. Author manuscript; available in PMC: 2016 Jan 31.

Published in final edited form as: Alcohol Clin Exp Res. 2015 Jan 16;39(2):355–362. doi: 10.1111/acer.12618

Table 3.

The prospective relationship between perceived tiredness and drugs-related problems

	Time 2
	Drug-related problems			Ever used illicit drugs

Variable	Wald χ²	Odds ratio	95% CI	Wald χ²	Odds ratio	95% CI

Gender	0.99	0.89	0.72–1.12	1.07	1.09	0.92–1.29
Age	0.90	0.93	0.80–1.08	0.78	0.95	0.84–1.07
Race-ethnicity	0.45	1.09	0.85–1.40	0.07	0.98	0.81–1.18
Education	3.69	1.18	1.00–1.40	0.83	1.06	0.93–1.21
Poverty status	1.22	0.83	0.60–1.16	0.17	0.95	0.76–1.20
Chronic health conditions	0.14	1.04	0.84–1.30	0.39	1.05	0.89–1.25
Drug-related problems (Time 1)^a	496.32	15.03^***	11.84–19.08	858.68	13.14^***	11.06–15.62
Trouble falling asleep (Time 1)^b	1.90	1.08	0.97–1.19	5.60	1.10^*	1.02–1.19
Hours of sleep	4.39	0.92^*	0.85–0.99	5.82	0.93^*	0.87–0.99

	Time 3
	Drug-related problems			Ever used illicit drugs

Variable	Wald χ²	Odds ratio	95% CI	Wald χ²	Odds ratio	95% CI

Gender	26.44	0.47^***	0.35–0.63	48.61	0.58^***	0.45–0.67
Age	3.72	0.82^*	0.67–1.00	17.53	0.79^***	0.71–0.88
Race-ethnicity	1.83	1.25	0.91–1.73	29.96	1.63^***	1.37–1.95
Education	0.44	0.93	0.74–1.16	1.70	1.08	0.96–1.22
Poverty status	0.39	0.86	0.55–1.36	2.57	0.82	0.65–1.05
Chronic health conditions	1.23	1.17	0.89–1.55	0.47	0.95	0.81–1.10
Drug-related problems (Time 2)^a	69.29	4.23^***	3.01–5.95	201.45	3.46^***	2.91–4.11
Trouble falling asleep (Time 2)^b	1.66	1.10	0.95–1.27	2.32	1.07	0.98–1.16
Hours of sleep	0.30	1.03	0.93–1.14	1.04	0.97	0.92–1.03

Note.

Drug-related problems or the experience of using illicit drugs in a previous wave were controlled for in the analyses.

Note.

Frequency of trouble falling asleep or staying asleep in the last twelve months.

p < .05,

^**

p <.01,

^***

p <.001.