Table 1

Age-adjusted characteristics of women in the NHS2 by chronotype in 2009

Chronotype
Early
(n = 22,089)Intermediate
(n = 33,825)Late
(n = 7,029)
Age (years)154.3 (4.6)54.2 (4.6)54.2 (4.7)
Median annual family income ($)266,599 (24,714)65,767 (23,883)64,953 (23,393)
Family history of diabetes373738
BMI (kg/m2)26.4 (5.6)27.3 (6.1)28.6 (6.6)
Smoking status
 Never676764
 Past282827
 Current 1–14 cigarettes/day335
 Current ≥15 cigarettes/day224
Alcohol consumption 2007 (g/day)6.9 (10.4)6.6 (10.4)5.9 (10.5)
Physical activity (MET-h/week)328.2 (34.6)23.1 (27.6)19.8 (26.6)
Diet score (AHEI)456.8 (12)55.0 (12.1)53.4 (12.3)
Ever use of oral contraceptives888887
Postmenopausal666667
Ever use of postmenopausal hormones394039
Sleep duration in current work schedule
 ≤5 h558
 6 h202125
 7 h404134
 8 h322926
 ≥9 h347
Ever rotating night shift work707073
Cumulative night shift work exposure (years)53.3 (4.2)3.4 (4.4)4.2 (5.1)
Physician-diagnosed depression6182532
Ever regular antidepressive medication use7283543
  • Data are mean (SD) or %.

  • 1Value is not age adjusted.

  • 2At census tract level.

  • 3Weekly energy expenditure in MET-h from recreational and leisure-time activities.

  • 4AHEI 2010 [Chiuve et al. (23)] in 2007 (arbitrary units 0–100).

  • 5Restricted to women ever reporting rotating night shift work since 1989.

  • 6Self-reported from 2003 onward.

  • 7Self-reported; assessed in 1993, 1997, 2001, and 2003–2009.