Urban road-traffic noise and blood pressure in school children

摘要

Blood pressure regulation might be disturbed during a long term exposure to noise through the raise of circulatory stress hormones: adrenaline, nor-adrenaline and cortisol (Maschke et al. 2000). Several epidemiological studies have shown that road-traffic noise might increase the risk of arterial hypertension (RR between 1.5 and 3.0) in adults who live in areas with daytime average sound pressure levels exceeding 65 dB(A) (Babisch 2006). However, the results of the studies on noise exposure and children's blood pressure are less consistent. This association was found to be negative and non-significant (Lercher 1992), negative and significant (van Kempen et al. 2006), positive and borderline significant (Evans et al. 2001), or positive and significant (Regecova & Kellerova 1995; Belojevic et al. 2008). There are several possible reasons for inconsistency in the results of studies on road traffic noise and blood pressure in children: noise exposure was assessed in different settings - either at home or at school or at kindergartens, the children were of different age (ranging from preschool to school age), road traffic noise was sometimes combined with other sources of noise (aircraft, railway) and daytime noise level was predominantly used as a noise exposure indicator at home instead of nighttime noise level. We used the nighttime noise as an exposure indicator at home in our previous study on preschool children (Belojevic et al. 2008), as children spend a larger part of their evening and nighttime sleeping at home than the adults (Xue et al. 2004). The same noise exposure design was applied in this study. The aim of this study was to investigate the effects of urban road-traffic daytime noise around schools and nighttime noise around residences on blood pressure levels of school children.