Christina M Hultman1, Anna Torrång2, Catherine Tuvblad2, Sven Cnattingius2, Jan-Olov Larsson2, Paul Lichtenstein2. 1. Dr. Hultman is with the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, and the Department of Neuroscience Psychiatry, Ulleråker, University of Uppsala, Sweden; Ms. Torrång, Ms. Tuvblad, and Drs. Cnattingius and Lichtenstein are with the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet; and Dr. Larsson is with the Department of Child and Adolescent Psychiatry, Karolinska University Hospital, Stockholm, Sweden. Electronic address: Christina.Hultman@ki.se. 2. Dr. Hultman is with the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, and the Department of Neuroscience Psychiatry, Ulleråker, University of Uppsala, Sweden; Ms. Torrång, Ms. Tuvblad, and Drs. Cnattingius and Lichtenstein are with the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet; and Dr. Larsson is with the Department of Child and Adolescent Psychiatry, Karolinska University Hospital, Stockholm, Sweden.
Abstract
OBJECTIVE: To determine whether low birth weight increases the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood and early adolescence. METHOD: In a population-based sample of 1,480 twin pairs born in the period 1985-1986 ascertained from the Swedish Twin Registry, birth weight was collected prospectively through the Medical Birth Registry. ADHD symptoms were measured with a 14-item checklist covering DSM-III-R criteria (parental rating) at age 8 to 9 years and 13 to 14 years. We used both a dichotomous approach for birth weight (>400 g or 15% weight difference) and ADHD (eight or more symptoms) and continuous measures to investigate between- and within-twin pair effects. RESULTS: Our results showed that low birth weight was a risk factor for symptoms of ADHD and the associations did not diminish when we controlled for genetic influence. The lighter twin in birth weight-discordant pairs had on average 13% higher ADHD symptom score at age 8 to 9 years (p = .006) and 12% higher ADHD score at age 13 to 14 years (p = .018) compared with the heavier twin. The genetic correlations suggest modest or no genetic overlap between birth weight and ADHD. CONCLUSIONS: The hypothesis that low birth weight is associated with the development of ADHD symptoms was supported in this prospective twin study. Fetal growth restriction seems to represent a modest but fairly consistent environmental influence on the development of ADHD symptoms.
OBJECTIVE: To determine whether low birth weight increases the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood and early adolescence. METHOD: In a population-based sample of 1,480 twin pairs born in the period 1985-1986 ascertained from the Swedish Twin Registry, birth weight was collected prospectively through the Medical Birth Registry. ADHD symptoms were measured with a 14-item checklist covering DSM-III-R criteria (parental rating) at age 8 to 9 years and 13 to 14 years. We used both a dichotomous approach for birth weight (>400 g or 15% weight difference) and ADHD (eight or more symptoms) and continuous measures to investigate between- and within-twin pair effects. RESULTS: Our results showed that low birth weight was a risk factor for symptoms of ADHD and the associations did not diminish when we controlled for genetic influence. The lighter twin in birth weight-discordant pairs had on average 13% higher ADHD symptom score at age 8 to 9 years (p = .006) and 12% higher ADHD score at age 13 to 14 years (p = .018) compared with the heavier twin. The genetic correlations suggest modest or no genetic overlap between birth weight and ADHD. CONCLUSIONS: The hypothesis that low birth weight is associated with the development of ADHD symptoms was supported in this prospective twin study. Fetal growth restriction seems to represent a modest but fairly consistent environmental influence on the development of ADHD symptoms.
Authors: Lucy Thompson; Jeremy Kemp; Philip Wilson; Rachel Pritchett; Helen Minnis; Louise Toms-Whittle; Christine Puckering; James Law; Christopher Gillberg Journal: Eur Child Adolesc Psychiatry Date: 2009-07-28 Impact factor: 4.785
Authors: Quetzal A Class; Martin E Rickert; Henrik Larsson; Paul Lichtenstein; Brian M D'Onofrio Journal: Br J Psychiatry Date: 2014-09-25 Impact factor: 9.319