A comparison of longitudinal modelling approaches: Alcohol and cannabis use from adolescence to young adulthood.

BACKGROUND: Modelling trajectories of substance use over time is complex and requires judicious choices from a number of modelling approaches. In this study we examine the relative strengths and weakness of latent curve models (LCM), growth mixture modelling (GMM), and latent class growth analysis (LCGA). DESIGN: Data were drawn from the Australian Temperament Project, a 36-year-old community-based longitudinal study that has followed a sample of young Australians from infancy to adulthood across 16 waves of follow-up since 1983. Models were fitted on past month alcohol use (n = 1468) and cannabis use (n = 549) across six waves of data collected from age 13-14 to 27-28 years. FINDINGS: Of the three model types, GMMs were the best fit. However, these models were limited given the variance of numerous growth parameters had to be constrained to zero. Additionally, both the GMM and LCGA solutions had low entropy. The negative binomial LCMs provided a relatively well-fitting solution with fewer drawbacks in terms of growth parameter estimation and entropy issues. In all cases, model fit was enhanced when using a negative binomial distribution. CONCLUSIONS: Substance use researchers would benefit from adopting a complimentary framework by exploring both LCMs and mixture approaches, in light of the relative strengths and weaknesses as identified. Additionally, the distribution of data should inform modelling decisions.

Predicting common maternal postpartum complications: leveraging health administrative data and machine learning.

OBJECTIVE: We aimed to predict the risk of common maternal postpartum complications requiring an inpatient episode of care. DESIGN AND SETTING: Maternal data from the beginning of gestation up to and including the delivery, and neonatal data recorded at delivery, were used to predict postpartum complications. SAMPLE: Administrative health data of all inpatient live births (n = 422 509) in the Australian state of Queensland between January 2009 and October 2015. METHOD: Gradient boosted trees were used with five-fold cross-validation to compare model performance. The best performing models for each outcome were then assessed in the independent validation data using the area under the receiver operating curve (AUC-ROC). MAIN OUTCOME MEASURE: Postpartum complications occurring in the first 12 weeks after delivery requiring hospital admission. RESULTS: Postpartum hypertensive disorders obtained good discrimination in the independent validation data (AUC = 0.879, 95% CI 0.846-0.912), as did obstetric surgical wound infection (AUC = 0.856, 95% CI 0.838-0.873), whereas postpartum sepsis and haemorrhage obtained poor discrimination. CONCLUSIONS: Our study suggests that routinely collected health data have the potential to play an important role in helping determine women's risk of common postpartum complications leading to hospital admission. This information can be presented to clinical staff after delivery to help guide immediate postpartum care, delayed discharge, and post-discharge patient follow up. For such a system to be effective and valued, it must produce accurate predictions, and our findings suggest areas where routine data collection could be strengthened to this end. TWEETABLE ABSTRACT: Improved prediction of maternal postnatal hypertensive disorders and wound infection via machine learning.

The natural history of risky drinking and associated harms from adolescence to young adulthood: findings from the Australian Temperament Project.

BACKGROUND: We aimed to describe the natural history of heavy episodic drinking (HED) and associated harms from adolescence to young adulthood in a large Australian population cohort study. METHOD: The Australian Temperament Project consists of mothers and babies (4-8 months) recruited from Infant Welfare Centres and followed every 2 to 4 years until age 28 years. Analyses were based on data from 1156 young people (497 male; 659 female) surveyed repeatedly at ages 16, 18, 20, 24 and 28 years. We used dual processes latent class growth analysis to estimate trajectories of HED and associated harms, employing a piecewise approach to model the hypothesized rise and subsequent fall across adolescence and the late twenties, respectively. RESULTS: We identified four sex-specific trajectories and observed little evidence of maturing-out across the twenties. In males, a normative pattern of increasing HED across the twenties with little related harm was observed (40% of the male sample). Early and late starter groups that peaked in harms at age 20 years with only minor attenuation in binging thereafter were also observed (6.1% and 35%, respectively). In females, a normative pattern of increasing, but moderate, HED with little related harm was observed (44% of the female sample). Early and late starter groups were also identified (18% and 17%, respectively); however, unlike males, the female late starter group showed a pattern of increasing HED and related harms. CONCLUSIONS: Continued patterns of risky alcohol use and related harms are apparent for both males and females across the twenties.

