Publications

Importance

The incidence of epilepsy is higher in older age than at any other period of life. Stroke, dementia, and hypertension are associated with late-onset epilepsy; however, the role of other vascular and lifestyle factors remains unclear.

Objective

To identify midlife vascular and lifestyle risk factors for late-onset epilepsy.

Design, Setting, and Participants

The Atherosclerosis Risk in Communities (ARIC) study is a prospective cohort study of 15 792 participants followed up since 1987 to 1989 with in-person visits, telephone calls, and surveillance of hospitalizations (10 974 invited without completing enrollment). The ARIC is a multicenter study with participants selected from 4 US communities. This study included 10 420 black or white participants from ARIC with at least 2 years of Medicare fee-for-service coverage and without missing baseline data. Data were analyzed betweeen April 2017 and May 2018.

Exposures

Demographic, vascular, lifestyle, and other possible epilepsy risk factors measured at baseline (age 45-64 years) were evaluated in multivariable survival models including demographics, vascular risk factors, and lifestyle risk factors.

Main Outcomes and Measures

Time to development of late-onset epilepsy (2 or more International Classification of Diseases, Ninth Revision codes for epilepsy or seizures starting at 60 years or older in any claim [hospitalization or outpatient Medicare through 2013]), with first code for seizures after at least 2 years without code for seizures.

Results

Of the 10 420 total participants (5878 women [56.4%] and 2794 black participants [26.8%]; median age 55 years at first visit), 596 participants developed late-onset epilepsy (3.33 per 1000 person-years). The incidence was higher in black than in white participants (4.71; 95% CI, 4.12-5.40 vs 2.88; 95% CI, 2.60-3.18 per 1000 person-years). In multivariable analysis, baseline hypertension (hazard ratio [HR], 1.30; 95% CI, 1.09-1.55), diabetes (HR, 1.45; 95% CI, 1.17-1.80), smoking (HR, 1.09; 95% CI, 1.01-1.17), apolipoprotein E ε4 genotype (1 allele HR, 1.22; 95% CI, 1.02-1.45; 2 alleles HR, 1.95; 95% CI, 1.35-2.81), and incident stroke (HR, 3.38; 95% CI, 2.78-4.10) and dementia (HR, 2.56; 95% CI, 2.11-3.12) were associated with an increased risk of late-onset epilepsy, while higher levels of physical activity (HR, 0.90; 95% CI, 0.83-0.98) and moderate alcohol intake (HR, 0.72; 95% CI, 0.57-0.90) were associated with a lower risk. Results were similar after censoring individuals with stroke or dementia.

Conclusions and Relevance

Potentially modifiable risk factors in midlife and the APOE ε4 genotype were positively associated with risk of developing late-onset epilepsy. Although stroke and dementia were both associated with late-onset epilepsy, vascular and lifestyle risk factors were significant even in the absence of stroke or dementia.

OBJECTIVE

To identify the association between brain vascular changes and cortical volumes on MRI and late-onset epilepsy.

METHODS

In 1993-1995, 1,920 participants (median age 62.7, 59.9% female) in the community-based Atherosclerosis Risk in Communities (ARIC) Study underwent MRI, and white matter hyperintensities were measured. In addition, in 2011-2013, 1,964 ARIC participants (median age 72.4, 61.1% female) underwent MRI, and cortical volumes and white matter hyperintensities were measured. We identified cases of late-onset epilepsy (starting at age 60 or later) from ARIC hospitalization records and Medicare claims data. Using the 1993-1995 MRI, we evaluated the association between white matter hyperintensities and subsequent epilepsy using survival analysis. We used the 2011-2013 MRI to conduct cross-sectional logistic regression to examine the association of cortical volumes and white matter hyperintensities with late-onset epilepsy. All models were adjusted for demographics, hypertension, diabetes, smoking, and ε4 allele status.

