Omega-3 and -6 Fatty Acid Intake and Colorectal Cancer Risk in Swedish Women’s Lifestyle and Health Cohort / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We aimed to assess the association between the dietary intake of fish-derived omega-3 polyunsaturated fatty acids and the risk of colorectal cancer among Swedish women. @*Materials and Methods@#A total of 48,233 women with information on dietary intake were included in the analysis. Participants were followed for incident colorectal cancer until 31 December 2012. Cox proportional hazard models were used to assess the association between baseline fatty acid intake and colorectal cancer risk. All analyses were stratified by colon and rectal cancers. @*Results@#During a median of 21.3 years of follow-up, a total of 344 colorectal cancer cases were ascertained. Although there was no overall association between omega-3 fatty acid intake and colorectal cancer risk, high intake of fish-derived docosahexaenoic acid was associated with reduced risk of rectal cancer (hazard ratios for the third and the highest quartiles were 0.59 (95% confidence interval [CI], 0.37 to 0.96) and 0.62 (95% CI, 0.39 to 0.98), respectively). @*Conclusion@#In conclusion, we found only limited support for an association between omega-3 polyunsaturated fatty acids and colorectal cancer in a large Swedish cohort of middle-aged women.

Association between Body Mass Index and Gastric Cancer Risk According to Effect Modification by Helicobacter pylori Infection / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Few studies investigated roles of body mass index (BMI) on gastric cancer (GC) risk according to Helicobacter pylori infection status. This study was conducted to evaluate associations between BMI and GC risk with consideration of H. pylori infection information. MATERIALS AND METHODS: We performed a case-cohort study (n=2,458) that consists of a subcohort, (n=2,193 including 67 GC incident cases) randomly selected from the Korean Multicenter Cancer Cohort (KMCC) and 265 incident GC cases outside of the subcohort. H. pylori infection was assessed using an immunoblot assay. GC risk according to BMI was evaluated by calculating hazard ratios (HRs) and their 95% confidence intervals (95% CIs) using weighted Cox hazard regression model. RESULTS: Increased GC risk in lower BMI group (< 23 kg/m²) with marginal significance, (HR, 1.32; 95% CI, 0.98 to 1.77) compared to the reference group (BMI of 23-24.9 kg/m²) was observed. In the H. pylori non-infection, both lower (< 23 kg/m²) and higher BMI (≥ 25 kg/m²) showed non-significantly increased GC risk (HR, 10.82; 95% CI, 1.25 to 93.60 and HR, 11.33; 95% CI, 1.13 to 113.66, respectively). However, these U-shaped associations between BMI and GC risk were not observed in the group who had ever been infected by H. pylori. CONCLUSION: This study suggests the U-shaped associations between BMI and GC risk, especially in subjects who had never been infected by H. pylori.

Workplace Diesel Exhausts and Gasoline Exposure and Risk of Colorectal Cancer in Four Nordic Countries

BACKGROUND: Evidence on associations between occupational diesel exhaust and gasoline exposure and colorectal cancer is limited. We aimed to assess the effect of workplace exposure to diesel exhaust and gasoline on the risk of colorectal cancer. METHODS: This caseecontrol study included 181,709 colon cancer and 109,227 rectal cancer cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden. Cases and controls were identified from the Nordic Occupational Cancer Study cohort and matched for country, birth year, and sex. Diesel exhaust and gasoline exposure values were assigned by country-specific job-exposure matrices. Odds ratios and 95% confidence intervals were calculated by using conditional logistic regression models. The results were adjusted for physical strain at work and occupational exposure to benzene, formaldehyde, ionizing radiation, chlorinated hydrocarbons, chromium, and wood dust. RESULTS: Diesel exhaust exposure was associated with a small increase in the risk of rectal cancer (odds ratio 1/4 1.05, 95% confidence interval 1.02–1.08). Gasoline exposure was not associated with colorectal cancer risk. CONCLUSION: This study showed a small risk increase for rectal cancer after workplace diesel exhaust exposure. However, this finding could be due to chance, given the limitations of the study.

Mesothelioma in Sweden: Dose–Response Analysis for Exposure to 29 Potential Occupational Carcinogenic Agents

BACKGROUND: There is little information on the dose–response relationship between exposure to occupational carcinogenic agents and mesothelioma. This study aimed to investigate this association as well as the existence of agents other than asbestos that might cause mesothelioma. METHODS: The Swedish component of the Nordic Occupational Cancer (NOCCA) study consists of 6.78 million individuals with detailed information on occupation. Mesothelioma diagnoses recorded in 1961–2009 were identified through linkage to the Swedish Cancer Registry. We determined cumulative exposure, time of first exposure, and maximum exposure intensity by linking data on occupation to the Swedish NOCCA job-exposure matrix, which includes 29 carcinogenic agents and corresponding exposure for 283 occupations. To assess the risk of mesothelioma, we used conditional logistic regression models to estimate hazard ratiosand 95% confidence intervals. RESULTS: 2,757 mesothelioma cases were identified in males, including 1,416 who were exposed to asbestos. Univariate analyses showed not only a significant excess risk for maximum exposure intensity, with a hazard ratio of 4.81 at exposure levels 1.25–2.0fb/ml but also a clear dose–response effect for cumulative exposure with a 30-, 40-, and 50-year latency time. No convincing excess risk was revealed for any of the other carcinogenic agents included in the Swedish NOCCA job-exposure matrix. CONCLUSION: When considering asbestos exposure, past exposure, even for short periods, might be enough to cause mesothelioma of the pleura later in life.

