Table 2 Basic characteristics of the study participants
Controls(n = 272) | Cases(n = 272) | χ 2 | P | |
|---|---|---|---|---|
Age (years, mean ± SD) | 31.70 ± 7.67 | 32.48 ± 7.58 | −1.192a | 0.234 |
Sex, n (%) | 0 | 1 | ||
Male | 241(88.6) | 241(88.6) | ||
Female | 31(11.4) | 31(11.4) | ||
Marriage status, n (%) | 0.427 | 0.808 | ||
Single | 69(25.4) | 64(23.5) | ||
Married | 201(73.9) | 205(75.4) | ||
Divorce | 2(0.7) | 3(1.1) | ||
Education, n (%) | 1.890 | 0.389 | ||
Primary school and below | 96(35.3) | 110(40.4) | ||
Junior middle school | 123(45.2) | 118(43.4) | ||
High school and above | 53(19.5) | 44(16.2) | ||
Income [yuan/month, n (%)] | 2.488 | 0.288 | ||
< 2500 | 104(38.2) | 118(43.4) | ||
2500- | 79(29.0) | 81(29.8) | ||
≧3500 | 89(32.7) | 73(26.8) | ||
Smoking, n (%) | 1.843 | 0.175 | ||
No | 187(68.8) | 172(63.2) | ||
Yes | 85(31.2) | 100(36.8) | ||
Music listening time (h/day) | 17.770 | <0.001 | ||
0 | 174(64.0) | 130(47.8) | ||
< 2 | 88(32.4) | 115(42.3) | ||
≧2 | 10(3.7) | 27(9.9) | ||
Telephone using time (min/day) | 27.224 | <0.001 | ||
0 | 51(18.8) | 20(7.7) | ||
< 16 | 142(52.2) | 120(44.1) | ||
≧16 | 79(29.0) | 131(48.2) | ||
Time go to sleep | 48.818 | <0.001 | ||
Early than 22:00 | 128(47.1) | 56(20.6) | ||
22:00~ | 77(28.3) | 86(31.6) | ||
Later than 23:00 | 67(24.6) | 130(47.8) | ||
Working time (h/week)b | 48.00(40.00–60.00) | 50.00(40.00–60.00) | −1.370c | 0.171 |
Noise exposure time (years)b | 5.13(3.02–8.96) | 5.04(3.00–8.50) | −0.046c | 0.963 |
Noise intensity exposure, dB(A)b | 83.20(80.00–87.40) | 83.65(80.00–87.40) | −0.744c | 0.457 |
CNEb | 90.86(85.48–95.49) | 91.13(86.59–96.15) | −0.665c | 0.506 |