Tobacco smoking as a risk factor for colon polyps

Self-reported gastrointestinal disorders among veterans with gulf war illness with and without posttraumatic stress disorder

BACKGROUND

Gulf War Illness (GWI) is a chronic, multi-symptom disorder affecting 25%-32% of Gulf War veterans. Veterans with GWI disproportionately suffer from gastrointestinal (GI) disorders. Given the increasing evidence supporting a gut-brain axis, we explore the relationship between post-traumatic stress disorder (PTSD), GWI, and self-reported GI disorders among GW veterans.

METHODS

Veterans from the Gulf War Era Cohort and Biorepository responded to a mail-based survey (N = 1058). They were stratified by GWI (Centers for Disease Control definition) and PTSD status. This yielded three groups: GWI-, GWI+/PTSD-, and GWI+/PTSD+. Multivariable logistic regression adjusting for demographic and military characteristics examined associations between GWI/PTSD groups and GI disorders. Results were expressed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI).

KEY RESULTS

The most frequently reported GI disorders were irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), and colon polyps (CP). The GWI+/PTSD+ group had a higher odds of these disorders than the GWI+/PTSD- group (aOR_IBS  = 3.12, 95% CI: 1.93-5.05; aOR_GERD  = 2.04, 95% CI: 1.44-2.90; aOR_CP  = 1.85, 95% CI: 1.23-2.80), which had a higher odds of these disorders than the GWI- group (aOR_IBS  = 4.38, 95% CI: 1.55-12.36; aOR_GERD  = 2.51 95% CI: 1.63-3.87; aOR_CP  = 2.57, 95% CI: 1.53-4.32).

CONCLUSIONS & INFERENCES

GW veterans with GWI and PTSD have significantly higher odds of specific self-reported GI disorders than the other groups. Given the known bidirectional influences of the gut and brain, these veterans may benefit from a holistic healthcare approach that considers biopsychosocial contributors to the assessment and management of disease.

Risk factors including night shift work of colorectal polyp

Background

The destruction of circadian rhythms by night shift work affects major circadian genes, which are known to play a role in advancing or killing the cell cycle through tumor suppressor genes. To find out whether night shift work affects the incidence of colorectal cancer, which was found to be associated with long-term night shift work in previous studies, we surveyed effect of night shift work on colorectal polyps that have a higher incidence than colorectal cancer and can progress to colorectal cancer.

Methods

To examine the correlation between rotating night shifts and colorectal polyps, a survey was conducted with 299 men aged 40–60 years from two university hospitals. We examined lifestyle, work history, work patterns, and colonoscopy results. The differences in prevalence among the groups was compared, and prevalence ratio (PR) was calculated via generalized linear modeling.

Results

The prevalence of colorectal polyps in night shift and non-shift workers were 53.0% and 33.5%, respectively. After adjusting for age, smoking status, dietary habits, family history of colorectal cancer, obesity, job type, night shift work (PR: 1.13, 95% CI: 1.02–1.25) was a risk factor of colorectal polyps.

Conclusions

The risk of colorectal polyps was greater in night shift workers than non-shift workers. Also risk of colorectal polyp was higher in older group. Our study investigated colorectal polyp instead of colorectal cancer and lacks information about types and gene mutations of colorectal polyps. Further study is needed to clarify effect of night shift work on development of colorectal cancer.

Colorectal Polyp Prevalence According to Alcohol Consumption, Smoking and Obesity

This study aimed to analyze colorectal polyp prevalence associated with health behavior. Data from 1180 Korean men (young adult (YA), aged 40-49; middle age (MA) aged 50-59; old aged (OA), aged 60-79 years) were collected. Health behavior included alcohol consumption, smoking status, and obesity. Obesity was determined using body mass index (BMI) and waist circumference (WC). Odds ratio (OR) was calculated by logistic regression. The prevalence of polyps increased for current smokers by 2.642 times in the YA group, 3.468 times in the MA group, and 3.104 times in the OA group compared to the never-smokers. The OR for WC increased in subjects with obesity by 1.514 in the MA and 1.451 in the OA group compared to normal. The prevalence of three or more polyps increased with WC obesity by 2.3 times in YA, 2.2 times in MA, and 1.9 times in OA compared to normal WC. Therefore, smoking cessation and obesity management may reduce the risk of colorectal polyps.

