{'fraction_non_alphanumeric': 0.02614795918367347, 'fraction_numerical': 0.01211734693877551, 'mean_word_length': 5.226190476190476, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 2, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effects of urban noise pollution on blood pressure and heart rate in preschool children

Objective To investigate the association between long-term exposure to high-level urban traffic noise and blood pressure in preschool children. Design Normotensive children (n = 1542), aged 3–7 years and attending kindergartens, had their blood pressures and heart rate measured. Mean values of these circulatory variables were related to 24-h equivalent traffic noise emission levels measured near their kindergartens and homes. Methods Supine systolic (SBP) and diastolic blood pressure (DBP) were measured by a Doppler ultrasonic device, heart rate by palpitation. Weighted average sound pressure levels were measured for 24 h a working day at 275 places in the city. An anthropometric investigation was performed. Demographic, socio-economic and health status questionnaires were completed by the parents of the children. Results Children attending kindergartens situated in areas with traffic noise [>60dB(A)] had higher mean SBP and DBP and lower mean heart rate than children in quiet areas. Noise at kindergartens had a greater impact than at homes. Conclusions Medium- and high-level urban traffic noise [>60dB(A)] near kindergartens is associated in preschool children with higher mean SBP and DBP, and with a higher incidence of children with blood pressure values above the respective 95th centiles. The increase in DBP could be ascribed to the rise in peripheral vascular tone and the decrease in heart rate, possibly owing to activation of a baroreceptor mechanism.