Table 1.
Baseline Demographic and Clinical Data for Subjects
| Group | All subjects | CN | MCI | AD dementia | F or χ2 | df | P |
|---|---|---|---|---|---|---|---|
| N | 402 | 104 | 203 | 95 | |||
| Age (years) | 75.4 +/− 6.7 (Median: 75.5) | 75.9 +/− 4.8 (Median: 75.8) | 75.0 +/− 7.2 (Median: 75.0) | 75.6 +/− 7.4 (Median: 75.8) | 0.652 | 2, 399 | 0.521 |
| Sex (% male) | 63.9 | 61.5 | 67.5 | 59.0 | 2.40 | 2 | 0.302 |
| Education (years) | 15.5 +/− 3.1 (Median: 16.0) | 15.9 +/− 3.1 (Median: 16.0) | 15.8 +/− 2.9 (Median: 16.0) | 14.6 +/− 3.2 (Median: 16.0) | 5.48 | 2, 399 | <0.05* |
| AMNART IQ | 117.5 +/− 11.5 (Median: 121.0) | 120.7 +/− 11.3 (Median: 123.0) | 117.2 +/− 11.0 (Median: 121.0) | 114.4 +/− 11.9 (Median: 115.0) | 7.72 | 2, 398 | <0.01** |
| APOE4(%non-carrier/heterozygous carrier/homozygous carrier) | 51.0/38.3/10.7 | 75.0/23.1/1.9 | 46.8/40.4/12.8 | 33.7/50.5/15.8 | 38.9 | 4 | <0.0001**** |
| MMSE | 26.8+/− 2.6 (Median: 27.0) | 29.0 +/− 1.1 (Median: 29.0) | 27.2 +/− 1.7 (Median: 27.0) | 23.5 +/− 2.1 (Median: 24.0) | 280.69 | 2, 399 | <0.0001*** |
| RAVLT total learning | 32.2 +/− 11.1 (Median: 31.0) | 42.2 +/− 9.8 (Median: 41.0) | 31.4 +/− 9.1 (Median: 30.0) | 22.9+/− 6.9 (Median: 22.0) | 120.61 | 2, 399 | <0.0001*** |
| Digit Symbol | 36.5 +/− 13.0 (Median: 37.5) | 44.5 +/− 10.4 (Median: 43.0) | 37.4 +/− 10.9 (Median: 38.0) | 25.9 +/−12.4 (Median: 26.0) | 69.99 | 2, 399 | <0.0001*** |
| NPI-Q Apathy (% present) | 0.25 +/− 0.6 (18.2) (Median: 0.0) | 0.02 +/− 0.1 (1.9) (Median: 0.0) | 0.2 +/− 0.5 (15.3) (Median: 0.0) | 0.6 +/− 0.8 (42.1) Median: 0.0) | 28.88 | 2, 399 | <0.001++ |
| Antidepressant use (% present) | 22.6 | 11.5 | 23.2 | 33.7 | 13.97 | 2 | <0.001+ |
All values (except N, sex, APOE4, and antidepressant use) represent mean ± standard deviation. Medians are given in parentheses. AD (Alzheimer’s disease), AMNART IQ (American National Adult Reading Test intelligence quotient), APOE4 (Apolipoprotein E ε4), CN (cognitively normal elderly), MCI (mild cognitive impairment), MMSE (Mini-Mental State Examination), NPI-Q (Neuropsychiatric Inventory Questionnaire), RAVLT (Rey Auditory Verbal Learning Test).
Significance tests used: χ2 test (categorical variables), analysis of variance (continuous variables).
Additional post-hoc pairwise comparisons of diagnostic groups were carried out using Bonferroni corrected t-tests:
For education: df = 399, error mean square = 9.201 for all comparisons; for AMNART IQ: df = 398, error mean square = 127.76 for all comparisons; for MMSE: df = 399, error mean square = 2.767 for all comparisons; for RAVLT: df = 399, error mean square = 77.707 for all comparisons; for Digit Symbol: df = 399, error mean square = 124.773 for all comparisons; for NPI-Q apathy: df = 399, error mean square = 0.302 for all comparisons. The p values given in the table pertain to the overall main effect of group whereas the * and + symbols indicate the results of the pertinent Bonferroni corrected post hoc pairwise comparisons as follows:
p<0.05 for CN vs. AD and MCI vs. AD;
p<0.05 for CN vs. MCI and CN vs. AD;
p< 0.0001 for CN vs. MCI; CN vs. AD and MCI vs. AD;
p<0.0001 for CN vs. MCI and CN vs. AD;
p<0.05 for CN vs. MCI, CN vs. AD and MCI vs. AD,
p<0.001 for CN vs. MCI and CN vs. AD.