Long-chain ω-6 plasma phospholipid polyunsaturated fatty acids and association with colon adenomas in adult men: a cross-sectional study

Dietary lipid intake can be associated with an increased risk for colorectal cancer depending on its composition. Carcinogenesis alters lipid metabolism to facilitate cell growth and survival. For instance, metabolites of polyunsaturated fatty acids (PUFAs) are associated with increasing colon cell proliferation. Moreover, precancerous colon lesions (i.e. adenomas) increase the risk for colorectal cancer. In this study, we investigated associations between plasma PUFAs and the number of colon polyps and polyp type (i.e. hyperplastic and adenoma). Healthy male participants (n=126) of 48-65 years of age were recruited before a routine colonoscopy screening. Plasma phospholipid (PPL) PUFAs were isolated by means of solid phase extraction and methylated. Fatty acid methyl esters were analyzed using gas chromatography. Factor analysis was used to cluster PUFAs into groups, and then generated factors and individual PUFAs were analyzed using polytomous logistic regression. In our age-adjusted and smoking-adjusted polytomous logistic regression, for each unit increase in PPL docosatetraenoic acid (DTA), individuals were 1.43 (1.00-2.06) and 1.33 (0.99-1.80) times more likely to have hyperplastic polyps and adenomas rather than no polyps, respectively. In our factor analysis, high PPL ω-6 PUFA and trans-fatty acid loading scores were associated with increased odds of adenoma presence rather than no polyps. Increases in long-chain PPL ω-6 PUFAs are associated with an increased risk for adenomas. As relative levels of DTA increase in PPLs, individuals had increased odds of having hyperplastic polyps and adenomas. Elevated conversion of ω-6 PUFAs to longer-chain ω-6s such as DTA may indicate altered PUFA metabolism at the tissue level.

An infodemiology study on breast cancer in Iran

Purpose

According to the studies conducted in Iran, the breast cancer is the most frequent type of cancer among women. This study aimed to explore the state of health information supply and demand on breast cancer among Iranian medical researchers and Iranian Web users from 2011 to 2015.

Design/methodology/approach

A mixed method research is conducted in this study. In qualitative part, a focus group interview is applied to the users to identify their selected keywords searched for breast cancer in Google. The collected data are analyzed using Open Code software. In quantitative part, data are synthesized using the R software in two parts. First, users’ internet information-seeking behavior (ISB) is analyzed using the Google Trends outputs from 2011 to 2015. Second, the scientific publication behavior of Iranian breast cancer specialists are surveyed using PubMed during the period of the study.

Findings

The results show that the search volume index of preferred keywords on breast cancer has increased from 4,119 in 2011 to 4,772 in 2015. Also, the findings reveal that Iranian scholars had 873 scientific papers on breast cancer in PubMed from 2011 to 2015. There was a significant and positive relationship between Iranian ISB in the Google Trends and SPB of Iranian scholars on breast cancer in PubMed.

Research limitations/implications

This study investigates only the state of health information supply and demand in PubMed and Google Trends and not additional databases often used for medical studies and treatment.

Originality/value

This study provides a road map for health policymakers in Iran to direct the breast cancer studies.

Multiple behavioral factors are associated with occurrence of large, flat colorectal polyps

PURPOSE

The prevalence of advanced dysplasia and synchronous lesions is particularly high in patients with large, flat colorectal polyps. However, the impact of lifestyle on the development of such polyps is poorly investigated. Hence, this study aims to identify associations between behavioral factors and the occurrence of large, flat colorectal polyps.

METHODS

Behavioral factors were retrospectively analyzed in patients with large, flat polyps and control patients with at most one diminutive polyp. Information on lifestyle factors, comorbidities, and demographic parameters were determined by a structured, self-administered questionnaire.

RESULTS

Questionnaires of 350 patients with large, flat polyps and 489 control patients were included in the analysis. Most large, flat colorectal polyps contained adenoma with low-grade neoplasia and were located in the right colon. Multivariate analysis showed that advanced age (per 1-year increase-OR 1.09, CI 1.07-1.11, p < 0.0001), frequent cigarette smoking (OR 2.04, CI 1.25-3.32, p = 0.0041), daily consumption of red meat (OR 3.61, CI 1.00-12.96, p = 0.0492), and frequent bowel movements (OR 1.62, CI 1.13-2.33, p = 0.0093) were independent risk factors for occurrence of large, flat colorectal polyps. In contrast, frequent intake of cereals (OR 0.62, CI 0.44-0.88, p = 0.0074) was associated with a reduced risk.

CONCLUSION

Multiple behavioral factors modulate the risk for developing large, flat colorectal polyps. This knowledge can be used to improve prevention of colorectal cancer.

