Table 1.
Sociodemographic characteristics and proportion of short sleepers for each study
| Year of Study |
||||||||
|---|---|---|---|---|---|---|---|---|
| 1975 | 1985 | 1992-94 | 1998-99 | 2003 | 2004 | 2005 | 2006 | |
| n | 2,235 | 4,939 | 7,106 | 1,096 | 19,759 | 13,318 | 12,419 | 12,200 |
| Age (mean ± SD; years) | 43±18 | 50±24 | 43±16 | 45±17 | 45±17 | 46±17 | 46±17 | 46±17 |
| Sex (% female) | 56 | 51 | 54 | 52 | 52 | 52 | 52 | 52 |
| Race | ||||||||
| White (%) | 88.8 | n/a | 79.6 | 79.9 | 72.6 | 72.7 | 71.5 | 71.7 |
| African American (%) | 8.4 | n/a | 8.9 | 11.6 | 11.0 | 10.8 | 11.1 | 11.6 |
| Hispanic | 2.2 | n/a | 8.3 | 6.3 | 11.8 | 12.0 | 12.5 | 12.9 |
| Asian | 0.4 | n/a | 2.0 | 0.8 | 2.8 | 2.5 | 2.8 | 3.2 |
| Other (%) | 0.3 | n/a | 1.3 | 1.5 | 1.8 | 2.0 | 2.1 | 0.7 |
| Education | ||||||||
| ≤11th grade (%) | 31.7 | 17.7 | 10.4 | 16.2 | 13.8 | 12.6 | 13.0 | 12.5 |
| High school graduate (%) | 36.5 | 42.8 | 36.3 | 34.0 | 33.8 | 34.4 | 34.2 | 33.9 |
| Some college (%) | 17.6 | 17.2 | 25.1 | 27.2 | 26.5 | 25.9 | 26.1 | 26.7 |
| College graduate (%) | 14.2 | 22.2 | 28.2 | 22.6 | 25.9 | 27.2 | 26.6 | 27.0 |
| Employment | ||||||||
| Full-time (%) | 53.3 | 60.2 | 57.4 | 59.3 | 52.8 | 52.5 | 53.8 | 53.7 |
| Part-time (%) | 2.5 | 9.7 | 11.4 | 10.8 | 13.7 | 13.7 | 13.5 | 13.3 |
| Student (%) | 4.3 | 3.8 | 3.0 | 2.8 | 3.1 | 2.9 | 2.5 | 2.8 |
| Retired or homemaker (%) | 35.0 | 22.9 | 20.0 | 20.0 | 26.8 | 27.4 | 27.1 | 26.9 |
| Unemployed (%) | 5.0 | 3.3 | 8.2 | 7.1 | 3.7 | 3.5 | 3.1 | 3.4 |
| Marital status | ||||||||
| Married | 61.4 | 64.0 | n/a | 59.5 | 58.2 | 59.2 | 58.3 | 58.6 |
| Single | 15.7 | 20.0 | n/a | 20.6 | 24.3 | 23.7 | 24.0 | 24.1 |
| Divorced/Separated | 11.6 | 9.2 | n/a | 12.9 | 11.2 | 11.2 | 11.7 | 11.4 |
| Widowed | 11.4 | 6.9 | n/a | 7.1 | 6.3 | 5.9 | 6.0 | 5.9 |
| Short sleepers, <6 h (%) | 7.6 | 9.9 | 7.5 | 11.8 | 8.7 | 8.8 | 8.3 | 9.3 |
n/a – not available
Separate sample weights were used for each study.