[Associations between blood thallium and lipid profile in Chinese adults aged 18-79 years].

Objective: To analyze the association of the blood thallium exposure with lipid profile in Chinese adults aged 18-79 years. Methods: From 2017 to 2018, 9 795 adults aged 18-79 years were enrolled in China National Human Biomonitoring (CNHBM). The information about their demographic characteristics, lifestyles, and physical examinations were collected. Fasting venous blood samples were collected to measure blood thallium level. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) concentrations were also under testing. Study subjects were divided into five groups (Q₁, Q₂, Q₃, Q₄ and Q₅) according to the blood thallium concentration. Weighed linear regression model was used to analyze the association of blood thallium and lipid levels. Restricted cubic spline (RCS) was used to analyze the dose-response relationship between blood thallium and lipid profile. Results: The weighed average age of the 9 795 participants was 47.42 (0.24) years, of which 4 912 were male. The median level of blood thallium M(Q₁,Q₃) was 0.03 (0.02,0.06) μg/L. The levels of TC, TG, LDL-C, and HDL-C were 5.12 (4.47, 5.84) mmol/L, 1.42 (1.02, 2.13) mmol/L, 2.90 (2.34, 3.52) mmol/L, and 1.37 (1.12, 1.68) mmol/L, respectively. Weighted linear regression model showed that thallium after natural logarithmic transformation was associated with TC and the β(95%CI) was 0.07 (0-0.13) (P=0.040). When TC was used as the dependent variable, compared with Q₁, the β(95%CI) of Q₂, Q₃, Q₄ and Q₅ were 0.13 (0.05-0.21), 0.12 (0.01-0.24), 0.12 (0.02-0.23) and 0.16 (0.03-0.30), respectively. When TG was used as the dependent variable, compared with Q₁, the β(95%CI) of Q₅ was 0.28 (0.13-0.42) (P<0.001). In the RCS model, blood thallium was positively and linearly associated with TC and TG levels (P_linear 0.006, and 0.004, respectively), and had a nonlinear dose-response relationship with HDL-C (P_non-linear=0.027). Conclusions: Blood thallium exposure is associated with elevated TC and TG levels in Chinese adults aged 18-79 years. There is a nonlinear dose-response relationship between thallium and HDL-C.