Associations of ambient particulate matter with homocysteine metabolism markers and effect modification by B vitamins and MTHFR C677T gene polymorphism

Effect of Lead Exposure and Lifestyle Factors on Methylation Index Markers Among Pb-Exposed Workers

S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) and the ratio of SAM and SAH in Pb-exposed workers need to be assessed. In this study, we investigated the effects of Pb exposure on SAM, SAH, and methylation index (MI) in Pb-exposed workers with contemplation of lifestyle factors. Blood lead levels (BLLs), SAM, SAH, MI, and lifestyle factors were assessed in 338 male Pb-exposed workers. BLLs are estimated by ICP-OES method. SAM and SAH levels in serum were determined by ELISA method. The MI was calculated using SAM and SAH individual values. The lifestyle factors were collected using standard questionnaire. Levels of SAM and MI were significantly decreased with increased age, experience > 5 years, habits of tobacco chewing, smoking, alcohol consumption, and BLLs 10-30, 30-50, and > 50 µg/dL. Levels of SAH were significantly increased with increased age, habits of tobacco chewing and smoking, and BLLs 10-30, 30-50, and > 50 µg/dL. The association between BLLs and methylation index markers (SAM and MI) was reported as negative and significant. The association between BLLs and SAH was noted positive and significant. The influence of BLLs and lifestyle factors on SAM was noted at 12%, SAH at 35%, and MI at 27%, respectively. The highest percentage of influence was noted in SAH, followed by MI and SAM. In the workers exposed to Pb, lifestyle factors resulted in decreased SAM and MI and increased SAH levels. Adaptation of healthy lifestyle factors, personal hygiene practices, and use of PPE were suggested to minimize the reduction of methylation index markers.

Association between cooking fuel and folate insufficiency among pregnant women in Northern China

This study explored whether using a coal or biomass stove for cooking was associated with a greater risk of red blood cell (RBC) folate insufficiency among pregnant women compared to using clean energy. A researcher-designed questionnaire was used to collect information on exposure-related factors and confounding factors. RBC folate concentrations were examined by microbiological assay. Binary logistic regression analysis was used to identify factors related to RBC folate insufficiency. The use of coal or firewood for cooking was associated with an increased risk of RBC folate insufficiency (<906 nmol/L) compared to gas. In subgroup analyses, associations between the use of polluting cooking fuels and folate insufficiency were positive for both urban and rural residents and statistically significant for rural women. Efforts to promote the use of clean energy and proper ventilation, especially in rural areas, are recommended to improve the health of pregnant women and their offspring.

The underlying mechanism of PM2.5-induced ischemic stroke

Under the background of global industrialization, PM_2.5 has become the fourth-leading risk factor for ischemic stroke worldwide, according to the 2019 GBD estimates. This highlights the hazards of PM_2.5 for ischemic stroke, but unfortunately, PM_2.5 has not received the attention that matches its harmfulness. This article is the first to systematically describe the molecular biological mechanism of PM_2.5-induced ischemic stroke, and also propose potential therapeutic and intervention strategies. We highlight the effect of PM_2.5 on traditional cerebrovascular risk factors (hypertension, hyperglycemia, dyslipidemia, atrial fibrillation), which were easily overlooked in previous studies. Additionally, the effects of PM_2.5 on platelet parameters, megakaryocytes activation, platelet methylation, and PM_2.5-induced oxidative stress, local RAS activation, and miRNA alterations in endothelial cells have also been described. Finally, PM_2.5-induced ischemic brain pathological injury and microglia-dominated neuroinflammation are discussed. Our ultimate goal is to raise the public awareness of the harm of PM_2.5 to ischemic stroke, and to provide a certain level of health guidance for stroke-susceptible populations, as well as point out some interesting ideas and directions for future clinical and basic research.

Effects of household cooking with clean energy on the risk for hypertension among women in Beijing

Outdoor air pollution and indoor burning of biomass fuel can cause high blood pressure. However, little is known about the effects of cooking with clean energy on hypertension. We thus explored whether cooking with clean energy is associated with the risk for hypertension. The study used baseline data from 12,349 women from a large population-based cohort study in Beijing, China. Information on cooking habits, health status, and other characteristics was collected by questionnaire and physical examination. Fasting blood samples were collected to measure total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and homocysteine (HCY). An index of cooking exposure was constructed. Log-binomial regression models were used to estimate the association between cooking exposure and risk for hypertension. The prevalence of hypertension was 26.7%. Any cooking exposure at all was associated with an increased risk for hypertension with an adjusted prevalence ratio (aPR) of 2.27 (95% confidence interval [CI]: 2.01, 2.57). The risk for hypertension increased with increases in cooking frequency, time spent cooking, and the cooking index, all showing a dose-effect relationship (P < 0.001). An increased risk for hypertension was associated with both cooking using mainly electricity (aPR: 1.75, 95% CI: 1.41, 2.17) and cooking using mainly natural gas (aPR: 2.30, 95% CI: 2.03, 2.60). The cooking index was positively correlated with plasma concentrations of TC, TG, LDL-C, and HCY and negatively correlated with HDL-C. Abnormal levels of all these biomarkers were associated with an increased prevalence of hypertension after adjustment for confounding factors. Cooking with clean energy, mainly cooking habit, may contribute to an increased risk for hypertension among female residents of Beijing. Abnormal metabolism of lipids or HCY may be an important mechanism involved in the development of cooking-related hypertension.

Homocysteine - from disease biomarker to disease prevention

We have reviewed the literature and have identified more than 100 diseases or conditions that are associated with raised concentrations of plasma total homocysteine. The commonest associations are with cardiovascular diseases and diseases of the central nervous system, but a large number of developmental and age-related conditions are also associated. Few other disease biomarkers have so many associations. The clinical importance of these associations becomes especially relevant if lowering plasma total homocysteine by B vitamin treatment can prevent disease and so improve health. Five diseases can at least in part be prevented by lowering total homocysteine: neural tube defects, impaired childhood cognition, macular degeneration, primary stroke, and cognitive impairment in the elderly. We conclude from our review that total homocysteine values in adults of 10 μmol/L or below are probably safe, but that values of 11 μmol/L or above may justify intervention. Homocysteine is more than a disease biomarker: it is a guide for the prevention of disease.