Conséquences imprévues : comprendre les maladies cardiovasculaires chez les adultes âgés atteints d’épilepsie

INTRODUCTION. The global burden of cardiovascular disease (CVD) is steadily increasing. A population particularly vulnerable to these diseases are the older adults with a neurological condition: epilepsy. Several studies show that older adults with epilepsy have a higher risk of developing CVD when compared to the general population. This association is surprisingly poorly studied among people with epilepsy. In order to develop health care programs to prevent the onset of CVD comorbidity in people with epilepsy, creating an accurate portrait of older adults with epilepsy is required. OBJECTIVES. In order to fill the gaps in the scientific literature on the causes of the high burden of CVD in older adults with epilepsy, the purpose of this thesis is to investigate the distribution of social factors, lifestyle and behaviors, as well as chronic disease CVD risk factors, in people with epilepsy as compared to the general population. In addition, we aim to measure the cross-sectional association between epilepsy and CVD in older adults, with and without adjustments for a history of stroke as well as looking for evidence of interactions between epilepsy and CVD risk factors. METHODS. We analysed data for 44,817 participants in the Canadian Longitudinal Study on Aging (CLSA), a longitudinal study cohort of individuals aged at least 45 years and where more than 700 individuals have a lifetime self-reported history of epilepsy. Adjusting for age, sex and stroke, we used log-binomial regression to model the cross-sectional associations between CVD risk factors, epilepsy, and CVD such as heart disease, peripheral vascular disease, and myocardial infarction. We compared the CVD burden attributable to stroke in the population with and without epilepsy. Multivariable regression models were also stratified across levels of epilepsy status to observe for differences in these associations between epilepsy and people without epilepsy. Finally, we tested the existence of interactions between CVD risk factors and epilepsy and their association with CVD status. We used multiple imputation to replace missing data. RESULTS. The majority of the sociodemographic characteristics, lifestyle and behavior and chronic diseases, selected as CVD risk factors in our study, were significantly more prevalent in people with epilepsy as compared to the general population without epilepsy. The CVD burden attributable to stroke in people with epilepsy was only 36%, similar to the general population which reached 32%. Even after adjusting for a history of stroke, as well as age and sex, people with epilepsy had a significantly higher prevalence of heart disease [prevalence ratio (PR) = 1.27 (95% CI: 1.02, 1.57)] and peripheral vascular disease [PR = 1.88 (95% CI: 1.50, 2.36)]. Although no longer significant, the trend towards an increase in the prevalence of myocardial infarction in people with epilepsy was maintained [PR = 1.19 (95% CI: 0.89, 1.60)]. Finally, among all the CVD risks factors, only age, hypertension, and chronic obstructive pulmonary disease were associated with significant increases in the prevalence of one or more of the CVD. CONCLUSION. The large sample size and breadth of health information captured by the CLSA (i.e. demographic, social, physical, psychological, economic, physiological) allowed us to model in-depth analysis and present a fair reflection of an older adult population. The presented thesis demonstrates that CVD risk factors are more frequently seen in people with epilepsy and that the association between epilepsy and CVD is independent of the association between epilepsy and stroke. These findings are important first steps in more comprehensively understanding the origins of CVD in people with epilepsy. Mediation analysis could have been a way of further examining my analysis. This was not possible with the current analysis given that we had no way to establish the temporal sequence of our data. Older adults are a vulnerable population in which health care providers should pay particular attention. Conducting longitudinal studies of individuals with newly diagnosed epilepsy seizures and fully characterized chronic disease, sociodemographic characteristics and lifestyle (prior to and post a epilepsy diagnosis) are needed.

Keyphrases: comorbidity, seizure, heart disease, social determinants of health