[Comparison of blood leptin concentration and colonic mucosa leptin expression in colon adenoma patients and healthy control]

BACKGROUND/AIMS

Obesity increases the risk of colorectal cancer and adenomatous polyp, and one of the underlying mechanisms of this increase is considered to be due to the growth promoting effects of adipokines, such as leptin. In order to investigate this finding, leptin expression in the colonic tissue and blood leptin concentration of the colonic adenoma patients were compared to those of the control group.

METHODS

Colonic adenoma tissues were obtained by polypectomy (n=60). In these patients, normal colonic mucosa at remote areas from the polyp was also obtained and blood samples were collected as well. Age and sex matched control subjects were selected among those who showed normal colonic mucosa in health screening colonoscopy (n=60).

RESULTS

There was no significant difference in serum leptin concentration between the colonic adenoma patients and control subjects. Leptin expression was noted in 43.3% of the colonic adenomas, but only in 6.7% of normal colonic mucosa from the control subjects (p<0.01). There were ten cases of concurrent adenocarcinoma in situ in adenoma patients, eight cases of which expressed leptin (p=0.01). In adenoma group, leptin expression rate was significantly high in larger adenomas and in obese patients (p<0.05). However, there was no statistically significant relationship between leptin expression in colonic mucosa and serum leptin level.

CONCLUSIONS

Leptin expression was more frequently observed in colonic adenomas, especially in larger adenomas associated with adenocarcinoma in situ, but blood leptin level was not related to tissue leptin expression. Leptin expression was more frequently observed in obese patients from the adenoma group. Therefore, leptin may play an important role in colonic tumorigenesis and progression, especially in obese patient.

Lifestyle, genes, and cancer

It is estimated that almost 1.5 million people in the USA are diagnosed with cancer every year. However, due to the substantial effect of modifiable lifestyle factors on the most prevalent cancers, it has been estimated that 50% of cancer is preventable. Physical activity, weight loss, and a reduction in alcohol use can strongly be recommended for the reduction of breast cancer risk. Similarly, weight loss, physical activity, and cessation of tobacco use are important behavior changes to reduce colorectal cancer risk, along with the potential benefit for the reduction of red meat consumption and the increase in folic acid intake. Smoking cessation is still the most important prevention intervention for reducing lung cancer risk, but recent evidence indicates that increasing physical activity may also be an important prevention intervention for this disease. The potential benefit of lifestyle change to reduce prostate cancer risk is growing, with recent evidence indicating the importance of a diet rich in tomato-based foods and weight loss. Also, in the cancers for which there are established lifestyle risk factors, such as physical inactivity for breast cancer and obesity for colorectal cancer, there is emerging information on the role that genetics plays in interacting with these factors, as well as the interaction of combinations of lifestyle factors. Integration of genetic information into lifestyle factors can help to clarify the causal relationships between lifestyle and genetic factors and assist in better identifying cancer risk, ultimately leading to better-informed choices about effective methods to enhance health and prevent cancer.

Factors that increase risk of colon polyps

Adenomatous polyps are common and factors that increase risk include race, gender, smoking, and obesity. This author summarizes the evidence supporting increased risk with these factors and describes how epidemiological data may be used to tailor screening programs.

Cigarette smoking and adenomatous polyps: a meta-analysis

BACKGROUND & AIMS

Through the past 2 decades, a consistent association between cigarette smoking and colorectal adenomatous polyps, recognized precursor lesions of colorectal cancer, has been shown. We performed a meta-analysis to provide a quantitative pooled risk estimate of the association, focusing on the different characteristics of the study populations, study designs, and clinical feature of the polyps.

METHODS

We performed a comprehensive literature search of studies linking cigarette smoking and adenomas. We used random effects models to evaluate pooled relative risks and performed dose-response, heterogeneity, publication bias, and sensitivity analyses.

RESULTS

Forty-two independent observational studies were included in the analysis. The pooled risk estimates for current, former, and ever smokers in comparison with never smokers were 2.14 (95% confidence interval [CI], 1.86-2.46), 1.47 (95% CI, 1.29-1.67), and 1.82 (95% CI, 1.65-2.00), respectively. The association was stronger for high-risk adenomas than for low-risk adenomas. Studies in which all controls underwent full colonoscopy showed a higher risk compared with studies in which some or all controls underwent partial colon examination.

CONCLUSIONS

This meta-analysis provides strong evidence of the detrimental effect of cigarette smoking on the development of adenomatous polyps. Smoking is important for both formation and aggressiveness of adenomas.

