Epidemiological studies on noise and blood pressure in children: Observations and suggestions

Objective: The goal of this review was to investigate methodological differences in studies on the effects of aircraft or road-traffic noise on blood pressure (BP) of urban children, emphasizing the similarities and differences in blood pressure measurements. Methods: A literature search has identified eight peer-reviewed studies, four conference proceedings and one PhD thesis on the effects of aircraft or road-traffic noise on children's blood pressure published in English in the last 30 years. Most of the studies were cross-sectional, and four studies were longitudinal, with follow-up period from one to three years. The studies were analyzed according to the following methodological issues: study design, children's characteristics, noise exposure assessment and blood pressure measurements. The effects of noise on systolic and diastolic pressure were presented in detail. Results: Studies on aircraft noise had more uniform methodology, indicating a slight tendency towards a positive relationship between aircraft noise exposure and BP in children. The studies on road-traffic noise were methodologically diverse, but compared to aircraft noise studies they showed a more uniform trend in the direction of a positive relationship with systolic BP. The time, place and number of BP measurements, as well as the devices and cuff sizes varied among the studies. Children's age, gender, body composition and ethnicity, and socio-economic status remain the greatest source of diversity in BP values. Conclusions: The reviewed studies were methodologically diverse concerning noise exposure assessment. BP measurement, study design and control for confounders. In spite of this, they indicate a tendency toward positive association between noise exposure and children's blood pressure. We recommended strategies that might help researchers adopt similar procedures when measuring BP in future field studies. (C) 2011 Elsevier Ltd. All rights reserved.