Current cigarette smokers have a higher risk of bladder cancer than previously
reported, and the risk in women is now comparable to that in men, according
to a study by scientists from the National Cancer Institute (NCI), part of
the National Institutes of Health. The report was published on Aug. 16, 2011,
in the Journal of the American Medical Association.
This latest study uses data from over 450,000 participants in the NIH-AARP
Diet and Health Study ,
a questionnaire-based study that was initiated in 1995, with follow-up through
the end of 2006.
While previous studies showed that only 20 to 30 percent of bladder cancer
cases in women were caused by smoking, these new data indicate that smoking
is responsible for about half of female bladder cancer cases – similar
to the proportion found in men in current and previous studies. The increase
in the proportion of smoking-attributable bladder cancer cases among women
may be a result of the increased prevalence of smoking by women, so that men
and women are about equally likely to smoke, as observed in the current study
and in the U.S. population overall, according to surveillance by the CDC. The
majority of the earlier studies were conducted at time periods or in geographic
regions where smoking was much less common among women.
The researchers found that the amount of risk brought on by smoking, called
excess risk, was higher in this study than in previously reported. “Current
smokers in our study had a fourfold excess risk of developing bladder cancer,
compared to a threefold excess risk in previous studies. The stronger association
between smoking and bladder cancer is possibly due to changes in cigarette
composition or smoking habits over the years,” said study author Neal
Freedman, Ph.D. ,
in NCI’s Division of Cancer Epidemiology
and Genetics (DCEG). “Incidence rates of bladder cancer in the United States have
been relatively stable over the past 30 years, despite the fact that smoking
rates have decreased overall. The higher risk, as compared to studies reported
in the mid-to-late 1990s, may explain why bladder cancer rates haven’t
declined.”
Although there have been reductions in the concentrations of tar and nicotine
in cigarette smoke, there have been apparent increases in the concentrations
of certain carcinogens associated with bladder cancer. A 2009 NCI/DCEG study
was the first to suggest a higher risk for smoking-induced bladder cancer than
previously reported. That report, based on data from the New
England Bladder Cancer Study ,
found that the association between cigarette smoking and risk of bladder cancer
appeared to be stronger than it was in the mid-1990s. The results of the new
study confirm the 2009 report.
In the current study, former smokers were twice as likely to develop bladder
cancer as never smokers, and current smokers were four times more likely than
those who never smoked. As with many other smoking-related cancers, smoking
cessation was associated with reduced bladder cancer risk. Participants who
had been smoke-free for at least 10 years had a lower incidence of bladder
cancer compared to those who quit for shorter periods of time or who still
smoked.
“Our findings provide additional evidence of the importance of preventing
smoking initiation and promoting cessation for both men and women,” said
senior author Christian
Abnet, Ph.D. ,
also from DCEG. “Although the prevalence of cigarette smoking has declined,
about 20 percent of the U.S. adult population continues to smoke.”
Even though smoking carries the same risk for men and women, men are still
about four times more likely to be diagnosed with bladder cancer. These
results, as well as those from previous studies, suggest that difference in
smoking rates explain only part of the higher incidence rates in American men. The
researchers suggest that occupational exposures, as well as physiologic differences,
may contribute to the gender disparity.
In 2011, approximately 69,250 people will be diagnosed with bladder cancer
in the United States, and 14,990 will die from the disease.
For more information about NCI’s Division of Cancer Epidemiology and
Genetics, please visit: http://dceg.cancer.gov .
For more information about smoking cessation, and resources for those who
want to quit, please visit: http://smokefree.gov or
call 1-800-QUIT-NOW.
NCI leads the National Cancer Program and the NIH effort to dramatically reduce
the burden of cancer and improve the lives of cancer patients and their families,
through research into prevention and cancer biology, the development of new interventions,
and the training and mentoring of new researchers. For more information about
cancer, please visit the NCI Web site at
www.cancer.gov or
call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers
and is a component of the U.S. Department of Health and Human Services. NIH
is the primary federal agency conducting and supporting basic, clinical, and
translational medical research, and is investigating the causes, treatments,
and cures for both common and rare diseases. For more information about NIH
and its programs, visit www.nih.gov .
