TABLE 1.
Description of full sample and by insomnia symptom frequency
| Full sample | Sleep disturbances | |||
|---|---|---|---|---|
| Never/rarely | Sometimes | Usually | ||
| N | 487,728 | 118,217 (24.2%) | 233,177 (47.8%) | 136,334 (28.0%) |
| Age (years) a | 56.5 (8.1) | 55.2 (8.4) | 56.6 (8.1) | 57.5 (7.7) |
| Female a | 54.4% | 42.5% | 56.3% | 61.7% |
| White ethnicity a | 94.4% | 93.6% | 94.2% | 95.5% |
| Smoking status a | ||||
| Never | 54.6% | 57.1% | 55.4% | 51.1% |
| Previous | 34.6% | 32.3% | 34.1% | 37.3% |
| Current | 10.5% | 10.3% | 10.1% | 11.3% |
| Depression a | 5.6% | 3.3% | 5.2% | 8.2% |
| Diabetes a | 5.0% | 4.4% | 4.6% | 6.3% |
| BMI (kg/m2) a | 27.4 (4.8) | 27.2 (4.5) | 27.3 (4.7) | 27.9 (5.1) |
| Sleep duration (h) a | 7.2 (1.1) | 7.4 (1.0) | 7.3 (1.0) | 6.7 (1.3) |
Mean (standard deviation) for continuous variables; % for categorical.
Abbreviation: BMI, body mass index.
a
p < 0.01 comparing insomnia symptom groups based on ANOVA (continuous variables) or chi squared (categorical variables).