**9.2.7 Occupation**

Our data show that exposure to petrol and metal is a risk factor for CRP and CRC. It is possible that petrol derivates and metals exert harmful effect upon colonic mucosa. Other exogenous risk factors are: use of anthranoid laxatives, working in petrol industry, production of synthetic materials, wood- and metal processing. Ionizing radiation increases the risk for CRC in radiation treatment of small pelvis after latent period of 15 years (Levin et al., 2002).

#### **9.2.8 Gut flora**

Pathological gut flora could produce potential carcinogens, deconjugate bile acids and impair cell DNA molecule (Aries et al., 1969). Our study ascertained the fact that *H. pylori*  infection serves as a risk factor for CRC development. Similar results are reported from other authors (Zumkeller et al., 2006). However, more extensive studies are needed to prove

Risk and Protective Factors for Development of Colorectal Polyps and Cancer 191

basic part of the selenium-dependent glutathione-reductase, which removes free radical and protects the integrity of cell membrane and DNA stability. Selenium also activates tumorsuppressor gene p53 (Seo et al., 2002). Our data in patients who use selenium as prophylaxis

Our data show that consumption of milk products has protective effect against developing CRC and CRP. Calcium in milk products bind luminal bile and fat acids in insoluble soaps and inhibits proliferation of colon cells (Bostick et al., 1995). Calcium also enhances cell apoptosis in colon mucosa (Fedirko et al., 2009). Probably, calcium has a modulating role in the western diet, rather than anticarcinogenic properties. Optimal intake of calcium in >50 year old persons is 1200 mg per day (Institute of Medicine, Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. Food and Nutrition Board,

Regular intake of mineral water is protective factor for CRP according to our data. Epidemiological studies showed that protective effect of fibers depends on the volume of drank fluids (Lubin et al., 1997). This phenomenon is associated with the decreased

There are data that vitamin D, alone or in combination with calcium plays protective role for CRC (Hawk et al., 2004). Vitamin D induces cell differentiation and inhibits cell proliferation and metastatic potential (Giovannucci, 2006). Vitamin A has similar properties as vitamin D, but there is no clear evidence of its protective role for CRC. Significant side effects of vitamin D and vitamin A restrict their usage. No convincing data exist and for the protective role of folic acid for CRC. Combined use of some vitamins with antioxidant properties, like vitamin C and vitamin E, and minerals, like selenium could enhance their impact (Patterson et al., 2000). Our data confirm this result, because we used combination formula composed of vitamin E – 80 mg, vitamin C – 100 mg, β-caroten – 10 mg and selenium – 250 μg) as a

A lot of foods containing bioactive compounds are with protective effect for CRC and CRP according to our data – garlic, tea, fruit, vegetables, onions, grapes, vegetable food, legumes etc. Bioactive compounds include numerous chemical substances, which own anticancer properties (Greenwald, 2002). Some of the most studied bioactive compounds are found in green tea, tomatoes, and different sorts of onions, carrots, lemons and garlic. There are flavonoids and polyphenols in green tea, fruit and vegetables, which possess antioxidant properties. Bioactive compounds d-limonen and perilil alcohol are found in citrus fruit and their impact is associated with the induction of glutathione S-transferase. Red grapes have antioxidant properties, because of the bioactive compound resveratrol. In cereals and in beans are found phytoestrogens, which change the metabolism of steroid hormones. A lot of

concentration of carcinogens, accompanied with a high amount of fluid intake.

prophylactic drug in 12 patients for period of 5 years.

**9.3.8 Bioactive compounds** 

confirm its protective role.

Washington, DC., 1997).

**9.3.6 Fluid intake** 

**9.3.7 Vitamins** 

**9.3.5 Calcium** 

this observation. *H. pylori* could exert negative effect not only on upper parts of gastrointestinal tract, but may be also on colorectal mucosa.

#### **9.2.9 Association with other diseases**

Chronic and extensive IBD is connected with increased cell turnover and elevated risk of developing CRC. The risk for development of CRC in patients with IBD depends on the duration (8-10 years) and the extent of disease (Ekbom et al., 1990). We observed malignant transformation in one patient with ulcer colitis and inflammatory pseudopolyposis with duration more than 10 years. Some big population based studies have found slightly elevated risk of developing CRC in right colon in women 15 years after cholecystectomy (Ekbom et al., 1993). Acromegaly is associated with elevated risk for CRC (Jenkins et al., 1997). We do not have any patient with acromegaly and CRP or CRC. We did not observe association between the patients who have undergone cholecystectomy and the frequency of CRC and CRP. The possible mechanism of this risk factor is associated with the constant free leakage of bile in the gut and with the toxic and carcinogenic effect of secondary bile salts.
