problems, parental mental health problems, parental offending, inter-parental violence, parental drug misuse, and physical, emotional and sexual abuse.

RESULTS

Two thirds of the sample reported at least one ACE. Mother's mental health problems was the most frequently reported ACE (32.3 %). LCA identified four ACE classes - 'Low ACEs' (81.1 %), 'Maternal mental health problems' (10.3 %), 'Maternal mental health problems and physical abuse' (6.3 %) and 'Parental conflict, mental health problems and emotional abuse' (2.4 %). Parental separation/divorce was associated with higher IL-6. Parental alcohol problems, paternal mental health problems, parental convictions and emotional abuse were associated with lower levels of IL-6. Associations for paternal mental health problems and emotional abuse were only observed for boys. ACE score and LCA-derived ACE classes were not associated with differences in IL-6. Girls in the 'Maternal mental health problems' cluster had lower CRP levels.

CONCLUSIONS

Specific adversities and adversity combinations are important for differences in childhood inflammation. Some associations were only observed for girls or boys.

Adverse childhood experiences and adult inflammation: Single adversity, cumulative risk and latent class approaches

BACKGROUND

Adverse childhood experiences (ACEs) have long been known to be related to poorer health across the life course. Previous studies typically relied on cumulative risk scores or individual adversities measured through retrospective self-reports. However, these approaches have important limitations. Cumulative risk scores assume equal weighting of adversities and the single adversity approach ignores the high probability that adversities co-occur. In contrast, latent class analysis (LCA) offers an alternative approach to operationalise ACEs that respects the clustering of adversities and may identify specific patterns of ACEs important for health outcomes. Furthermore, prospective and retrospective reports of ACEs show poor agreement. Therefore, it is important to compare findings based on prospective and retrospective measures in the same individuals. Despite an increasing number of studies applying LCA to ACEs data, no studies have yet simultaneously investigated LCA to cumulative risk and single adversity approaches in their relationships with adult inflammation. Identifying the specific ACEs or combinations of ACEs which are strongly related to inflammation is important for investigating the mechanisms involved and the planning of effective interventions.

METHODS

Using data on 8810 members of the 1958 British birth cohort we investigated 12 ACEs - physical, psychological and sexual abuse, physical and emotional neglect, parental mental health problems, witnessing abuse, parental conflict, parental divorce, parental offending, parental substance misuse and parental death. LCA was applied to explore the clustering of prospectively and retrospectively reported ACEs separately. Associations between latent classes, cumulative risk scores and individual adversities with three inflammatory markers (C-Reactive Protein, fibrinogen and von Willebrand Factor) were tested using linear regression.

RESULTS

There was co-occurrence between adversities, and particularly for retrospectively reported adversities. Three latent classes were identified in the prospective data - 'Low ACEs' (95.7%), 'Household dysfunction' (2.8%) and 'Parental loss' (1.5%) which were related to increased inflammation in mid-life, as were high ACE scores and individual measures of offending, death, divorce, physical neglect and family conflict. Four latent classes were identified in the retrospective data - 'Low ACEs', 'Parental mental health and substance misuse', 'Maltreatment and conflict' and 'Polyadversity.' The latter two (5.2%) were related to raised inflammation in mid-life, as was a retrospective ACE score of 4+ (8.3%) and individual measures of family conflict, psychological and physical abuse, emotional neglect and witnessing abuse.

CONCLUSIONS

Specific ACEs or ACE combinations might be important for chronic inflammation. LCA is an alternative approach to operationalising ACEs data but further research is needed.

Practitioner Review: Twenty years of research with adverse childhood experience scores - Advantages, disadvantages and applications to practice

BACKGROUND

Adverse childhood experience (ACE) scores have become a common approach for considering childhood adversities and are highly influential in public policy and clinical practice. Their use is also controversial. Other ways of measuring adversity - examining single adversities, or using theoretically or empirically driven methods - might have advantages over ACE scores.

METHODS

In this narrative review we critique the conceptualisation and measurement of ACEs in research, clinical practice, public health and public discourse.

