Table 3.

Age- and Sex-Adjusted Odds Ratios for Short Sleep Duration (<6 Hours) Versus Normal Sleep Duration (6–8 Hours) According to Selected Correlates, Whitehall II Study (London, United Kingdom; 1997–1999) and Western New York Health Study (Buffalo, New York; 1996–2001)

Variable	Whitehall II Study (486/6,379)a						Western New York Health Study (414/2,854)
	No. of Cases	No. of Subjects	OR	95% CI	P for Trendb	P for Interaction With Sexc	No. of Cases	No. of Subjects	OR	95% CI	P for Trend	P for Interaction With Sex
Aged, years
Men
≤50	67	991	1.00				88	451	1.00
51–60	163	2,321	1.04	0.78, 1.40			34	276	0.58	0.38, 0.89
>60	66	1,278	0.75	0.53, 1.07	0.09		69	509	0.65	0.46, 0.91	0.01
Women
≤50	30	338	1.00				73	619	1.00
51–60	101	845	1.39	0.91, 2.14			66	429	1.36	0.95, 1.95
>60	59	606	1.11	0.70, 1.76	0.95		84	570	1.29	0.92, 1.81	0.13
Marital status
Married	305	4,841	1.00				285	2,170	1.00
Unmarried	160	1,312	1.84	1.49, 2.27	<0.001	0.43	129	679	1.58	1.25, 2.01	<0.001	0.84
Socioeconomic status
Highest	150	2,906	1.00				62	613	1.00
Medium	240	2,718	1.67	1.35, 2.07			182	1,284	1.56	1.14, 2.12
Lowest	92	717	2.35	1.73, 3.18	<0.001	0.56	147	799	2.52	1.74, 3.63	<0.001	0.17
Body mass indexe
<25	135	2,118	1.00				108	894	1.00
25–29.9	157	2,157	1.21	0.96, 1.54			152	1,070	1.12	0.85, 1.46
≥30	88	682	2.12	1.59, 2.82	<0.001	0.40	144	809	1.57	1.19, 2.06	0.001	0.15
Tertile of waist circumference
1 (lowest)	109	1,487	1.00				102	936	1.00
2	93	1,496	1.16	0.84, 1.60			146	971	1.41	1.04, 1.90
3 (highest)	143	1,479	1.85	1.36, 2.52	<0.001	0.69	153	868	1.79	1.31, 2.45	<0.001	0.08
Smoking status
Non-current smoker	417	5,678	1.00				328	2,420	1.00
Current smoker	64	680	1.22	0.93, 1.61	0.16	0.24	86	431	1.57	1.20, 2.04	0.001	0.15
Alcohol drinking status
Non-current drinker	100	878	1.00				162	892	1.00
Current drinker	380	5,440	0.65	0.51, 0.82	<0.001	0.16	247	1,936	0.63	0.51, 0.79	<0.001	0.11
Physical activity
High	159	2,826	1.00				169	1,397	1.00
Low	327	3,553	1.61	1.32, 1.96	<0.001	0.11	245	1,457	0.69	0.56, 0.86	0.001	0.27
Median Short Form-36 score
Physical
High	186	3,105	1.00				150	1,389	1.00
Low	276	3,090	1.51	1.24, 1.84	<0.001	0.70	241	1,335	1.92	1.53, 2.40	<0.001	0.11
Mental
High	146	3,092	1.00				149	1,357	1.00
Low	316	3,103	2.22	1.80, 2.73	<0.001	0.40	242	1,367	1.79	1.43, 2.24	<0.001	0.28
Depressive symptoms
No	343	5,509	1.00				304	2,332	1.00
Yes	134	777	3.08	2.47, 3.82	<0.001	0.85	65	233	2.72	1.98, 3.73	<0.001	0.80
Hypertension
No	279	4,105	1.00				267	1,967	1.00
Yes	152	1,695	1.44	1.17, 1.78	0.001	0.13	147	887	1.30	1.03, 1.64	0.02	<0.001f
Diabetes mellitus
No	396	5,506	1.00				365	2,495	1.00
Yes	24	141	2.85	1.81, 4.48	<0.001	0.48	30	216	0.95	0.63, 1.42	0.79	0.83

Abbreviations: CI, confidence interval; OR, odds ratio.

^aNumber of short sleepers/number of short sleepers plus number of normal sleepers.

^bP value for linear trend for nondichotomous variables.

^cP value for interaction between sex and the specific correlate.

^dOdds ratios for age are presented for men and women separately because of significant sex × age interactions.

^eWeight (kg)/height (m)².

^fThere was a significant sex × hypertension interaction in the Western New York Health Study; age-adjusted odds ratios for men and women were 0.90 (95% CI: 0.63, 1.27) and 1.80 (95% CI: 1.32, 2.47), respectively.