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October 2007
Compiled
by Rob Lipsitz, MD, MPH
Resident, Pfizer Practicum Rotation in Health Policy and
Preventive Medicine
ACPM
periodically compiles and abstracts journal articles of
interest to preventive medicine physicians. The latest
entries include articles on cancer risk, prostrate cancer,
asthma rates in 9/11 workers, obesity and soft drink
consumption.
SMOKING MAY CAUSE PERMANENT DAMAGE TO GENES CAUSING
LIFELONG CANCER RISK
DEBATE CONTINUES OVER EFFICACY OF
PROSTATE CANCER SCREENING
Swiss study finds prostatectomy may afford best
opportunity for long-term prostate cancer survival
9/11 RESCUE AND RECOVERY WORKERS HAVE HIGHER RATES OF
ASTHMA
OBESITY TRANSMITTED VIA NETWORKING
SOFT DRINK CONSUMPTION ASSOCIATED WITH INCREASED RISK FOR
METABOLIC SYNDROME FOR MIDDLE AGED ADULTS
SMOKING MAY CAUSE PERMANENT DAMAGE TO GENES CAUSING
LIFELONG CANCER RISK
The
August 2007 issue of
BMC Genomics suggests smoking permanently
alters some genes leading to a lifelong risk of lung
cancer.
Investigators at the British Columbia Cancer Research
Center, British Columbia, Canada found expression of GSK3B
was irreversibly decreased in smokers. GSK3B is a gene
which inhibits COX2 expression which is viewed to play a
significant role in development of cancer in the
endothelial lining of the lung.
The
authors conclude that expression levels of some of the
genes related to tobacco smoking return to levels similar
to non-smokers upon cessation of smoking, while expression
of others such as the GSK3B appear to be permanently
altered despite prolonged smoking cessation. These
irreversible changes may account for the persistent lung
cancer risk despite smoking cessation.
Chari R et al.
"Effect of active smoking on the human bronchial
epithelium transcriptome."
BMC Genomics
2007; 297: doi:10.1186/1471-2164-8-297
Table of Contents
DEBATE CONTINUES OVER EFFICACY OF
PROSTATE CANCER SCREENING
In the
August issue of the
Journal of the National Cancer Institute,
investigators published results of a study which found
that there was no difference in the cumulative incidence
of interval cancer or aggressive cancer between men
screened every two years vs. those screened every four
years with PSA testing.
This
study was done as part of the larger European Randomized
Study of Screening for Prostate Cancer (ERSPC).
Researchers in Sweden and the Netherlands compared
cumulative incidence of interval cancer in men screening
for prostate cancer every two or four years. 4202 men in
Gothernberg, Sweden were screened every two years and
13301 men in Rotterdam, Netherlands were screened every
four. The investigators found the 10-year cumulative
incidence of all prostate cancers in Rotterdam
versus Gothenburg was 1118 (8.41%) versus 552 (13.14%)
(P<.001),
the cumulative incidence of interval cancer was
57 (0.43%) versus 31 (0.74%) (P
= .51), and the cumulative incidence of
aggressive interval cancer was 15 (0.11%) versus 5 (0.12%)
(P =
.72).
While
this study provides evidence to limit PSA screening to
every four years, the overarching question, ‘is prostate
cancer screening efficacious?’ remains unanswered.
Roobol
MJ, Grenabo J, Schröder FH, Hugosson J. Interval cancers
in prostate cancer screening: comparing 2- and 4-year
screening intervals in the European Randomized study of
Screening for Prostate Cancer, Gothenburg and Rotterdam.
In: J Natl Cancer Inst
(2007) 99:1296–303.
Table of Contents
Swiss study finds prostatectomy may afford best
opportunity for long-term prostate cancer survival
In a new
study published in the October Archives of Internal
Medicine investigators found that individuals undergoing a
prostatectomy for prostate cancer had a significantly
lower risk of dying from the cancer when compared to those
who had radiotherapy or opted for watchful waiting.
In the Swiss based study researches used a
population-based cohort of all 844 Geneva patients
having a diagnosis of localized prostate cancer
between January 1, 1989, and December 31,
1998. Treatments followed were prostatectomy (n = 158),
radiotherapy (n = 205), watchful waiting
(n = 378), hormone therapy (n = 72), and other
types of therapy (n = 31). They found treatment options
minimally affected 5-year prostate cancer
specific mortality but had a significant effect on
long-term mortality. For patients who underwent surgery,
radiotherapy, and watchful waiting, respectively
ten-year specific survival was 83% (95%
confidence interval [CI], 73%-93%), 75% (95% CI, 67%-83%),
and 72% (95% CI, 66%-80%). At 10 years
radiotherapy and watchful waiting patients’
risk of death from prostate cancer was significantly
increased when compared with patients who underwent
prostatectomy (multi-adjusted hazard ratio, 2.3
[95% CI, 1.2-4.3] and 2.0 [95% CI, 1.1-3.8]). It was noted
that the radiotherapy and watchful waiting
mortality increase was mostly seen in patients with poorly
differentiated cancer and those younger than 70.
Arnaud
Merglen, MD; Franz Schmidlin, MD; Gerald Fioretta, BSc;
Helena M. Verkooijen, MD, PhD; Elisabetta Rapiti, MD, MPH;
Roberto Zanetti, MD; Raymond Miralbell, MD; Christine
Bouchardy, MD, MPH, Short- and Long-term Mortality With
Localized Prostate Cancer,
Arch Intern Med. 2007;167:
1944-1950.
Table of Contents
9/11 RESCUE AND RECOVERY WORKERS HAVE HIGHER RATES OF
ASTHMA
A large
retrospective cohort reported in the August issue of
Environmental Health
Perspectives found that the rate of
self-reported newly-diagnosed asthma in 9/11 rescue and
recovery workers was twelve times higher then the general
population.