The natural history of internalizing behaviours from adolescence to emerging adulthood: findings from the Australian Temperament Project.

BACKGROUND: The aims of the study were to describe the patterning and persistence of anxiety and depressive symptoms from adolescence to young adulthood and to examine long-term developmental relationships with earlier patterns of internalizing behaviours in childhood. METHOD: We used parallel processes latent growth curve modelling to build trajectories of internalizing from adolescence to adulthood, using seven waves of follow-ups (ages 11-27 years) from 1406 participants of the Australian Temperament Project. We then used latent factors to capture the stability of maternal reported child internalizing symptoms across three waves of early childhood follow-ups (ages 5, 7 and 9 years), and examined relationships among these patterns of symptoms across the three developmental periods, adjusting for gender and socio-economic status. RESULTS: We observed strong continuity in depressive symptoms from adolescence to young adulthood. In contrast, adolescent anxiety was not persistent across the same period, nor was it related to later depressive symptoms. Anxiety was, however, related to non-specific stress in young adulthood, but only moderately so. Although childhood internalizing was related to adolescent and adult profiles, the associations were weak and indirect by adulthood, suggesting that other factors are important in the development of internalizing symptoms. CONCLUSIONS: Once established, adolescent depressive symptoms are not only strongly persistent, but also have the potential to differentiate into anxiety in young adulthood. Relationships with childhood internalizing symptoms are weak, suggesting that early adolescence may be an important period for targeted intervention, but also that further research into the childhood origins of internalizing behaviours is needed.

Generational increase in obesity among young women: a prospective analysis of mother-daughter dyads.

BACKGROUND/OBJECTIVES: Increases in obesity in young adults over recent decades are shown by national survey data but have yet to be replicated using prospective data. We aim to quantify the increase in obesity and overweight over two generations of young adult women using prospective measures of body mass index (BMI). SUBJECTS/METHODS: Data are from the Mater University Study of Pregnancy (MUSP), a prospective pre-birth cohort study started in 1981 in Brisbane, Australia. Analyses were restricted to 992 mother-daughter dyads who were at similar ages at the time they were assessed and for whom measures of BMI were available. We also conducted an additional analysis to test whether there was a similar increase amongst father-son dyads. We used multinomial logistic regression for clustered data to compare the same prospective measures of BMI categories between mother and daughters. RESULTS: Controlling for a number of sociodemographic and lifestyle factors in the female sample, daughters had 5.04 (3.03, 8.85) times the odds of being obese and 2.54 (1.86, 3.54) times the odds of being overweight compared with their mothers. A large increase in obesity was also observed in the male sample. CONCLUSIONS: Using a longitudinal design to partly account for familial confounding of obesity risk factors, this study confirms a large and concerning increases in obesity rates over two generations of young adults and suggests increases in obesity over the past 20 years may be greater than previously anticipated.

The role of parental alcohol use, parental discipline and antisocial behaviour on adolescent drinking trajectories.

BACKGROUNDS: Parental drinking, harsh parental discipline and adolescent antisocial behaviour have been independently implicated in adolescent alcohol use. Robust prospective studies are required to examine developmental relationships between these factors and their effect on trajectories of alcohol use across adolescence. METHODS: Data were ascertained at three consecutive adolescent waves (13.5, 15.5 and 17.5 years) from the Australian Temperament Project, a 15-wave (30 year) general population birth cohort in Victoria, Australia. Adolescent alcohol trajectories, adjusted for time-varying measures of parenting and antisocial behaviour, were regressed on time-stable measures of parental alcohol use. The full case analysis comprised 751 individuals with complete data. RESULTS: Two distinct alcohol trajectories were identified across the three adolescent waves after adjusting for time-varying factors: a higher and lower drinking group. Both trajectories increased linearly over the study period. Antisocial behaviour was positively associated with both trajectories while harsh parental discipline was positively associated with alcohol use in the lower-use group only. Increased maternal and paternal drinking at 13.5 years placed teenagers at a greater risk of being included in the high-risk trajectory. CONCLUSION: Parental drinking was the strongest predictor of different drinking trajectories in adolescence. This finding underscores the importance of comprehensive public heath approaches that target both parental and adolescent drinking attitudes and behaviour.