draft a detailed response to the below discussion

The study design, participants, and data collection methods used Cao et al. (2025) utilized retrospective population-based cohort study design to examine onset colorectal cancer and diagnosis among individuals ages 20 and older in Australia. This study is deemed a retrospective population-based cohort study design primarily because the researchers utilized pre-existing or secondary data from a particular study population to assess long- term survival outcomes in young- onset colorectal cancer (Cao et al., 2025; Creswell, 2009; Frankfort-Nachmias & Nachmias, 2008). Furthermore, the study retrospectively looks back in time, utilizing data already collected, in addition to also, in terms of population-based aspect, the researchers got the cohort from a particularly well-defined population, and this can foster generalizability of the study findings (Cao et al., 2025; Creswell, 2009; Frankfort-Nachmias & Nachmias, 2008). For example, the researchers used all colorectal cancer diagnoses between 2001 and 2020 in the state of Queensland, Australia among Young- onset colorectal cancer individuals ages 18 years and older.

According to Creswell (2009); Frankfort-Nachmias & Nachmias (2008), the study participants are normally defined as a specific population group including people living in a defined geographic area or share similar culture. The researchers' study participants fell into this category. Thus, the inclusion criteria for this study were all adult patients diagnosed with colorectal cancer between 2001 and 2020 in Queensland, Australia; all adult patients aged 18years and older diagnosed with colorectal cancer and the exclusion criteria were basically, all individuals aged 20 years and younger, living outside Queensland, Australia (Cao et al., 2025).

Cao et al. (2025) used a data collection method that entailed using existing databases/secondary and data sources. For example, they collected data from the pre- existing Queensland Oncology Repository (QOR), a state- wide clinical cancer database that has cancer diagnostic, treatment and outcomes data information on all cancers diagnosed among Queensland residents since 1982. They also collected and used data from the Queensland Cancer Control Analysis Team (QCCAT) database and some census data for demographic information (Cao et al., 2025). The researchers extracted deidentified data records of all adult patients aged 18years and older diagnosed with colorectal cancer in Queensland, Australia, in addition to extracting baseline demographics including age, sex, comorbidities and socioeconomic status.

How the exposure and outcome variables were measured Clearly, Creswell (2009); Frankfort-Nachmias & Nachmias (2008), mentioned that exposure variables found in the data source usually are known to be factors that are hypothesized to affect outcomes or dependent variables. Thus, in Cao et al. (2025)'s study, exposure variables from the data source are the factors that are hypothesized to affect survival outcomes in young-onset colorectal cancer patients such as demographics including sex, age, comorbidities and socioeconomic status such as poverty level. The researchers used two- sample t- test for continuous variables, chi- square test for categorical variables, Kaplan-Meier survival curves and the log- rank test for cancer- specific survival, and multivariable Cox regression models for overall and cancer- specific death after adjusting or accounting for sex, stage, and socioeconomic status. Also, the exposure variables were measured by the researchers through baseline demographics including age, sex, comorbidities and socioeconomic status and compared between the groups (Cao et al., 2025). Furthermore, the outcome variable in the study is long-term survival or cancer- specific survival and thus, is measured as the time from when the patient was diagnosed to death or the end of the study period using existing data/ secondary data. Or basically, by carefully tracking the survival time of the patients within the cohort study (Cao et al., 2025). Cao et al. (2025) for example, compared young- onset colorectal cancer (20-49years) with late- onset colorectal cancer (50years+) and additionally, cancer- specific data such as age at diagnosis and cancer- specific survival were reviewed by the researchers.

Ethics involved in the study According to Aschengrau et al (2020); Creswell (2009); Frankfort-Nachmias & Nachmias (2008), maintaining rigorous ethical standards are vital to ensure rigorous, safe, and credible research, and thus, such ethical considerations entail properly maintaining patient confidentiality to protect participants from unfavorable problems in the community. For example, in the study, the researchers used deidentified data from secondary or pre- existing Queensland Oncology Repository and Team (QCCAT) database, received ethics approval from the Metro South Human Research Ethics Committee (IRBs) (EX/2023/QMS/103458). The researchers also used strict safety and quality, quality cancer care, and adhered to data protection regulations, in addition to properly obtaining participant's written consent before participating in the study.

The costs and benefits to the participants in the study Clearly, as Creswell (2009); Frankfort-Nachmias & Nachmias (2008) noted, for example, costs to participants in a retrospective population-based cohort study design are fairly usually very low and thus, this could be mainly attributed to the fact that no new data or information is gathered or collected directly from them. Furthermore, in such a study, benefits to participants may generally entail better understanding of health outcomes such as colorectal cancer, more improvements in people's health behaviors, improve healthcare provision, bring about better social determinants factors in the community, and better health policies based on the study results (Aschengrau et a,2020; Cao et al., 2025; Creswell, 2009; Frankfort-Nachmias & Nachmias, 2008).