Environmental+Risk+Factors

=Environmental Risk Factors =
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__Cigarette Smoking__
 Nearly 20.6% of all U.S. adults and 20% of high school students in the U.S. smoke [10]. Each and every one of these individuals are susceptible to different forms of cancer, such as lung and pancreatic. According to the International Agency for Research on Cancer, the tobacco found within cigarettes is categorized as a Group 1 [|carcinogen] All Group 1 carcinogens are known to cause cancer within humans, whether they are individual agents, or mixed agents, making deadly combinations. Carcinogens cause mutations in the cells DNA, affecting either the genome or the cell's metabolic pathway. Carcinogens can be introduced into an individual whether it is inherently from their parents or due to environmental stimuli. Carcinogens usually, but not always, induce cancer due to prolonged exposure over time.

A [|study] produced by John Hopkins Bloomberg School of Public Health tested the affects of smoking on an individuals chance of getting pancreatic cancer. The final results showed that cigarette smoking causes nearly 20% of all cases within their study. The study was produced in order to "examine the risk of pancreatic cancer in relation to cigarette smoking, including evaluating the magnitude of effect of smoking intensity, duration, pack-years, and cessation". The case included both men and women, most who were overweight, the majority Caucasian, 89% of the group were over the age of 60, and all cases excluded endocrine tumors. Overall only 44% of all pancreatic cases during this study were from non-smokers. The study concluded that smoking cigarettes creates a 2-fold risk compared to individuals who never smoked before and that individuals who smoke increase their chances of getting pancreatic cancer by 80%. When compared to individuals who had never smoked, current smokers had a odds ratio of 1.77, while formers smokers had an odds ration of 1.09 (see table below). Age had no affect on increasing individuals chances of getting pancreatic cancer, rather it was the number of years and the intensity of smoking the individual would consume which would truly increase their chances. The conclusion of the study states that smoking will not be the main contributor for pancreatic cancer, yet after years of smoking it will provide that extra factor to induce a tumor in the final stage of obtaining this form of cancer. See the table below for the results of this specific study.



Smnking cessation (no longer consuming tobacco products) can reduce an individual's chances after 10-15 years. Individuals who had stopped smoking for less then ten years had on odds ratio of 2.19 when compared to individuals who had never smoked. This number changed for individuals who had stopped smoking for over 15-30 years in which there odds ratio was 0.91. Exact reasoning for why this is true is still unknown, and more research needs to be conducted, but it does provide a positive incentive for current smokers who are trying to quit. Much more research needs to be done in order to determine how smoking is correlated with pancreatic cancer, but one major hypothesis is that smoking induces Chronic Pancreatitis (see Alcohol Consumption) which is known for inducing diabetes and now potentially pancreatic cancer.

__Alcohol Consumption -> Cirrhosis of the Liver & Chronic Pancreatitis__
Although there are numerous forms of alcohol available to the general public, all forms of alcohol contain different percentages of ethanol. In regards to one’s risk for obtaining cancer due to alcohol consumption, it is not the choice of drink which plays the largest factor yet rather the amount of alcohol a person consumes regularly which plays a large role at increasing an individual’s risk for cancer. Not all drinks are created equal so it is important to know the percent alcohol in each type of drink in comparison to what has been set to as the ‘standard drink.



In general alcohol increases individual’s chances for multiple cancers across the board due to its ability to damage body tissues, reducing folates, and assisting harmful chemicals, such as tobacco, to enter into cells’ lining. Individuals who consume alcohol after being diagnosed with a certain cancer will most likely by diagnosed with another form of cancer due to its wide negative effects throughout the body. Consuming large amounts of alcohol, more specifically though will result in toxic results and oxidative stress in the pancreas. Under this form of stress, the pancreas will respond by synthesizing digestive enzymes, destabilize intracellular membranes, and eventually lead to autodigestion. With excessive amounts of alcohol, especially over time, these side effects can develop into pancreatitis.

 Pancreatitis, also known as inflammation of the pancreas, can either be caused by alcohol toxicity or by gallstones. Pancreatitis can either be acute and last for a few days, or chronic which occurs over the period of years. Inflammation of the pancreas occurs when the digestive enzymes, produced by the pancreas, become active in the pancreas before their normal activation in the small intestine. Chronic Pancreatitis can develop into pancreatic cancer since chronic pancreatitis has a carcinogenic affect. Pancreatitis has numerous symptoms which mirror some symptoms of pancreatic cancer such as unexplained weight loss, abdominal pain after consuming food, nausea, vomiting, oily smelling stools (steatorrhea), and back pain.

 A [|study] published in May 2011 in [|Annals of Oncology Journal] show that although occasional non-excessive drinking does not increase an individual’s chances by much, it is quite clear the excessive alcohol assumption can greatly increase this chance, especially when done in unison with smoking. Smoking has been shown to “accelerate the progression of established pancreatitis” and unfortunately many individuals who smoke, tend to drink frequently as well.The data obtained from the study (see Table 2 Alcohol below) shows that individuals who consume alcohol heavily (>9 drinks per day) have an average 1.73 odds ratio of obtaining pancreatic cancer compared to occasional drinkers (<1 drink per day) who have an odds ratio of 1.01. When comparing different types of alcohol, wine had a great odds ratio of 1.46 to beer at 0.69 for individuals who consumed more than 4 drinks a day. More research needs to be done to understand how alcohol affects the pancreas separate from its relationship with smoking. It is clear however though, that the combination of heaving smoking and drinking greatly increases an individual's chances of getting pancreatic cancer.



