Table 3

Potential confounders by cumulative extremely low-frequency magnetic field exposure in the subcohort

	Extremely low-frequency ELF
	0 unit-years			0.5–9 unit-years			9.5–28 unit-years			28.5–208 unit-years
	n	%/mean	SD	n	%/mean	SD	n	%/mean	SD	n	%/mean	SD
Sex (%)
Male	926	48.7		143	23.6		270	38.7		598	88.6
Female	977	51.3		463	76.4		427	61.3		77	11.4
Age at baseline (%)
55–60 years	692	36.4		251	41.4		259	37.2		133	29.8
60–65 years	656	34.5		206	34.0		237	34.0		152	34.1
65–70 years	555	29.2		149	24.6		201	28.8		161	36.1
Age at baseline (mean, SD) Years	1903	61.6	4.3	606	61.2	4.1	697	61.5	4.3	675	61.6	4.2
Smoked cigarettes (%)
Never	733	38.5		288	47.5		273	39.2		100	14.8
Former smoker	644	33.8		175	28.9		243	34.9		355	52.6
Current smoker	526	27.6		143	23.6		181	26.0		220	32.6
Number of cigarettes smoked per day (mean, SD)	1903	9.6	11.2	606	7.5	10.9	697	9.2	10.8	675	13.5	10.3
Number of years smoking cigarettes (mean, SD)	1903	19.5	18.3	606	15.4	17.5	697	18.8	17.8	675	28.4	15.9
Highest level of education attained (%)
Primary vocational	497	26.1		186	30.7		215	30.9		155	23.0
Lower vocational	354	18.6		148	24.4		154	22.1		185	27.4
Secondary and medium vocational	645	33.9		233	38.5		278	39.9		259	38.4
University and higher vocational	407	21.4		39	6.4		50	7.2		76	11.3
Body Mass Index (mean, SD)kg/m²	1903	24.9	3.1	606	25.3	3.4	697	25.2	3.2	675	24.9	2.6
Alcohol consumption (mean, SD) g/day	1903	11.2	15.3	606	7.7	11.8	697	9.6	14.0	675	11.9	13.6