Fulfilling the Potential of Cancer Prevention and Early Detection (2003) / Chapter Skim
Currently Skimming:
3. Lifestyle Behaviors Contributing to the Burden of Cancer
3. Lifestyle Behaviors Contributing to the Burden of Cancer
Pages 41-86
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 41... ...
This chapter summarizes the epidemiological evidence with respect to cancer incidence for each of the five selected risk factors by using the criteria outlined by the World Cancer Research Fund and the American Institute of Cancer Research. For each epidemiological association the level of evidence is categorized as convincing, probable, or possible (Box 3.1~.
|
From page 42... ...
TOBACCO Tobacco is the scourge of public health. In the United States alone, tobacco use, primarily in the form of cigarette smoking, causes more than 440,000 premature deaths from cancer and other causes each year and is responsible for approximately 30 percent of all cancer-related deaths (ACS, 2002b)
|
From page 44... ...
The data available at that time were able to support a causal link between smoking and only two cancers: lung cancer and laryngeal cancer. Over the following 35 years, however, enough evidence has accrued to now support smoking as a cause of eight cancers: lung, oral, pharyngeal, laryngeal, esophageal, bladder, kidney, and pancreatic cancer.
|
From page 45... ...
There is convincing evidence from numerous case-control and cohort studies that former smokers have a lower risk of lung cancer than current smokers (US DHHS, 1990~. The benefits begin 2 to 3 years after quitting, and the risk steadily drops over the next 10 years.
|
From page 46... ...
In a study of U.S. veterans, current smokers experienced 10 times the risk of mortality from laryngeal cancer than those who never smoked, a risk similar to that seen in the American Cancer Society's Cancer Prevention Study II (Kahn, 1966; US DHHS, 1990~.
|
From page 47... ...
As with lung cancer and smoking cessation, there is also good evidence that the excess risk of oropharyngeal cancer decreases with younger age at cessation (US DHHS,1990~. For laryngeal and esophageal cancer, numerous studies have demonstrated significant drops in risk for former smokers compared with that for current smokers beginning 3 to 4 years after cessation (US DHHS, 1990~.
|
From page 48... ...
There is convincing evidence that smoking cessation can lower the risk of bladder cancer in former smokers compared with that in current smokers. A recent pooled analysis of 11 case-control studies conducted by the International Agency for Research on Cancer found that the risk of bladder cancer in former smokers compared with that in current smokers began to decrease almost immediately after smoking cessation and continued to do so with the duration of cessation (Brennan et al., 2000~.
|
From page 49... ...
A Swedish prospective study of nearly 57,000 men and women found a 60 percent increased risk of colon cancer in smokers compared with that in nonsmokers after 11 to 20 years of follow-up (Knekt et al., 1998~. The Nurses' Health Study and the Health Professionals Follow-Up Study demonstrated significant elevations in risk in long-term smokers as well (Giovannucci et al., 1994a,b)
|
From page 50... ...
Data from the American Cancer Society's Cancer Prevention Study II indicate that the risk of colon cancer drops with the number of years of smoking cessation as well as a younger age at the time of cessation (Chao et al., 2000~. Tobacco Use and Stomach Cancer Stomach cancer is one of the most common cancers worldwide.
|
From page 51... ...
There is evidence of a probable inverse association between smoking cessation and cervical cancer. Taken as a whole, there are good data that former smokers experience a lower risk of cervical cancer than current smokers (US DHHS, 1990~.
|
From page 52... ...
There is evidence of a probable positive association between smoking and liver cancer. Although some studies on this topic have not adequately controlled for alcohol intake and viral hepatitis infection two key factors that can potentially confound the relationship the evidence supports a positive relationship with cigarette smoking and suggests a dose-response association.
|
From page 53... ...
A number of large, prospective cohort studies have documented a link between smoking and mortality from prostate cancer, with some demonstrating a dose-response relationship with the amount smoked (Hsing et al., 1990b; Hsing et al., 1991; Coughlin et al., 1996; Rodriguez et al., 1997; Giovannucci et al., 1999~. Overall, relative risks for mortality from prostate cancer seem to range from 1.3 to 2.0 for smokers compared with nonsmokers.
|
From page 54... ...
Lung cancer risk was increased about fivefold, and the risk of pancreas and bladder cancers about threefold (Shapiro et al., 2000~. An analysis of a large cohort of U.S.
|
From page 55... ...
More than a third of high school students are current smokers (Table 3.3~. Although cigarette smoking increased among high school students in the 1990s and is the most prevalent form of tobacco use among this age group, smokeless tobacco and cigars are becoming more commonly used (Table 3.3)
|
From page 56... ...
Lowincome African-American men and women are about twice as likely to be smokers as African Americans with middle or high incomes. A similar, although slightly lower, disparity in smoking rates exists between income groups among whites.
|
From page 57... ...