Researchers reviewed interview data from 29,626
participants of the World Trade Center Health Registry (WTCHR).
Variables studied included gender, age, NYC residence
status on September 11, 2001, education, affiliated
organization at the WTC site, smoking status, exposure to
the initial dust cloud, first date of work, work history
on the pile, use of masks and respirators, and asthma
history. Those under age 18, with a prior history of
asthma and/or missing any of the analytic variable data
were excluded.
The
researchers asked “Have you ever been told by a doctor or
other health professional that you had asthma?” If
registrants responded positively, they were asked to
further specify, “Did a doctor or other health
professional first tell you that you had asthma before
9/11 or after 9/11?” They defined newly diagnosed asthma
as cases diagnosed after September 11, 2001.
They
found 926 registrants reported being told they had asthma
for the first time after September 11, 2001, which was
equivalent to a three-year risk of 3.6%. This was twelve
times higher than the expected 0.3% three-year risk of
asthma, based on the reported incidence of asthma in the
general adult population of 100/100,000 person-years.
Interestingly the frequency of workers reporting
newly-diagnosed asthma increased with arrival dates closer
to the time of the collapse and with longer duration of
work. The highest three-year risk of newly-diagnosed
asthma was reported by workers who arrived on September 11
and worked over 90 days.
The
authors conclude the findings underscore the need for
adequate and timely distribution of appropriate protective
equipment, and the enforcement of its use when other
methods of controlling respiratory exposures are not
feasible.
Wheeler K, et al, Asthma Diagnosed after September 11,
2001 among Rescue and Recovery Workers: Findings from the
World Trade Center Health Registry
Environmental Health Perspectives
doi:10.1289/ehp.10248 (available at
http://dx.doi.org/), Online 27 August 2007
Table of Contents
OBESITY TRANSMITTED VIA NETWORKING
A study
published in the July 26th issue of the
New England Journal of
Medicine found that “networking phenomena”
appear to be relevant to the biologic and behavioral trait
of obesity, and obesity appears to spread through social
ties.
The
study looked at individual weight gain over 32 years and
compared it with the individual’s ‘network’; friends,
siblings, spouse, and neighbors. The researchers evaluated
12,067 people numerous times between 1971-2003 as part of
the Framingham Heart Study in which BMI was the key data
point followed. They used a longitudinal statistical mode
to evaluate densely interconnected social networks. They
found ‘discernible
clusters of obese persons (as defined by BMI) were present
in the network at all time points, and the clusters
extended to three degrees of separation.’
If a friend became obese in a given interval, the chance
of becoming obese increased by 57% (95% confidence
interval [CI], 6 to 123). The chance of becoming obese if
one sibling became obese was increased by 40% (95% CI, 21
to 60). If one spouse became obese, the likelihood that
the other spouse would become obese increased by 37% (95%
CI, 7 to 73). Neighbors in the immediate geographic
location of these individuals did not have the same
effect. There was a relatively greater influence on each
other among persons of the same sex compared to those of
the opposite sex. There appeared to be no correlation
between obesity and smoking cessation within the network.
The researchers concluded, ‘network phenomena appear to be
relevant to the biologic and behavioral trait of obesity,
and obesity appears to spread through social ties’.
Christakis NA, Fowler JH The Spread of Obesity in a Large
Social Network Over 32 years N Engl J Med 357:370, July
26, 2007
Table of Contents
SOFT DRINK CONSUMPTION ASSOCIATED WITH INCREASED RISK FOR
METABOLIC SYNDROME FOR MIDDLE AGED ADULTS
A recent study in
Circulation analyzed soft drink consumption and
development of Metabolic Syndrome in Middle Aged
Americans. They found that consumption of soft drinks in
quantities greater then or equal to one per day gave an
increased risk for metabolic syndrome in adults. Further
it was noticed that the association was significant
regardless of whether the soft drink was diet or not.
Previous research has shown that there is a positive
association between soft drink consumption and obesity in
children and adolescents but there was no related research
for adults. The researchers utilized the Framingham
Offspring Study (FOS) cohort to prospectively follow soft
drink consumption and development of metabolic syndrome.
Since the FOS did not specify diet vs. non diet beverages,
the researchers used the Food Frequency Questionnaire to
discriminate type of soft drink.
Of the original 10,130 FOS cohort members, 6039 were
enrolled in the study after excluding those with CVD,
metabolic syndrome (MS) and incomplete covariate data. A
four year interval was used to evaluate for development of
MS. They found
Individuals who consumed at least 1 soft drink per day had
a 44% higher adjusted risk (95% CI, 20% to 74%) of
developing metabolic syndrome compared with infrequent
drinkers in multivariable-adjusted analyses. They noted no
effect modification by age, body mass index, or sex. They
additionally adjusted for blood sugar, systolic and
diastolic blood pressure, triglycerides, HDL-C, and
alcohol consumption noting the incidence of metabolic
syndrome remained robust (odds ratio [OR], 1.44; 95% CI,
1.19, 1.74).
The
researches postulated three reasons for the associated
risk being physiologic, dietary and economic. Physiologic
refers to caloric intake related to high fructose corn
syrup consumption. Dietary factors related to soda
consumption act as a marker for poor dietary habits, so
regardless if drinking diet soda or not, overall diet is
poor. Economic incentives can lead to a soft drink
consumption choice as they are cheaper then healthier but
more expensive beverage options.
Dhingra,
et al, Soft Drink Consumption and Risk of Developing
Cardio-metabolic Risk Factors and the Metabolic Syndrome
in Middle-Aged Adults in the Community
Circulation.
2007 Jul 31; 116(5):480-8. Epub 2007 Jul 23
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