RESULTS

Ninety-seven ARIC participants developed epilepsy after having an MRI in 1993-1995 (incidence 3.34 per 1,000 person-years). The degree of white matter hyperintensities measured at ages 49-72 years was associated with the risk of late-onset epilepsy (hazard ratio 1.27 per age-adjusted SD, 95% confidence interval [CI] 1.06-1.54). Lower cortical volume scores were associated cross-sectionally with higher odds of late-onset epilepsy (odds ratio 1.87, 95% CI 1.16-3.02) per age-adjusted SD.

CONCLUSIONS

This study demonstrates associations between earlier-life white matter hyperintensities on MRI and later-life incident epilepsy, and between cortical volumes measured later in life and late-onset epilepsy. These findings may help illuminate the causes of late-onset epilepsy.

Isolated systolic hypertension (ISH) and elevated pulse pressure (PP) are common blood pressure (BP) abnormalities in older adults, reflect poor vascular compliance, and can signify risk for cardiovascular outcomes. We sought to characterize the associations of ISH and widened PP with high-sensitivity Troponin-T (hs-cTnT; a marker of myocardial damage) and N-terminal pro-B-type natriuretic peptide (NT-proBNP; a marker of hemodynamic stress) levels in older adults. We performed a cross-sectional analysis of 5,251 Atherosclerosis Risk in Communities (ARIC) study participants without heart failure who attended visit 5 (2011 to 2013). We used logistic regression to evaluate the association of ISH (systolic BP ≥140 mm Hg and diastolic BP < 90 mm Hg) and quartiles of PP with detectable (≥5 ng/L) and elevated hs-cTnT (≥14 ng/L); as well as elevated NT-proBNP (≥100 pg/mL). The mean age was 75 years, 58% were women, and 78% were white. ISH was present in 24.7% and PP ≥ 70 mm Hg in 30.3% of this cohort. Compared to participants with nonhypertensive BP (<140/90 mm Hg), ISH was independently associated with hs-cTnT and NT-proBNP; adjusted odds ratio of 1.5 (95% confidence interval: 1.1 to 1.9) for detectable hs-cTnT; 1.3 (1.1 to 1.5) for elevated hs-cTnT; and 1.8 (1.6 to 2.1) for elevated NT-proBNP. Increasing quartiles of PP were also significantly associated with both elevated hs-cTnT (p-for-trend <0.0001) and NT-proBNP (p-for-trend <0.0001). These associations were not modified by BP treatment status. In conclusion, ISH and wide PP are relatively common in older adults despite contemporary BP treatment and are associated with abnormalities in hs-cTnT and NT-pro BNP, findings that could guide personalized treatment of older patients with these BP aberrations.

Cancer survivors might have an excess risk of cardiovascular disease (CVD) resulting from toxicities of cancer therapies and a high burden of CVD risk factors. We sought to evaluate the association of cancer survivorship with subclinical myocardial damage, as assessed by elevated high-sensitivity cardiac troponin T (hs-cTnT) test results. We included 3,512 participants of the Atherosclerosis Risk in Communities Study who attended visit 5 (2011-2013) and were free of CVD (coronary heart disease, heart failure, or stroke). We used multivariate logistic regression to evaluate the cross-sectional associations of survivorship from any, non-sex-related, and sex-related cancers (e.g., breast, prostate) with elevated hs-cTnT (≥14 ng/L). Of 3,512 participants (mean age, 76 years; 62% women; 21% black), 19% were cancer survivors. Cancer survivors had significantly higher odds of elevated hs-cTnT (OR = 1.26, 95% CI: 1.03, 1.53). Results were similar for survivors of non-sex-related and colorectal cancers, but there was no association between survivorship from breast and prostate cancers and elevated hs-cTnT. Results were similar after additional adjustments for CVD risk factors. Survivors of some cancers might be more likely to have elevated hs-cTnT than persons without prior cancer. The excess burden of subclinical myocardial damage in this population might not be fully explained by traditional CVD risk factors.