Long-Term Sleep Duration as a Risk Factor for Breast Cancer: Evidence from a Systematic Review and Dose-Response Meta-Analysis

Table 3

The relative risks (RRs) for nonlinear and linear model.

	Number of studies			RR
				Nonlinear								Linear
				4 h	5 h	6 h	7 h	8 h	9 h	10 h		1 h increment
All	10	0.064	0.012	0.986	0.980	0.982	1.000	1.03	1.061	1.091		—	0.028
				1.004	0.998	1.000	1.018	1.049	1.08	1.111
Premenopausal	4	0.132	0.139	—								1.012	0.198
Postmenopausal	5	0.241	0.298	—								1.003	0.506
ER+	3	0.705	0.013	0.971	0.966	0.974	1.000	1.042	1.096	1.16		—	0.024
				0.997	0.992	1.000	1.027	1.070	1.126	1.192
ER−	3	0.018	0.139	—								1.035	0.352