TABLE 1.
Baseline characteristics of participants aged 60+ years in the VITAL cognitive substudy by N‐3 supplement assignment for VITAL‐Cog (n = 3424) and CTSC‐Cog (n = 794)*
| VITAL‐Cog (n = 3424) | CTSC‐Cog (n = 794) | |||
|---|---|---|---|---|
| N‐3 group (n = 1699) | Placebo group (n = 1725) | N‐3 group (n = 396) | Placebo group (n = 398) | |
| mean (SD) | ||||
|
Age at first interview, years * (n = 2984 in VITAL‐Cog; n = 776 in CTSC‐Cog) |
71.9 (5.6) (n = 1498) |
71.8 (5.3) (n = 1486) |
67.1 (5.3) (n = 385) |
67.1 (5.3) (n = 391) |
|
Age at second interview, years * (n = 2923 in VITAL‐Cog; n = 515 in CTSC‐Cog) |
73.4 (5.7) (n = 1440) |
73.3 (5.7) (n = 1483) |
69.4 (5.4) (n = 251) |
69.7 (5.3) (n = 264) |
| Cognitive test scores at first interview | ||||
| VITAL‐Cog only tests | ||||
| TICS | 33.9 (2.8) | 33.9 (2.8) | – | – |
| OTMT‐Part A, seconds | 10.4 (3.5) | 10.5 (3.8) | – | – |
| OTMT‐Part B, seconds | 38.5 (24.7) | 37.4 (23.5) | – | – |
| Digit span backward | 6.8 (2.3) | 6.8 (2.4) | – | – |
| CTSC‐Cog only tests | ||||
| 3MS | – | – | 94.5 (4.8) | 95.2 (4.4) |
| TMT‐Part A, seconds | – | – | 29.9 (10.6) | 29.2 (10.4) |
| TMT‐Part B, seconds | – | – | 82.1 (44.8) | 80.5 (42.3) |
| Vegetable naming test | – | – | 15.4 (4.5) | 15.6 (4.5) |
| Common tests across VITAL‐Cog and CTSC‐Cog | ||||
| TICS 10‐word list recall‐immediate | 4.7 (1.7) | 4.7 (1.7) | 4.7 (1.4) | 4.8 (1.3) |
| TICS 10‐word list recall‐delayed | 2.7 (1.9) | 2.8 (1.9) | 1.9 (1.7) | 2.0 (1.8) |
| EBMT‐immediate | 9.6 (1.7) | 9.6 (1.7) | 9.7 (1.7) | 9.8 (1.6) |
| EBMT‐delayed | 9.3 (1.8) | 9.2 (1.8) | 9.3 (1.9) | 9.4 (1.6) |
| Animal naming test | 19.5 (5.6) | 19.6 (5.6) | 20.9 (5.8) | 20.5 (6.2) |
| Global composite score | –0.003 (0.6) | 0.003 (0.6) | –0.03 (0.6) | 0.03 (0.6) |
| Baseline omega‐3 (EPA+DHA) Index (%) † | 2.7 (0.9) | 2.7 (0.9) | 3.0 (0.9) | 3.0 (1.0) |
| Body mass index (kg/m2) | 27.4 (5.4) | 27.5 (5.3) | 28.5 (5.5) | 27.7 (5.1) |
| n (%) | ||||
| Vitamin D3 assignment | ||||
| Active group | 844 (49.7) | 866 (50.2) | 198 (50.0) | 198 (49.8) |
| Placebo group | 855 (50.3) | 859 (49.8) | 198 (50.0) | 200 (50.3) |
| Sex | ||||
| Female | 987 (58.1) | 1029 (59.7) | 202 (51.0) | 198 (49.8) |
| Male | 712 (41.9) | 696 (40.4) | 194 (49.0) | 200 (50.3) |
| Self‐reported race/ethnicity | ||||
| Non‐Hispanic White | 1219 (73.4) | 1210 (71.8) | 338 (88.0) | 348 (89.2) |
| Black | 359 (21.6) | 384 (22.8) | 21 (5.5) | 23 (5.9) |
| Other | 83 (5.0) | 92 (5.5) | 25 (6.5) | 19 (4.9) |
| Highest attained education | ||||
| High school or under | 187 (11.0) | 185 (10.7) | 31 (7.8) | 32 (8.1) |
| College | 648 (38.2) | 694 (40.3) | 147 (37.1) | 143 (36.0) |
| Graduate school | 860 (50.7) | 843 (49.0) | 218 (55.1) | 222 (55.9) |
| Depression ‡ | ||||
| No | 1365 (82.7) | 1381 (82.9) | 313 (80.3) | 320 (83.3) |
| Yes | 286 (17.3) | 284 (17.1) | 77 (19.7) | 64 (16.7) |
Abbreviations: 3MS, Modified Mini‐Mental State Examination (range = 0–100); 25 CTSC, Clinical and Translational Science Center for VITAL in Boston, MA; DHA, docosahexaenoic acid; EBMT, East Boston Memory Test (range = 0–12); 20 EPA, eicosapentaenoic acid; OTMT, Oral Trail Making Test (range = 0–120 seconds) 23 , 24 ; SD, standard deviation; TICS, Telephone Interview for Cognitive Status (range = 0–41); 19 TMT, Trail Making Test (range= 0–150 seconds for part A and range = 0–300 seconds for part B); 26 , 27 VITAL, Vitamin D and Omega‐3 Trial.
Characteristics as of randomization unless noted otherwise; for categorical variables, the percentages do not add to 100% due to rounding errors and numbers do not add to the total due to missing values, which were taken out of descriptive statistical analyses. In the VITAL‐Cog, 501 completed only the baseline, 440 completed only the second assessment and 2483 completed both assessments. In the CTSC‐Cog, 498 completed both assessments, 279 completed only the baseline and 17 completed only the second assessment.
The plasma Omega‐3 Index is a measure of the amount of EPA and DHA relative to other fatty acids in the plasma.
Depression is defined as a lifetime history of a depression diagnosis or of treatment for depression; current use of antidepressants; experiencing 2 or more weeks of depression in the past 2 years; or scoring 10 points or higher on the Patient Health Questionnaire‐8.