(1) Copper is usually utilized in organisms as a cofactor in enzymes or electron transfer proteins that catalyze redox reactions or oxygen chemistry.(2) Alcohol intake is a cofactor in the rate of progression of chronic HCV infection.(3) To negate the effect of proximity to the microchip plant as a cofactor , the author compared clients and nonclients in the 3 zones of the exposure area.(4) Drugs and alcohol were a notable cofactor : 58 percent of the subjects reported being intoxicated during their last unprotected incident.(5) Magnesium is an important cofactor in many enzymatic reactions.(6) Anorectal infections are a potent cofactor for HIV transmission.(7) Thiamine pyrophosphate, the active form of vitamin B-1, is a key cofactor of the essential enzymes involved in carbon metabolism.(8) One potentially important cofactor is human immunodeficiency virus type 1.(9) Modifications of proteins that depend upon vitamin C as a cofactor include proline and lysine hydroxylations.(10) The anaesthetics bind in a hydrophobic pocket which is the normal binding site for a necessary cofactor .(11) Vitamin B 6 functions as a cofactor of many diverse enzymes in amino acid metabolism.(12) The other cofactors we considered are the other three families of drugs, the driver's age and sex, the type of vehicle driven, and the time of crash.(13) Other cofactors include smoking, oral contraceptive use, multiparity, and possibly inflammation.(14) The causes are clearly different from risk factors, which are the diseases accompanying cofactors .(15) Counseling can be offered to all patients with HCV infection to modify or prevent the adverse effects of cofactors , such as alcohol consumption, on disease progression.(16) Other cofactors also deserve vigorous investigation.