Bachmann Christine Strand, Risnes Kari, Bjørngaard Johan Håkon, Schei Jorun, Nilsen Sara Marie, Pape Kristine
Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway
Children's Clinic, St Olav's University Hospital, Trondheim, Norway.
BMJ Paediatr Open. 2025 Apr 5;9(1):e003186. doi: 10.1136/bmjpo-2024-003186.
To assess relative age effects (how the youngest children in a school class are at increased risk compared with their older classmates) on healthcare use with psychiatric diagnoses in childhood and adolescence within preterm and term-born boys and girls.
DESIGN/SETTING/PATIENTS: Registry-based cohort study including individuals born in Norway from 1991 to 2012 with follow-up data from the National Patient Registry from 2008 to 2017 when they were aged between 4 and 18 years.
Relative age was defined according to birth month and grouped in four 3-month periods. Gestational age at birth (GA week+days) was categorised into preterm (GA 23+0-36+6) and term (GA 37+0-41+6).
The presence of psychiatric diagnoses (any diagnosis and specific diagnosis groups according to ICD-10) in data from specialist healthcare contacts at different ages during follow-up was compared between relative age groups in preterm and term born using generalised estimating equation logistic regression analyses.
Of 1 109 411 individuals, 7% were born preterm. Relative age effects for psychiatric diagnosis and specific diagnosis groups were seen for both preterm and term-born boys and girls, with the strongest estimates for any psychiatric diagnosis in the relatively younger preterm girls born in October-December, compared with the relatively older preterm girls born in January-March (OR 1.43 (95% CI 1.25 to 1.63) at ages 4-10 years).
Relative age effects were widely demonstrated for healthcare use with psychiatric diagnoses within term and preterm born, for both girls and boys. The excess risk for those born late in the year added to already existing adversity in children born preterm, emphasising the need for additional consideration related to school and societal structures.
评估相对年龄效应（即与同班年龄较大的同学相比，班级中年龄最小的儿童如何面临更高的风险）对早产和足月出生的男孩及女孩在童年和青少年时期患有精神疾病诊断时医疗保健使用情况的影响。
设计/地点/患者：基于登记处的队列研究，纳入1991年至2012年在挪威出生的个体，并从国家患者登记处获取2008年至2017年他们4至18岁时的随访数据。
相对年龄根据出生月份定义，并分为四个3个月的时间段。出生时的孕周（孕周+天数）分为早产（孕周23+0 - 36+6）和足月（孕周37+0 - 41+6）。
使用广义估计方程逻辑回归分析，比较早产和足月出生的相对年龄组在随访期间不同年龄的专科医疗接触数据中精神疾病诊断（根据国际疾病分类第10版的任何诊断和特定诊断组）的存在情况。
在1109411名个体中，7%为早产。早产和足月出生的男孩及女孩均出现了精神疾病诊断和特定诊断组的相对年龄效应，对于10月至12月出生的相对较年轻的早产女孩，与1月至3月出生的相对较年长的早产女孩相比，任何精神疾病诊断的估计值最强（4至10岁时的比值比为1.43（95%置信区间为1.25至1.63））。
在足月和早产出生的人群中，无论男孩还是女孩，在患有精神疾病诊断时的医疗保健使用方面，相对年龄效应都得到了广泛证实。年末出生者的额外风险叠加了早产儿童已有的不利因素，强调了在学校和社会结构方面需要额外考虑的必要性。
