Table 2 Baseline cardiovascular factors and employment characteristics by exposure group (controls only).

	Unexposed* (n = 416)	Cumulative exposure, NIL85
		Low* (n = 232)	Medium* (n = 220)	High* (n = 233)
Age at recruitment (median years)	36	38	39	38
Height (median cm)	171	171	171	170
High blood pressure at recruitment (% with BP⩾160 and/or DBP⩾95)	23%	19%	20%	25%
Overweight at recruitment: (% with BMI >25)	31%	28%	30%	29%
Smoking
(1) % smokers among those with smoking data	67%	70%	69%	66%
(2) % missing	42%	31%	13%	2%
Shiftwork
(1) % ever among those with data	50%	59%	70%	74%
(2) % missing	7%	8%	3%	3%
Employment duration (median years)	2	3	13	21

*Unexposed, less than one year above 85dB(A); low, 85⩽NIL₈₅<94.8; medium, 94.8⩽NIL₈₅<99.7; high, NIL₈₅⩾99.7.