Overall cancer incidence

Drinking water quality concerns range from (1) infectious disease risks that are large, obvious, and quantifiable (2) acute or chronic chemical hazards such as those from arsenic or lead that are infrequent but potentially identifiable in cause and effect when they occur (3) postulated carcinogenic risks from radionuclides or certain organic chemicals that are largely undetectable and empirically unquantifiable and usually small in magnitude relative to overall cancer incidence rates. 

Supplementation with p-carotene, a-tocopherol, and selenium in a malnourished population at high risk of gastric cancer in Linxian, China, was associated with a 21% decrease in mortality from gastric cancer. In contrast, snpplementation of well-nourished populations with vitamin C, a-tocopherol, and p-carotene, individnally or in combinations, has not been found to decrease overall cancer incidence or... 

In addition, cancer incidence and mortality was reported in seven of the eight randomized controlled trials in CVD prevention (Clarke et al. 2010). It appeared that supplementation with folic acid (0.8-40 mg/d) had no effect on overall cancer incidence (RR 1.05 95% Cl 0.98-1.13) and mortality (RR 1.00 95% Cl 0.85-1.18). It has to be noted that none of these trials was specifically designed to investigate cancer incidence or mortality, and that there was no analysis for specific cancers. A combined analysis of two of these trials... 

Healthy Czech Republic residents (N= 11,834) with cytogenetic records, 1975-2000 Lymphocyte CA evaluation cancer cases in the national registry (N = 485) versus the cytogenetic records, various occupational backgrounds Significant association between overall cancer incidence and CSAs but not CTAs stomach cancer strongly linked with total CAs Rossner et al. (2005)... 

As previously mentioned, HT is considered to increase risk for invasive breast cancer. The ability of raloxifene to reduce breast cancer risk was evaluted after MORE (Lippman 2001 Johnell et al. 2004) and has been evaluated recently with a consideration of all the breast cancer cases diagnosed after MORE + CORE (Purdie et al. 2004). Previous HT use was reported by 2235 women and no previous HT use by 5447 women. In these women, the overall reduction in invasive breast cancer incidence for the 8 years of MORE plus CORE was 66% (HR = 0.34 95% Cl = 0.22-0.50). In the placebo group the incidence of invasive breast cancer was 2.7% in those with prior HT use compared to 2.1% in those with no prior use (p = 0.279). In women with a history of prior HT use, raloxifene significantly reduced invasive breast cancer incidence by 71% (HR = 0.29 95% Cl = 0.14-0.59) compared to placebo. In women with no prior exposure to HT, a 64% reduction in incidence of invasive breast cancer was found in those receiving raloxifeneX (HR = 0.36 95% Cl = 0.22-0.59). The magnitude of risk reduction with raloxifene did not differ irrespective of the previous exposure to HT (interaction p = 0.618). 

In a cohort study of workers in two Danish chemical plants (Lynge, 1985), potential exposure to 2,4,5-trichlorophenol occurred between 1951 and 1959, when small amounts were produced or purchased to make 2,4,5-T. No overall increase in cancer incidence rate was observed, but there were significantly increased risks of soft-tissue sarcoma and lung cancer in certain subcohorts. [The Working Group noted that 2,4-dichlorophenol is an intermediate in the production of 2,4-D, which was produced by the larger of the two plants.]... 

Just as there is a male-female difference in susceptibility to the effects of sodium cyclamate (16), there is a difference between male and female Sprague-Dawley rats in their susceptibility to DMH-induced colon cancer and to the effects of bran on tumor incidence (38). Male rats given 15 mg/kg of DMH exhibited an 804 incidence of tumors and a 15% incidence of multiple tumors, whereas females given the same dose of carcinogen exhibited a 204 incidence of tumors with no multiple tumors. Addition of 204 bran to the diet reduced tumor incidence by 504 in both groups. When the dose of carcinogen was 30 mg/kg, tumor incidence was 1004 in male rats and 304 in females. Addition of 204 bran to the diet led to a 294 increase of multiple tumors in male rats and a 174 reduction in females. Overall tumor incidence was not affected. 

Studies of occupational exposures to sulfur mustard indicate an elevated risk of respiratory tract and skin tumors following long-term exposure to acutely toxic concentrations. Overall, several factors are important regarding the assessment of the carcinogenicity of sulfur mustard. Increased cancer incidence in humans appears to be associated only with exposures that caused severe acute effects, and occupational exposures tended to involve repeated exposures and repeated injury of the same tissues. Because the therapeutic use of the sulfur mustard analog nitrogen mustard is associated with an increased incidence of CML, the reports of CML in HD-exposed individuals appear to be relevant to the eareinogenicity of sulfur mustard. 

In cases of inflammatory bowel disease, no overall increased incidence of cancer was noted after a median of 9 years follow-up in 755 patients who had taken less than 2 mg/kg/day of azathioprine over a median period of 12.5 years (69). Only colorectal cancers (mostly adenocarcinoma) were more frequent, but their incidence was also increased in chronic inflammatory bowel diseases. More specifically, there was no excess of non-Hodgkin s lymphoma, but the power of the study to detect an increased risk of this disorder was low. 

Prostate cancer is the second most frequently diagnosed cancer in men, with 782600 new cases projected to occur in 2007 [31]. Incidence rates vary widely between countries and ethnic populations, and disease rates differ by more that 100-fold between populations. The lowest yearly incidence rates occur in Asia (1.9 cases per 100000 in Tainjin, China) and the highest in North America and Scandinavia, especially in African-Americans (272 cases per 100000) [79, 80]. African-American men have furthermore the highest mortality rate for prostate cancer of any racial or ethnic group in the US. The age-adjusted prostate cancer-related mortality is 2.4 times higher for African-Americans than for whites. This dilference accounts for about 40% of the overall cancer mortality disparity between African-American and white men [31]. 

The risk of breast cancer in women of childbearing age is very low, and current oral contraceptive users in this group have only a very small increased relative risk of 1.1-1.2 that is not substantially (Reeled by duration of use, dose or type of component, age at first use, or parity. Importantly, 10 years ttfter discontinuation of oral contraceptives, breast cancer incidence is comparable in past users and never users. In addition, breast cancers diagnosed in women who have used oral contraceptives are more likely to be localized to the breast and thus easier to treat. Thus, overall there is no significant difference in the cumulative risk of breast cancer between those who have ever used oral contraceptives and those who have never used them. 

It can be seen in Figure 78.6 that the incidence of thyroid cancer (all forms) is at the same level today as in 1971, with about 4.6 (women) and 2.0 (men). The overall thyroid cancer incidence in Sweden is somewhat higher than the incidence reported from the UK (number of cases/100000/year) 1.4 (men) and 3.7 (women), respectively (Office for National Statistics Registrations, UK, 2006) but clearly lower than that reported in the United States 4.3 (men) and 12.5 (women), respectively. In the US, an increase in incidence of about 4.8% was observed from 1992 to 2002 National Cancer Institute. The increase in thyroid cancer incidence has been postulated to be correlated with an increased iodine intake in a population. There is a suggested increase in thyroid cancer of the papillary type about 20 years after the... 

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