Excess noise is thought to cause stress responses in the body with subsequent acute changes in blood pressure. Long-time exposure to noise could result in lasting cardiovascular changes such as atherosclerosis and increase cardiovascular risk, as well as hypertension. Swedish researchers have studied the effects of traffic noise, to try to determine which segments of the population are most susceptible to its ill-effects. They report in the BioMed Central journal Environmental Health.
The data, which covered health information from 24,000-plus adults living in southern Sweden, included the average road noise at the subject’s residential address. The participants were asked to report if they had been diagnosed with high blood pressure or were taking anti-hypertensive medication. The analysis of the possible association between road noise and hypertension was adjusted for possible risk factors for the condition - sex, age, body mass index (BMI), physical activity, level of education, alcohol consumption, smoking and socioeconomic status.
The results showed a modest effect of traffic noise on the likelihood of high blood pressure, after adjustment for the above risk factors. An average day/night noise level of 45 decibels or more increased the risk of hypertension by 10%, a non-significant degree. But higher levels – 64 decibels, the level of a dishwasher or a typical conversation – increased the risk by 45%.
Age played a role in the risk assessment. More marked effects were seen at the higher exposure levels in relatively young adults and the middle-aged, whereas there were no effects measured in the over 60s. (Of course, it may be that there was a modicum of deafness in the older folk. Or perhaps the annoyance produced by noise had worn off after some years, so that stress was less.)