Tag Archive | "smoking"

Study Finds Strong Association Between Smoking and Risk for Bladder Cancer

Data from a large cohort study showed that smoking’s contribution to bladder cancer risk increased over the past 25 years, and the attributable risk in women caught up with that of men.

Current smokers increased risk of bladder cancer by four times compared to people who never smoked.  The risk among former smokers two times that of people who never smoked.  Previous cohort studies had shown about a threefold increased risk of bladder cancer among current smokers.

According to a recent article published in JAMA, smoking accounted for about half of the population-attributable risk of bladder cancer in men and women alike.

This apparent association between smoking and bladder cancer could reflect changes in cigarette manufacturing.

From the 1980s, the rates of bladder cancer in the U.S. has remained stable, ranging from 123.8 to 142.2 cases per 100,000 person-years in men, and from 32.5 to 33.2 cases per 100,000 person-years in women.

The authors noted in their introduction that the prevalence of smoking and cigarette composition have changed considerably during the same period, which perhaps changes the nature of the association between smoking and bladder cancer.

Neal D. Freedman, PhD, of the National Cancer Institute in Bethesda, Md., and co-authors revisited risk estimates for smoking and bladder cancer by examining data from the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study.

The NIH-AARP cohort study had follow-up data through December 31, 2006.  The participants, who were ages 50 to 71 at enrollment, completed a lifestyle questionnaire during 1995 and 1996.  This follow-up continued until the end of the study, a diagnosis of bladder cancer, a move outside the study’s catchment area, or death.

State cancer registries provided bladder cancer diagnoses information.  The foma; analysis included 281,394 men and 186,134 women.  During 4,518,941 person-years of follow up, 3,896 men had new diagnoses of bladder cancer, resulting in an incidence of 144 per 100,000 person-years.  During this same follow-up period, 627 women had a new diagnosis of bladder cancer for an incidence of 34.5 per 100,000 person-years.  Rates among people who never smoked were 69.8 and 16.1 per 100,000 person-years in men and women, respectively.  These rates increased to 154.6 and 276.4 per 100,000 person-years among men who were former or current smokers. Corresponding rates in women were 40.7 and 73.6 per 100,000 person-years.

The research team performed a systematic review and meta-analysis of prospective cohort studies of current smoking and bladder cancer started between 1963 and 1987.

Limitations of the study included lack of information on the year smoking had started and lack of follow-up data on smoking after the baseline survey to know how many people may have quit.

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Smoking Can Cause Bladder Cancer

We all associate smoking to lung, mouth and larynx cancer but what about bladder cancer? Is there a relation between smoking and bladder cancer?

Smoking is the leading risk factor for bladder cancer.  Smoking is associated with over half of bladder cancer cases in men and one third of cases among women.

Cigarette smoke contains harmful cancer causing chemicals called carcinogen.  The carcinogens in the tobacco are absorbed by the lungs and in turn enter the blood stream.  The blood is then filtered by the kidneys and concentrated in the urine.  The bladder which stores and discharges the urine has a lining that consists of mucous layer of surface cells (urothelial cells), smooth muscle and fibrous layer.  The carcinogens in the urine damage the urothelial cells that line the bladder walls. It is this damage that increases a smoker’s chance of developing tumors. Tumors may be superficial or muscle invasive.

There are several symptoms of bladder cancer.  The primary symptom is painless blood in the urine. Other symptoms may include frequent and painful urination.

Bladder cancer is diagnosed by taking a thorough medical history, physical examination, urological and imaging tests which includes an intravenous pyelogram (IVP).  IVP uses an intravenously administered radiopaque dye to produce a contrasting image visible in x-rays. As the dye moves to the urinary tract, x-rays are taken.   Laboratory tests include BladderChek, urinalysis, and urine cytology and urine culture.

If bladder cancer is suspected, a cystoscopy is performed. A tiny telescopic camera called a cystoscope is inserted through the urethra into the bladder. Tissue samples are taken from the lesion(s) and examined for cancerous cells.

Although many factors contribute to the development of bladder cancer, you can drastically decrease your chances of getting the disease by quitting smoking.

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Bladder Cancer Risk Higher for Women Smokers Than Men

A study led by preventive medicine researchers at the University of Southern California revealed that smoking leads to a higher bladder cancer risk in women than in men.

Overall, cigarette smokers incurred a 2.5 percent higher risk of developing bladder cancer than nonsmokers, but within this statistic, women faced a higher risk than men. “Our large, case-control study provides the first evidence, to our knowledge, that when comparable numbers of cigarettes are smoked, the risk of bladder cancer is higher in women than in men,” said J. Esteban Castelao, researcher in preventive medicine and lead author of the study.

For both genders, the bladder cancer risk increased both with the number of cigarettes smoked each day, and with the number of years the participants had regularly smoked. However, in nearly every category, women incurred a greater risk than men. For example, women who smoked 40 or more cigarettes daily for 40 years or more were twice as likely to develop bladder cancer as men with the same smoking habit. Additionally, researchers found no difference in risk associated with filtered versus unfiltered cigarettes, low-tar versus high-tar or deep versus shallow inhalation.

The American Cancer Society estimates that 53,200 Americans were diagnosed with cancer in 2000, and that 12,000 Americans died from it in the same year. Around half of the cases were believed to be caused by smoking, and bladder cancer accounts for 6 percent of all new cancer cases in men and 2 percent of all new cancer cases in women.

The study authors also noted that when smoking levels are equal, women are at higher risk of lung cancer than men. The study was funded by grants from the National Cancer Institute and the National Institute of Environmental Health Sciences.

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