Psychosomatic symptoms during South East Asian haze crisis are related to changes in cerebral hemodynamics

• Published in: PloS one 2019-01, Vol.14 (1), p.e0208724
• Main Authors: Tan, Benjamin Y, Leong, Adriel Z, Leow, Aloysius S, Ngiam, Nicholas J, Ng, Bridget S, Sharma, Manasi, Yeo, Leonard L, Seow, Philip A, Hong, Chiew S, Chee, Young H, Chen, Jintao, Du, Zhengdao, Wong, Lily Y, Batra, Amit, Sarkar, Nabin, Teoh, Hock-Luen, Ho, Roger C, Sharma, Vijay K
• Format: Article
• Language: English
• Subjects: Adult; Air conditioners; Air Pollutants - toxicity; Air pollution; Air Pollution - adverse effects; Arteries; Asia; Biology and Life Sciences; Blood flow; Blood Flow Velocity - drug effects; Blood Flow Velocity - physiology; Blood pressure; Carbon Dioxide - toxicity; Cerebrovascular Circulation - drug effects; Cerebrovascular Circulation - physiology; Circulatory system; Diabetes; Doppler effect; Ecology and Environmental Sciences; Environmental aspects; Exposure; Female; Flow velocity; Forest & brush fires; Forest fires; Haze; Haze effects; Head injuries; Health aspects; Healthy Volunteers; Hemodynamics; Hemodynamics - drug effects; Hemodynamics - physiology; Humans; Insomnia; Male; Medicine; Medicine and Health Sciences; Middle Cerebral Artery - physiology; Neurology; Parameters; Patients; People and Places; Physical Sciences; Physiology; Pollutants; Pollution levels; Psychosomatic disorders; Pulsatile Flow - drug effects; Pulsatile Flow - physiology; South Asia; Statistical analysis; Subgroups; Ultrasonography, Doppler, Transcranial; Ultrasound; Vasoactive agents; Vasodilation
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0208724

Forest fires in South Asia lead to widespread haze, where many healthy individuals develop psychosomatic symptoms. We investigated the effects of haze exposure on cerebral hemodynamics and new symptoms. We hypothesised that vasoactive substances present in the haze, would lead to vasodilation of cerebral vasculature, thereby altering cerebral hemodynamics, which in turn may account for new psychosomatic symptoms. Seventy-four healthy volunteers were recruited, and serial transcranial Doppler (TCD) ultrasonography was performed to record blood flow parameters of bilateral middle cerebral arteries (MCA). The first TCD was performed in an air-conditioned environment. It was repeated outdoors after the participants spent 30-minutes in the haze environment. The prevailing level of pollutant standards index (PSI) was recorded. Appropriate statistical analyses were performed to compare cerebral hemodynamics at baseline and after haze exposure in all participants. Subgroup analyses were then employed to compare the findings between symptomatic and asymptomatic participants. Study participants' median age was 30 years (IQR 26-34), and new psychosomatic symptoms were reported by 35 (47.3%). There was a modest but significant decrease in pulsatility index (PI) and resistivity index (RI) in the left MCA after haze exposure (PI: p = 0.026; RI: p = 0.021). When compared to baseline parameters, haze exposure resulted in significantly lower mean PI (p = 0.001) and RI (p = 0.001) in symptomatic patients, but this difference was not present in asymptomatic patients (PI: p = 0.919; RI: p = 0.970). Haze causes significant alterations in cerebral hemodynamics in susceptible individuals, probably responsible for various psychosomatic symptoms. The prognostic implications and health effects of haze require evaluation in a larger study.