Understanding the hierarchy of evidence in academic research allows evaluating their results more accurately and, therefore, apply research outcomes to clinical situations appropriately. In their respective studies, AbdelKader and Nassar (2019), Bai and Dai (2018), and Hollams et al. (2011) examine a similar issue of pulmonary issues in children, yet the levels of evidence that they set are quite different. Due to the differences in the approaches toward constructing a case study (cross-sectional, case-control, and longitudinal cohort ones respectively), AbdelKader and Nassar (2019), Bai and Dai (2018), and Hollams et al. (2011), the extent of causality varies significantly across the articles.
Examining the results of each study, one will notice a significant difference in the levels of causality and the rate of research bias. Specifically, the papers by AbdelKader and Nassar (2019) and Hollams et al. (2011) have established clearer causality and provided more compelling evidence than the article by Bai and Dai (2018) due to the limitations of the case-control study framework that Bai and Dai’s (2018) research inherently contained. Specifically, AbdelKader and Nassar (2019) state explicitly that the deficiency in Vitamin D leads to a rise in the risk of wheezing in children. Likewise, Hollams et al. (2011) has managed to prove a clear cause-and-effect relationship between the presence of Vitamin D in children and the resulting development of apathy. In turn, Bai and Dai’s (2018) analysis shows that the increase in Vitamin D reflects proper pulmonary function, which is a significantly weaker statement.
A similar paradigm can be found in the implications of each study, with AbdelKader and Nassar’s (2019) research and Hollams et al.’s (2011) paper making a much stronger case for an appropriate intervention. Finally, the gaps in AbdelKader and Nassar’s (2019) and Hollams et al.’s (2011) papers fail to access incidence and rare conditions, whereas Bai and Dai’s (2018) paper may contain sampling bias since some of the conditions may not be typical for the studied population.
AbdelKader, A. M., & Nassar, M. F. (2019). Serum 25-hydroxyvitamin D status and wheezing in pre-school children, Kuwait. Eastern Mediterranean Health Journal, 25(3), 197–204. Web.
Bai, Y. J., & Dai, R. J. (2018). Serum levels of vitamin A and 25-hydroxyvitamin D3 (25OHD3) as reflectors of pulmonary function and quality of life (QOL) in children with stable asthma: A case–control study. Medicine, 97(7), 1-7. Web.
Hollams, E. M., Hart, P. H., Holt, B. J., Serralha, M., Parsons, F., De Klerk, N. H.,… & Holt, P. G. (2011). Vitamin D and atopy and asthma phenotypes in children: A longitudinal cohort study. European Respiratory Journal, 38(6), 1320-1327. Web.