Increased prevalence of Parkinson's disease in soils with high arsenic levels.

INTRODUCTION: Exposure to arsenic (As)-containing pesticides was associated with an increased risk for Parkinson's disease (PD). Arsenic also induced in murine brains α-synuclein aggregates, a pathognomic feature of PD. OBJECTIVES: People living on farms irrigated with high As water in Taiwan are likely exposed to increased As. We addressed whether increased farm soil As levels correlate with an increased PD risk. METHODS: We used the information from several national surveys (1983-1986) on soil metal contents to study the relationships between soil metal contents and PD prevalence in Taiwan. PD prevalence (2009-2013) was calculated with a database from Taiwan's compulsory national health insurance. A patient is defined by a PD diagnosis and prescriptions of Levodopa in three or more office visits in twelve months. We used regression models to study the correlation between PD prevalence and soil metal contents. RESULTS: The PD prevalence ranged from 83 to 213 per one hundred thousand persons in different regions of Taiwan. Among the studied heavy metals, we found only As was significantly associated with the PD prevalence. The top three regions (Yunlin, Chiayi, Tainan) in the PD prevalence list correspond exactly with the top three in soil As levels. Soil As levels and PD prevalence had a strong correlation (r = 0.75). CONCLUSION: PD prevalence is statistically correlated with farm soil As levels in Taiwan.

Increased prevalence of Sjogren's syndrome in where soils contain high levels of chromium.

Previously, we showed that farm soil levels of chromium were strongly correlated with people's serum chromium levels and an increase (3.6 fold) in both the incidence and prevalence of sicca syndrome in areas where farm soil chromium was high. Because Sjogren's syndrome (SS) is the major disease causing a dry mouth and dry eyes, we aimed in the study to investigate whether these areas with high soil chromium have a high SS prevalence. We used a database from the authority in charge of catastrophic illness certificates. Heavy metal concentrations in farm soils were retrieved from nationwide surveys. We used spatial regression models to study the relationships between the SS prevalence and soil metal concentrations. There were 11,220 people, 1165 men and 10,055 women who received a SS certificate from 2000 to 2011. The SS prevalence was 31 per 105 people, 5.59 for men and 55.01 for women. The highest SS prevalence in Taiwan (53 per 105) was located in an area where farm soils contain the highest amounts of chromium. In contrast, other types of heavy metal did not show such a strong association. In conclusion, the SS prevalence is significantly increased in areas where soils contain high levels of chromium. Chromium is likely a risk for SS.

Increased Prevalence of Esophageal Cancer in Areas with High Levels of Nickel in Farm Soils.

Background: Heavy metal pollution in farm soils is a grave concern in Taiwan. Previously, we found the incidence of oral cancer (OC) correlated positively with levels of nickel and arsenic in farm soils. Many OC patients have a second malignancy, among which esophageal cancer (EC) is the most common one in Taiwan. Objectives: We aimed to investigate whether these two cancers share some common risk factors. Methods: Taiwan began a compulsory national health insurance program in 1995. We used a database from this program to calculate the prevalence of EC and OC in Taiwan. We compared the prevalence of EC with prevalence of betel nut chewers in adults and the information of heavy metal in farm soils to look for any association. Results: The prevalence of OC and prevalence of EC were strongly correlated. The prevalence of betel nut chewing correlated with OC prevalence, but not with EC prevalence. An increased prevalence (1.9 fold) of EC was found where the farm soils contained high levels of nickel. Meanwhile, among the eight heavy metals studied, only the levels of nickel in the farm soils correlated statistically with the prevalence of EC. Conclusion: Nickel is probably a common environmental risk factor for esophageal cancer and oral cancer.

Two stages weighted sampling strategy for detecting the relation between gene expression and disease.

For microarray data analysis, most of them focus on selecting relevant genes and calculating the classification accuracy by the selected relevant genes. This paper wants to detect the relation between the gene expression levels and the classes of a cancer (or a disease) to assist researchers for initial diagnosis. The proposed method is called a Two Stages Weighted Sampling strategy (TSWS strategy). According to the results, the performance of TSWS strategy is better than other existing methods in terms of the classification accuracy and the number of selected relevant genes. Furthermore, TSWS strategy also can use to understand and detect the relation between the gene expression levels and the classes of a cancer (or a disease).