Table 5.

Independent correlates of PMPU.

Variable	β	95% CI (Lower)	95% CI (Upper)	P
Monthly allowances (RMB)
1,000–1,499	3.52	1.39	5.66	0.001
1,500–1,999	3.24	1.02	5.46	0.004
2,000–2,499	5.85	3.38	8.31	<0.001
2,500–2,999	5.00	1.98	8.03	0.006
≥3,000	5.02	1.45	8.59	0.002
Insomnia
Seldom ( ≤ 3 times/month)	5.00	3.47	6.54	<0.001
Sometimes (1–2 times/week)	7.47	5.67	9.27	<0.001
Often (3–5 times/week)	10.28	7.68	12.87	<0.001
Daily	14.01	9.61	18.42	<0.001
Phone use duration	0.28	0.12	0.43	<0.001

Bold value for p < 0.05.