RESULTS

The ACE score approach has the advantages - and limitations - of simplicity: its simplicity facilitates wide-ranging applications in public policy, public health and clinical settings but risks over-simplistic communication of risk/causality, determinism and stigma. The other common approach - focussing on single adversities - is also limited because adversities tend to co-occur. Researchers are using rapidly accruing datasets on ACEs to facilitate new theoretical and empirical approaches but this work is at an early stage, e.g. weighting ACEs and including severity, frequency, duration and timing. More research is needed to establish what should be included as an ACE, how individual ACEs should be weighted, how ACEs cluster, and the implications of these findings for clinical work and policy. New ways of conceptualising and measuring ACEs that incorporate this new knowledge, while maintaining some of the simplicity of the current ACE questionnaire, could be helpful for clinicians, practitioners, patients and the public.

CONCLUSIONS

Although we welcome the current focus on ACEs, a more critical view of their conceptualisation, measurement, and application to practice settings is urgently needed.

Informal caregiving patterns and trajectories of psychological distress in the UK Household Longitudinal Study

BACKGROUND

Approximately seven million people in the UK are engaged in informal caregiving. Informal caregivers are at risk of poorer mental and physical health. However, less is known about how the relationship between the informal caregiving and psychological distress changes over time. The aim of this study was to investigate longitudinal associations between the informal caregiving and psychological distress amongst UK men and women aged 16+.

METHODS

Data were analysed from the UK Household Longitudinal Study (UKHLS, n = 9368), a nationally representative study of UK households. Longitudinal linear mixed modelling was used to estimate associations between the longitudinal patterns of informal caregiving (non-caregiver/one episode of 1-2 years/intermittent caregiving/3+ years caregiving) and trajectories of psychological distress across seven waves of UKHLS data.

RESULTS

Informal caregiving was not associated with psychological distress for men. Women engaged in long-term (⩾3 years) or intermittent caregiving had higher levels of psychological distress at the point of initiation, compared with women who were not caregivers throughout the study period (3+ years caregiver: regression coefficient 0.48, 95% confidence interval (CI) 0.07-0.89; intermittent caregiver: regression coefficient 0.47, 95% CI 0.02-0.92). Trajectories of psychological distress changed little over time, suggesting a plateau effect for these caregiving women.

CONCLUSIONS

Women engaged in long-term or repeated shorter episodes of informal caregiving reported more symptoms of psychological distress than non-caregiving women. Given the increased risk of reporting psychological distress and the increasing importance of the informal care sector, the risk of poorer mental health of informal caregivers should be a priority for public health.

Informal caregiving and markers of adiposity in the UK Household Longitudinal Study

OBJECTIVES

The aim was to investigate associations between caregiving and adiposity using a representative UK longitudinal study. We also investigated whether associations differed by age, gender and caregiving characteristics.

METHODS

Data on 9,421 participants aged 16+ from three waves (2009-2012) of the UK Household Longitudinal Study were used. Body mass index, waist circumference and percentage body fat were assessed. Caregiving and caregiving characteristics (hours per week, number of people cared for, co-resident caregiving and combining working and caregiving) was available from the prior wave. Gender-stratified associations between caregiving/caregiving characteristics with adiposity were tested. Covariates included caregiver's health, socioeconomic position, parenthood and partnerships.

RESULTS

Caregiving was associated with higher adiposity for women but not men. Younger women caregivers had particularly higher levels of adiposity. Men combining part-time paid work with caregiving had higher levels of adiposity than men working full-time and not caregiving. Women aged 16-44 or 65+ had particularly high levels of adiposity when combining full-time work and caregiving, compared to full-time work alone.

CONCLUSION

The health of caregivers should be a public health priority, particularly for younger women and those combining paid work with caregiving responsibilities.

Parental absence in early childhood and onset of smoking and alcohol consumption before adolescence

BACKGROUND

Parental absence, due to death or separation from a parent, has been associated with smoking and alcohol consumption in adolescence and adulthood. The aim of this study was to investigate whether parental absence in early childhood was associated with smoking and alcohol uptake before adolescence.

METHODS

Data on 10 940 children from the UK's Millennium Cohort Study were used. Logistic regression was used to test associations between parental absence (0-7 years) and reports of smoking and alcohol consumption at age 11.

