Causal relationship among obesity and body fat distribution and epilepsy subtypes

Abstract

ObjectiveThe observational studies indicate an association between obesity and epilepsy, but it is unclear whether such an association responds to causality. The objective of this study was to determine the causal relationship between obesity and fat distribution and epilepsy subtypes based on waist circumference, hip circumference (HP), waist-hip ratio (WHR), and body mass index (BMI).MethodsA two-sample Mendelian randomization study was conducted separately for the four indicators of obesity and epilepsy and its seven subtypes, with reverse Mendelian randomization and multivariate Mendelian randomization for significant outcomes.ResultsA two-sample Mendelian randomized analysis informed us that waist circumference was a risk factor for juvenile myoclonic epilepsy (beta = 0.0299, P = 4.60 × 10−3). The increase in hip circumference increased the risk of juvenile myoclonic epilepsy and epilepsy, with effect values of 0.0283 (P = 2.01 × 10−3) and 0.0928 (P = 1.40 × 10−2), respectively. Furthermore, children with a higher BMI exhibit a higher risk of epilepsy (beta = 0.0148 P = 1.05 × 10−3). The reverse Mendelian randomization study revealed that childhood absence epilepsy increased its BMI (beta = 0.8980, P = 7.52 × 10−7), and juvenile myoclonic epilepsy increased its waist circumference (beta = 0.7322, P = 3.26 × 10−2). Multivariate Mendelian randomization revealed that an increase in hip circumference and waist-hip ratio increased the risk of juvenile myoclonic epilepsy, with an effect value of 0.1051 (P = 9.75 × 10−4) and 0.1430 (P = 3.99 × 10−3), respectively, while an increase in BMI and waist circumference instead decreased their risk, with effect values of −0.0951 (P = 3.14 × 10−2) and−0.0541 (P = 1.71 × 10−2). In contrast, multivariate Mendelian randomization for childhood absence epilepsy and epilepsy did not identify any independent risk factors.SignificanceOur findings provide novel evidence in favor of obesity as a risk factor for epilepsy and waist circumference as a risk factor for juvenile myoclonic epilepsy. Increased hip circumference confers an elevated risk of juvenile myoclonic epilepsy and epilepsy (all documented cases), and a high BMI increases the risk of childhood absence epilepsy. With this, new insights are provided into the energy metabolism of epilepsy, which supports further nutritional interventions and the search for new therapeutic targets.

Genetic causal role of body mass index in multiple neurological diseases

“…A recent prospective study concluded an association between obesity and idiopathic generalized EP and a family history of EP, but not drug-resistant EP 119 . A MR analysis investigated the relationship between obesity, institutional distribution, and EP subtypes and found that obesity, a risk factor for EP, can lead to an increased risk of spasmodic seizures in adolescents, while a high BMI raised the risk of cataplectic seizures in children 120 . Early studies identified the possibility of co-morbidity between EP and obesity, suggesting a risk of obesity-induced EP 121 – 123 .…”

Mendelian randomization study shows a causal effect of asthma on epilepsy risk

“…Assumption 1 (Relevance), SNPs significantly (P<5E-08) associated with asthma. Assumption 2 (Independence), SNPs not associated with confounding factors that correlated with both asthma and epilepsy, including atopic dermatitis ( 13 ), celiac disease ( 14 ), inflammatory bowel disease ( 15 ), rheumatoid arthritis ( 16 ), hypothyroidism ( 17 ), migraine ( 18 ), multiple sclerosis ( 19 ), educational attainment ( 20 ), and body mass ( 21 ). Assumption 3 (Exclusivity), SNPs affected epilepsy susceptibility directly through asthma and are not associated with epilepsy (P>1E-05).…”