Table 4.
Partial correlation analyses between baseline serum IGF-I and baseline levels of MRI- estimated brain volumes and neuropsychological test performances in SCI/MCI and AD patients
| SCI/MCI(n = 106) | AD(n = 59) | |
| Brain volumes (cm3) | ||
| Total white matter | r = –0.13, p = 0.23 | r = –0.20, p = 0.23 |
| Total corpus callosum* | r = –0.04, p = 0.69 | r = –0.01, p = 0.95 |
| WMHs | r = 0.03, p = 0.79 | r = 0.09, p = 0.62 |
| Global cognitive function | ||
| MMSE | r = 0.24, p = 0.04 | r = 0.11, p = 0.60 |
| Speed and executive function (response time in s) | ||
| TMT-A | r = 0.07, p = 0.57 | r = 0.23, p = 0.25 |
| TMT-B | r = 0.06, p = 0.62 | r = –0.40, p = 0.04 |
| Stroop Test I | r = –0.09, p = 0.42 | r = –0.38, p = 0.049 |
| Stroop Test II | r = –0.29, p = 0.01 | r = –0.18, p = 0.37 |
| Stroop Test III | r = –0.17, p = 0.15 | r = –0.05, p = 0.81 |
Correlations were calculated using partial correlation analyses with adjustment for age, gender, BMI, smoking habits, serum LDL/HDL ratio and MAP. Additionally, ICV was added as a covariate in the partial correlation analyses between baseline serum IGF-I and baseline brain volumes. Serum IGF-I was logarithmically transformed prior to the analyses. Significant correlations are reported as bold text. *Subsections of corpus callosum were not evaluated as there were no significant baseline correlations between IGF-I and total corpus callosum in SCI/MCI or AD. AD, Alzheimer’s disease; BMI, body mass index; ICV, intracranial volume; IGF-I, insulin-like growth factor-I; HDL, high-density lipoprotein-cholesterol; LDL, low-density lipoprotein-cholesterol; MAP, mean arterial pressure; MMSE, Mini Mental State Examination; MRI, magnetic resonance imaging; SCI/MCI, subjective/objective mild cognitive impairment; TMT-A, trail making test A; TMT-B, trail making test B; WMH, white matter hyperintensity.