Table 2.
Prevalence of NSSI by sample characteristics
| Variables | N(%) | NSSI (%) | Non-NSSI (%) | χ2 | φ/V |
|---|---|---|---|---|---|
| Regional areas | 21.170** | 0.038** | |||
| YangJiang | 3539(24.1) | 1103(31.2) | 2436(68.8) | ||
| ShenYang | 3162(21.5) | 935(29.6) | 2227(70.4) | ||
| XinXiang | 3968(27.0) | 1060(26.7) | 2908(73.3) | ||
| ChongQing | 4007(27.3) | 1219(30.4) | 2788(69.6) | ||
| Sex | 35.341** | −0.049** | |||
| Male | 7017(47.8) | 2228(31.8) | 4789(68.2) | ||
| Female | 7659(52.2) | 2089(27.3) | 5570(72.7) | ||
| Grade | 22.538** | −0.039** | |||
| Junior middle school | 7377(50.3) | 2301(31.2) | 5076(68.8) | ||
| Senior middle school | 7299(49.7) | 2016(27.6) | 5283(72.4) | ||
| Urban/rurality | 0.001 | 0.000 | |||
| Rural | 7493(51.1) | 2205(29.4) | 5288(70.6) | ||
| Urban | 7183(48.9) | 2112(29.4) | 5071(70.6) | ||
| Only child | 6.727* | −0.021* | |||
| Yes | 6608(45.0) | 2015(30.5) | 4593(69.5) | ||
| No | 8068(55.0) | 2302(28.5) | 5766(71.5) | ||
| Father’s education level | 11.609* | 0.028* | |||
| Less than junior middle school | 2158(14.7) | 689(31.9) | 1469(68.1) | ||
| Junior middle school | 6239(42.5) | 1840(29.5) | 4399(70.5) | ||
| Senior middle school | 4256(29.0) | 1186(27.9) | 3070(72.1) | ||
| College or more | 2023(13.8) | 602(29.8) | 1421(70.2) | ||
| Mother’s education level | 15.825* | 0.033* | |||
| Less than junior middle school | 2686(18.3) | 867(32.3) | 1819(67.7) | ||
| Junior middle school | 6331(43.1) | 1854(29.3) | 4477(70.7) | ||
| Senior middle school | 4027(27.4) | 1119(27.8) | 2908(72.2) | ||
| College or more | 1632(11.1) | 477(29.2) | 1155(70.8) | ||
| Family economic status | 62.899** | 0.065** | |||
| Poor | 2020(13.8) | 741(36.7) | 1279(63.3) | ||
| General | 10,860(74.0) | 3036(28.0) | 7824(72.0) | ||
| Good | 1796(12.2) | 540(30.1) | 1256(69.9) | ||
| Sleep quality | 254.451** | 0.132** | |||
| Very Good | 2416(16.5) | 457(18.9) | 1959(81.8) | ||
| Good | 6426(43.8) | 1788(27.8) | 4638(72.7) | ||
| Poor | 4500(30.7) | 1544(34.3) | 2956(65.6) | ||
| Very poor | 1334(9.1) | 528(39.6) | 806(60.6) | ||
| Psychological symptoms | 906.125** | 0.248** | |||
| Yes | 4027(27.4) | 1926(47.8) | 2101(52.2) | ||
| No | 10,649(72.6) | 2391(22.5) | 8258(77.5) | ||
| Weekday video time (h) | 74.449** | 0.071** | |||
| 0 | 6331(43.1) | 1701(26.9) | 4630(73.1) | ||
| ≤ 0.5 | 3090(21.1) | 874(28.3) | 2216(71.7) | ||
| 0.5–1 | 2198(15.0) | 696(31.7) | 1502(68.3) | ||
| 1–2 | 1387(9.5) | 438(31.6) | 949(68.4) | ||
| 2–4 | 761(5.2) | 258(33.9) | 503(66.1) | ||
| 4–6 | 376(2.6) | 139(37.0) | 237(63.0) | ||
| >6 | 533(3.6) | 211(39.6) | 322(60.4) | ||
| Weekend video time (h) | 167.631** | 0.107** | |||