RESULTS

Children who experienced parental absence were more likely to have smoked (OR=2.58, 95% CI 1.88 to 3.56) and consumed alcohol (OR=1.46, 95% CI 1.25 to 1.72). No differences were found by child sex or age, or parent absent. Children who experienced parental death were less likely to have drunk alcohol but those who had were more likely to have consumed enough to feel drunk.

CONCLUSIONS

Parental absence was associated with early uptake of risky health behaviours in a large, nationally representative UK cohort. Children who experience parental absence should be supported in early life in order to prevent smoking and alcohol initiation.

Adverse childhood experiences and adult inflammation: Findings from the 1958 British birth cohort

BACKGROUND

The relationship between adverse childhood experiences (ACE) and poorer health across the life course is well established. Increased chronic inflammation might be one mechanism through which these associations operate. The aim of this study was to explore the relationship between ACE and adult inflammation using a prospective longitudinal study. We also investigated whether associations were explained by life course socioeconomic, psychological and health behavioural factors, and whether associations differed by gender.

METHODS

Multiply imputed data on 7464 participants of the National Child Development Study (1958 British birth cohort) were used. Prospectively collected data on ACE included care placement, physical neglect, parental separation, family history of offences, mental illness, domestic conflict and alcohol misuse across childhood (0-16 years). Adult inflammation was indicated by C-reactive protein (CRP), fibrinogen and Von Willebrand factor (vWF) at age 44/45. Multivariable linear regression models were used to estimate associations between ACE and adult inflammation.

RESULTS

Graded associations for ACE with CRP and fibrinogen were observed (e.g. CRP: 1 ACE: 4.61% higher, 95% CI: -3.13, 12.97; 2+ ACE: 16.35% higher, 95% CI: 6.87, 26.66). Socioeconomic and health behavioral factors were found to particularly explain these associations. After inclusion of all covariates associations between ACE and mid-life inflammation were no longer significant. Associations did not differ for men and women.

CONCLUSIONS

ACE were associated in a graded manner with adult inflammation in a British birth cohort. The association was explained by life course socioeconomic and health behavioral factors, in particular. This study highlights the importance of protecting children from ACE and its negative health effects, and in supporting children through education and into skilled, secure work.

Informal caregiving and metabolic markers in the UK Household Longitudinal Study

OBJECTIVES

Informal caregiving is associated with poorer mental and physical health. Little research has yet focused on objectively measured health risk factors, such as metabolic markers. The aim of this study was to investigate whether informal caregiving was associated with markers of metabolism in a large, representative UK longitudinal study. We also investigated whether more intensive caregiving, as indicated by more caregiving hours, was associated with a less favourable metabolic profile.

STUDY DESIGN/OUTCOME MEASURES

Using data on 9408 participants aged 16+ from the UK Household Longitudinal Study, we explored the relationship between caregiving and metabolic markers (blood pressure, total and high density lipoprotein cholesterol, glycated haemoglobin and triglycerides). We additionally investigated the importance of caregiving intensity (number of hours spent caregiving per week). Associations between caregiving/caregiving intensity and metabolic markers were tested using gender-stratified linear regression models adjusted for age, household income, education, social class, chronic illness, number of dependent children in the household, body mass index and partnership status.

RESULTS

Men who were informal caregivers had higher total cholesterol levels than non-caregivers (3.25% higher, 95% CI: 0.07, 6.53). Women caregivers also had higher total cholesterol levels and women providing intensive care (over 20 h per week) had higher triglyceride levels (19.91% higher, 95% CI: 7.22, 34.10) and lower levels of high density lipoprotein cholesterol (8.46% lower, 95% CI: 14.51, 1.99); however, associations for women were attenuated in our final models.

CONCLUSIONS

Informal caregiving is associated with less favourable lipid profiles. This may be one mechanism through which informal caregiving is associated with increased disease risk. The health of informal caregivers should be a priority for public health.

