Table 2.

Mean decline in 37-MMSE score during follow-up (points).

	Sleep duration (hours per day)
	≤5	6 to 8	≥9
All participants	0.5 [0.0] ± 4.0	0.2 [0.0] ± 3.8	0.6 [0.0] ± 4.3
Age Strata
Tertile 1 (≤ 69)	0.6 [0.0] ± 3.5 (67.1 ± 1.4)	−0.1 [0.0] ± 3.5 (67.1 ± 1.3)	0.5 [0.0] ± 4.3 (67.1 ± 1.4)
Tertile 2 (70-74)	0.4 [0.0] ± 3.7 (71.9 ± 1.4)	0.0 [0.0] ± 3.7 (71.8 ± 1.4)	0.5 [0.0] ± 3.8 (72.0 ± 1.3)
Tertile 3 (≥ 75)	0.6 [0.0] ± 4.6 (80.2 ± 4.0)	0.6 [0.0] ± 4.2 (79.9 ± 4.0)	0.9 [1.0] ± 4.7 (80.3 ± 4.3)
Depressive symptoms or antidepressant use strata
Yes	0.3 [0.0] ± 4.5	0.2 [0.0] ± 3.6	0.8 [0.0] ± 4.4
No	0.6 [0.0] ± 3.7	0.2 [0.0] ± 3.9	0.6 [0.0] ± 4.3
Medications with central nervous system effects strata
Yes	0.2 [0.0] ± 4.1	0.6 [0.0] ± 3.6	1.0 [0.5] ± 4.1
No	0.7 [0.0] ± 4.0	0.1 [0.0] ± 3.8	0.5 [0.0] ± 4.3
Geographical área
Las Margaritas	0.2 [0.0] ± 3.9	0.3 [0.0] ± 3.7	0.7 [0.0] ± 4.5
Lista	0.1 [0.0] ± 4.4	0.1 [0.0] ± 3.9	0.3 [0.0] ± 4.3
Arévalo	1.1 [1.0] ± 4.0	0.1 [0.0] ± 3.8	0.8 [1.0] ± 4.2

Mean [Median] ± standard deviation and frequency (%) are reported. Negative value indicates that the baseline 37-MMSE score was lower than the 37-MMSE score at follow-up (i.e., improvement in score). All positive values indicate a decline in score (i.e., baseline 37-MMSE ± follow-up 37-MMSE). In each age stratum, the numbers in parentheses indicate the mean ± standard deviation age of participants in that stratum; these values demonstrate that cases and controls had similar ages within the three age strata.