The 1989 Behavioral Risk Factor Surveillance System found that whites had a quit rate of 47 percent and African Americans had a quit rate of 39 percent (US DHHS, 1998~. In 1994-1995, the percentage of adult African-American ever smokers who had quit was 35.4 percent (US DHHS, 1998~.
|
From page 58... ...
1998; Marrett et al., 2000; International Agency TABLE 3.4 Reduction in Risk of Incident Cancer Associated with Physical Activity Relative Risk (RR) Level of Evidence Small (RR 0.76-0.90)
|
From page 59... ...
The same study showed that among men who were sedentary at the initial assessment, those who increased their activity during the 11- to 15-year follow-up period were 13 percent less likely to develop colon cancer than those who remained sedentary during the same time period (Lee et al., 1991~. Data from at least two prospective studies indicated that both men and women can lower their risk of colon cancer simply by engaging in moderate physical activity such as brisk walking or stair climbing for an hour a day (Giovannucci et al., 1995a; Martinez et al., 1997~.
|
From page 60... ...
Physical Activity and Lung Cancer Several studies have examined the impact of physical activity on lung cancer risk, and most have suggested a protective effect (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~. Researchers cannot completely control for the confounding effects of cigarette smoking, however.
|
From page 61... ...
Follow-up of 28,129 men and women in Sweden showed a 33 percent excess risk of cancer among obese individuals than among nonobese individuals (Work et al., 2001~. Obesity contributes to the incidence of cancers through several possible mechaTABLE 3.5 Increase in Risk of Incident Cancer Associated with Obesity Relative Risk (RR)
|
From page 62... ...
The IARC estimates that about 10 percent of breast cancer and colorectal cancer may be attributable to overweight and obesity, and between 25 and 40 percent of kidney, esophageal, and endometrial cancer may be attributed to obesity. Obesity and Breast Cancer Consistent relationships have been seen between obesity and postmenopausal breast cancer, reflecting the role of adipose cells in the production of estrogen after menopause (Hunter and Willett, 1993; Hankinson et al., 1995; World Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 63... ...
Obesity is related to increased insulin resistance and hyperinsulinemia, which in turn are related to proliferation of colon cells in laboratory studies (McKeown-Eyssen, 1994; Giovannucci, l995b; Kono et al., 19981. Further evidence supporting this mechanism comes from studies of the insulin-like growth factor pathway, which have demonstrated that insulin-like growth factor is directly related to colon cancer risk (Ma et al., 19991.
|
From page 64... ...
Other studies have observed relative risks of about 3-5 (Brown et al., 1995; Vaughan et al., 1995; Ji et al., 1997; Chow et al., 1998~. Trends in Obesity In the United States, the age-adjusted prevalence of obesity increased from 15 percent in the late 1970s to 27 percent in 1999.
|
From page 65... ...
Setting Weight Guidelines One essential part of effective policy planning is basing action on consistent messages. Yet, despite solid epidemiological evidence that weight affects the risk of cancer and other chronic diseases including heart disease, stroke, and diabetes setting weight guidelines has long been problematic, and recommendations have varied over time.
|
From page 66... ...
The majority of this evidence has arisen from case-control studies, while the prospective data have been less consistent (Table 3.6~. Fruits and vegetables lower the risk of hypertension, coronary heart disease, and ischemic stroke, in addition to containing vitamins and minerals that may protect against cancer and a host of other conditions (World Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 67... ...
Most of the evidence for this comes from case-control studies, which have consistently shown a moderate to large reduction in risk among those who consume at least one serving of fruits and vegetables a day (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~. Very few prospective data support these findings, however; and the possibility of residual confounding by tobacco and alcohol use and/or recall bias cannot be eliminated.
|
From page 68... ...
Fruit and Vegetable Consumption and Bla~l~ler Cancer There is evidence of a probable inverse association between fruit and vegetable consumption and the risk of bladder cancer. Nearly all studies on the topic have adequately controlled for smoking, the primary cause of bladder cancer, and most suggest that both fruits and vegetables offer some degree of protection against bladder cancer (World Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 69... ...
Fruit and Vegetable Consumption and Lung Cancer An inverse association between high levels of consumption of fruits and vegetables and the risk of lung cancer has been observed in both casecontro! studies and large cohort studies (Worici Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 70... ...
However, data from two randomized controlled trials recently failed to support a link between increased fiber intake over three years and the risk of recurrence of colon polyps, the precursor lesion for colon cancer (Alberta et al., 2000; Schatzkin et al., 2000~. Fruit and Vegetable Consumption and Ovarian Cancer A high level of consumption of vegetables may reduce the risk of ovarian cancer, although few studies have addressed the issue (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 71... ...
Fruit and Vegetable Consumption and Cervical Cancer There is evidence of a possible inverse relationship between fruit and vegetable consumption and the risk of cervical cancer. Of the five studies published on the topic, four reported a reduced risk with one or more measures of fruit and vegetable intake (World Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 72... ...
