Obstetrical mode of delivery and behavioural outcomes in childhood and adolescence: findings from the Millennium Cohort Study

Purpose To examine the association between mode of delivery (in particular caesarean section) and behavioural outcomes in offspring at six time-points between age 3 and 17 years. Methods Similar to previous work examining the association between mode of delivery and behavioural outcomes in offspring at age 7, we used maternal-reported data from the Millennium Cohort Study. Data on mode of delivery were collected when children were 9 months and categorised as spontaneous vaginal delivery, assisted vaginal delivery, induced vaginal delivery, emergency caesarean section, planned caesarean section and caesarean section after induction of labor. Data on behavioural outcomes were collected at ages 3, 5, 7, 11, 14 and 17 years using the Strengths and Difficulties Questionnaire (SDQ). Crude and adjusted logistic regression examined mode of delivery–behavioural difficulties relationship, using validated SDQ cut-off points (total SDQ ≥ 17, emotional ≥ 5, conduct ≥ 4, hyperactivity ≥ 7, peer problems ≥ 4 and prosocial behaviour ≤ 4). Multilevel models with linear splines examined the association between mode of delivery and repeated measures of SDQ. Results There were 18,213 singleton mother–child pairs included at baseline, 13,600 at age 3; 13,831 at age 5; 12,687 at age 7; 11,055 at age 11; 10,745 at age 14 and 8839 at age 17. Adjusted logistic regression suggested few associations between mode of delivery and behavioural outcomes at ages 3, 5, 11, 14 and 17 years using validated SDQ cut-off points. After correction for multiple testing, only the protective association between planned caesarean section-Conduct difficulties at age 5 years (OR 0.63, 95% CI 0.46, 0.85) and positive association between caesarean section after induction-Emotional difficulties at age 11 years (OR 1.57, 95% CI 1.19, 2.07) remained statistically significant. Multilevel modelling suggested mean SDQ scores were similar in each mode of delivery group at each time point. Conclusions Results of this study indicate that mode of delivery is unlikely to have a major impact on behavioural outcomes.

Mutual relationships between head injury and conduct problems in children aged 9 months to 14 years in the UK Millennium Cohort Study

Background: Research suggests a link between acquired head injury and signs of conduct disorder, with a majority of findings based on retrospective reports and comparison samples. The relationship between head injuries and conduct problems and how they may influence one another during development is currently unclear. This study aimed to investigate direct and indirect associations between head injury and conduct problems through to early adolescence. Methods: Data from the UK Millennium Cohort Study was used to investigate the relationship between conduct problems as assessed by the Strengths and Difficulties Questionnaire and parent reported head injury over time, at ages 9 months, 3, 5, 7, 11 and 14 years, using a cross-lagged path analysis. This is data from 18,552 children, participating in a UK cohort study that is representative of the UK population. We included 7,041 (3,308 male) children, who had full information about head injuries and conduct problems at age 14. Results: We found a mutual association between childhood head injuries and conduct problems but with distinct timings: Head injury between 5-7 years predicted greater chance of conduct problems at age 11 and 14 years, while greater conduct problems at 5 years predicted a significantly greater chance of a head injury at age 7-11 years. Conclusions: These findings have important implications for the timing of preventive and ameliorative interventions. Prior to school entry, interventions aiming to reduce conduct problems would appear most effective at reducing likelihood of head injuries in future years. However, equivalent interventions targeting head injuries would be better timed either as children are entering formal primary education, or soon after they have entered.

