LWBK1006-04 LWW-Govindan-Review November 24, 2011 11:19
Chapter 4•Etiology of Cancer Part 2 67Answer 4.24. The answer is A.
The food frequency questionnaire requests subjects to recall and
report their average intake of a variety of food over the preceding year.
Although this instrument tends to overrepresent foods considered healthy
(vegetables and fruits, so-called social desirability bias), it is the most
widely used in large studies of dietary pattern reporting in large studies.
The 24-hour recall method offers too narrow a window to accurately
reflect dietary patterns, and the 7-day diary record is cumbersome for
data transfer and extraction.Answer 4.25. The answer is C.
In this study of more than 900,000 individuals who were cancer free at
enrollment in 1982, an increased BMI was associated with an increased
risk of cancer-related death. Cancers of the esophagus, pancreas, liver, gall
bladder, colorectal, kidney, breast, uterus, and cervix were among those
in which this association was noted, whereas no such relation was found
for cancers of the brain and bladder and for melanoma. The relative risk
of death from cancer was 1.52 and 1.62 in men and women, respectively,
who had a BMI greater than 40, compared with individuals of normal
weight. Elevated levels of endogenous estrogen, insulin, and proinflam-
matory factors, and decreased levels of sex hormone binding proteins and
insulin-like growth factor, are believed to contribute to the increased risk
of cancer in overweight individuals.Answer 4.26. The answer is B.
Acetaldehyde is a known carcinogen that increases the proliferation of
epithelial cell and forms DNA adducts. Alcohol consumption has been
associated with development of breast and colorectal malignancies. In
the developed world, approximately 75% of the esophageal and head and
neck malignancies are associated with alcohol and tobacco consumption,
which have a synergistic carcinogen effect. For most malignancies, there
are no significant differences regarding the type of alcoholic beverage,
suggesting the pivotal role of alcohol in carcinogenesis.Answer 4.27. The answer is B.
Initial case-control studies examining the relation of breast cancer in
women to the consumption of dietary fat suggested a positive correla-
tion with a pooled relative risk of 1.35 in a meta-analysis of 12 studies.
This risk was greater in postmenopausal women. However, cohort studies
have failed to confirm these findings, including the large Nurses’ Health
Study and the Women’s Health Initiative Randomized Controlled Dietary
Modification Trial.Answer 4.28. The answer is B.
Several studies have demonstrated an increased risk of colorectal cancer
with the regular consumption of red meat, with a stronger association
with processed meat. A meta-analysis of prospective studies examining
this subject confirms these findings with a relative risk of 1.24.