Dear editor
We read with great interest the recently published article by Vasheghani et al.Citation1 In the article, the authors showed that the prevalence of CAN was increased with prolonged duration of DM, but not the glycemic control level. In the study, the CAN was assessed based on heart rate variation during physical examination (at rest tachycardia and orthostatic hypotension) and standard Ewing’s tests (deep-breathing and laying-to-standing tests) with bedside continuous ECG recording.
Without doubt, HRV is the popular indicator for CAN, however, there are still some influence factors, and the most easily unnoticeably one may be the air pollution or fine particles exposure. Consistent links between fine particles exposure and decreased HRV in healthy volunteers have been documented in studies.Citation2,Citation3 In their study, an increase in 30 mg/m3 of the average PM2.5 personal exposure in the previous 2 h decreased the pNN50 in 0.08%, which suggest short term exposure to high level of fine particles could effect the HRV or CAN.
Moreover, in the susceptible population, the individual coronary risk profiles and underlying diabetes or impaired glucose tolerance might confer reduced autonomic function of heart due to particulate air pollution exposure.Citation4–Citation6 In Vasheghani et al’s study, the HRV and other tests were set standardly, however, the PM exposure of the subjects shortly before the HRV test was ignored, which might affect the conclusion if setting the level of PM as the correction factor.
Disclosure
The authors report no conflicts of interest in this communication.
References
- Vasheghni M , Sarvghadi F , Beyranvand MR . The association between cardiac autonomic neuropathy and diabetes control. Diabetes Metab Syndr Obes . 2019;12:581–587. doi:10.2147/DMSO.S196729 31118721
- Fan ZT , Meng Q , Weisel C , et al. Acute exposure to elevated PM2.5 generated by traffic and cardiopulmonary health effects in healthy older adults. J Expo Sci Environ Epidemiol . 2009;19(5):525. doi:10.1038/jes.2008.46 18841167
- Vallejo M , Ruiz S , Hermosillo AG , Borja-Aburto VH , Cárdenas M . Ambient fine particles modify heart rate variability in young healthy adults. J Expo Sci Environ Epidemiol . 2006;16(2):125–130. doi:10.1038/sj.jea.7500447 16151470
- Sun Y , Song X , Han Y , et al. Size-fractioned ultrafine particles and black carbon associated with autonomic dysfunction in subjects with diabetes or impaired glucose tolerance in Shanghai, China. Part Fibre Toxicol . 2015;12:8. doi:10.1186/s12989-015-0084-6 25884677
- Feng Y , Huang X , Sun H , et al. Framingham risk score modifies the effect of PM10 on heart rate variability. Sci Total Environ . 2015;523:146–151. doi:10.1016/j.scitotenv.2015.04.009 25863505
- Zheng N . Chapter 11, Sudden death and the effects on particulate matter air pollution In: Sudden Death, Causes, Risk Factors and Prevention . 1st USA: Nova Science Publishers, Inc; 2013: 195–210. Available from: http://www.novapublishers.org/catalog/product_info.php?products_id=41834. Accessed July 16, 2019.