Fruit and Vegetable Consumption and Kidney Cancer A number of case-control studies have demonstrated an inverse association between fruit and vegetable consumption and the risk of kidney cancer (Mellemgaard et al., 1996; Wolk et al., 1996; Lindblad et al., 1997; World Cancer Research Fund and American Institute for Cancer Research, 1997; Yuan et al., 1998~. In the largest of these studies, the International Renal Cell Cancer Study, Wolk and colleagues (1996)
|
From page 73... ...
Red Meat Consumption and Prostate Cancer The relationship between red meat consumption and the risk of prostate cancer has been examined in a number of cohort and case-control studies, with results suggesting a positive association (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~. In the largest cohort study to address this issue, the risk of advanced prostate cancer was more than twice as high among men who consumed red meat frequently than among those who consumed it rarely (Giovannucci et al., 1993a)
|
From page 74... ...
studies have gone one step further by evaluating the effects of specific types of red meat, including beef and pork, as well as processed meats, like bacon and sausage. Those studies have consistently shown a positive association between pork consumption and pancreatic cancer risk, although they have yielded inconsistent results for other meats (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 75... ...
Milk and Dairy Products The effects of dairy products on cancer risk have not been well studied, and most links between the two have been made only indirectly (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 76... ...
studies generally support a positive association between the consumption of dairy products and prostate cancer risk, whereas cohort studies are less consistent (WorId Cancer Research Fund and American Institute for Cancer Research 1997~. A higher level of milk consumption was related to an increased risk of prostate cancer in three of the seven cohort studies on dairy products (Snowdon et al., 1984; Le Marchand et al., 1994; Schuurman et al., 1999~.
|
From page 77... ...
Macronutrients Fat, carbohydrates, fiber, and protein have each been linked with cancer in some way (Table 3.8~. A number of studies support a possible association between a high total fat intake and an increased risk of lung, colorectal, and prostate cancer (WorId Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 78... ...
. Osltlve assoclatlon: · Endometrial cancer · Lung cancer · Colorectal cancer · Prostate cancer · Non-Hodgkin's lymphoma Positive association: · Non-Hodgkin's lymphoma Inverse association: · Breast cancer P
|
From page 79... ...
. Osltlve assoclatlon: · Prostate cancer · Kidney cancer · Ovary cancer Inverse association: · Lung cancer · Prostate cancer · Colorectal cancer the Colorectal cancer risk and that supplementation with a multivitamin that contained folate offered additional reductions (Giovannucci et al., 1998b)
|
From page 80... ...
Blood selenium levels rose rapidly following this ecological intervention, but there has been no apparent decline in incidence or mortality rates for prostate or colon cancer (Willett, 1999~. Whether supplemental selenium might reduce prostate cancer risk is now being tested, along with vitamin E, in the SELECT trial (http:// www.cancer.gov/newscenter/SELECT)
|
From page 81... ...
. On the basis of this growing evidence relating insulin, glycemic load, and colon cancer risk, further research is needed to determine if the insulin pathway might also contribute to other .
|
From page 82... ...
The Impact of Alcohol on Cancer Incidence Because alcohol use tends to be associated with cigarette use and other high-risk behaviors, its independent effects on cancer have long been questioned. However, in 1988, on the basis of abundant epidemiological evidence, the International Agency for Research on Cancer concluded that alcohol is, in fact, a Group A carcinogen and an independent risk factor for cancers of the upper aerodigestive tract and liver (World Cancer Research Fund and American Institute for Cancer Research, 1997~.
|
From page 83... ...
Alcohol Consumption and Cancers of the Mouth, Pharynx, Larynx, and Esophagus There is convincing epidemiological evidence from both cohort and case-control studies that alcohol consumption increases the risk of cancers of the mouth, pharynx, larynx, and esophagus (WorId Cancer Research Fund and American Institute for Cancer Research, 1997; Kjaerheim et al., 1998~. All of the cohort studies that have examined this association, including those that controlled for smoking, have demonstrated a substantially increased risk.
|
From page 84... ...
Alcohol Consumption and Breast Cancer More than 25 studies have shown that alcohol increases breast cancer risk, most likely by raising the level of estrogen in the bloodstream or making the breast more vulnerable to carcinogens (Smith-Warner et al., 1998~. A randomized feeding trial indicated that estrogen levels are increased when women consume even low levels of alcohol on a regular basis (Reichman et al., 1993)
|
From page 85... ...
SUMMARY AND CONCLUSIONS There is overwhelming evidence that lifestyle factors affect cancer risk. As detailed throughout this chapter, current epidemiological evidence links the major behavioral risk factors with several major cancers.
|
From page 86... ...
Regular physical activity lowers the risk of cancers of the colon and breast cancer, and, possibly, endometrial cancer as well. Regular alcohol intake increases the risk of cancers of the oropharynx, larynx, esophagus, breast, liver, colon, and rectum.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.