Why does formaldehyde cause leukemia?

Introduction: Mouse experiments have shown that formaldehyde may affect the expression of certain genes related to cancer after entering the body; epidemiological studies have shown that exposure to formaldehyde may increase the risk of leukemia. . However, the occurrence of leukemia is the result of many factors, and formaldehyde may be just one of the causes. Formaldehyde is a colorless chemical substance with a pungent odor at room temperature. Indoors, its main source is decoration materials. In addition to plywood, artificial ceilings and other materials commonly used in indoor decoration, even wallpaper and carpets contain formaldehyde. gas. Formaldehyde has a certain impact on human health. According to toxicological research, when the concentration of inhaled formaldehyde is greater than 0.24ppm, it can make people become irritable and aggressive. When the concentration of formaldehyde is greater than 13.8ppm, it can cause respiratory problems such as tearing and coughing. Discomfort reaction. Does formaldehyde cause cancer? The World Health Organization's International Agency for Research on Cancer (IARC) classifies formaldehyde as a Group 1 carcinogen. In the 1980s, laboratory studies showed that exposure to formaldehyde could cause nasal cancer in rats, a finding that raised questions about whether formaldehyde exposure could cause cancer in humans. Since then, the National Cancer Institute has launched a series of studies to discover the relationship between formaldehyde exposure and cancer risk. Their survey of professionals exposed to formaldehyde at work, such as anatomists, found that these people had an increased risk of leukemia and brain cancer compared with the general population. In a study of funeral workers who died between 1960 and 1986, researchers compared those who died from leukemia, lymphoma and brain tumors with those who died from other causes. showed that those who were more exposed to preservatives, that is, those who were more exposed to formaldehyde, had the highest risk of myeloid leukemia. However, based on current research evidence, it cannot be fully proven that excessive formaldehyde in houses will definitely cause leukemia in adults, because the causative factors are often multiple and complex. Since cancer is the result of a combination of multiple factors, the causative factors include not only external factors such as formaldehyde, but also internal factors such as oncogenes. Therefore, the most accurate statement is that excessive exposure to formaldehyde will increase the risk of leukemia. Zhang Qunling, a hematologist at the Shanghai Cancer Hospital of Fudan University, said that as far as decoration materials are concerned, they also contain many organic solvents and chemical components, not just formaldehyde. For example, pathologists who are often exposed to formalin (formaldehyde solution) have not found an increase in the incidence of leukemia. What is the possible connection between formaldehyde and leukemia? At present, studies have shown that in in vitro experiments, formaldehyde can break and cross-adhere DNA strands originally arranged in a double helix structure after combining with DNA molecules. Some researchers have proposed that there may be three mechanisms by which formaldehyde induces leukemia. One is that, like other causes of leukemia, it can directly destroy stem cells in the bone marrow; the other is that it destroys hematopoietic stem cells in the peripheral blood. After these cells enter the bone marrow, It may lead to leukemia; third, it destroys multifunctional stem cells in tissues such as nasal mucosa. These cells can enter the bone marrow through the blood, leading to the occurrence of leukemia. In addition, in experiments on mice, researchers found that the expression of several genes was also affected by formaldehyde. As the concentration of formaldehyde increases, the c-myc gene (a gene that promotes cell division), the MDM2 gene (an oncogene, associated with tumor metastasis), and the p53 gene (a tumor suppressor gene) in mouse bone marrow tissue ) will change. The first two genes will become more active, while the expression of the latter gene will be inhibited to a certain extent. Overexpression of the first two genes may destroy the tumor suppressor function of p53 through certain mechanisms. This may also be a mechanism by which formaldehyde causes leukemia. However, the above possible mechanisms were all discovered in mouse experiments and were limited to the gene expression level. There is currently no clear conclusion on what physiological and biochemical reactions formaldehyde will cause in the human body. How to discharge formaldehyde from the room? Since it is known that long-term excessive formaldehyde exposure may bring health risks such as leukemia, we need to be vigilant and preventive in our daily lives. The first thing you need to understand is that the release of formaldehyde is a long-term process and is related to indoor temperature, relative humidity, indoor air exchange rate and indoor building materials. In a home environment, reasonable control of the indoor environment is an effective way to reduce formaldehyde concentration. way. Indoor ventilation is an effective way to remove formaldehyde. Ventilation devices or natural ventilation are beneficial to the dispersion and emission of formaldehyde in indoor materials. We can determine the frequency of ventilation according to different seasons, weather, and the number of people indoors. For example, in spring, summer, and autumn, vents can be left appropriately, and in cold winter, windows should be opened for at least 30 minutes of ventilation every day. minutes or more. In addition, studies have found that the release of formaldehyde increases with increasing humidity and temperature. When the temperature drops from 30°C to 25°C, the formaldehyde release can be reduced by 50%. The relative humidity drops from 70% to 30%, and the formaldehyde release can be reduced by 40%. If you want to release formaldehyde in indoor materials as quickly as possible, you can increase the temperature and humidity. Therefore, baking methods are generally used in newly renovated houses, or placing clean water indoors can speed up the release of formaldehyde in indoor materials, and then pass through Ventilation will emit formaldehyde. From the source point of view, choosing products that meet environmental protection standards when decorating and purchasing furniture can greatly reduce the formaldehyde content in the home.

