Exploring the association between low birthweight and adolescent mental health in the United Kingdom

Abstract Low birthweight (LBW) is associated with a range of medical conditions including behavioural and emotional problems over the life course. This study aimed to explore the association between LBW and internalising and externalising mental health problems (MHP) in adolescents born in the United Kingdom between 2000 and 2002. Data were analysed for 10,485, 9,228, and 8,402 Millennium Cohort Study participants at ages 11, 14 and 17, respectively. Internalising and externalising MHP were measured using the Strengths and Difficulties Questionnaire (SDQ). LBW was subcategorised by size for gestational age and prematurity. Crude and adjusted associations between LBW subgroup and internalising and externalising MHP were estimated using binary logistic regression. Internalising MHP were more prevalent in LBW than NBW participants at ages 11 (14.2% vs 10.3%, p < 0.001), 14 (19.4% vs 13.7%, p < 0.001), and 17 (parent-report: 20.3% vs 14.8%, p < 0.001; self-report: 25.7% vs 20.1%, p < 0.001), respectively. Externalising MHP were more common amongst LBW participants at ages 11 (9.4% vs 7.3%, p = 0.02) and 14 (9.0% vs 6.6%, p = 0.01). Compared with NBW peers, the odds of internalising (males: aOR 2.18, 95% CI 1.21-3.73, p = 0.007; females: aOR 2.17, 95% CI 1.22-3.66, p = 0.005) and externalising MHP (males: aOR 2.01, 95% CI 1.05-3.60, p = 0.014; females: aOR 2.58, 95% CI 1.14-5.24, p = 0.016) were significantly increased in male and female premature small for gestational age (SGA) participants at age 11. Externalising MHP were significantly increased amongst premature SGA females aged 14 (aOR: 2.53, 95% CI 1.01-5.66, p = 0.016). Internalising MHP were significantly increased in premature SGA females at age 17 based on parent (aOR: 2.41, 95% CI 1.38-4.22, p = 0.005) and self-report (aOR: 1.95, 95% CI 1.14-3.31, p = 0.014). Amongst LBW individuals, premature SGA females have the greatest risk of internalising and externalising MHP during adolescence, thus identifying an important target group for intervention. Key messages • This study provides evidence for the longitudinal association between low birth weight and mental health in adolescents born in the United Kingdom in the 21st century. • Stratification of low birth weight individuals by size for gestational age and prematurity enabled the identification of a subgroup of adolescents for mental health promotion.