Parental separation in childhood and adult smoking in the 1958 British birth cohort

Background

Parental separation or divorce is a known risk factor for poorer adult health. One mechanism may operate through the uptake of risky health behaviours, such as smoking. This study investigated the association between parental separation and adult smoking in a large British birth cohort and also examined potential socioeconomic, relational and psychosocial mediators. Differences by gender and timing of parental separation were also assessed.

Methods

Multiply imputed data on 11 375 participants of the National Child Development Study (the 1958 British birth cohort) were used. A series of multinomial logistic regression models were estimated to investigate the association between parental separation (0-16 years) and adult smoking status (age 42), and the role of potential socioeconomic, relational and psychosocial mediators.

Results

Parental separation in childhood was associated with an increased risk of being a current (RRR = 2.14, 95% CI: 1.77, 2.60) or ex-smoker (RRR = 1.50, 95% CI: 1.22, 1.85) at age 42. This association remained after consideration of potential socioeconomic, psychosocial and relational mediators. Relational (parent-child relationship quality, parental involvement and adult partnership status) and socioeconomic factors (overcrowding, financial hardship, housing tenure, household amenities, free school meal receipt and educational attainment) appeared to be the most important of the groups of mediators investigated. No differences by gender or the timing of parental separation were observed.

Conclusion

Parental separation experienced in childhood was associated with increased risk of smoking. Families undergoing separation should be further supported in order to prevent the uptake of smoking and to prevent later health problems.

Crossing the road in time: Inequalities in older people's walking speeds

Pedestrian crossings in the UK and US require people to walk at 1.2 m/s to cross the road in time; however a large proportion of older people do not walk this fast, potentially discouraging walking or putting older people at risk of injury. We use longitudinal data to investigate changes in walking speed, and ability to cross the road in time, at older ages. 31,015 walking speed measurements were taken from 10,249 men and women aged 60+ years in waves 1-7 of the English Longitudinal Study of Ageing (2002-2014). Growth curve analyses were used to model how walking speed changes with increasing age, and predicted probabilities of being able to cross the road in time were estimated. 10% of measured walking speeds were fast enough to cross the road in time. Walking speed declined with age (-5.7×10^-3m/s/yr (95% CI -7.6×10^-3, -3.9×10^-3)), and the decline accelerated with increasing age (-0.3 ×10^-3m/s/yr (-0.4 ×10^-3, -0.3 ×10^-3)). Female, less wealthy and less healthy older people had slower walking speeds. For instance, predicted probability of crossing the road in time at age 60 was 14.8% (10.1, 18.5) and 2.7% (1.5, 3.8) for the richest and poorest men and 8.4% (6.0, 1.1) and 1.5% (0.9, 2.2) for the richest and poorest women, and at age 80 they were 7.1% (3.6, 10.5) and 1.0% (0.3, 1.7) for the richest and poorest men and 3.7% (1.6, 5.9) and 0.5% (0.1, 0.9) for the richest and poorest women. Most older people do not walk fast enough to cross the road in time. Even the majority of the wealthiest and healthiest people aged 60 years and older do not walk fast enough to cross pedestrian crossings in the allocated time. Crossing times should be increased to allow for older peoples' slower walking speeds or other policies considered to improve walkability, and to help avoid injuries and social isolation.

Age at first birth and cardiovascular risk factors in the 1958 British birth cohort

BACKGROUND

To assess relationships between age at first birth and cardiovascular risk factors in a large longitudinal study of men and women. By assessing associations for both genders, we were able to investigate biological versus social and behavioural explanations from early life through to adulthood.

METHODS

Multiply-imputed data on more than 7600 men and women of a British birth cohort study (National Child Development Study, 1958 British birth cohort) were used. Cardiovascular risk factors at age 44/45 years included body mass index, waist:hip ratio, blood pressure (systolic and diastolic), cholesterol (total, low and high-density lipoprotein), triglycerides, glycated haemoglobin, C reactive protein, von Willebrand factor and fibrinogen. Age at first birth was categorised as <20 years, 20-24 years, 25-29 years, 30-34 years or >34 years.

