Abstract
Objective: We investigated the independent and joint associations of changes in estimated cardiorespiratory fitness (eCRF) and symptoms of anxiety and depression with brain volumes in individuals from the general population.Method: 751 participants (52% women, aged 50–67 years) from the Nord-Trøndelag Health Study (HUNT) MRI cohort were included. eCRF obtained from a non-exercise algorithm and symptoms of anxiety and depression were assessed twice; at HUNT2 (1995–97) and HUNT3 (2006–08). Brain MRI was performed shortly after HUNT3. Brain parenchymal fraction (BPF), bilateral hippocampal and total cortical volume were extracted from brain MRI obtained at 1.5T, using FreeSurfer and Statistical Parametric Mapping.Results: Multiple regression revealed that participants whose eCRF increased had larger BPF (β = 0.09, 95% CI 0.02, 0.16) and larger hippocampal volume (β = 0.09, 95% CI 0.03, 0.16) compared to participants whose eCRF remained low. Participants whose eCRF remained high had larger BPF (β = 0.15, 95% CI 0.07, 0.22) and larger cortical volume (β = 0.05, 95% CI 0.01, 0.09). Participants whose anxiety symptoms worsened had smaller BPF (β = −0.09, 95% CI −0.15, −0.02) and cortical volume (β = −0.05, −0.08, −0.01) than participants whose anxiety symptoms remained low. Each ml/kg/min increase in eCRF was associated with larger cortical volume among individuals with worsening of anxiety symptoms (β = 0.13, 95% CI 0.001, 0.27), and larger BPF among individuals whose depressive symptoms improved (β = 0.28, 95% CI 0.02, 0.53).Conclusion: Promoting exercise intended to improve eCRF may be an important public health initiative aimed at maintaining brain health among middle-aged individuals with and without changing psychological symptoms.
Highlights
It is well established that the volume of the human brain decreases in normal aging
There was no evidence of any meaningful correlation between changes in estimate CRF (eCRF) and Hospital Anxiety and Depression Scale (HADS); eCRF and HADS-A, r = 0.03, p = 0.410, eCRF and Hospital Anxiety and Depression Scale depression subscale (HADS-D), r = 0.004, p = 0.903, categorical eCRF change and HADS-A change, φc = 0.06, p = 0.497, categorical eCRF change and HADS-D change, φc = 0.09, p = 0.024
In our study of 751 adults from the general population, we found that increasing or maintaining a high eCRF during middle-age was associated with larger brain parenchymal fraction (BPF), hippocampal and total cortical volume
Summary
Accelerated hippocampal and cortical atrophy may be an indicator of the development of mild cognitive impairment or dementia in older adults (Driscoll et al, 2009; Fotuhi et al, 2012; Hartikainen et al, 2012). Studies have shown an association between CRF and larger whole brain (Zhu et al, 2015), hippocampal (Erickson et al, 2009; Szabo et al, 2011), and cortical volumes (Williams et al, 2017). In a cross-sectional study, eCRF was associated with cognitive function and hippocampal volume, and these associations did not differ significantly from when applying objectively measured CRF (McAuley et al, 2011). ECRF may serve as a suitable proxy for the objectively assessed CRF in epidemiological studies with larger populations, where exercise testing may not be feasible (Ross et al, 2016)
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