The conclusion that nonsedating antihistamines and antibiotics contribute to CRS-related fatigue rests, as noted in the article, on the variable chosen as a control for the confounder
of disease symptomatic severity.
That particular confounder
was the whole reason the Ranch Hand study could even be done.
In this paper a confounder
is defined as a variable that wholly or partially accounts for, or masks, an association with a third variable.(2) In the case of drinking and driving, a confounder
is a correlate of DWI that is associated with other predictors but is not a consequence of those predictors.
Suppose there is an unmeasured confounder
. Because we are conducting a time-series analysis, the confounder
must be correlated with exposure and outcome over time (but within month).
Because the included studies were all observational, a final sensitivity analysis was done to assess the possible effect of unknown and unmeasured confounders
. This revealed that an unmeasured confounder
would have to be severely imbalanced between the acid-suppression users and nonusers, by an odds ratio of 10, or would have to increase the risk of CDI by at least twofold to account for this association.
That is, rather than assume an M structural design which suggests that "X" is a collider but not a confounder
, the authors adopt what they consider to be a more reasonable position and that is "X" is both a collider and confounder
Maternal intelligence, however, has largely been overlooked as a potential confounder
in studies investigating the effects of breast-feeding, according to Geoff Der, a statistician at the Medical Research Council's Social and Public Health Sciences Unit in Glasgow, Scotland.
However, one of the most prominent limitations of observational studies based on those data sources is the lack of important confounder
The study authors recommend that future EDC studies consider whether a confounder
might have a sex-specific impact on the outcome of interest and incorporate the augmented product term approach in statistical analysis to reduce the risk of inaccurate conclusions.
adjustment, lean multivitamin users had a 71% reduction in pre-eclampsia risk compared with lean non-users.
Boosting may at times produce large reactions and in all serial TB studies will be a potential confounder
TABLE 1 Instrumental variables and categories of associated confounders
(with example and variables) Instrumental variable category Distance to facility instrument Confounder
category violating IV assumptions (associated with IV and mortality) Geographic Urban/rural, U.S.