ORIGINAL ARTICLE

Gestational age, birth weight, and the risk of hyperkinetic disorder

K M Linnet¹, K Wisborg¹, E Agerbo², N J Secher³, P H Thomsen⁴, T B Henriksen¹

¹ Perinatal Epidemiology Research Unit, Department of Obstetrics and Pediatrics, Aarhus University Hospital, Denmark
² National Centre for Register-Based Research, Aarhus University, Denmark
³ Department of Obstetrics and Gynaecology, Hvidovre Hospital, Copenhagen, Denmark
⁴ Psychiatric Hospital for Children and Adolescents, Aarhus University Hospital, Denmark

Correspondence to:
Dr K M Linnet
Perinatal Epidemiology Research Unit, Department of Obstetrics and Pediatrics, Aarhus University Hospital, Skejby, DK-8200 Aarhus N, Denmark; kmlinnet{at}ki.au.dk

Aims: To study the association between gestational age and birth weight and the risk of clinically verified hyperkinetic disorder.

Methods: Nested case-control study of 834 cases and 20 100 controls with incidence density sampling.

Results: Compared with children born at term, children born with gestational ages of 34–36 completed weeks had a 70% increased risk of hyperkinetic disorder (rate ratio (RR) 1.7, 95% confidence interval (CI) 1.2 to 2.5). Children with gestational ages below 34 completed weeks had an almost threefold increased risk (RR 2.7, 95% CI 1.8 to 4.1). Children born at term with birth weights of 1500–2499 g had a 90% increased risk of hyperkinetic disorder (RR 1.9, 95% CI 1.2 to 2.9), and children with birth weights of 2500–2999 g had a 50% increased risk (RR 1.5, 95% CI 1.2 to 1.8) compared with children born at term with birth weights above 2999 g. The results were adjusted for socioeconomic status of the parents, family history of psychiatric disorders, conduct disorders, comorbidity, and maternal smoking during pregnancy. Results related to birth weight were unchanged after adjusting for differences in gestational age.

Conclusions: Children born preterm, also close to term, and children born at term with low birth weights (1500–2499 g) have an increased risk of clinically verified hyperkinetic disorder. These findings have important public health perspectives because the majority of preterm babies are born close to term.

Abbreviations: ADHD, attention–deficit hyperactivity disorder; CI, confidence interval; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, 4th edition; HKD, hyperkinetic disorder; IUGR, intrauterine growth retardation; ICD-8, International Classification of Diseases, 8th edition; ICD-10, International Classification of Diseases, 10th edition; IDA database, Integrated Database for Labour Market Research; RR, rate ratio

Keywords: preterm delivery; birth weight; intrauterine growth retardation; hyperkinetic disorder; attention-deficit hyperkinetic disorder

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• van Baar, A. L., Vermaas, J., Knots, E., de Kleine, M. J. K., Soons, P. (2009). Functioning at School Age of Moderately Preterm Children Born at 32 to 36 Weeks' Gestational Age. Pediatrics 124: 251-257 [Abstract] [Full Text]  
• Shiri, R., Solovieva, S., Husgafvel-Pursiainen, K., Taimela, S., Saarikoski, L. A., Huupponen, R., Viikari, J., Raitakari, O. T., Viikari-Juntura, E. (2008). The Association between Obesity and the Prevalence of Low Back Pain in Young Adults: The Cardiovascular Risk in Young Finns Study. Am J Epidemiol 167: 1110-1119 [Abstract] [Full Text]  
• Sun, Y., Vestergaard, M., Pedersen, C. B., Christensen, J., Basso, O., Olsen, J. (2008). Gestational Age, Birth Weight, Intrauterine Growth, and the Risk of Epilepsy. Am J Epidemiol 167: 262-270 [Abstract] [Full Text]  
• Schlotz, W., Jones, A., Phillips, N. M.M., Godfrey, K. M., Phillips, D. I.W. (2007). Size at Birth and Motor Activity During Stress in Children Aged 7 to 9 Years. Pediatrics 120: e1237-e1244 [Abstract] [Full Text]  
• Currie, J., Lin, W. (2007). Chipping Away At Health: More On The Relationship Between Income And Child Health. Health Aff (Millwood) 26: 331-344 [Abstract] [Full Text]