Unfortunately, the authors overlooked the majority of the studies specific to their study question including seventy-four studies that were left out of their literature review. In addition, these authors included studies with invalid methods of measuring the sagittal plane lumbar curve and pooled this data with valid measurement methods thereby further diluting health benefit correlative findings.
The authors chose the odds ratio and risk ratio as the gold standard and gave lower ratings to studies that used other forms of statistical analysis including ROC curves, linear regression modeling, and linear correlation between variables. They additionally applied the STROBE instrument in an inappropriate manner and inappropriately grouped disparate spinal displacements together as spinal curves.
Using the data provided by these authors combined with the studies cited herein reveals that the majority of the studies (100/128 or 78%) have found a positive association between sagittal plane curves/posture and health disorders. Thus, the evidence indicates that altered sagittal plane curves and posture are associated with a variety of health disorders.
Better designed and executed systematic reviews are necessary to accurately evaluate the strength of the evidence for the relationship between sagittal spinal configuration (and sagittal plane posture) and various health parameters.
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