Is Motor Milestone Assessment in Infancy Valid and Scaled Equally Across Sex, Birth Weight, and Gestational Age? Findings From the Millennium Cohort Study

Is the assessment of motor milestones valid and scaled equivalently for all infants? It is not only important to understand if the way we use gross and fine motor scores are appropriate for monitoring motor milestones but also to determine if these scores are confounded by specific infant characteristics. Therefore, the aim of the study is to investigate the latent structure underlying motor milestone assessment in infancy and measurement invariance across sex, birth weight, and gestational age. For this study, the birth cohort data from the United Kingdom Millennium Cohort Study (MCS) was used, which includes the assessment of eight motor milestone tasks from the Denver Developmental Screening Test in 9-month-old infants (N = 18,531), depicting early motor development of the first children of generation Z. Confirmatory factor analyses showed a better model fit for a two-factor structure (i.e., gross and fine motor development) compared to a one-factor structure (i.e., general motor development), and multiple indicators multiple causes modeling revealed no differential item functioning related to sex, birth weight, and gestational age. The study provides support for the use of gross and fine motor scores when assessing motor milestones in infants—both boys and girls with different birth weights and of varying gestational ages. Further investigation into widely adopted assessment tools is recommended to support the use of valid composite scores in early childhood research and practice.

The Association between Fast Food Outlets and Overweight in Adolescents Is Confounded by Neighbourhood Deprivation: A Longitudinal Analysis of the Millennium Cohort Study

The aim of our study is to utilise longitudinal data to explore if the association between the retail fast food environment and overweight in adolescents is confounded by neighbourhood deprivation. Data from the Millennium Cohort Study for England were obtained for waves 5 (ages 11/12; 2011/12; n = 13,469) and 6 (ages 14/15; 2014/15; n = 11,884). Our outcome variable was overweight/obesity defined using age and sex-specific International Obesity Task Force cut points. Individuals were linked, based on their residential location, to data on the density of fast food outlets and neighbourhood deprivation. Structural Equation Models were used to model associations and test for observed confounding. A small positive association was initially detected between fast food outlets and overweight (e.g., at age 11/12, Odds Ratio (OR) = 1.0006, 95% Confidence Intervals (CI) = 1.0002–1.0009). Following adjusting for the confounding role of neighbourhood deprivation, this association was non-significant. Individuals who resided in the most deprived neighbourhoods had higher odds of overweight than individuals in the least deprived neighbourhoods (e.g., at age 11/12 OR = 1.95, 95% CIs = 1.64–2.32). Neighbourhood deprivation was also positively associated to the density of fast food outlets (at age 11/12 Incidence Rate Ratio = 3.03, 95% CIs = 2.80–3.28).

Impaired vision and physical activity in childhood and adolescence: findings from the Millennium Cohort Study

Background/aimsInvestigate if impaired vision is associated with reduced levels and differences in types of physical activity (PA) to identify barriers or enablers to achieving healthy PA levels.MethodsData from the Millennium Cohort Study of children born in the UK in 2000–2001 and followed-up to age 14 years (n=11 571). Using parental report on eye conditions coded by clinicians, children were categorised as having no, unilateral or bilateral impaired vision. Outcomes included objective accelerometer-derived time spent in moderate-to-vigorous physical activity (MVPA), and 16 PA types reported by parents, teachers and/or participants, covering physical education (PE), organised sports, self-organised sports and hobbies.ResultsOverall, 50% of 7-year-olds and subsequently 41% as 14-year-olds achieved the internationally recommended level of ≥60 MVPA min/day, irrespective of vision status, and mainly attributable to PE and organised sports. Bilateral impaired vision (vs none) was associated with parent-reported difficulties with PE (adjusted OR, 4.67; 95% CI, 2.31 to 9.41), self-rated poor ability in PE (3.21; 1.44 to 7.15) and not enjoy indoor PA (0.48; 0.26 to 0.88). Unilateral impaired vision was associated with both parent-rated difficulties (1.80; 1.26 to 2.59) and teachers’ perception of low ability in PE (2.27; 1.57 to 3.28), and reduced odds of high participation in organised sports (0.77; 0.59 to 0.99). Age-related trajectories showed suboptimal PA in childhood tracked into adolescence, with no difference by vision status.ConclusionPopulation-wide programmes to increase PA levels in children should pay special attention to those with impaired vision and include early interventions to encourage participation and confidence in PE and organised sports, starting in primary school and maintained afterwards.

