Association between Selenium in Soil and Diabetes in Chinese Residents Aged 35-74 Years: Results from the 2010 National Survey of Chronic Diseases and Behavioral Risk Factors Surveillance.

OBJECTIVE: To explore the association between soil selenium levels and the risk of diabetes in Chinese adults aged 35-74 years. METHODS: Data for this study were derived from the China Chronic Diseases and Behavioral Risk Factors Surveillance 2010 survey. Selenium concentrations in soil were obtained from the Atlas of Soil Environmental Background Values in China. A two-level binary logistic regression model was used to determine the association between soil selenium concentrations and the risk of diabetes, with participants nested within districts/counties. RESULTS: A total of 69,332 participants aged 35-74 years, from 158 districts/counties were included in the analysis. Concentrations of selenium in soil varied greatly across the 158 districts/counties, with a median concentration of 0.219 mg/kg ( IQR: 0.185-0.248). The results showed that both Quartile 1 (0.119-0.185 mg/kg) and Quartile 4 (0.249-0.344 mg/kg) groups were positively associated with diabetes compared to a soil selenium concentration of 0.186-0.219 mg/kg (Quartile 2), crude odds ratios ( ORs) (95% CI) were 1.227 (1.003-1.502) and 1.280 (1.048-1.563). The P values were 0.045 and 0.013, for Quartile 1 and Quartile 4 groups, respectively. After adjusting for all confounding factors of interest, the Quartile 1 group became non-significant, and the Quartile 4 group had an adjusted OR (95% CI) of 1.203 (1.018-1.421) relative to the reference group (Quartile 2), the P values was 0.030. No significant results were seen for the Quartile 3 group (0.220-0.248 mg/kg) compared to the reference group. CONCLUSION: Excessive selenium concentrations in soil could increase the risk of diabetes among Chinese adults aged 35-74 years.

Effects and action mechanisms of sodium fluoride (NaF) on the growth and cephalotaxine production of Cephalotaxus mannii suspension cells.

To explore the effects of NaF on the growth and cephalotaxine production of Cephalotaxus mannii suspension cells, NaF was added into the C mannii cell suspension cultures at day 15 of culture time. It is documented that NaF suppressed cell growth but enhanced cephalotaxine production. The largest yield obtained of cephalotaxine reached to 9.57mg/L when the cultures were treated with an appropriate dosage of 15mg/L NaF, which was 3.7 times that of the control cultures (2.58mg/L). Additionally, NaF markedly enhanced the activity of glucose 6-phosphate dehydrogenase (G6PDH) and reduced the level of hydrogen peroxide (H2O2) of cells. It was also found that NaF weakened the oxidative damage of cell membrane and led to lower content of malonyl dialdehyde (MDA) in NaF-treated cells compared with the control cells. The MDA content of NaF-treated cells decreased 91% compared to the controls. Although lower membrane lipid peroxidation in NaF-treated cells, its membrane permeability was higher than the control cells and showed a high product secret rate. What is more, NaF boosted the activity of phenylalanine ammonium-lyse (PAL), but did not burst a peak of PAL activity in the time curve of PAL activity. These results indicated NaF acted as an inhibitor of the Enbden Parnas (EMP) pathway, not as an elicitor to promote cephalotaxine production.