Estimated means of serum and urine heavy metal levels between patients with RA and controls analysed by complex sample design
| RA | Control | P value | ||
| Group 1 | Serum Cd (μg/L) | 1.30±0.07 | 1.17±0.01 | <0.01 |
| Serum Pb (μg/dL) | 2.38±0.07 | 2.44±0.02 | 0.51 | |
| Serum Hg (μg/L) | 4.70±0.26 | 4.85±0.06 | 0.82 | |
| Group 2 | Serum Mn (μg/dL) | 1.29±0.04 | 1.34±0.01 | 0.26 |
| Urine As (μg/L) creatinine | 143.90±14.16 | 154.07±3.51 | 0.49 | |
| Group 3 | Serum Zn (μg/dL) | 131.42±4.53 | 134.94±1.70 | 0.54 |
All serum and urine heavy metal levels were adjusted by age, sex, socioeconomic status and smoking status (serums Cd, Pb, Hg, Mn and Zn by WHO definition of smoking, urine As by definition of current smoking).
The WHO definition of smoking: those who have smoked 100 cigarettes or more in their whole life. Definition of current smoking: those who are currently smoking and have smoked 100 cigarettes or more in their whole life.
RA, rheumatoid arthritis.