Reference:Freedman ND, Silverman DT, Hollenbeck AR, Schatzkin A, and Abnet CC. Association between smoking and risk of bladder cancer among men and women. JAMA. Online August 16, 2011.
Current cigarette smokers have a higher risk of bladder cancer than previously reported, and the risk in women is now comparable to that in men, according to a study by scientists from the National Cancer Institute (NCI), part of the National Institutes of Health. The report was published on Aug. 16, 2011, in the Journal of the American Medical Association.
This latest study uses data from over 450,000 participants in the NIH-AARP Diet and Health Study , a questionnaire-based study that was initiated in 1995, with follow-up through the end of 2006.
While previous studies showed that only 20 to 30 percent of bladder cancer cases in women were caused by smoking, these new data indicate that smoking is responsible for about half of female bladder cancer cases – similar to the proportion found in men in current and previous studies. The increase in the proportion of smoking-attributable bladder cancer cases among women may be a result of the increased prevalence of smoking by women, so that men and women are about equally likely to smoke, as observed in the current study and in the U.S. population overall, according to surveillance by the CDC. The majority of the earlier studies were conducted at time periods or in geographic regions where smoking was much less common among women.
The researchers found that the amount of risk brought on by smoking, called excess risk, was higher in this study than in previously reported. “Current smokers in our study had a fourfold excess risk of developing bladder cancer, compared to a threefold excess risk in previous studies. The stronger association between smoking and bladder cancer is possibly due to changes in cigarette composition or smoking habits over the years,” said study author Neal Freedman, Ph.D. , in NCI’s Division of Cancer Epidemiology and Genetics (DCEG). “Incidence rates of bladder cancer in the United States have been relatively stable over the past 30 years, despite the fact that smoking rates have decreased overall. The higher risk, as compared to studies reported in the mid-to-late 1990s, may explain why bladder cancer rates haven’t declined.”
Although there have been reductions in the concentrations of tar and nicotine in cigarette smoke, there have been apparent increases in the concentrations of certain carcinogens associated with bladder cancer. A 2009 NCI/DCEG study was the first to suggest a higher risk for smoking-induced bladder cancer than previously reported. That report, based on data from the New England Bladder Cancer Study , found that the association between cigarette smoking and risk of bladder cancer appeared to be stronger than it was in the mid-1990s. The results of the new study confirm the 2009 report.
In the current study, former smokers were twice as likely to develop bladder cancer as never smokers, and current smokers were four times more likely than those who never smoked. As with many other smoking-related cancers, smoking cessation was associated with reduced bladder cancer risk. Participants who had been smoke-free for at least 10 years had a lower incidence of bladder cancer compared to those who quit for shorter periods of time or who still smoked.
“Our findings provide additional evidence of the importance of preventing smoking initiation and promoting cessation for both men and women,” said senior author Christian Abnet, Ph.D. , also from DCEG. “Although the prevalence of cigarette smoking has declined, about 20 percent of the U.S. adult population continues to smoke.”
Even though smoking carries the same risk for men and women, men are still about four times more likely to be diagnosed with bladder cancer. These results, as well as those from previous studies, suggest that difference in smoking rates explain only part of the higher incidence rates in American men. The researchers suggest that occupational exposures, as well as physiologic differences, may contribute to the gender disparity.
In 2011, approximately 69,250 people will be diagnosed with bladder cancer in the United States, and 14,990 will die from the disease.
For more information about NCI’s Division of Cancer Epidemiology and Genetics, please visit: http://dceg.cancer.gov .
For more information about smoking cessation, and resources for those who want to quit, please visit: http://smokefree.gov or call 1-800-QUIT-NOW.
NCI leads the National Cancer Program and the NIH effort to dramatically reduce the burden of cancer and improve the lives of cancer patients and their families, through research into prevention and cancer biology, the development of new interventions, and the training and mentoring of new researchers. For more information about cancer, please visit the NCI Web site at www.cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov .
Reference:Freedman ND, Silverman DT, Hollenbeck AR, Schatzkin A, and Abnet CC. Association between smoking and risk of bladder cancer among men and women. JAMA. Online August 16, 2011.