Fig. 3: A U-shaped relationship between sleep length and BP persists in day shift workers and permanent night shift workers.

Relationship between sleep length versus SBP and DBP in day shift (A, B) and permanent night shift workers (C, D) with (baseline model, red) and without adjustment for BMI (BMI adj model, blue). Data are expressed as β-estimate ± 95% CI, which are presented as the centre circle and corresponding error bars, respectively. P-values are estimated using multivariate logistic regression. *p < 0.05 versus are non-shift workers who reported an average of is 7 h sleep per day denoted by the solid grey triangle. Please see also Supplementary Table S10A and S10B.