# Table 3 Descriptive statistics for sleep outcome measures according to study sample

Overall
n = 512
N = 13,503,522
Plasma fluoride sample
n = 473
N = 12,531,822
Water fluoride sample
n = 419
N = 11,577,700
Sleep durationa; N (%)
Less than recommended3,912,903 (29.08)3,616,486 (28.97)3,519,194 (30.52)
Recommended7,763,278 (57.70)7,181,883 (57.53)6,549,336 (56.80)
More than recommended1,779,421 (13.22)1,685,533 (13.50)1461, 250 (12.67)
Sleep apnea symptoms; N(%)b
Never11,968,414 (89.81)11,010,121 (89.11)10,217,865 (89.51)
At least 1 night per week1,358,534 (10.19)1,345,127 (10.89)1,196,827 (10.49)
Snoring; N(%)c
Never7,564,062 (58.07)6,919,753 (57.40)6,602,728 (59.35)
At least 1 night per week5,462,602 (41.93)5,135,211 (42.60)4,521,444 (40.65)
Trouble sleeping; N(%)
Yes1,874,575 (13.88)1,764,264 (14.08)1,629,889 (14.08)
No11,628,947 (86.12)10,767,558 (85.92)9,947,810 (85.92)
Daytime sleepiness
Never1,307,017 (9.68)1,185,750 (9.46)1,120,797 (9.68)
Rarely – 1 time a month2,789,385 (20.66)2,532,161 (20.21)2,321,968 (20.06)
Sometimes – 2-4 times a month4,255,661 (31.52)4,047,114 (32.29)3,638,287 (31.43)
Often – 5-15 times a month4,104,292 (30.39)3,912,334 (31.22)3,596,810 (31.07)
Almost always – 16-30 times a month1,047,168 (7.75)854,464 (6.82)899,838 (7.77)
Wake time; Mean (SE)a7.15 (0.09)7.17 (0.10)7.15 (0.09)
Bedtime; Mean (SE)a4.00 (0.10)d4.02 (0.11)4.02 (0.11)
1. Note. a There was one missing participant for this outcome; b Overall sample n = 505, plasma fluoride sample n = 466, and water fluoride sample n = 413 due to missing data on this variable. c Overall sample n = 493, plasma fluoride sample n = 454, and water fluoride sample n = 402 due to missing data on this variable
2. dBedtime was rescaled such that the earliest bedtime (i.e. 7 pm) = 0 and the latest bedtime (i.e. 7 am) = 12; bedtime of 11 pm = 4; wake time was not rescaled and therefore the numeric time is presented. For example, 7.15 is equal to 7:09 am (i.e. the 7th hour and 0.15 of 60 min). Sampling weights were applied for calculation of all descriptive statistics. For water fluoride, mean (SE) and percentages remained the same following reweighting of sampling weights; therefore, frequencies of the sample prior to re-weighting are reported