While obtaining a client's health history related to smoking cigarettes, the nurse plans to determine the client's smoking pack years. What information should the nurse obtain for this calculation? Select all that apply.

A. The number of packs of cigarettes smoked per day is essential for calculating smoking pack years, as it directly impacts the total exposure to cigarette smoke. This figure, multiplied by the number of years the client has smoked, gives the pack years. B. While the age when the client started smoking can provide context, it is not directly used in the calculation of pack years. The calculation requires the total number of years smoked, not the starting age. C. The client's current age is not necessary for the calculation of pack years. What matters is the total number of years the client has smoked. D. The number of attempts to quit smoking is not relevant to calculating pack years. This information may be useful for understanding the client’s smoking history and readiness to quit but does not factor into the pack year calculation. E. The number of years the client smoked is crucial for determining pack years, as it, along with the packs per day, determines the total exposure to cigarette smoke over time.