What type of study is being conducted when a nurse investigates the use of smokeless tobacco and its long-term effects?

The study being conducted by the nurse is classified as a prospective study because it aims to follow a group of individuals over a period of time to observe the long-term effects of smokeless tobacco use. In this type of study, participants are identified based on their exposure status (in this case, using smokeless tobacco) and are then followed forward in time to determine outcomes, such as health effects or disease development.

Prospective studies are particularly valuable for examining causal relationships and capturing changes as they happen, which enhances the reliability of the findings regarding how smokeless tobacco impacts health over an extended period. This method allows researchers to gather data on multiple variables that may influence outcomes, providing a comprehensive understanding of the long-term effects of the exposure under investigation.

In contrast, other study designs, such as retrospective studies, gather data from past records, cross-sectional studies assess individuals at a single point in time without a temporal element, and case-control studies compare individuals with a specific outcome to those without to identify prior exposures. These methodologies do not fit the description of a study examining long-term effects in the same forward-looking manner that a prospective study does.