Effect of cooking fuels use on increased maternal carotid intima media thickness and preeclampsia among self-cooking pregnant women in Nay Pyi Taw area, Myanmar: a cohort study

Fuels burned in households for cooking causes indoor air pollution. Exposure to pollutants emitted from burning cooking fuels poses a considerable risk for human health including preeclampsia through systemic inflammation process for which carotid intima-media thickness (CIMT) is an important surrogate arthrosclerosis biomarker. This study aimed to examine the association of cooking fuels use with increased maternal carotid intima-media thickness and preeclampsia among cooking pregnant women in Myanmar. A cohort study was conducted in Nay Pyi Taw Area, Myanmar from September 2019 to March 2020. A total of 192 pregnant women over 18 years with gestational weeks less than 18 at baseline were recruited by a purposive sampling from 15 rural health centers in Nay Pyi Taw, and 176 completed the follow-up. Based on the type of cooking fuels use, pregnant women were grouped as firewood user, charcoal user and electricity user. Sociodemographic data, residential data and fuels use data were collected with semi-structured questionnaires in face-to-face interviews. At baseline and at follow-up, anthropometry, hemodynamics, Complete Blood Count, blood lipids and ultrasound CIMT measurements were performed under standard protocols. Multivariate linear regression analysis was used to explore associations with adjustments for potential confounding factors. The results revealed that, after adjusting for pregnancy-related factors and factors related to CIMT, firewood use had a significant association with increase of all CIMT (combined mean CIMT, mean CIMT of the LCCA and mean CIMT of the RCCA). More specifically, a greater increase of mean CIMT of the right common carotid artery (RCCA; β=0.033mm; 95%CI: 0.006, 0.058; P<0.05) had significant association with charcoal use compared to firewood use (β=0.029mm; 95%CI: 0.010, 0.049; P<0.05). At follow-up, only charcoal use was significantly associated with increase of all CIMT; combined mean CIMT (β=0.035mm; 95%CI: 0.010, 0.060; P<0.05), mean CIMT of the LCCA (β=0.029mm; 95%CI: 0.004, 0.054; P<0.05) and mean CIMT of the RCCA (β=0.041mm; 95%CI: 0.012, 0.071; P<0.05). There was no significant association between firewood use and increased CIMT. Moreover, in firewood users, combined mean CIMT at baseline 0.42±0.05mm was reduced to 0.41±0.06 mm at follow-up (P=0.039) and mean CIMT of RCCA at baseline 0.43±0.06mm was decreased to 0.41±0.07mm at follow-up (P=0.008). CIMT levels of charcoal and electricity users at baseline and at follow-up remains unchanged (P>0.05). No significant association between fuels use and preeclampsia was found. In addition, there was no significant association between CIMT and preeclampsia in this study. Our findings demonstrate that the indoor use of cooking fuels that cause indoor air pollution, such as firewood and charcoal, is a considerable risks factor for human health and is associated with increased CIMT, wherein charcoal use was consistently associated with increase of CIMT. However, no association between fuels use and preeclampsia; and no association between CIMT and preeclampsia was found. Therefore, measures to prevent health risks related to the use of such fuels especially charcoal use should be instituted early on during pregnancy and beyond. Further studies to examine the exposure effects of pollution on acute and later health problems of women burning solid fuels in cooking are suggested.