The paper “Menopausal hormone use and ovarian cancer risk: individual participant meta-analysis of 52 epidemiological studies”, by the Collaborative Group on Epidemiological Studies of Ovarian Cancer, 2015 Lancet Feb 12, pii: S0140-6736(14)61687-1, doi: 10.1016/S0140-6736(14)61687-1 was published in a high impact factor journal (The Lancet IF=39.207).
It has many study strengths that match the high impact and breadth of study of The Lancet. These include the large sample (21,448 patients), and the use of data from 52 epidemiological studies worldwide, including those in Europe, the United States, Australia, and China. These features increase the external validity of the study and enable the findings to be extrapolated to other populations.
In comparison to example #1, the paper “Effects of hormone replacement therapy on depressive and anxiety symptoms after oophorectomy”, by Ðoković et al. 2015, Med Glas (Zenica), 12:79–85 was better suited to the lower impact factor journal Med Glas (Zenica) (IF=0.202) because it is has a much narrower scope.
For example, the study had a smaller sample (80 patients) and the study specifically analyzed the effect of hormone replacement therapy on depressive and anxiety scores.