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. 2024 Apr 22;10(9):e30009. doi: 10.1016/j.heliyon.2024.e30009

Table 3.

Longitudinal impact of sleep duration and bedtime on cognitive function (n = 1310).


Immediate word recall
Delayed word recall
Number series test

Model 1
Model 2
Model 1
Model 2
Model 1
Model 2
IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value
Duration <6h 0.900 (0.831,0.975) 0.010 0.966 (0.891,1.047) 0.397 0.840 (0.770,0.916) <0.001 0.926 (0.849,1.011) 0.087 0.890 (0.825,0.960) 0.003 1.022 (0.947,1.102) 0.583
Duration 6–7h reference
Duration 7–8h 0.972 (0.903,1.047) 0.454 0.958 (0.889,1.031) 0.252 0.927 (0.855,1.004) 0.061 0.902 (0.833,0.977) 0.012 0.952 (0.887,1.022) 0.175 0.959 (0.893,1.030) 0.246
Duration >8h 0.788 (0.723,0.859) <0.001 0.835 (0.765,0.911) <0.001 0.738 (0.671,0.811) <0.001 0.783 (0.712,0.861) <0.001 0.681 (0.624,0.742) <0.001 0.812 (0.744,0.886) <0.001
Lagged-Duration <6h 1.051 (0.925,1.200) 0.452 0.984 (0.865,1.126) 0.815 1.076 (0.935,1.246) 0.314 0.964 (0.836,1.118) 0.617 0.828 (0.740,0.929) 0.001 0.783 (0.698,0.880) <0.001
Lagged-Duration 6–7h reference
Lagged-Duration 7–8h 1.011 (0.864,1.184) 0.894 0.945 (0.808,1.108) 0.485 0.957 (0.804,1.142) 0.620 0.863 (0.724,1.030) 0.100 0.887 (0.772,1.022) 0.095 0.795 (0.691,0.916) 0.001
Lagged-Duration >8h 1.006 (0.847,1.195) 0.950 1.008 (0.849,1.199) 0.924 1.000 (0.827,1.210) 1.000 0.990 (0.818,1.199) 0.916 0.706 (0.598,0.832) <0.001 0.710 (0.601,0.837) <0.001
reference
Bedtime≤22:00 0.899 (0.823,0.983) 0.019 0.994 (0.909,1.088) 0.888 0.836 (0.761,0.921) <0.001 0.959 (0.872,1.057) 0.395 0.805 (0.741,0.875) <0.001 0.976 (0.898,1.062) 0.572
Bedtime>22:00 to 23:00 reference
Bedtime>23:00 to 1:00 0.988 (0.847,1.147) 0.871 0.900 (0.772,1.045) 0.170 1.009 (0.856,1.185) 0.913 0.893 (0.758,1.048) 0.171 1.091 (0.952,1.248) 0.205 0.866 (0.756,0.991) 0.037
Bedtime >1:00 1.267 (0.829,1.852) 0.247 1.020 (0.659,1.510) 0.926 1.258 (0.798,1.885) 0.294 0.927 (0.577,1.417) 0.740 1.748 (1.252,2.374) 0.001 1.080 (0.757,1.497) 0.659
Lagged-Bedtime≤22:00 0.858 (0.791,0.933) <0.001 0.941 (0.866,1.024) 0.154 0.892 (0.815,0.978) 0.014 0.999 (0.913,1.096) 0.989 0.791 (0.732,0.855) <0.001 0.976 (0.902,1.057) 0.544
Lagged-Bedtime>22:00 to 23:00 reference
Lagged-Bedtime>23:00 to 1:00 1.016 (0.869,1.184) 0.836 1.058 (0.905,1.232) 0.472 0.951 (0.797,1.127) 0.566 1.006 (0.845,1.192) 0.944 0.836 (0.720,0.967) 0.018 0.886 (0.764,1.025) 0.107
Lagged-Bedtime>1:00 0.984 (0.542,1.640) 0.954 1.199 (0.653,2.030) 0.528 1.206 (0.661,2.020) 0.509 1.567 (0.844,2.691) 0.126 0.915 (0.544,1.440) 0.718 1.156 (0.672,1.876) 0.577

Vocabulary test
Mathematic test

Model 1
Model 2
Model 1
Model 2
IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value IRR (95 % CI) p-value
Duration <6h 0.922 (0.903,0.941) <0.001 1.046 (1.025,1.068) <0.001 0.861 (0.835,0.889) <0.001 1.008 (0.977,1.041) 0.609
Duration 6–7h reference
Duration 7–8h 1.017 (0.997,1.038) 0.104 1.003 (0.983,1.024) 0.766 1.043 (1.012,1.076) 0.007 1.009 (0.978,1.041) 0.575
Duration >8h 0.814 (0.795,0.835) <0.001 0.921 (0.898,0.944) <0.001 0.853 (0.822,0.885) <0.001 0.967 (0.932,1.004) 0.079
Lagged-Duration <6h 0.886 (0.867,0.905) <0.001 0.927 (0.908,0.948) <0.001 0.903 (0.873,0.933) <0.001 0.929 (0.899,0.961) <0.001
Lagged-Duration 6–7h reference
Lagged-Duration 7–8h 0.939 (0.916,0.962) <0.001 0.969 (0.945,0.994) 0.013 0.980 (0.944,1.018) 0.305 1.003 (0.965,1.042) 0.881
Lagged-Duration >8h 0.812 (0.788,0.836) <0.001 0.899 (0.873,0.926) <0.001 0.860 (0.822,0.899) <0.001 0.940 (0.899,0.983) 0.007
reference
Bedtime≤22:00 0.823 (0.806,0.839) <0.001 0.974 (0.955,0.994) 0.011 0.789 (0.765,0.814) <0.001 0.975 (0.946,1.006) 0.108
Bedtime>22:00 to 23:00 reference
Bedtime>23:00 to 1:00 1.030 (0.998,1.063) 0.067 0.972 (0.941,1.003) 0.080 1.032 (0.983,1.083) 0.201 0.957 (0.911,1.004) 0.071
Bedtime >1:00 0.903 (0.814,0.998) 0.050 0.925 (0.833,1.023) 0.135 0.818 (0.691,0.960) 0.016 0.847 (0.716,0.995) 0.048
Lagged-Bedtime≤22:00 0.844 (0.827,0.861) <0.001 0.978 (0.958,0.998) 0.028 0.854 (0.828,0.881) <0.001 1.010 (0.980,1.042) 0.516
Lagged-Bedtime>22:00 to 23:00 reference
Lagged-Bedtime>23:00 to 1:00 0.961 (0.928,0.994) 0.023 0.993 (0.959,1.028) 0.689 0.979 (0.929,1.032) 0.427 1.017 (0.964,1.071) 0.540
Lagged-Bedtime>1:00 0.934 (0.852,1.021) 0.137 0.944 (0.861,1.032) 0.212 0.974 (0.847,1.113) 0.701 0.982 (0.854,1.122) 0.791

Note. Model 1: crude model, Model 2: adjusted age, gender, education level.