**Meat Consumption**
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> Many studies have tested the relationship between consumption of charred or processed meats and exocrine pancreatic cancer. One study's data concluded that "red, and high-temperature cooked meat intake was positively associated with pancreatic cancer among men, but not women." The highest consumers of grilled, barbecued, and broiled meat may be at an increased risk of nearly 50% to contract pancreatic cancer, according to this data. Another study, published in the Journal of the National Cancer Institute, had similar results, concluding that " high intakes of red meat and of processed meat were associated with an increased risk for pancreatic cancer. However, they also noted that other animal-based food products like poultry, fish, dairy products, and eggs, had no causal association with pancreatic cancer.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> Some research has been done to find the reason meat has such carcinogenic effects, and many signs point to HCAs and PAHs. HCAs (heterocyclic amines) are compounds that form at high temperatures when amino acids, sugars, and creatine (all substances found in muscle meats) react, and its rate of formation is higher in meats cooked at temperatures above 300ºF, as well as meats cooked for long durations of time without rotation or flipping. Polycyclic aromatic hydrocarbons (PAHs), including the first discovered human carcinogen, benzo[a]pyrene, are formed when meat juices and fats drip onto an open flame, and accumulate on the cooking surface or the meat itself. Cooking methods that expose meat to smoke or charring also increase formation of PAHs. Only after enzymes in the human digestive system metabolize these chemicals do they have mutagenic effects on DNA.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px;">**Sugary Foods and Beverages**
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> Consumption of sugary foods and drinks has been positively correlated to pancreatic cancer incidence in many studies. One study, <span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> by the Journal of Cancer Epidemiology, Biomarkers and Prevention, published data indicating that consuming two or more soft drinks per day had a statistically significant increase in risk for pancreatic cancer, with a [|hazard ratio]of 1.87. A similar study by the Institute of Environmental Medicine <span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> in Stockholm, Sweden, found hazard ratios of 1.93 for soft drinks, and 1.51 for sweetened fruit soups or stews. Other data show heightened risks (up to 78%) for people with diets highest in Glycemic Index, as well as diets high in sugar, candy, honey, and jam. The actual mechanism by which sugar contributes to pancreatic risk is still unknown, but excess consumption of sugary foods contributes to obesity, which is also a risk factor for type two diabetes. Both of these conditions may increase the risk of pancreatic cancer themselves, thus all of these risk factors are likely related in some manner. <span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;"> There are still some conflicting studies regarding the effect of diet on pancreatic cancer, and additional research is necessary to determine its true effect.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 16px;">**Obesity**
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt;">People who have been classified as obese, according to their BMI, are at higher risk for getting pancreatic cancer. Among the environmental risk factors for cancer, obesity is one of the most controllable and preventable. Obese individuals often times create excess glucose in non-fasting periods (inappropriate gluconeogenesis), which can eventually lead to insulin resistance, or type 2 diabetes. Starting in the teenage years, studies have shown that obese individuals are at a higher risk for contracting pancreatic cancer. The Journal of the American Medical Association published a study concluding that adults who were overweight between 14 and 19 years old had a 60 percent higher risk of developing pancreatic cancer later in life and those who were obese in their 20s and 30s had a two to three times’ higher risk. Another study by the JAMA found that among those who are overweight or obese, those who lacked significant physical activity in their lifestyle were at an even higher risk for pancreatic cancer. Overweight individuals who participated in daily, moderate physical activity were up to 45% less risk than those who did not exercise at all.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 16px; margin: 0in 0in 10pt;"> **Diabetes** <span style="background-color: transparent; color: #000000; font-family: Arial,Helvetica,sans-serif; font-size: 12px; margin: 0in 0in 10pt; text-align: start; text-decoration: none; vertical-align: baseline;"> Diabetes mellitus and pancreatic cancer have been shown to be linked by numerous studies, but the cause-and-effect relationship between the two is still unclear. The Mayo Clinic summarizes the enigmatic correlation; "While long-standing diabetes may slightly increase the risk of pancreatic cancer, new-onset diabetes is more likely to signal the presence of underlying cancer. However, distinguishing those who have pancreatic cancer-induced diabetes from the more common type 2 diabetes is a significant challenge." There are a multitude of studies on the relationship between the two, and there seems to be evidence that diabetes is a risk factor and symptom of pancreatic cancer. One study from the Johns Hopkins University School of Medicine reported that among members participating in their study, "long-standing diabetes increases the risk of pancreatic cancer by 40% to 100%, and recent-onset diabetes is associated with a 4- to 7-fold increase in risk, such that 1% to 2% of patients with recent-onset diabetes will develop pancreatic cancer within 3 years." The same study showed evidence that some forms of diabetes, notably type 3, may be an effect, and therefore a potential warning sign of pancreatic cancer in many patients. Pancreatic cancer can often disrupt the beta cells of the pancreas<span style="background-color: transparent; color: #000000; margin: 0in 0in 10pt; text-align: start; text-decoration: none; vertical-align: baseline;"><span class="wiki_link_ext">, which are responsible for producing insulin, a hormone that regulates blood glucose levels. If a tumorous growth disrupts the function of these cells, insulin levels can become too low, leading to diabetes.