Formaldehyde Causes Childhood Leukemia
Formaldehyde has been tested for carcinogenicity by inhalation, oral administration, topical application, and subcutaneous injections in rodents. It has been proposed that, based on the weight of evidence from in vivo studies, the likely mode of action for formaldehyde-induced nasal tumors in animals is relevant to humans at least qualitatively (McGregor et al., 2006). Based on comprehensive research and large-scale human studies conducted internationally, the International Agency for Research on Cancer (1ARC) recently classified formaldehyde as a human carcinogen that causes nasopharyngeal cancer (IARC, 2006). Popularly known as the “Cantonese Cancer”, nasopharyngeal malignancy kills as many as 13,000 Chinese people each year — more than 10 times the nasopharyngeal fatalities in the rest of the world (Jia, 2008). Although viral infection has been suspected to be the cause, formaldehyde exposure from Guangdong’s industries and possibly from seafood consumption cannot be excluded. Despite this, China has conducted only limited research on formaldehyde’s carcinogenic effects.
To date, there have only been 4 small retrospective cohort studies on the carcinogenicity of formaldehyde in China, all of which lack clear epidemiological design and are more than 10 years old (Cui et al., 1997, Dai and Bao, 1999; Jiang et al., 1990; Wang et al., 1989). The cancel mortality rate increased in all of the studies, while the incidences of gastric cancer and brain tumor increased in 3 and 2 of 4 studies respectively. More recently, two cases were reported of thyroid cancer in female textile workers in shanghai but formaldehyde exposure data was not reported, though formaldehyde was suspected, and co-exposure to benzene may have occurred (Wong et al. 2006).
Additionally, one case of malignant lymphoma (Jiang et al. 1990) and one case of leukemia (Cui et al., 1997) were reported. In a 2006 court case, a local judge in Fujian Province awarded compensation for the first case of formaldehyde induced childhood leukemia in China. After being exposed to a formaldehyde concentration of 0.39 mg/m3 for 8 months in a newly decorated home, a 4-year-old girl suffered from fatal leukemia, and the decorating company was required to provide compensation (Dai, 2006). Some studies have suggested that increase in childhood leukemia cases is associated with the increase in indoor air formaldehyde pollution from newly remodeled home.