RESULTS

Being younger than 20 years of age at time of first birth was associated with an adverse cardiovascular profile by mid-life. Conversely, older parents had a lower cardiovascular risk as captured by lower body mass index, waist:hip ratio, blood pressure, high and low-density lipoprotein cholesterol, triglycerides, glycated haemoglobin, C reactive protein and fibrinogen. The relationship between age at first birth and cardiovascular risk factors was graded. Few differences between men and women were observed. Associations were largely unchanged after adjustment for early life factors but were partially mediated through adult social and behavioural factors.

CONCLUSIONS

Age at first birth is inversely associated with differences in cardiovascular risk factors in mid-life in a large prospective birth cohort. Our results potentially suggest a social and behavioural rather than a biological explanation.

Work-Family Life Courses and Metabolic Markers in the MRC National Survey of Health and Development

The aim was to investigate whether the combined work-family life courses of British men and women were associated with differences in metabolic markers-waist circumference, blood pressure, high density lipoprotein cholesterol, triglycerides, and glycated haemoglobin-in mid-life. We used data from the Medical Research Council's National Survey of Health and Development-the 1946 British birth cohort. Multi-channel sequence analysis was used to create a typology of eight work-family life course types combining information on work, partnerships and parenthood between ages 16-51. Linear regression tested associations between work-family types and metabolic outcomes at age 53 on multiply imputed data (20 imputations) of >2,400 participants. Compared with men with strong ties to employment and early transitions to family life, men who made later transitions to parenthood and maintained strong ties to paid work had smaller waist circumferences (-2.16cm, 95% CI: -3.73, -0.59), lower triglycerides (9.78% lower, 95% CI: 0.81, 17.94) and lower blood pressure (systolic: -4.03mmHg, 95% CI: -6.93, -1.13; diastolic: -2.34mmHg, 95% CI: -4.15, -0.53). Married men and women who didn't have children had increased high density lipoprotein cholesterol (7.23% higher, 95% CI: 0.68, 14.21) and lower waist circumferences (-4.67cm, 95% CI: -8.37, -0.97), respectively. For men later transitions to parenthood combined with strong ties to paid work were linked to reduced metabolic risk in mid-life. Fewer differences between work-family types and metabolic markers were seen for women.

Work-family life courses and metabolic markers in mid-life: evidence from the British National Child Development Study

Background

Previous studies have found generally better health among those who combine employment and family responsibilities; however, most research excludes men, and relies on subjective measures of health and information on work and family activities from only 1 or 2 time points in the life course. This study investigated associations between work-family life course types (LCTs) and markers of metabolic risk in a British birth cohort study.

Methods

Multichannel sequence analysis was used to generate work-family LCTs, combining annual information on work, partnership and parenthood between 16 and 42 years for men and women in the British National Child Development Study (NCDS, followed since their birth in 1958). Associations between work-family LCTs and metabolic risk factors in mid-life (age 44–45) were tested using multivariate linear regression in multiply imputed data.

Results

Life courses characterised by earlier transitions into parenthood were associated with significantly increased metabolic risk, regardless of attachment to paid work or marital stability over the life course. These associations were only partially attenuated by educational qualifications, early life circumstances and adult mediators. The positive association between weak labour markets ties and metabolic risk was weaker than might be expected from previous studies. Associations between work-family LCTs and metabolic risk factors did not differ significantly by gender.

Conclusions

Earlier transitions to parenthood are linked to metabolic risk in mid-life.

Work-family life courses and markers of stress and inflammation in mid-life: evidence from the National Child Development Study

Background: This study investigated associations between work-family life courses and biomarkers of inflammation and stress in mid-life among British men and women. Gender differences in these associations were also explored.

Methods: A novel statistical method—multi-channel sequence analysis—defined work-family life courses between the ages of 16 and 42 years, combining annual information on work, partnership and parenthood. Associations between work-family life courses and inflammation [C-reactive protein (CRP), fibrinogen and von Willebrand factor] and cortisol at age 44/45 years were tested using multivariate linear regression using multiply-imputed data on almost 6500 participants from the National Child Development Study 1958 British birth cohort.

