[Contribution of environmental lead exposure to blood lead level among infants based on IEUBK model].

OBJECTIVE: To evaluate the influence of environmental lead exposure on infant's blood lead through integrated exposure uptake biokinetic model for lead in children (IEUBK) model, based on environmental lead and prenatal lead exposure. METHODS: The data is from a prospective study conducted among pregnant women during 2005 -2007. Blood lead of the pregnant women in the late pregnancy, environmental lead values including lead concentration in soil, air and drink-water were measured. Moreover, the blood lead concentrations of infants were measured as well. RESULTS: Infants were exposed to lead from the pregnant women during the pregnancy, and in the late pregnancy the geometric mean blood lead of pregnant women was (40.3 +/- 3.7) microg/L. The geometric mean blood lead concentration of six-month old infants was (54.7 +/- 6.7) microg/L and there were 17.3% infants whose blood lead concentration were above 100 microg/L. Lead in soil,atmosphere and drink-water were 45.57 mg/kg, 0.023 microg/m3 and 3.25 microg/L respectively. While based on the calculation of the IEUBK model, the value attributed to environmental lead exposure was 12.4 microg/L, accounting for 22.7% of the real blood lead level. CONCLUSION: The results indicated that environmental lead contamination in the rural area might not be the main reason of elevation in blood lead among infants, other lead resources such as food lead exposure might be the major sources for the intake of lead among infants and should be paid more attentions in future.

[Analysis on the association between job stress factors and depression symptoms].

OBJECTIVE: To identify the prevalence of depression symptoms among employees in Shanghai and to explore the association of job stress factors with depression symptoms. METHODS: Seven kinds of occupations were selected as subjects by convenient cluster sampling. Job stresses were assessed by core job stress scale and depression symptoms were measured by epidemiological survey depression scale (CES-D). Logistic regression and hierarchical moderated multiple regression were used for analysis. RESULTS: There were 1301 participants completing the questionnaires. The CES-D score reached 16. 83 +/- 8.63 and depression symptoms were in 46.2% of participants. The CSE-D score and the rate of depression symptoms were varied in different age, education and occupational status. Personal hobbies were helpful to reduce depression symptoms (OR = 0.63, 95% CI = 0.48-0.82). High social supports and high rewards were protect factors for depression symptoms, and the ORs were 0.38 (95% CI= 0.25-0.55) and 0.35 (95% CI = 0.21-0.58) respectively. High over-commitment and effort-reward imbalance were risk factors for depression symptoms, and the ORs were 2.72 (95% CI = 1.76-4.21) and 2.77 (95% CI = 1.09-7.05) respectively. The effort-reward imbalance model is more powerful in predicting depression symptoms than the job demand-control model. CONCLUSION: Effort-reward imbalance and high over-commitment are the risk factors for depression symptoms, more social supports and having hobbies are the protect factors for depression symptoms.