| 0 | 1737(11.8) | 362(20.8) | 1375(79.2) | ||
| ≤ 0.5 | 1818(12.4) | 475(26.1) | 1343(73.9) | ||
| 0.5–1 | 2276(15.5) | 618(27.2) | 1658(72.8) | ||
| 1–2 | 2601(17.7) | 727(28.0) | 1874(72.0) | ||
| 2–4 | 2484(16.9) | 784(31.6) | 1700(68.4) | ||
| 4–6 | 1692(11.5) | 574(33.9) | 1118(66.1) | ||
| >6 | 2068(14.1) | 777(37.6) | 1291(62.4) | ||
| Weekday video game time (h) | 32.089** | 0.047** | |||
| 0 | 8334(56.8) | 2347(28.2) | 5987(71.8) | ||
| ≤ 0.5 | 2770(18.9) | 817(29.5) | 1953(70.5) | ||
| 0.5–1 | 1486(10.1) | 457(30.8) | 1029(69.2) | ||
| 1–2 | 891(6.1) | 274(30.8) | 617(69.2) | ||
| 2–4 | 472(3.2) | 160(33.9) | 312(66.1) | ||
| 4–6 | 285(1.9) | 93(32.6) | 192(67.4) | ||
| >6 | 438(3.0) | 169(38.6) | 269(61.4) | ||
| Weekend video game time (h) | 123.035** | 0.092** | |||
| 0 | 2790(19.0) | 698(25.0) | 2092(75.0) | ||
| ≤ 0.5 | 2354(16.0) | 635(27.0) | 1719(73.0) | ||
| 0.5–1 | 2173(14.8) | 560(25.8) | 1613(74.2) | ||
| 1–2 | 2330(15.9) | 671(28.8) | 1659(71.2) | ||
| 2–4 | 1820(12.4) | 613(33.7) | 1207(66.3) | ||
| 4–6 | 1392(9.5) | 475(34.1) | 917(65.9) | ||
| >6 | 1817(12.4) | 665(36.6) | 1152(63.4) | ||
| Daily sleep duration (h) | 55.717** | 0.062** | |||
| < 6 | 712(4.9) | 284(39.9) | 428(60.1) | ||
| 6–7 | 3343(22.8) | 1036(31.0) | 2307(69.0) | ||
| 7–8 | 5771(39.3) | 1688(29.2) | 4083(70.8) | ||
| 8–9 | 3359(22.9) | 911(27.1) | 2448(72.9) | ||
| 9–10 | 1145(7.8) | 309(27.0) | 836(73.0) | ||
| ≥ 10 | 346(2.4) | 89(25.7) | 257(74.3) | ||
| Weekday sleep duration (h) | 43.605** | 0.055** | |||
| < 6 | 1125(7.7) | 413(36.7) | 712(63.3) | ||
| 6–7 | 4386(29.9) | 1305(29.8) | 3081(70.2) | ||
| 7–8 | 4546(31.0) | 1354(29.8) | 3192(70.2) | ||
| 8–9 | 3182(21.7) | 854(26.8) | 2328(73.2) | ||
| 9–10 | 1020(7.0) | 284(27.8) | 736(72.2) | ||
| ≥ 10 | 417(2.8) | 107(25.7) | 310(74.3) | ||
| Weekend sleep duration (h) | 49.429** | 0.058** | |||
| < 6 | 287(2.0) | 130(45.3) | 157(54.7) | ||
| 6–7 | 716(4.9) | 244(34.1) | 472(65.9) | ||
| 7–8 | 1376(9.4) | 431(31.3) | 945(68.7) | ||
| 8–9 | 3729(25.4) | 1054(28.3) | 2675(71.7) | ||
| 9–10 | 3020(20.6) | 860(28.5) | 2160(71.5) | ||
| ≥ 10 | 5548(37.8) | 1598(28.8) | 3950(71.2) | ||
| Weekend catch-up sleep (h) | 59.123** | 0.063** | |||
| < 0 | 966(6.6) | 365(37.8) | 601(62.2) | ||
| 0–1 | 1998(13.6) | 529(26.5) | 1469(73.5) | ||
| 1–2 | 3101(21.1) | 825(26.6) | 2276(73.4) | ||
| 2–3 | 4032(27.5) | 1174(29.1) | 2858(70.9) | ||
| ≥ 3 | 4579(31.2) | 1424(31.1) | 3155(68.9) | ||
| Total | 14,676(100.0) | 4317(29.4) | 10,359(70.6) |
* P < 0.05, ** P < 0.001; Statistical methods: Chi-square test, φ/V is effect sizes. NSSI is non-suicidal self-injury