Increased risk for childhood epilepsy was associated with maternal overweight or obesity in early pregnancy, in a study of babies born in Sweden.
The cause of epilepsy is poorly understood and in most cases a definitive cause cannot be determined. Maternal overweight and obesity have increased globally over time and there is growing concern about the long-term neurologic effects of children exposed to maternal obesity in pregnancy, according to the report.
Dr Neda Razaz, of the Karolinska Institutet in Stockholm, Sweden, and co-authors conducted a nationwide study that included more than 1.4m live singleton births in Sweden to examine early pregnancy body-mass index (BMI) in women in their first trimester and the risk for childhood epilepsy.
Of the more than 1.4m children born between 1997 and 2011, there were 7,592 children (0.5%) diagnosed with epilepsy through 2012. The overall incidence of epilepsy in children (ages 28 days to 16 years) was 6.79 per 10,000 child-years.
Risk of childhood epilepsy increased by maternal BMI from 6.30 per 10,000 child-years among normal-weight women (BMI less than 25) to 12.4 per 10,000 child-years among women with grade III obesity (BMI of 40 or more), according to the results.
Risk of epilepsy increased by 11% in children of overweight mothers (BMI of 25 to less than 30) compared with children and normal-weight mothers, while grade I obesity (BMI 30 to less than 35) was associated with a 20% increased risk, grade II obesity (BMI 35 to less than 40) was associated with a 30% increased risk and grade III obesity was associated with an 82% increased risk of epilepsy, the authors report.
The authors speculate on possible reasons, including that maternal overweight and obesity may increase the risk of brain injury, leading to a range of neuro-developmental disorders, or that maternal obesity might affect neuro-development through obesity-induced inflammation.
The study also suggests that asphyxia-related neonatal complications, as well as less severe neonatal complications, were independently associated with increased risk of childhood epilepsy. However, the elevated risk of childhood epilepsy associated with overweight or obese mothers could not be explained by obesity-related pregnancy or neonatal complications, the authors write in the article.
Limitations of the study include possible misclassification and underreporting in some of the data, as well as an acknowledgment that the cause of epilepsy may be multidimensional, with interaction between genetic and environmental factors
“Given that overweight and obesity are potentially modifiable risk factors, prevention of obesity in women of reproductive age may be an important public health strategy to reduce the incidence of epilepsy,” the article concludes.
Abstract
Importance: There is growing concern about the long-term neurologic effects of prenatal exposure to maternal overweight and obesity. The causes of epilepsy are poorly understood and, in more than 60% of the patients, no definitive cause can be determined.
Objectives: To investigate the association between early pregnancy body mass index (BMI) and the risk of childhood epilepsy and examine associations between obesity-related pregnancy and neonatal complications and risks of childhood epilepsy.
Design, Setting, and Participants: A population-based cohort study of 1 441 623 live single births at 22 or more completed gestational weeks in Sweden from January 1, 1997, to December 31, 2011, was conducted. The diagnosis of epilepsy as well as obesity-related pregnancy and neonatal complications were based on information from the Sweden Medical Birth Register and National Patient Register. Multivariate Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) and 95% CIs after adjusting for maternal age, country of origin, educational level, cohabitation with partner, height, smoking, maternal epilepsy, and year of delivery. Data analysis was conducted from June 1 to December 15, 2016.
Main Outcomes and Measures: Risk of childhood epilepsy.
Results: Of the 1 421 551 children born between January 1, 1997, and December 31, 2011, with covariate information available, 7592 (0.5%) were diagnosed with epilepsy through December 31, 2012. Of these 3530 (46.5%) were female. The overall incidence of epilepsy in children aged 28 days to 16 years was 6.79 per 10 000 child-years. Compared with offspring of normal-weight mothers (BMI 18.5 to <25.0), adjusted HRs of epilepsy by maternal BMI categories were as follows: overweight (BMI 25.0 to <30.0), 1.11 (95% CI, 1.04-1.17); obesity grade I (BMI 30.0 to <35.0), 1.20 (95% CI, 1.10-1.31); obesity grade II (BMI 35.0 to <40.0), 1.30 (95% CI, 1.12-1.50); and obesity grade III (BMI≥40.0), 1.82 (95% CI, 1.46-2.26). The rates of epilepsy were considerably increased for children with malformations of the nervous system (adjusted HR, 46.4; 95% CI, 42.2-51.0), hypoxic ischemic encephalopathy (adjusted HR, 23.6; 95% CI, 20.6-27.1), and neonatal convulsions (adjusted HR, 33.5; 95% CI, 30.1-37.4). The rates of epilepsy were doubled among children with neonatal hypoglycemia (adjusted HR, 2.10; 95% CI, 1.90-2.33) and respiratory distress syndrome (adjusted HR, 2.43; 2.21-2.66), and neonatal jaundice was associated with more than a 50% increased risk of epilepsy (adjusted HR, 1.47; 95% CI, 1.33-1.63). The elevated risk of epilepsy in children of overweight or obese mothers was not explained by obesity-related pregnancy or neonatal complications.
Conclusions and Relevance: The rates of childhood epilepsy increased with maternal overweight or obesity in a dose-response manner. Given that overweight and obesity are modifiable, prevention of obesity may be an important public health strategy to reduce the incidence of childhood epilepsy.
Authors
Neda Razaz; Kristina Tedroff; Eduardo Villamor; Sven Cnattingius
[link url="http://media.jamanetwork.com/news-item/is-early-pregnancy-bmi-associated-with-increased-risk-of-childhood-epilepsy/"]JAMA material[/link]
[link url="http://jamanetwork.com/journals/jamaneurology/fullarticle/2614289"]JAMA Neurology abstract[/link]
[link url="http://jamanetwork.com/journals/jamaneurology/fullarticle/2614286"]JAMA Neurology editorial[/link]