You are commissioned to write a quantitative systematic review.Which of the following research questions is framed in the most epidemiologically appropriate
Way?
A)What is the relation between body size and genito‐urinary cancers?
B)What is the relation between obesity and genito‐urinary cancers?
C)By how much does obesity (measured as body mass index, BMI) increase a woman's risk of developing genito‐urinary cancer?
D)By how much does obesity (measured as BMI) increase a woman's risk of developing renal (kidney) cancer?
E)By how much does body size increase risk of renal cancer?

Question

Quizplus · Accepted Answer

One of the key elements of a research question is its specificity.Genito‐
urinary cancers include cancers at all different sites in the genitor‐urinary (GU) tract and
of course these differ between men and women as well as having different sets of risk
factors.So while we might ultimately want to know about GU cancer more broadly, it
will require a series of reviews of individual cancers first.Thus A, B and C are not
appropriate, despite the more precise nature of C - even among women there are
major differences in the causes of different GU cancers; e.g.cancer of the uterine body
is related to obesity, but cancer of the uterine cervix is not.Clearly substantial
background knowledge is needed to make these judgements, and you should never
wade into a review without such insights.Both D and E focus on one cancer (although
there are subtypes of renal cancer too), and both include a quantitative element (how
big is the effect?).However D is the more precise of the two, with respect to both
exposure measurement (body size includes height and weight, as well as obesity) and
the sex‐specificity of the outcome.However both men and women have kidneys and
many studies of the association will include both sexes, so why exclude men? And while
obesity is the exposure of public health concern given its modifiability and influence on
many other diseases, there is also intrinsic biological interest in the relations between
height and disease.So perhaps if E included further specification of the subset of body
size measures to be included, and an intention to conduct sex‐specific as well as overall
analyses, that would be optimal.

You Are Commissioned to Write a Quantitative Systematic Review