Early-life maternal attachment and risky health behaviours in adolescence: findings from the United Kingdom Millennium Cohort Study

Background Early uptake of multiple risky behaviours during adolescence, such as substance use, antisocial and sexual behaviours, can lead to poor health outcomes without timely interventions. This study investigated how early-life maternal attachment, or emotional bonds between mothers and infants, influenced later risky behaviours in adolescence alongside other potential explanatory pathways using the United Kingdom Millennium Cohort Study. Methods Total maternal attachment scores measured at 9 months using the Condon (1998) Maternal Postnatal Attachment Scale compared higher and lower attachment, where mothers in the lowest 10th percentile represented lower attachment. Multiple risky behaviours, defined as two or more risky behaviours (including smoking cigarettes, vaping, alcohol consumption, illegal drug use, antisocial behaviour, criminal engagement, unsafe sex, and gambling), were scored from 0 to 8 at age 17. Five multivariate logistic regression models examined associations between maternal attachment and multiple risky behaviours among Millennium Cohort Study members (n = 7796). Mediation analysis sequentially adjusted for blocks of explanatory mechanisms, including low attachment mechanisms (multiple births, infant prematurity, sex, breastfeeding, unplanned pregnancy and maternal age at birth), maternal depression, and social inequalities (single-parent status, socioeconomic circumstance by maternal education and household income) at 9 months and poor adolescent mental health at 14 years. Results Children of mothers with lower maternal attachment at 9 months had 23% increased odds of multiple risky behaviours at 17 years (OR: 1.23, 95% CI: 1.00–1.50) in the unadjusted baseline model. All five explanatory blocks attenuated baseline odds. Low attachment mechanisms attenuated 13%, social inequalities 17%, and poor mental health 17%. Maternal depression attenuated the highest proportion (26%) after fully adjusting for all factors (30%). Conclusions Lower maternal attachment in early life predicted increased adolescent multiple risky behaviours. Almost a third of the excess risk was attributable to child, maternal and socioeconomic factors, with over a quarter explained by maternal depression. Recognising the influence of early-life risk factors on adolescent health could innovate current policies and interventions addressing multiple risky behaviour uptake affecting health inequalities across the life course.

Explaining ethnic variations in adolescent mental health: a secondary analysis of the Millennium Cohort Study

Purpose The relationship between ethnicity and adolescent mental health was investigated using cross-sectional data from the nationally representative UK Millennium Cohort Study. Methods Parental Strengths and Difficulties Questionnaire reports identified mental health problems in 10,357 young people aged 14 (n = 2042 from ethnic minority backgrounds: Mixed n = 492, Indian n = 275, Pakistani n = 496, Bangladeshi n = 221, Black Caribbean n = 102, Black African n = 187, Other Ethnic Group n = 269). Univariable logistic regression models investigated associations between each factor and outcome; a bivariable model investigated whether household income explained differences by ethnicity, and a multivariable model additionally adjusted for factors of social support (self-assessed support, parental relationship), participation (socialising, organised activities, religious attendance), and adversity (bullying, victimisation, substance use). Results were stratified by sex as evidence of a sex/ethnicity interaction was found (P = 0.0002). Results There were lower unadjusted odds for mental health problems in boys from Black African (OR 0.15, 95% CI 0.04–0.61) and Indian backgrounds (OR 0.42, 95% CI 0.21–0.86) compared to White peers. After adjustment for income, odds were lower in boys from Black African (OR 0.10, 95% CI 0.02–0.38), Indian (OR 0.40, 95% CI 0.21–0.77), and Pakistani (OR 0.49, 95% CI 0.27–0.89) backgrounds, and girls from Bangladeshi (OR 0.18, 95% CI 0.05–0.65) and Pakistani (OR 0.63, 95% CI 0.41–0.99) backgrounds. After further adjustment for social support, participation, and adversity factors, only boys from a Black African background had lower odds (OR 0.16, 95% CI 0.03–0.71) of mental health problems. Conclusions Household income confounded lower prevalence of mental health problems in some young people from Pakistani and Bangladeshi backgrounds; findings suggest ethnic differences are partly but not fully accounted for by income, social support, participation, and adversity. Addressing income inequalities and socially focused interventions may protect against mental health problems irrespective of ethnicity.