Immunological investigations point to a contribution of responses outside the Th2 pathway and multiple potential but unproven control mechanisms.
Oligonucleotides spotted in multiple locations for use as potential controls included 76 Arabidopsis thaliana gene spots, 17 beta tubulin spots, 17 glyceraldehyde-3-phosphate dehydrogenase spots, 85 heat shock protein gene spots, 69 ribosomal protein gene spots, 112 randomly generated negative control spots and 470 blanks.
These observations were robust to analytic control for multiple potential confounders including age, sex, insurance status, geography and hospital ownership.
These results were significant after extensive and rigorous control for multiple potential confounders, including several non-PCB contaminants (prenatal MeHg, DDE, HCB, and pre- and postnatal Pb).
They control for multiple potential confounds, and possibly the most important is data quality enabling confidence in the results.
However, a randomised trial of indoor tanning is not realistic, and most of the included studies controlled for multiple potential confounders, making this the best level of evidence possible.
The novel finding in our population-based study, controlled for multiple potential confounders, was that vitamin B12 levels showed an independent linearly inverse association with the risk of melancholic DS but not with non-melancholic DS.
SWIFT is the first study to prospectively examine whether lactation intensity and duration are associated with a lower the 2-year incidence of type 2 diabetes after GDM pregnancy, controlling for multiple potential confounders.
General strengths of our study include the population-based, prospective design, the ability to control for multiple potential confounding factors in multivariate risk models and the molecular pathological epidemiology approach linking life style exposures to different tumour markers [ 14].
Third, the nonrandomized design may subject the results to treatment selection bias; however, the completeness of the KPSC database allowed us to control for multiple potential confounders, including laboratory results and hospitalization data.
