Gait and balance in apolipoprotein 4 allele carriers in older adults and Parkinson's disease

Background: Gait and balance impairments are among the most troublesome and heterogeneous in Parkinson's disease (PD). This heterogeneity may, in part, reflect genetic variation. The apolipoprotein E (APOE) gene has three major allelic variants (epsilon 2, epsilon 3 and epsilon 4). Previous work has demonstrated that older adult (OA) APOE epsilon 4 carriers demonstrate gait deficits. This study compared gait and balance measures between APOE epsilon 4 carriers and non-carriers in both OA and PD. Methods: 334 people with PD (81 APOE epsilon 4 carriers and 253 non-carriers) and 144 OA (41 carriers and 103 non-carriers) were recruited. Gait and balance were assessed using body-worn inertial sensors. Two-way analyses of covariance (ANCOVA) compared gait and balance characteristics between APOE epsilon 4 carriers and non-carriers in people with PD and OA, controlling for age, gender, and testing site. Results: Gait and balance were worse in people with PD compared to OA. However, there were no differences between APOE epsilon 4 carriers and non-carriers in either the OA or PD group. In addition, there were no significant group (OA/PD) by APOE epsilon 4 status (carrier/non-carrier) interaction effects for any measures of gait or balance. Conclusions: Although we found expected impairments in gait and balance in PD compared to OA, gait and balance characteristics did not differ between APOE epsilon 4 carriers and non-carriers in either group. While APOE status did not impact gait and balance in this cross-sectional study, future work is needed to determine whether progression of gait and balance deficits is faster in PD APOE epsilon 4 carriers.