Table 2

Rate ratio with 95% CI IHD, as a function of weekly working hours among employees in Denmark 2000–2014, with and without stratification by sex, socioeconomic status night work status and calendar year of interview, respectively

Population	Weekly working hours	Person years	Cases	Rate ratio	95% CI
All workers	>48	71 258	284	1.07	0.94 to 1.21
	41–48	124 106	380	0.95	0.85 to 1.06
	32–40	931 403	2971	1.00	–
Male workers	>48	55 968	256	1.10	0.96 to 1.26
	41–48	77 153	294	0.97	0.86 to 1.10
	32–40	459 262	2027	1.00	–
Female workers	>48	15 290	28	0.88	0.61 to 1.29
	41–48	46 953	86	0.90	0.72 to 1.12
	32–40	472 141	944	1.00	–
Workers with a high socioeconomic status	>48	26 597	99	1.04	0.84 to 1.29
	41–48	44 809	129	0.96	0.79 to 1.16
	32–40	238 046	591	1.00	–
Workers with a medium socioeconomic status	>48	10 487	35	0.93	0.66 to 1.31
	41–48	20 801	70	1.07	0.83 to 1.37
	32–40	189 350	497	1.00	–
Workers with a low socioeconomic status	>48	22 486	115	1.27	1.05 to 1.53
	41–48	46 095	138	0.85	0.71 to 1.01
	32–40	421 053	1636	1.00	–
Workers with unknown socioeconomic status	>48	11 689	35	0.84	0.59 to 1.19
	41–48	12 401	43	1.14	0.82 to 1.58
	32–40	82 954	247	1.00	–
Workers with night-time work	>48	21 262	97	1.22	0.97 to 1.52
	41–48	17 677	59	0.98	0.74 to 1.29
	32–40	108 410	378	1.00	–
Workers without night-time work	>48	49 997	187	1.01	0.87 to 1.18
	41–48	106 429	321	0.95	0.84 to 1.06
	32–40	822 994	2593	1.00	–
Workers interviewed 1999–2000	>48	20 837	88	1.08	0.86 to 1.35
	41–48	36 010	87	0.72	0.58 to 0.90
	32–40	283 012	954	1.00	–
Workers interviewed 2001–2006	>48	34 230	141	1.14	0.95 to 1.36
	41–48	61 746	203	1.04	0.89 to 1.21
	32–40	348 992	1117	1.00	–
Workers interviewed 2007–2013	>48	16 192	55	0.93	0.71 to 1.23
	41–48	26 350	90	1.08	0.87 to 1.35
	32–40	299 399	900	1.00	–

IHD, ischaemic heart disease.