Occupation and mesothelioma in Sweden: updated incidence in men and women in the 27 years after the asbestos ban / 한국역학회지

OBJECTIVES: We updated the Swedish component of the Nordic Occupational Cancer (NOCCA) Study through 2009 in order to investigate the incidence of mesothelioma of the peritoneum and pleura in both genders, and explored occupational exposures that may be associated with mesothelioma. METHODS: The Swedish component of the NOCCA Study includes 6.78 million individuals. Data from this cohort were linked to the population-based Swedish Cancer Registry and Swedish Total Population Registry for three periods between 1961 and 2009, and then further linked to the Swedish NOCCA job-exposure matrix, which includes 25 carcinogenic substances and the corresponding exposure levels for 280 occupations. Multivariate analysis was used to calculate standardized incidence ratios (SIRs) for mesothelioma of the peritoneum and pleura by gender, occupational category, carcinogenic substance, and for multiple occupational exposures simultaneously. RESULTS: A total of 3,716 incident mesotheliomas were recorded (21.1% in women). We found a significantly increased risk of mesothelioma in 24 occupations, as well as clear differences between the genders. Among men, increased risks of mesothelioma of the pleura were observed in male-dominated occupations, with the greatest elevation of risk among plumbers (SIR, 4.99; 95% confidence interval, 4.20 to 5.90). Among women, increased risks were observed in sewing workers, canning workers, packers, cleaners, and postal workers. In multivariate analysis controlling for multiple occupational exposures, significant associations were only observed between asbestos exposure and mesothelioma. CONCLUSIONS: Asbestos exposure was associated with mesothelioma incidence in our study. The asbestos ban of 1982 has yet to show any clear effect on the occurrence of mesothelioma in this cohort. Among women, the occupations of canning workers and cleaners showed increased risks of mesothelioma of the pleura without evidence of asbestos exposure.

Alcohol as a Risk Factor for Cancer: Existing Evidence in a Global Perspective / 예방의학회지

The purpose of the present review is to give an overview of the association between alcohol intake and the risk of developing cancer. Two large-scale expert reports; the World Cancer Research Fund (WCRF)/American Institute of Cancer Research (AICR) report from 2007, including its continuous update project, and the International Agency for Research of Cancer (IARC) monograph from 2012 have extensively reviewed this association in the last decade. We summarize and compare their findings, as well as relate these to the public health impact, with a particular focus on region-specific drinking patterns and disease tendencies. Our findings show that alcohol intake is strongly linked to the risk of developing cancers of the oral cavity, pharynx, larynx, oesophagus, colorectum (in men), and female breast. The two expert reports diverge on the evidence for an association with liver cancer and colorectal cancer in women, which the IARC grades as convincing, but the WCRF/AICR as probable. Despite these discrepancies, there does, however, not seem to be any doubt, that the Population Attributable Fraction of alcohol in relation to cancer is large. As alcohol intake varies largely worldwide, so does, however, also the Population Attributable Fractions, ranging from 10% in Europe to almost 0% in countries where alcohol use is banned. Given the World Health Organization's prediction, that alcohol intake is increasing, especially in low- and middle-income countries, and steadily high in high-income countries, the need for preventive efforts to curb the number of alcohol-related cancers seems growing, as well as the need for taking a region- and gender-specific approach in both future campaigns as well as future research. The review acknowledges the potential beneficial effects of small doses of alcohol in relation to ischaemic heart disease, but a discussion of this lies without the scope of the present study.

Malignant Tumors of the Female Reproductive System

This review summarizes the epidemiology of cancer of the female reproductive system and associated lifestyle factors. It also assesses the available evidence for occupational factors associated with these cancers. Cervical, endometrial, and ovarian cancers are relatively common, and cause significant cancer morbidity and mortality worldwide, whereas vulvar, vaginal, fallopian tube cancers, and choriocarcinomas are very rare. As several lifestyle factors are known to play a major role in the etiology of these cancers, very few published studies have investigated possible relationships with occupational factors. Some occupational exposures have been associated with increased risks of these cancers, but apart from the available evidence on the relationships between asbestos fibers and ovarian cancer, and tetrachloroethylene and cervical cancer, the data is rather scarce. Given the multifactorial nature of cancers of the female reproductive system, it is of the utmost importance to conduct occupational studies that will gather detailed data on potential individual confounding factors, in particular reproductive history and other factors that influence the body's hormonal environment, together with information on socio-economic status and lifestyle factors, including physical activity from multiple sources. Studies on the mechanisms of carcinogenesis in the female reproductive organs are also needed in order to elucidate the possible role of chemical exposures in the development of these cancers.

Risk Factors for Breast Cancer, Including Occupational Exposures

The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr). For breast cancer the following substances have been classified as "carcinogenic to humans" (Group 1): alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure). Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification "probably carcinogenic to humans" (Group 2A) includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women.

Lifestyle and Cancer Risk / 예방의학회지

The main behavioural and environmental risk factors for cancer mortality in the world are related to diet and physical inactivity, use of addictive substances, sexual and reproductive health, exposure to air pollution and use of contaminated needles. The population attributable fraction for all cancer sites worldwide considering the joint effect of these factors is about 35% (34 % for low-and middle-income countries and 37% for high-income countries). Seventy-one percent(71%) of lung cancer deaths are caused by tobacco use (lung cancer is the leading cause of cancer death globally). The combined effects of tobacco use, low fruit and vegetable intake, urban air pollution, and indoor smoke from household use of solid fuels cause 76% of lung cancer deaths. Exposure to these behavioural and environmental factors is preventable; modifications in lifestyle could have a large impact in reducing the cancer burden worldwide (WHO, 2009). The evidence of association between lifestyle factors and cancer, as well as the main international recommendations for prevention are briefly reviewed and commented upon here.