Results: Compared with those who combined strong ties to paid work with later transitions to stable family lives (‘Work, later family’ group), ‘Teen parents’ had higher CRP [40.6% higher, 95% confidence interval (CI): 5.6, 87.0] and fibrinogen (7.8% higher, 95% CI: 2.3, 13.5) levels, and homemakers (‘No paid work, early family’) had raised fibrinogen levels (4.7% higher, 95% CI: 0.7, 9.0), independent of childhood health and socioeconomic position, adult socioeconomic position, health behaviours and body mass index (BMI). Those who combined later transitions to stable family ties with a career break for childrearing had higher post-waking cortisol than the ‘Work, later family’ group; however, no associations were seen for other work-family types, therefore suggesting a null finding with cortisol. No statistically significant gender interactions in associations between work-family types and inflammatory or cortisol outcomes were found.

Conclusions: Work-family life courses characterised by early parenthood or weak work ties were associated with a raised risk profile in relation to chronic inflammation.

Social isolation in childhood and adult inflammation: evidence from the National Child Development Study

BACKGROUND

Social isolation is known to be associated with poorer health amongst adults, including coronary heart disease. It is hypothesized that this association may be mediated by inflammation. There has been little prospective research on the long-term impact of social isolation in childhood on adult health or the pathways which might be involved. The aim of this study was to investigate whether social isolation in childhood is associated with increased adult inflammation and the mechanisms involved across the life course.

METHODS

This study used multiply-imputed data on 7462 participants of the National Child Development Study in Great Britain. The association between child social isolation (7-11 yrs) and levels of C-reactive protein (CRP) in middle age (44 yrs) was examined. We additionally investigated the role of adult social isolation, psychological distress, health behaviors and socioeconomic factors as potential mediators using path analysis and concurrent measurements made across the life course.

RESULTS

Socially isolated children had higher levels of C-reactive protein in mid-life (standardized coefficient=0.05, p≤0.001). In addition, children who were socially isolated tended to have lower subsequent educational attainment, be in a less advantaged social class in adulthood, were more likely to be psychologically distressed across adulthood and were more likely to be obese and to smoke. All of these factors partially explained the association between childhood social isolation and CRP. However, this association remained statistically significant after considering all mediators simultaneously.

CONCLUSIONS

Social isolation in childhood is associated with higher levels of C-reactive protein in mid-life. This is explained in part through complex mechanisms acting across the life course. Identification and interventions targeted toward socially isolated children may help reduce long-term adult health risk.

Parental separation and adult psychological distress: an investigation of material and relational mechanisms

BACKGROUND

An association between parental separation or divorce occurring in childhood and increased psychological distress in adulthood is well established. However relatively little is known about why this association exists and how the mechanisms might differ for men and women. We investigate why this association exists, focussing on material and relational mechanisms and in particular on the way in which these link across the life course.

METHODS

This study used the 1970 British Cohort Study (n=10,714) to investigate material (through adolescent and adult material disadvantage, and educational attainment) and relational (through parent-child relationship quality and adult partnership status) pathways between parental separation (0-16 years) and psychological distress (30 years). Psychological distress was measured using Rutter's Malaise Inventory. The inter-linkages between these two broad mechanisms across the life course were also investigated. Missing data were multiply imputed by chained equations. Path analysis was used to explicitly model prospectively-collected measures across the life course, therefore methodologically extending previous work.

RESULTS

Material and relational pathways partially explained the association between parental separation in childhood and adult psychological distress (indirect effect=33.3% men; 60.0% women). The mechanisms were different for men and women, for instance adult partnership status was found to be more important for men. Material and relational factors were found to interlink across the life course. Mechanisms acting through educational attainment were found to be particularly important.

CONCLUSIONS

This study begins to disentangle the mechanisms between parental separation in childhood and adult psychological distress. Interventions which aim to support children through education, in particular, are likely to be particularly beneficial for later psychological health.

Parental separation in childhood and adult inflammation: the importance of material and psychosocial pathways

BACKGROUND

Childhood adversities are known to be associated with poorer health outcomes. A potential mechanism may be through changes in inflammatory processes. One such childhood adversity is separation of parents, however relatively little is known about the association between parental separation and inflammation in adulthood. The aims of this study were to (1) investigate whether parental separation is associated with inflammation in mid-life, (2) focus upon the mechanisms that may be involved in translating childhood adversities, such as parental separation, into poorer health outcomes in adulthood.

