Table 1.

Distribution of Sleep Disturbance Groups as a Function of Geographic Origin, Background Characteristics, Cognitive Functioning, and Wave 4 Outcomes

	No sleep disturbances n [%]	Sleep disturbances at W1 only n [%]	Sleep disturbances at W2 only n [%]	Chronic sleep disturbances n [%]
Geographical region
Not Mediterranean	3773 [77.7]	828 [74.3]	872 [76.2]	1309 [75.9]
Mediterranean	1080 [22.3]	286 [25.7]	273 [23.8]	415 [24.1]
Age
50–59	1833 [37.8]	439 [39.4]	454 [39.7]	645 [37.4]
61–69	1743 [35.9]	397 [35.6]	379 [33.1]	591 [34.3]
70+	1277 [26.3]	278 [25.0]	312 [27.2]	488 [28.3]
Gender
Men	2578 [53.1]	421 [37.8]	445 [38.9]	483 [28.0]
Women	2275 [46.9]	693 [62.2]	700 [61.1]	1241 [72.0]
Education
Primary or below	1420 [29.4]	390 [35.4]	378 [33.3]	640 [37.5]
Lower to upper secondary	2222 [46.1]	445 [40.3]	515 [45.4]	754 [44.2]
Post-secondary or above	1181 [24.5]	268 [24.3]	242 [21.3]	313 [18.3]
Marital status
Not married	1122 [23.3]	305 [27.8]	299 [26.4]	547 [32.0]
Married	3692 [76.7]	792 [72.2]	832 [73.6]	1162 [68.0]
Household income
Low tertile	1468 [30.3]	377 [33.8]	429 [37.5]	634 [36.8]
Middle tertile	1639 [33.8]	360 [32.3]	351 [30.7]	565 [32.8]
High tertile	1744 [36.0]	377 [33.8]	365 [31.9]	524 [30.4]
Work status
Working	2417 [49.8]	500 [44.9]	552 [48.2]	792 [45.9]
Not working	2436 [50.2]	614 [55.1]	593 [51.8]	932 [54.1]
Cognitive functioning
Low tertile	1443 [29.8]	397 [35.7]	382 [33.4]	673 [39.1]
Middle tertile	1648 [34.0]	350 [31.5]	377 [33.0]	542 [31.5]
High tertile	1753 [36.2]	365 [32.8]	385 [33.7]	508 [29.5]
Physical symptoms W4
No symptoms	1552 [33.2]	254 [24.1]	272 [24.9]	281 [17.0]
One or more symptoms	3116 [66.8]	802 [75.9]	819 [75.1]	1376 [83.0]
ADL W4
No difficulties	4354 [89.7]	968 [86.9]	980 [85.6]	1381 [80.1]
One or more difficulties	499 [10.3]	146 [13.1]	165 [14.4]	343 [19.9]
Quality of life W4
At or above median	2420 [51.2]	442 [40.8]	433 [39.1]	507 [30.4]
Below median	2305 [48.8]	642 [59.2]	674 [60.9]	1159 [69.6]

Note. Percentages refer to the ratio of variable categories within each of the sleep disturbance groups. χ²(3) = 7.24, p =.07, for geographical region; χ²(6) = 7.52, p = .27, for age; χ²(3) = 370.84, p < .0001, Cramer’s V = .21, for gender; χ²(6) = 59.90, p < .0001, Cramer’s V = .06, for education level; χ²(3) = 52.19, p < .0001, Cramer’s V = .08, for marital status; χ²(6) = 42.19, p < .0001, Cramer’s V = .05, for household income; χ²(3) = 13.44, p < .01, Cramer’s V = .04, for work status; χ²(6) = 58.03, p < .0001, Cramer’s V = .06, for cognitive functioning; χ²(3) = 177.73, p < .0001, Cramer’s V = .15, for physical symptoms W4; χ²(3) = 105.84, p < .0001, Cramer’s V = .11, for ADL W4; χ²(3) = 238.98, p < .0001, Cramer’s V = .17, for quality of life W4.