Lifestyle risk and cortical folding of older adults

N Bittner; C Jockwitz; S Moebus; N Pundt; UJ Bayen; K Zilles; K Amunts; S Caspers

doi:10.1055/s-0036-1586524

Das Gesundheitswesen, Table of Contents

Lifestyle risk and cortical folding of older adults

N Bittner ¹^,², C Jockwitz ¹^,², S Moebus ³, N Pundt ³, UJ Bayen ⁴, K Zilles ¹^,⁵^,⁶, K Amunts ¹^,²^,⁵, S Caspers ¹^,²

¹Research Centre Juelich, Institute of Neuroscience und Medicine (INM-1), Juelich
²C. & O. Vogt Institute for Brain Research, Heinrich-Heine-University, Duesseldorf
³Institute of Medical Informatics, Biometry and Epidemiology, University of Duisburg-Essen, Essen
⁴Institute of Experimental Psychology, Heinrich-Heine-University, Duesseldorf
⁵JARA-BRAIN, Juelich-Aachen Research Alliance, Juelich
⁶Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen

Abstract

Lifestyle might partly explain inter-individual variability in brain changes of older adults: Whereas alcohol intake and smoking might promote brain atrophy, physical exercise and social integration seem to be protective, e.g. against dementia. Nevertheless, the complex interplay between lifestyle factors has rarely been considered. Therefore, we examined the effects of overall lifestyle risk load, using an integrated lifestyle risk-score, on the folding of the brain's surface in older adults.

From the population-based 1000BRAINS cohort of older adults 130 participants had to be excluded due to missing data, 2 because of stroke and 22 due to depressive symptoms. Finally, we included 571 older adults (56 – 85 years, mean: 68 years, 261 females). An integrated risk-score was built from single risk (alcohol intake & pack-years of cigarettes) and protective (physical activity & social network size) factors. Single factors were z-transformed and signs were reversed for protective factors. A sum score was calculated, with higher scores indicating higher risk. All particpants underwent structural MR imaging of the brain. Cortical folding was calculated and variations in cortical folding in relation to overall risk and individual lifestyle factors were examined using general linear models. Results are reported at p < 0.05, corrected for multiple comparisons (covariates: age and gender).

The overall lifestyle risk-score was negatively related to cortical folding, i.e. higher risk was associated with less folding, in the following brain regions: (i) left sensorimotor cortex, (ii) left Broca's speech region, (iii) right posterior temporal cortex and (iv) right cuneus. Further, the protective factor 'physical activity' was positively correlated with cortical folding in the right hemisphere partially overlapping with risk-score-related regions. The risk factor 'alcohol intake' was negatively related to cortical folding in right sensorimotor cortex.

Lifestyle risk negatively affected cortical folding in older adults. The effects of the integrated risk-score partially differed from those of the individual lifestyle factors. This might indicate over-additive effects of lifestyle on brain structure if more than one risk factor is present in an individual. Further investigating these effects, e.g. using multiple regression, might help understanding the inter-individual variability of brain structure, and consecutively function, in older adults.