METHODS

We examine the association of parental separation in childhood, defined as the breakdown of the parent's partnership, and levels of C-reactive protein (CRP) in middle age. The role played by material (through material disadvantage and educational attainment), psychosocial (through parent-child relationship quality and psychological distress) and adiposity (through BMI) mechanisms is investigated using path analysis in a multiply-imputed dataset from a British birth cohort with concurrent measurements made throughout the life course (n=7462).

RESULTS

Participants that report parental separation have higher CRP levels at age 44 than those who grew up with both parents (β=0.16, 95% CI: 0.06, 0.27). This association is largely explained by BMI, material and psychosocial factors. Material disadvantage after separation and educational attainment seem to be particularly important in this association.

CONCLUSIONS

Parental separation increases CRP in adulthood via chains of disadvantage across the life course. This study points towards potential points for intervention and highlights a need to support separating families in order to minimise the long-term impact on adult health.

Impact of Dietary Supplemental Methionine Sources on Sensory Measurement of Odor-Related Compounds in Broiler Excreta

An experiment was conducted to detect differences in odor characteristics of broiler excreta due to utilization of different supplementary Met sources by a trained human descriptive aroma attribute sensory panel. The 5 treatment groups were no supplemental Met (control group), sodium methioninate aqueous solution, dry Met hydroxy analogue, liquid Met hydroxy analogue, and DL-Met. Two trials were conducted consisting of 5 treatment groups with 3 replications of 13 randomly distributed straight run broiler chicks per pen reared in battery cages. Starter and grower diets were formulated to contain 0.5 and 0.38% Met activity, respectively (except control group, 0.35% Met activity). Excreta were collected for 24 h in litter pans lined with aluminum foil at wk 4, 5, and 6 and analyzed by a trained sensory panel (7 people). Each panelist was given 25 g of manure heated at 27 degrees C for 5 min for sensory analysis. The 13 odor attributes used to determine differences in broiler excreta by the trained sensory panel were ammonia, dirty socks, wet poultry, fermented rotten fruit, hay, musty wet, sharp, sour, urinous, rotten eggs, irritating, pungent, and nauseating. Panelist marked intensities for each attribute ranging from 0 = none and 15 = extremely intense. Each panelist was given 2 replications of each treatment group in a random order each week (total of 10 samples per wk). All data were evaluated by ANOVA using the general linear model procedure of SAS software. No significant differences were observed in BW, feed consumption, or feed conversion among the treatments. The attributes of ammonia, wet poultry, rotten fruit, musty wet, sharp, and pungent differed (P < 0.05) across treatment groups. These findings demonstrate that supplemental Met sources significantly influence odor production in broiler excreta.

The impact of methionine source on poultry fecal matter odor volatiles

To determine the impact of Met source on volatile compounds of broiler excreta, 2 trials were conducted using straight-run broiler chicks that were randomly distributed in battery cages with 3 replicate pens of 16 birds each. The treatment groups were 1) dry Met hydroxy analogue (52% Met activity), 2) sodium methioninate aqueous solution (45.9% Met activity), 3) liquid Met hydroxy analogue (88% Met activity), 4) DL-Met, (98% Met activity), and 5) no supplemental Met. All starter diets were formulated to contain 3,135 kcal of ME/kg, 23% crude protein, and 0.8% total Met activity and otherwise met NRC nutrient requirements. Diets were fed ad libitum from d 1 to termination of the study (5 to 6 wk). Feed consumption and feed conversion were measured daily, and all birds were weighed weekly. There were no significant differences in BW, feed consumption, or feed conversion among the treatments in either trial. All excreta were collected in litter pans daily lined with aluminum foil. Litter pans for each pen were individually transferred to a separate room for weekly odor volatile analysis. An electronic nose was used to capture 3 to 4 air samples from various locations for each pan of broiler excreta resulting in a total of 10 air samples from each treatment group. All data taken from the electronic nose were evaluated using analysis of variance. Results indicated that there were significant differences in volatiles in the broiler excreta for all treatment groups. These data indicate that different Met sources may result in the production of different odor-related compounds in broiler excreta.

