Noise effects on health in studies in Low-Middle-income-countries (LMICs): a narrative review update of epidemiological evidence

Noise has been linked to adverse non-auditory health problems, including annoyance, sleep disturbance, cardiovascular disease, and impaired cognitive function. However, most studies on these topics have been conducted in developed countries. This review focussed on studies in Low-and Middle-income-countries (LMICs), which are generally considered to suffer from worse noise pollution. We conducted a literature search of Medline and Web of Science from 2009-2021, supplemented with specialist journal hand searches and identified relevant 56 studies in LMICs. Thirty-four (60.7%) of the 56 studies assessed exposure based on sound level meter monitoring, eleven with noise mapping, six with subjective ratings, three with portable sensor measurements, and two used meteorological data provided by atmospheric administration. Twenty-four (42.9%) of the 56 studies looked at noise annoyance and perception and found, as with non-LMIC studies, higher noise levels are associated with higher annoyance. Thirteen studies examined cardiovascular outcomes (mainly blood pressure or hypertension) of which 11 found adverse associations with noise exposure. Eleven studies considered mental health status, but the findings were inconclusive. A meta-analysis was not possible due to the variability of the study designs. This review will help inform further studies and health-based recommendations in LMICs.