Table 3.
Univariate associations of smartphone use and smartphone addiction. Values are represented in numbers unless stated otherwise
| Total sample (n = 1,519) | Smartphone addiction according to the SAS-SV | Smartphone Addiction No vs. Yes | |||
| No (n = 1,263) | Yes (n = 256) | OR (95% CI) | p | ||
| Duration of smartphone use on a typical daya | |||||
| Less than 10 minutes | 25 (1.6%) | ||||
| 11–60 minutes | 218 (14.4%) | 235 (18.6%) | 8 (3.1%) | Ref. | |
| 1–2 hours | 501 (33.0%) | 459 (36.3%) | 42 (16.4%) | 2.69 (1.23–5.89) | .01 |
| 3–4 hours | 472 (31.1%) | 375 (29.7%) | 97 (37.9%) | 7.60 (3.76–15.34) | <.01 |
| 5–6 hours | 178 (11.7%) | 116 (9.2%) | 62 (24.2%) | 15.70 (7.26–33.94) | <.01 |
| More than 6 hours | 125 (8.2%) | 78 (6.2%) | 47 (18.4%) | 17.70 (8.01–39.11) | <.01 |
| Frequency of smartphone use on a typical dayb, Md (Q1; Q3) | 25 (10; 50) | 20 (10; 50) | 40 (20; 100) | ||
| Less than 5 times/day | 204 (13.5%) | 182 (14.4%) | 22 (8.7%) | Ref. | |
| 6–10 times/day | 226 (14.9%) | 196 (15.6%) | 30 (11.8%) | 1.27 (0.75–2.15) | .38 |
| 11–20 times/day | 310 (20.5%) | 275 (21.8%) | 35 (13.8%) | 1.05 (0.55–2.01) | .88 |
| 21–50 times/day | 434 (28.7%) | 359 (28.5) | 75 (29.5%) | 1.73 (1.05–2.85) | .03 |
| 51–100 times/day | 227 (15.0%) | 168 (13.3%) | 59 (23.2%) | 2.91 (1.74–4.86) | <.01 |
| More than 100 times/day | 113 (7.5%) | 80 (6.3%) | 33 (13.0%) | 3.41 (1.83–6.37) | <.01 |
| Time until first smartphone use in the morning | |||||
| Within 5 minutes | 600 (39.5%) | 434 (34.4%) | 166 (64.8%) | Ref. | |
| Within 6–30 minutes | 558 (36.7%) | 491 (38.9%) | 67 (26.2%) | 0.36 (0.26–0.49) | <.01 |
| Within 31–60 minutes | 249 (16.4%) | 233 (18.4%) | 16 (6.3%) | 0.18 (0.10–0.32) | <.01 |
| After more than 60 minutes | 112 (7.4%) | 105 (8.3%) | 7 (2.7%) | 0.17 (0.07–0.41) | <.01 |
| Most personally relevant smartphone function | |||||
| Social networking | 1022 (67.3%) | 814 (64.4%) | 208 (81.3%) | Ref. | |
| Phone calls | 97 (6.4%) | 92 (7.3%) | 5 (2.0%) | 0.21 (0.08–0.53) | <.01 |
| Gaming | 10 (0.7%) | 8 (0.6%) | 2 (0.8%) | 0.98 (0.23–4.08) | .98 |
| Text messaging | 47 (3.1%) | 41 (3.2%) | 6 (2.3%) | 0.57 (0.25–1.29) | .18 |
| E-mailing | 7 (0.5%) | 5 (0.4%) | 2 (0.8%) | 1.56 (0.29–8.31) | .60 |
| Watching videos | 27 (1.8%) | 22 (1.7%) | 5 (2.0%) | 0.89 (0.39–2.03) | .78 |
| Listening to music | 271 (17.8%) | 247 (19.6%) | 24 (9.4%) | 0.38 (0.24–0.61) | <.01 |
| Reading news | 20 (1.3%) | 18 (1.4%) | 2 (0.8%) | 0.43 (0.11–1.76) | .24 |
| Other | 18 (1.2%) | 16 (1.3%) | 2 (0.8%) | 0.49 (0.11–2.24) | .35 |
Notes: Separate binary logistic regression model for each variable. SAS-SV = short version of the Smartphone Addiction Scale for Adolescents. aThe categories ‘less than 10 minutes’ and ‘11–60 minutes’ were collapsed for comparing persons with and without smartphone addiction to avoid small cell counts. bn = 5 missing due to implausible values.