JULY
2005
Compiled by Winfred Wu, MD
Resident, Pfizer Practicum Rotation in Health Policy and
Preventive Medicine
Statins and colorectal cancer
Low-Dose Aspirin
and cancer
Vitamin e and cancer
Race and Mortality
Chemical air pollution and emergency response
Statins and
colorectal cancer
Case-control study reveals that long-term statin use
appears to be associated with reduced rates of
colorectal cancer.
The
Molecular Epidemiology of Colorectal Cancer study
utilized a case-control design to examine the
association between statin use and colorectal cancer.
The study matched 1,953 patients who were diagnosed with
colorectal cancer between 1998 and 2004 by age, sex, and
ethnicity to controls from the same clinics.
Self-report on statin use was measured by interview and
confirmed by prescription records in a subgroup of the
study population.
The
use of a statin for at least 5-years was inversely
associated with colorectal cancer (unadjusted odds ratio
0.50, 95% confidence interval 0.40-0.63). When other
factors were controlled for, including physical
activity, family history, high cholesterol, and
vegetable consumption, there was still an inverse
association between the drug and colorectal cancer
(adjusted odds ratio 0.53, 95% confidence interval
0.39-0.74).
Poynter JN, Gruber SB, Higgins PD, Almog R, Bonner
JD, Rennert HS, Low M, Greenson JK, Rennert G.
Statins and the Risk of Colorectal Cancer. N Engl J
Med. 26 May 2005; 352:2184-2192.
July 2005 Index
Low-Dose Aspirin
and cancer
Results from the Women’s Health Study suggest that
long-term low-dose aspirin use does not decrease the
risk of breast or colorectal cancer in women.
Data
analysis from the Women’s Health Study shows that there
is no decrease in the risk of cancer for women who take
long-term low-dose aspirin. The Women’s Health Study
followed 39,876 healthy women ages 45 or older over an
average of 10.1 years. The researchers were studying
the effect of aspirin on cancer risk in healthy women.
It is the first randomized trial to look at the effect
of aspirin on breast cancer risk in women. The primary
outcome measure was invasive cancer of any time (except
nonmelanoma skin cancer). The results showed that there
was no effect on total cancer (relative risk 1.01, 95%
confidence interval 0.94-1.08), breast cancer (relative
risk 0.98, 95% confidence interval 0.87-1.09), or
colorectal cancer (relative risk 0.97, 95% confidence
interval 0.77-1.24).
Overall cancer mortality also was not effected by
aspirin use (relative risk 0.95, 95% confidence interval
0.81-1.11). However, there was an apparent reduction in
risk for lung cancer mortality with aspirin use
(relative risk 0.70, 95% confidence interval 0.50-0.99,
P=.04). Thus, the authors were unable to rule out a
possible protective effect on lung cancer.
Cook NR, Lee I, Gaziano JM, Gordon D, Ridker PM,
Manson JE, Hennekens CH, Buring JE. Low-Dose
Aspirin in the Primary Prevention of Cancer. JAMA.
6 July 2005; 294:47-55.
July 2005 Index
Vitamin e and cancer
Long-term vitamin E supplementation in women is not
found to be of benefit in overall major cardiovascular
events, cancer, or total mortality.
The
Women’s Health Study followed 39,876 women to study the
effect of Vitamin E on cardiovascular events and cancer
in healthy women. These same women were also part of
the low-dose aspirin study. The participants were
randomized to receive either 600 IU of natural-source
vitamin E every other day or placebo. Overall major
cardiovascular events (defined as nonfatal myocardial
infarction or stroke, and cardiovascular death) were not
significantly affected by vitamin E (relative risk 0.95,
95% confidence interval 0.82-1.05). However, when
analyzing cardiovascular death alone, there was a 24%
risk reduction in death with vitamin E (relative risk
0.76, 95% confidence interval 0.59-0.98, P=.03). In
addition, subgroup analysis revealed that women aged 65
and older experienced a 26% relative risk reduction
(relative risk 0.74, 95% confidence interval 0.59-0.93,
P=.009) in major cardiovascular events.
Analysis of vitamin E on cancer demonstrated that there
was no benefit rendered by supplementation. Overall
incidence of cancer between those who received vitamin E
and those who received placebo was not significant
(relative risk 1.01, 95% confidence interval
0.94-1.08). In addition, total mortality was not
significantly affected (relative risk 1.04, 95%
confidence interval 0.93-1.16).
The
researchers point out in the study that the risk
reduction of cardiovascular death is not consistent with
the body of research to date and that this needs to be
investigated further. Overall, the authors conclude
that the Women’s Health Study data does not support the
recommendation of vitamin E supplementation for primary
prevention of major cardiovascular events or cancer in
healthy women.
Lee I, Cook NR, Gaziano JM, Gordon D, Ridker PM,
Manson JE, Hennekens CH, Buring JE. Vitamin E in
the Primary Prevention of Cardiovascular Disease and
Cancer. JAMA. 6 July 2005; 294:56-65.
July 2005 Index
Race and Mortality
Study examining standardized mortality ratio trends
between blacks and whites shows improvement in some
areas, worsening in others.
The
researchers in this study examined the standardized
mortality ratio (SMR) trends between blacks and whites
from 1960 through 2000. Overall, the SMR for blacks has
decreased from 1.472 in 1960 to 1.412 in 2000. More
recent data analyzed by the authors has shown further
improvement (1.405 in 2002). This SMR still translates
into 40.5% more death (83,570 deaths) in blacks compared
to if they had the mortality rate of whites. Looking at
gender specifically, African American females have had
an SMR which has trended down between 1960 to 2000
(1.607 to 1.342). However, African American males have
experienced an increase (1.376 to 1.487). Infant
mortality rate between blacks and whites has also
worsened (male infants 1.970 to 2.519; female infants
2.073 to 2.515).
The
limitations of the study included not examining
covariates and not taking into account other measures
(morbidity, functional status, quality of life). The
authors called for a reduction in the disparities in the
system—both medical and community wide.
Satcher D, Freyer Jr GE, McCann J, Troutman A, et al. What
If We Were Equal? A Comparison of the Black-White
Mortality Gap in 1960 and 2000. Health Affairs.
Mar/Apr 2005; 24(2):459-464.
July 2005 Index
Chemical air pollution and emergency response
Adverse health symptom scores found to be lower in those
people sheltered at home compared to those evacuated
from area after a plastics factory fire in England.
Experts have advised that keeping people sheltered in
their homes versus evacuation is the preferred
response. Prior to this report, there has been no data
from an actual incident to confirm this recommendation.
The researchers from this study performed a
cross-sectional study of residents from the area
surrounding a plastics factory in England that had
experienced a fire. Researchers administered a
standardized questionnaire to 1,096 out of a total of
1,750 persons regarding the symptoms they experienced
during the emergency response to the fire. Of the 1,096
questioned, 299 had been evacuated and the remaining 797
had been instructed to remain indoors.
The average adverse symptoms scores of those who were
evacuated were higher compared with those instructed to
remain sheltered. One of the two modifiable risk
factors most associated with becoming a case (defined as
having four or more adverse health symptoms) was
evacuation (odds ration 2.5, 95% confidence interval
1.7-3.8). The other was direct exposure to the smoke
for more than two hours on the first day of the fire.
The distance from factory to residence had little impact
on the odds of becoming a case.
Kinra S, Lewendon G, Nelder R, Herriott N, Mohan R,
Hort M, Harrison S, Murray V. Evacuation decisions
in a chemical air pollution incident: cross
sectional survey. BMJ. 25 June 2005;
330:1471-1475.
July 2005 Index
