Inadvertent fetal exposure to contraceptive hormones is common, with a USA study
estimating that approximately 70 000 fetuses are exposed to oral contraceptives annually.23
Most of the data on fetal outcomes relate to COC. The CEU found no studies that specifically
assessed exposure through quick starting contraception. Studies are often limited by their
observational nature, potential confounding factors and small sample size. Reassuringly there
have been no consistent findings of specific fetal abnormalities.
The different sources of potential confounding in time series studies of air pollution and
mortality can be broadly classiﬁed as either measured or unmeasured. Important measured
confounders include weather variables such as temperature and dewpoint temperature. Daily
temperature measurements are readily available for metropolitan areas in the USA and numer-
ous studies have demonstrated a relationship between temperature and mortality which is gen-
erally positive for warm summer days and negative for cold winter days (e.g. Curriero et al.
The critical role of the NMMAPS in the development of the air quality standards attracted
intense scrutiny from the scientiﬁc community and industry groups regarding the statistical
models that are used and the methods that are employed for adjusting for potential confound-
ing. Confounding occurs when an attribute that is associated with an outcome is also associated
with the exposure of interest but is not a result of the exposure. In time series studies, we
are primarily concerned with potential confounding by factors that vary on similar timescales
as pollution or mortality.
Another limitation of the literature is that minorities have been dramatically under-
represented in psycho-oncology research (Anderson, 1992). Further, although the research
demonstrates the importance of the spousal relationship during the cancer experience,
there is a lack of controlled research concerning couples or family interventions. Finally,
a crucial question that remains unanswered is determining what these findings mean in
terms of clinical intervention and care.
Case studies for emerging risks in the second section include evidence-based
precautionary interventions to safeguard blood supplies, the evaluation of
nanoparticle deposition in the lung and nasal airways and the discourse surrounding
emerging potential health risks of genetically modified animals consumed as food.
The third chapter by Tyshenko et al.
In practice, signatures that predict toxicity or efficacy can be identified afterwards. For example,
therapies targeting the Epidermal Growth Factor Receptor have been first approved before it was
demonstrated that mutations in KRAS cancer gene were associated to failures of the relevant
therapies in metastatic colorectal carcinoma. This example shows that well-designed
retrospective analysis of data from prospective randomized controlled trials can bring forward
effective treatments to biomarker defined subgroups of patients in a timely manner.