This is the first biomarker-based study to show this link.
In a collaboration between researchers at Columbia University's Mailman School of Public Health, Columbia University Medical Center (CUMC), New York State Psychiatric Institute, and scientists in Finland, researchers report a newfound link between smoking during pregnancy and risk of schizophrenia in offspring.
Using data from a large national birth cohort of pregnant women in the Finnish Prenatal Study of Schizophrenia and their offspring from the Finnish Maternity Cohort, the researchers analyzed nearly 1,000 cases of schizophrenia. They also matched controls among offspring born in Finland from 1983 to 1998 from the country’s national registry and tobacco exposure was estimated based on the biomarker cotinine, a byproduct of metabolizing nicotine.
The findings, which are published online in the American Journal of Psychiatry, reveal that heavy maternal nicotine exposure during pregnancy is linked to a 38 percent increased chance of schizophrenia in children.
The results held after the researchers adjusted for factors like parental psychiatric history, socioeconomic status, and maternal age.
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"To our knowledge, this is the first biomarker-based study to show a relationship between fetal nicotine exposure and schizophrenia," senior author Alan Brown, Mailman School professor of epidemiology and professor of clinical psychiatry at CUMC, said in a media release. "We employed a nationwide sample with the highest number of schizophrenia cases to date in a study of this type."
Nicotine affects babies by crossing the placenta into the fetal bloodstream, and it specifically targets fetal brain development. It can cause both short- and long-term changes in cognition, and may contribute to neurodevelopmental abnormalities.
Schizophrenia is certainly not the only issue that can arise from smoking while pregnant. As the release informs, smoking during pregnancy is known to contribute to low birth weight and attentional difficulties.
In fact, Brown and colleagues conducted a previous study, which was also reported in the American Journal of Psychiatry, that analyzed a different birth cohort and found a link between smoking during pregnancy and an increased risk of bipolar disorder.
"These findings underscore the value of ongoing public health education on the potentially debilitating, and largely preventable, consequences that smoking may have on children over time," said Brown.
"Future studies on maternal smoking and other environmental, genetic, and epigenetic factors, as well as animal models, should allow identification of the biological mechanisms responsible for these associations,” he continued.
He says it’s of interest to look into maternal nicotine exposure in relation to other psychiatric disorders, like autism.