Table 3

Risk for type 2 diabetes in the NHS2 by chronotype and stratified by cumulative rotating night shift work history

Chronotype
IntermediateEarlyLate
Prevalence analysis: follow-up period 2005–2011
 No rotating night shift work1.00
(n = 10,131; 198 cases)0.81 (0.63–1.04)
(n = 6,774; 99 cases)1.51 (1.13–2.03)
(n = 1,857; 68 cases)
 <10 years1.00
(n = 21,829; 528 cases)0.84 (0.72–0.98)
(n = 14,232; 255 cases)0.93 (0.76–1.13)
(n = 4,571; 138 cases)
 ≥10 years1.00
(n = 2,726; 96 cases)1.15 (0.82–1.63)
(n = 1,696; 59 cases)0.86 (0.56–1.33)
(n = 799; 31 cases)
Incidence analysis: follow-up period 2009–2011
 No rotating night shift work1.00
(n = 10,086; 44 cases)0.75 (0.44–1.29)
(n = 6,690; 19 cases)1.43 (0.77–2.62)
(n = 1,862; 14 cases)
 <10 years1.00
(n = 20,893; 116 cases)0.91 (0.67–1.25)
(n = 13,711; 60 cases)0.86 (0.57–1.32)
(n = 4,289; 27 cases)
 ≥10 years1.00
(n = 2,846; 17 cases)1.63 (0.79–3.34)
(n = 1,688; 14 cases)1.01 (0.43–2.37)
(n = 878; 8 cases)
  • Data are MVOR (95% CI) in the prevalence analysis (n = 64,615; 1,472 cases) and hazard ratio (95% CI) in the incidence analysis (n = 62,943; 319 cases). The interaction between chronotype and cumulative shift work exposure is significant in both analyses. Models adjusted for age, family history of diabetes (yes/no), BMI (<25, 25–30, 30–35, >35 kg/m2), smoking status (never, past, current 1–14 cigarettes/day, current ≥15 cigarettes/day), alcohol intake (0, 0.1–5, 5.1–10, 10.1–15, >15 g/day), physical activity (quintiles of MET-h/week), diet score (quintiles, AHEI as assessed in 2007), oral contraceptive use (ever, never), menopausal status (pre-, postmenopause), postmenopausal hormone use (premenopause, ever, never), self-reported sleep duration (<5, 6, 7, 8, >9 h as assessed in 2009), median annual household income ($, in tertiles), and depressive symptoms (yes/no based on regular medication use or self-reported physician diagnosis).