Exposure to road traffic and railway noise and associations with blood pressure and self-reported hypertension: a cohort study

Table 2 Associations between road traffic noise and the systolic and diastolic blood pressure at enrolment

		Differences in systolic blood pressure (mm Hg) (95% CI)			Differences in diastolic blood pressure (mm Hg) (95% CI)
Road traffic noise (L_den)	N	Adjusted by age and gender	Adjusted by age, gender, calendar-year, area, lifestyle factors^a , air pollution^b, season, temperature and humidity	P	Adjusted by age, gender, calendar-year, area, lifestyle factors^a , air pollution^b, season, temperature and humidity	P
1-year mean (dB(A))^c
< 56.4	22,041	0 (ref)	0 (ref)		0 (ref)
56.4-67.3	17,635	0.12 (-0.27;0.50)	0.17 (-0.23; 0.58)	0.41	-0.00 (-0.22; 0.21)	0.98
> 67.3	4,407	0.23 (-0.39; 0.85)	0.79 (-0.04; 1.62)	0.06	0.11 (-0.33; 0.55)	0.62
Linear trend per 10 dB(A)	44,083	0.09 (-0.18; 0.37)	0.26 (-0.11; 0.63)	0.17	0.07 (-0.13; 0.27)	0.50
5-year mean (dB(A))^c
< 56.3	22,041	0 (ref)	0 (ref)		0 (ref)
56.3-67.3	17,635	0.04 (-0.35; 0.42)	0.08 (-0.33; 0.48)	0.71	-0.02 (-0.23; 0.20)	0.88
>67.3	4,407	0.40 (-0.23; 1.02)	0.85 (0.02; 1.67)	0.04	0.12 (-0.32; 0.55)	0.60
Linear trend per 10 dB(A)	44,083	0.07 (-0.21; 0.35)	0.14 (-0.24; 0.53)	0.47	0.03 (-0.18; 0.23)	0.78

All analyses include centre of enrolment as random factor
^a Lifestyle factors: smoking, BMI, length of school attendance, municipality SES, alcohol intake and physical activity.
^b Time-weighted average concentration of NO_x at residences 1 and 5 years preceding enrolment
^c The cut-off points between exposure groups were the 50^th and 90^th percentiles for the participants at the time of enrolment into the cohort

ISSN: 1476-069X