A new study from Karolinska Institutet shows that children born with low birth weight are at a higher risk of developing asthma later in life. The study, which is published in the journal Pediatrics, is based on data on the incidence of asthma in 10,918 twins from the Swedish Twin Registry.
Questionnaire data on asthma in 9- and 12- year old twins was linked to the national Swedish Medical Birth Registry which records, amongst other data, birth weight and gestational age (i.e. how long into the pregnancy the baby is born). Since twins have the same gestational age and share DNA, uterine environment and conditions of early infancy, twin studies are an excellent way to examine the relationship between foetal growth and childhood disease.
"Our study shows that there’s a distinct correlation between foetal growth and asthma that’s independent of gestational age and environmental or genetic factors," says Catarina Almqvist Malmros, paediatrician and Assistant professor at the Department of medical epidemiology and biostatistics, Karolinska Institutet.
According to the WHO some 300 million people currently suffer from asthma. It is the most common chronic disease among children, and the number of children with the condition has risen steadily during the last decades. At the same time, an increasing number of children are being born with a low birth weight, a possible symptom of malnutrition in the womb. The study suggests that impaired foetal growth affects lung development.
Ortqvist AK, Lundholm C, Carlström E, Lichtenstein P, Cnattingius’S, Almqvist CFamilial factors do not confound the association between birth weight and childhood asthma
Pediatrics 2009 Oct;124(4):e737-43, Epub 28 September 2009