Table 1.
Description of study participants and potential confounders at baseline.
| Characteristics and confounders | All participants (N=1017) | Non–app users (n=470) | App usersa (n=547) | P valueb | |
| Age (years), mean (SD) | 51.1 (15.0) | 53.2 (14.6) | 49.3 (15.0) | <.001 | |
| Gender, n (%) | |||||
|
|
Male | 224 (22.0) | 115 (24.5) | 109 (19.9) | .07 |
|
|
Female | 790 (77.7) | 355 (75.5) | 435 (79.5) |
|
|
|
Prefer not to answer | 3 (0.3) | 0 (0) | 3 (0.5) |
|
| Race, n (%) | |||||
|
|
White | 788 (77.5) | 351 (74.7) | 437 (79.9) | .14 |
|
|
Black | 149 (14.7) | 82 (17.4) | 67 (12.2) |
|
|
|
Asian | 29 (2.9) | 13 (2.8) | 16 (2.9) |
|
|
|
Pacific Islander, American Indian, or others | 17 (1.7) | 10 (2.1) | 7 (1.3) |
|
|
|
Two or more races | 34 (3.3) | 14 (3.0) | 20 (3.7) |
|
| Site, n (%) | |||||
|
|
Site A | 51 (5.0) | 23 (4.9) | 28 (5.1) | .004 |
|
|
Site B | 282 (27.7) | 105 (22.3) | 177 (32.4) |
|
|
|
Site C | 200 (19.7) | 96 (20.4) | 104 (19.0) |
|
| Educational level, n (%) | |||||
|
|
High school or less | 63 (6.2) | 40 (8.5) | 23 (4.2) | <.001 |
|
|
Some college | 205 (20.2) | 109 (23.2) | 96 (17.6) |
|
|
|
College graduate | 749 (73.6) | 321 (68.3) | 428 (78.2) |
|
| Annual household income (US $), n (%) | |||||
|
|
<35,000 | 120 (11.8) | 70 (14.9) | 50 (9.1) | .02 |
|
|
35,000 to <50,000 | 109 (10.7) | 53 (11.3) | 56 (10.2) |
|
|
|
50,000 to <75,000 | 148 (14.6) | 66 (14.0) | 82 (15.0) |
|
|
|
≥75,000 | 550 (54.1) | 234 (49.8) | 316 (57.8) |
|
|
|
Don’t know/choose not to answer | 90 (8.8) | 47 (10.0) | 43 (7.9) |
|
| Any child <18 years old, n (%) | 248 (24.4) | 129 (27.4) | 119 (21.8) | .04 | |
| Height (cm), mean (SD) | 168.9 (50.2) | 170.6 (73.3) | 167.4 (8.5) | .31 | |
| Weight (kg), mean (SD) | 85.8 (23.8) | 86.8 (25.1) | 85.0 (22.5) | .23 | |
| BMIc, mean (SD) | 30.5 (7.9) | 30.8 (8.2) | 30.3 (7.6) | .29 | |
| BMI categories, n (%) | |||||
|
|
Underweight (<18.5) | 14 (1.4) | 7 (1.5) | 7 (1.3) | .75 |
|
|
Normal (18.5 to <25) | 250 (24.6) | 111 (23.6) | 139 (25.4) |
|
|
|
Overweight (25 to <30) | 288 (28.3) | 129 (27.4) | 159 (29.1) |
|
|
|
Obese (≥30) | 465 (45.7) | 223 (47.4) | 242 (44.2) |
|
| Fruit or vegetable cup equivalent, mean (SD) | 2.9 (1.5) | 2.8 (1.6) | 3.0 (1.4) | .18 | |
| Added sugars tsp equivalent from sugar-sweetened beverages, mean (SD) | 0.8 (1.3) | 1.0 (1.5) | 0.7 (1.2) | .004 | |
| Physical activity, n (%) | |||||
|
|
Low | 20 (5.1) | 11 (6.3) | 9 (4.1) | .53 |
|
|
Medium | 221 (55.8) | 94 (53.7) | 127 (57.5) |
|
|
|
High | 155 (39.1) | 70 (40.0) | 85 (38.5) |
|
| Sleep quality, n (%) | |||||
|
|
Very good | 188 (18.5) | 76 (16.2) | 112 (20.5) | .02 |
|
|
Fairly good | 496 (48.8) | 222 (47.2) | 274 (50.1) |
|
|
|
Fairly bad | 274 (26.9) | 136 (28.9) | 138 (25.2) |
|
|
|
Very bad | 59 (5.8) | 36 (7.7) | 23 (4.2) |
|
| Nap frequency, n (%) | |||||
|
|
<1 per week | 581 (57.1) | 267 (56.8) | 314 (57.4) | .03 |
|
|
1 per week | 165 (16.2) | 69 (14.7) | 96 (17.6) |
|
|
|
2-3 per week | 176 (17.3) | 79 (16.8) | 97 (17.7) |
|
|
|
4-6 per week | 57 (5.6) | 28 (6.0) | 29 (5.3) |
|
|
|
Daily | 38 (3.7) | 27 (5.7) | 11 (2.0) |
|
| Number of health apps used in past month, n (%) | |||||
|
|
0 | 212 (20.8) | 127 (27.0) | 85 (15.5) | <.001 |
|
|
1-5 | 705 (69.3) | 299 (63.6) | 406 (74.2) |
|
|
|
>5 | 100 (9.8) | 44 (9.4) | 56 (10.2) |
|
| App use reasons, n (%) | |||||
|
|
Track how much exercise I get | 665 (65.4) | 269 (57.2) | 396 (72.4) | <.001 |
|
|
Track what I eat/improve what I eat | 531 (52.2) | 212 (45.1) | 319 (58.3) | <.001 |
|
|
Weight loss | 476 (46.8) | 206 (43.8) | 270 (49.4) | .08 |
|
|
Track a health measure | 203 (20.0) | 86 (18.3) | 117 (21.4) | .22 |
|
|
Track how much sleep I get | 346 (34.0) | 132 (28.1) | 214 (39.1) | <.001 |
aApp user is defined as downloading the app and recording at least one entry on at least one day.
bThe P value for a group of variables is reported in the row of the first variable.
cBMI is calculated as weight in kilograms divided by height in meters squared.