Spatiotemporal Trends in Oral Cancer Mortality and Potential Risks Associated with Heavy Metal Content in Taiwan Soil

Abstract

Central and Eastern Taiwan have alarmingly high oral cancer (OC) mortality rates, however, the effect of lifestyle factors such as betel chewing cannot fully explain the observed high-risk. Elevated concentrations of heavy metals in the soil reflect somewhat the levels of exposure to the human body, which may promote cancer development in local residents. This study assesses the space-time distribution of OC mortality in Taiwan, and its association with prime factors leading to soil heavy metal content. The current research obtained OC mortality data from the Atlas of Cancer Mortality in Taiwan, 1972–2001, and derived soil heavy metals content data from a nationwide survey carried out by ROCEPA in 1985. The exploratory data analyses showed that OC mortality rates in both genders had high spatial autocorrelation (Moran’s I = 0.6716 and 0.6318 for males and females). Factor analyses revealed three common factors (CFs) representing the major pattern of soil pollution in Taiwan. The results for Spatial Lag Models (SLM) showed that CF1 (Cr, Cu, Ni, and Zn) was most spatially related to male OC mortality which implicates that some metals in CF1 might play as promoters in OC etiology.

Collate literature data on toxicity of Chromium (Cr) and Nickel (Ni) in experimental animals and humans

“…A study in Taiwan of mortality due to oral cancer showed that some metals (Cr, Cu, Ni, and Zn) in soils might play as promoters in oral cancer etiology (Chiang et al, 2010). However, the evidence from four studies indicates that exposure to Nickel did not increase the risk of respiratory cancer:…”

Bayesian model and spatial analysis of oral and oropharynx cancer mortality in Minas Gerais, Brazil

“…This result arises from analysis performed from crude rates, in which the information about neighboring municipalities are not included in calculation of the rate 10,11 . Furthermore, spatial analysis also allows for identifying the formation of agglomerates of deaths and their relations with contextual and environmental factors 12,13 . Whereas, the use of the Empirical Bayesian method before the construction of thematic maps, refines the mortality rates, since they have been used in studies of other types of cancer 11,14 .…”

Multiple Sclerosis Incidence Associated with the Soil Lead and Arsenic Concentrations in Taiwan

“…The use of agricultural and residential land poses the highest risk to human health because ingestion is the dominant exposure pathway for heavy metals [9]. Some heavy metals, such as arsenic (As), lead (Pb) and mercury (Hg), are known to play a role in the development of various diseases including cancers [10], [11] and neurological disorders [12]. Relevant to this study, the accumulation of lead (Pb), molybdenum (Mo), arsenic (As) and aluminum (Al) may contribute to the etiology of MS in some cases [13].…”