Incense burning at home and the blood lead level of preschoolers in Taiwan

The growth and intellectual development of children less than 6 years old may be affected by exposure to low levels of lead. To further reduce environmental lead exposure, this study examined possible household-related factors that affect the blood lead levels of Taiwanese children. In total, based on a stratified random sampling strategy, 934 kindergarten students were recruited throughout Taiwan from April to October 2011 after their parents signed a statement of consent. A venous blood sample was drawn from each participant and analyzed for lead content using inductively coupled plasma mass spectrometry. Information on the demographics and household environment of the study subjects was collected by administering a questionnaire (Table 1). The geometric mean lead level in the blood samples of the study subjects was 1.84 μg/dL with a geometric standard deviation of 1.55. The blood lead level was negatively correlated with household income and parental educational levels (p < 0.0001). Study subjects with more siblings also tended to have higher blood lead levels (p < 0.0001). Incense burning in the home, an ethnic tradition, was also identified as a significant factor for increased blood lead levels (p < 0.0003) and demonstrated a dose-dependent relationship with frequency of incense burning at home (p = 0.0022). Because the health effects of low levels of lead exposure have been reported in recent years and because no consensus has been reached regarding a safety threshold for blood lead level in children, any trivial factor is worth investigating to further prevent lead exposure in children. Incense burning at home is a common traditional religious activity in Taiwan; therefore, more study is warranted to further eliminate the lead content in incense and reduce lead exposure for the families who practice this activity.