LAUSR

Cross-sectional studies - often defined as those in which exposure and outcome are assessed at the same point in time - are frequently viewed as minimally informative for causal inference. While cross-sectional studies may be susceptible to reverse causality, limited to assessment of disease prevalence rather than incidence, or only provide estimates of current rather than past exposures, not all cross-sectional studies suffer these limitations. Moreover, none of these concerns are unique to or inherent in the structure of a cross-sectional study. Regardless of when exposure and disease were ascertained relative to one another, a cross-sectional study may nonetheless provide insights into the causal effects of exposure on disease incidence. Simply labeling a study as "cross-sectional" and assuming that one or more of these limitations exist and are materially important fails to recognize the need for a more nuanced assessment and risks discarding evidence that may be useful in assessing causal relationships.