The Impact of Supplemental Dietary Methionine Sources on Volatile Compound Concentrations in Broiler Excreta

The impact of different Met sources on broiler fecal odor volatiles was determined by evaluating the types of sulfur compounds produced in broiler excreta. Two experiments were conducted using straight-run broiler chicks randomly distributed in battery cages, with 3 replicate pens of 16 birds each. The treatment groups were 1) dry Met hydroxy analogue (dry MetHA), 2) sodium methioninate aqueous solution (NaMet), 3) liquid Met hydroxy analogue (Liq MetHA), 4) D,L- Met, and 5) no supplemental Met (control group). The Met activities of each Met source were 52, 45.9, 88, and 98%, respectively. All diets were formulated to contain either 0.8% (experiment 1) total Met activity or 0.5% Met activity in the starter and 0.38% Met activity in the grower (experiment 2) (except the control group, 0.35% Met activity), but otherwise met NRC nutrient requirements (NRC, 1994). Diets were fed ad libitum from d 1 to 6 wk of age. There were no significant differences in BW among the treatments. All excreta were collected in litter pans lined with aluminum foil. In experiment 1, at wk 6, broiler excreta were collected for a 24-h period, and 4.5 g of broiler excreta from each treatment group was collected into 15-mL headspace vials. Samples were analyzed by gas chromatography/mass spectrometry (GC/MS). The volatile sulfur compounds that were identified and quantified in the broiler excreta were H2S, carbonyl sulfide (COS), methyl mercaptan (CH3SH), dimethyl disulfide (CH3SSCH3), and dimethyl trisulfide (CH3SSSCH3). The NaMet treatment group had significantly higher concentrations of H2S, COS, and CH3SSCH3 compared with all other treatment groups. The Liq MetHA group had significantly lower concentrations of H2S, COS, CH3SH, and CH3SSCH3 compared with the other treatment groups. The dry MetHA group significantly had the highest concentration of CH4SH. The D,L-Met treatment group had the significantly highest concentration of CH3SSSCH3 and the lowest concentration of H2S. The control group had the significantly lowest concentrations of CH3SH, CH3SSCH3, and CH3SSSCH3 compared with the other treatment groups. In experiment 2, at wk 6, an electronic nose was used to evaluate 15 air samples per treatment group. In addition, 15 air samples (containing 6 to 8 L of air in a Tedlar bag, 3 samples per treatment group) were collected for odor evaluation by a sensory panel. Electronic nose sensor data revealed that volatile compounds in broiler excreta from the control group were significantly different from the other 4 treatment groups. Evaluation of the air samples by a sensory panel determined that there was a statistically significant difference in odor threshold detection between the control group and the other treatment groups. The dilutions to threshold of control group, NaMet, dry MetHA, Liq MetHA, and D,L-Met were 350, 492, 568, 496, and 526 odor units, respectively. These findings demonstrate that dietary Met sources significantly influenced odorous volatile concentrations in broiler excreta.

Effects of ammonia nitrogen of H2 and CH4 production during anaerobic digestion of dairy cattle manure

A number of researchers have verified the inhibitory effects of elevated H2 concentrations on various anaerobic fermentation processes. The objective of this work was to investigate the potential for using hydrogen gas production to predict upsets in anaerobic digesters operating on dairy cattle manure. In an ammonia nitrogen overload experiment, urea was added to the experimental digesters to obtain increased ammonia concentrations (600, 1,500, or 3,000 mg N/l). An increase in urea concentration resulted in an initial cessation of H2 production followed by an increase in H2 formation. Additions of 600, 1,500, or 3,000 mg N/l initially resulted in the reduction of biogas H2 concentrations. After 24 h, the H2 concentration increased in the 600 and 1,500 mg N/l digesters, but production remained inhibited in the 3,000 mg N/l digesters. Both methane and total biogas production decreased following urea addition. Volatile solids reduction also decreased during these periods. The digester effluent pH and alkalinity increased due to the increased NH4 formed with added urea. Based on these results, changes in H2 concentration could be a useful parameter for monitoring changes due to increased NH3 in dairy cattle manure anaerobic digesters.