Table 1 Baseline characteristics of the participants by frequency of daytime napping
Characteristics | Overall (n = 53 916) | Daytime napping | P | ||
|---|---|---|---|---|---|
Habitual (n = 2757) | Only in summer (n = 17,648) | Non-napping (n = 33,511) |  | ||
Mean age (years) | 52.0 ± 9.9 | 53.1 ± 10.8 | 52.9 ± 9.8 | 51.3 ± 9.7 | < 0.0001 |
Females (%) | 58.1 | 43.1 | 51.0 | 63.2 | < 0.0001 |
High school or above (%) | 3.9 | 6.7 | 4.5 | 3.4 | < 0.0001 |
Married (%) | 93.1 | 93.1 | 93.5 | 92.8 | 0.0008 |
Household income ≥ 35,000 (yuan) (%) | 37.8 | 40.9 | 38.7 | 37.0 | < 0.0001 |
Current smokers (%) | 28.0 | 26.7 | 27.6 | 28.5 | < 0.0001 |
Current drinkers (%) | 17.1 | 17.9 | 17.7 | 16.7 | 0.0011 |
Physical activities (MET-h/d) | 30.6 ± 15.3 | 26.4 ± 16.3 | 29.3 ± 14.9 | 31.6 ± 15.1 | < 0.0001 |
Consuming meat daily (%) | 15.2 | 26.9 | 16.1 | 13.8 | < 0.0001 |
Consuming fruit daily (%) | 6.7 | 16.7 | 7.8 | 5.5 | < 0.0001 |
Consuming vegetable daily (%) | 93.8 | 93.7 | 92.9 | 94.3 | < 0.0001 |
BMI (kg/m2) | 22.9 ± 3.1 | 23.2 ± 3.3 | 23.0 ± 3.1 | 22.8 ± 3.1 | < 0.0001 |
WC (cm) | 76.5 ± 9.1 | 77.7 ± 9.6 | 76.7 ± 9.1 | 76.3 ± 8.9 | < 0.0001 |
Sleep duration (hours) | 7.6 ± 1.2 | 8.0 ± 1.3 | 7.8 ± 1.2 | 7.5 ± 1.1 | < 0.0001 |
Postmenopausal (%)a | 53.7 | 53.8 | 53.7 | 53.7 | 0.86 |