Is self-testing for formaldehyde reliable? In order to know whether the formaldehyde content in their homes exceeds the standard, many people will conduct testing. Some people buy some portable instruments online and do the testing themselves, while others find professional companies to do the testing. How accurate is the data detected in this way? Someone once purchased a portable formaldehyde detector online, but in the end they discovered that the value measured by the detector is closely related to the flow of air. The same air sample is in a stable container and a shaking container. , the detected values ​​are completely different. Some researchers said that portable detectors can be roughly divided into two types, one is a semiconductor detector, and the other is an electrochemical detector. No matter which one is used, it will be affected by the air flow rate. Such a detector does not comply with the national standard testing method. When compared with the national standard testing method, it will be found that the numerical deviation is large. If formaldehyde testing is carried out in accordance with strict national standards, there are clear requirements for indoor temperature and sealing time. According to the "Indoor Air Quality Standards" formulated by the Ministry of Health, doors and windows need to be closed for 12 hours before testing for formaldehyde. Doors and windows also need to be closed tightly during the testing process to be as close to daily living conditions as possible, so as to measure whether the house meets the health requirements of the living environment. Relevant standards also have strict regulations on the extraction and testing of indoor air samples. For example, when sampling, in principle, 1 to 3 points should be set up for rooms smaller than 50 square meters; 3 to 5 points should be set up for 50-100 square meters; and at least 5 points should be set up for rooms above 100 square meters. These sampling points need to be set in the right direction. Evenly distributed on the corners or in a plum blossom pattern. In addition, the height of the sampling point should be consistent with the height of the human breathing zone. After sampling, not only do the samples need to be sent back to the laboratory, but the atmospheric pressure, temperature, relative humidity, air flow rate, etc. at that time also need to be recorded in detail for comprehensive inspection during the final inspection. Only by testing according to these standards can the formaldehyde concentration obtained be more accurate.

Author | Li Xiaohui Science Popularization Author Reviewer | Zhang Qunling, Deputy Chief Physician, Department of Oncology, Shanghai Cancer Hospital, Fudan University The article was launched by the Tencent Science Popularization "Science Popularization China Headlines Creation and Push Project" team. Please indicate the source of the reprint from "Science Popularization China" References: 1 About Some facts about formaldehyde ki.net/KCMS/detail/detail.aspx?dbcode=CJFQ&dbname=CJFD2013&filename=ZGHJ201308031&v=Mjc5MjlEaDFUM3FUcldNMUZyQ1VSTEtmYnVacUZ5amdVNzNJUHlyRFpMRzRI3 Toxic effects of formaldehyde on mouse bone marrow tissue ki.net /KCMS/detail/detail.aspx?dbcode=CJFQ&dbname= CJFD2012&filename=ZGHJ201206035&v=MjkxNDZLZmJ1WnFGeWpoVnJ6TVB5ckRaTEc0SDlQTXFZOUdZWVI4ZVgxTHV4WVM3RGgxVDNxVHJXTTFGckNVUkw=4 Brief introduction to formaldehyde detection methods and control strategies in indoor air/Uploadfile/File/GB1888 3.pdf6 Review of rapid detection methods for formaldehyde and TVOC, the main indoor polluting gases/5/20111024/634550642984791250.pdf