Quality of life among medical students: Analysis of pooled cohorts in the prospective POLLEK cohort study.

BACKGROUND: We assessed whether two consecutively recruited cohorts of medical students were sufficiently comparable to support pooled analyses of quality of life (QoL) and health outcomes. DESIGN AND METHODS: A total of 892 first-year students from a single medical school in Poland, recruited in 2021/2022 (cohort A) and 2022/2023 (cohort B) academic years, were evaluated with standardized instruments (WHOQOL-BREF, AUDIT, GHQ-28). Cohorts were compared using the chi-square and Mann-Whitney U tests for sociodemographic, lifestyle, and health parameters; longitudinal changes were tested with paired Wilcoxon tests. RESULTS: Most baseline characteristics were similar between the two cohorts, with significant differences observed only for relationship status, residence, and smoking. Between the first and second academic years, a statistically significant deterioration was observed in the somatic and psychological domains of the WHOQOL-BREF (52.28→45.16 and 61.32→55.63, respectively), whereas GHQ-28 scores improved (32.73→29.69) (all p<0.001). Limitations include self-report bias, single-site sampling, and short follow-up. CONCLUSIONS: When baseline comparability is demonstrated, pooling consecutive student cohorts may be reasonable and may support more precise monitoring of QoL and mental health over time. Future research should consider advanced longitudinal methods to examine age and cohort effects over extended follow-up.