Table 1.
Baseline characteristics of the participants by sleep duration category by sex
| Sleep Duration (Hours) |
|||||||
|---|---|---|---|---|---|---|---|
| < 5 | 5 to < 6 | 6 to < 7 | 7 to < 8 | 8 to < 9 | ≥ 9 | P value | |
| Men | |||||||
| n | 811 | 4716 | 15262 | 8677 | 1576 | 164 | |
| Age, years | 39.4 (8.9) | 39 (8.7) | 39.6 (9.5) | 40.6 (10.1) | 42.3 (10.4) | 42 (11.2) | < 0.001 |
| Body mass index (BMI), kg/m2 | 24.4 (3.7) | 24.1 (3.4) | 23.8 (3.3) | 23.6 (3.2) | 23.6 (3.1) | 23.5 (3.5) | < 0.001 |
| BMI gain†, kg/m2 | |||||||
| Median | 0.07 | 0.05 | 0.03 | 0.00 | −0.04 | 0.07 | |
| Interquartile Range | |||||||
| 1st Quartile | −7.42, −0.45 | −6.52, −0.44 | −7.76, −0.44 | −6.41, −0.44 | −7.97, −0.50 | −1.80, −0.23 | |
| 2nd Quartile | −0.44, 0.07 | −0.44, 0.05 | −0.44, 0.03 | −0.44, 0.00 | −0.49, −0.04 | −0.23, 0.07 | |
| 3rd Quartile | 0.07, 0.58 | 0.05, 0.54 | 0.03, 0.47 | 0.00, 0.45 | −0.04, 0.42 | 0.07, 0.56 | |
| 4th Quartile | 0.59, 8.04 | 0.54, 5.51 | 0.47, 6.90 | 0.45, 5.37 | 0.43, 3.08 | 0.57, 6.58 | |
| Obesity‡, n (%) | 355 (43.8) | 1873 (39.7) | 5478 (35.9) | 2889 (33.3) | 533 (33.8) | 55 (33.5) | < 0.001 |
| Smokers, n (%) | 346 (42.7) | 1837 (39) | 6107 (40) | 3938 (45.4) | 799 (50.7) | 92 (56.1) | < 0.001 |
| Alcohol consumption, ethanol g/week | 89.5 (122.4) | 95.6 (121.4) | 106 (122.2) | 123.9 (133.7) | 143.8 (146) | 145.3 (152) | < 0.001 |
| Walking hours a week, hours/week | 12.3 (10.1) | 11.5 (9.6) | 12.1 (10) | 11.8 (9.9) | 12.1 (10.8) | 12.7 (13.8) | 0.01 |
| Shift workers, n (%) | 66 (8.1) | 314 (6.7) | 1270 (8.3) | 966 (11.1) | 240 (15.2) | 35 (21.3) | < 0.001 |
| Depressive symptoms, n (%) | 54 (6.7) | 180 (3.8) | 344 (2.3) | 202 (2.3) | 43 (2.7) | 8 (4.9) | < 0.001 |
| Women | |||||||
| n | 131 | 760 | 1764 | 831 | 145 | 15 | |
| Age, years | 41.5 (8.9) | 39.7 (8.9) | 38.3 (9.5) | 35.8 (8.9) | 35.4 (8.3) | 36.3 (10.3) | < 0.001 |
| Body mass index (BMI), kg/m2 | 21.9 (3.6) | 21.2 (3.5) | 21.1 (3.2) | 20.7 (3.1) | 20.8 (2.8) | 21.7 (5.7) | < 0.001 |
| BMI gain, kg/m2 | |||||||
| Median | 0.10 | 0.08 | 0.08 | 0.12 | 0.16 | 0.08 | |
| Interquartile Range | |||||||
| 1st Quartile | −2.51, −0.33 | −4.99, -0.34 | −5.47, −0.31 | −5.15, −0.32 | −3.19, −0.28 | −0.67, −0.53 | |
| 2nd Quartile | −0.32, 0.10 | −0.33, 0.08 | −0.31, 0.08 | −0.32, 0.12 | −0.28, 0.14 | −0.49, −0.14 | |
| 3rd Quartile | 0.10, 0.53 | 0.08, 0.47 | 0.08, 0.47 | 0.12, 0.53 | 0.16, 0.53 | 0.08, 0.63 | |
| 4th Quartile | 0.54, 2.98 | 0.47, 3.79 | 0.47, 4.04 | 0.53, 4.62 | 0.55, 3.35 | 1.02, 2.43 | |
| Obesity, n (%) | 27 (20.6) | 105 (13.8) | 221 (12.5) | 88 (10.6) | 13 (9) | 3 (20) | 0.01 |
| Smokers, n (%) | 9 (6.9) | 50 (6.6) | 127 (7.2) | 73 (8.8) | 10 (6.9) | 1 (6.7) | 0.65 |
| Alcohol consumption, ethanol g/week | 41.6 (89.4) | 32.4 (68.1) | 29.8 (61.3) | 28.9 (59) | 27.3 (53.7) | 84.7 (170.9) | < 0.01 |
| Walking hours a week, hours/week | 12.8 (12.5) | 13.6 (13.2) | 12 (11.3) | 11.4 (11.6) | 11.7 (13.8) | 7.9 (5.9) | < 0.01 |
| Shift workers, n (%) | 5 (3.8) | 37 (4.9) | 73 (4.1) | 30 (3.6) | 7 (4.8) | 1 (6.7) | 0.85 |
| Depressive symptoms, n (%) | 10 (7.6) | 48 (6.3) | 62 (3.5) | 38 (4.6) | 1 (0.7) | 1 (6.7) | < 0.01 |
*
Data are expressed as the mean (standard deviation) or as the number (percentages).
†
BMI gain: difference from BMI followed for a year to BMI at baseline.
‡
“Obesity” defined as a body mass index ≥ 25 kg/m2.