Which statement best describes hazard quotient and cancer slope factor?

Which statement best describes hazard quotient and cancer slope factor?

• A. Hazard quotient assesses non-cancer risk for a specific exposure (HQ = CDI/RfD); cancer slope factor quantifies cancer risk per unit dose, used to estimate ILCR (ILCR = CDI × CSF).
• B. Hazard quotient is used for cancer risk estimation only.
• C. The CSF is not used for cancer risk assessment, and HQ is not defined by CDI/RfD.
• D. Hazard quotient equals LD50.

Answer: (C)

Hazard quotient describes non-cancer risk by comparing exposure to a reference dose. It’s calculated as HQ = CDI / RfD, where CDI is chronic daily intake and RfD is the reference dose deemed without appreciable non-cancer effects. For cancer risk, we use the cancer slope factor, which gives risk per unit dose; lifetime cancer risk is estimated with ILCR = CDI × CSF, where CSF is the cancer slope factor in units that convert dose to risk. So the statement that hazard quotient is for cancer risk or that CSF isn’t used for cancer risk is not correct. Also LD50 is a measure of acute lethality, not a hazard quotient. The described relationship—HQ for non-cancer risk and ILCR = CDI × CSF for cancer risk—is the accurate framework.

Hazard quotient describes non-cancer risk by comparing exposure to a reference dose. It’s calculated as HQ = CDI / RfD, where CDI is chronic daily intake and RfD is the reference dose deemed without appreciable non-cancer effects. For cancer risk, we use the cancer slope factor, which gives risk per unit dose; lifetime cancer risk is estimated with ILCR = CDI × CSF, where CSF is the cancer slope factor in units that convert dose to risk. So the statement that hazard quotient is for cancer risk or that CSF isn’t used for cancer risk is not correct. Also LD50 is a measure of acute lethality, not a hazard quotient. The described relationship—HQ for non-cancer risk and ILCR = CDI × CSF for cancer risk—is the accurate framework.