Tobacco smoking and colorectal hyperplastic and adenomatous polyps

Colorectal adenomas and possibly some hyperplastic polyps are precursors of colorectal cancer. Tobacco use is associated in epidemiologic studies with these polyps, although links between smoking and colorectal cancer are less consistent. To characterize the role of tobacco in early colorectal carcinogenesis, we compared tobacco use among 4,383 subjects with histologically verified benign (hyperplastic or adenomatous) polyps of the distal colon (descending colon, sigmoid, and rectum) with tobacco use among 33,667 subjects who were endoscopy negative for distal colon tumors, in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Trial, a randomized trial of flexible sigmoidoscopy. Risks, estimated by the odds ratio (OR), associated with current cigarette use were OR = 4.4 [95% confidence interval (95% CI), 3.7-5.2] for hyperplastic polyps only, OR = 1.8 (95% CI, 1.5-2.1) for adenomas only, and OR = 6.2 (95% CI, 4.7-8.3) for subjects with both hyperplastic and adenomatous polyps concurrently. Effects were weaker among ex smokers; the smoking-associated ORs remained consistently higher for hyperplastic polyps. This pattern was also seen in relation to cigarettes smoked per day, smoking duration, and pack-years. Tobacco-associated risks for multiple polyps were also stronger when hyperplastic disease was involved. In conclusion, tobacco use, particularly recent use, increases risk for both adenomatous and hyperplastic polyps, but the risks are substantially greater for hyperplastic lesions.

Mismatch repair polymorphisms and colorectal polyps: hMLH1-93G>A variant modifies risk associated with smoking

BACKGROUND AND AIM

Mutations in the mismatch repair (MMR) enzymes hMLH1 and hMSH6 are known causes of hereditary nonpolyposis colorectal cancer and act by inducing a mutator phenotype characterized by microsatellite instability. The aim of our study was to determine if polymorphisms in the DNA MMR genes hMLH1 and hMSH6 are associated with an increased risk of colorectal polyps, and to evaluate interactions with exposures known to cause DNA damage.

METHODS

In a Minnesota-based case-control study of individuals with adenomas (N=401), hyperplastic polyps (N=195), or both adenomas and hyperplastic polyps (N=123) versus polyp-free controls (N=624), we investigated the role of hMLH1-93G>A, hMLH1 I219V, and hMSH6 G39E polymorphisms in increasing the risk of colorectal polyps. Polytomous multivariate logistic regression analysis was used, adjusting for age, sex, body mass index, postmenopausal hormone use, aspirin use, and NSAID use.

RESULTS

Overall, no evidence of an association between any of the three polymorphisms or hMLH1 haplotypes and colorectal polyps was observed. However, risk associated with the hMLH1-93A variant differed by smoking: smoking-associated risks were stronger among those with variant -93AA or -93AG genotypes, showing a twofold greater risk of adenoma with >25 pack-years of smoking compared with nonsmokers, and a corresponding eightfold greater risk of hyperplastic polyps (genotype smoking: p-interaction=0.02 for hyperplastic polyps and p-interaction=0.08 for adenomas).

CONCLUSIONS

These data are consistent with the observation that smoking is associated with MMR in colorectal neoplasia and suggest that the risk increase with smoking may differ by hMLH1-93G>A genotype.

The Association Between Cigarette Smoking and Colorectal Polyp Recurrence (United States)

OBJECTIVE

Although evidence exists linking smoking to precancerous colorectal adenomatous polyps, few studies have examined the association between cigarette smoking and recurrence of colorectal polyps. This association was investigated prospectively with data from the Polyp Prevention Trial.

METHODS

Cigarette smoking data were collected through baseline interviews. The study was completed by 1872 men and women with presence of adenomas at baseline colonoscopy. Multiple logistic regression analysis was used to examine the association between cigarette smoking and polyp recurrence (adenomatous and hyperplastic) up to four years from baseline.

RESULTS

Adenoma recurrence was not related to cigarette smoking. Current smokers had increased odds of hyperplastic polyps at follow-up compared to never smokers (OR 2.88, 95% CI 2.06-4.01). Current smoking was associated with subsequent distal (OR 3.44, 95% CI 2.38-4.95) and rectal (OR 3.53, 95% CI 2.15-5.78) hyperplastic polyps, but not subsequent proximal hyperplastic polyps. Cigarette smoking was associated with subsequent multiple and small size (4 mm) hyperplastic polyps. Significant linear trends were observed between development of subsequent hyperplastic polyps and all smoking variables.

CONCLUSIONS

Although no association with recurrent adenomas was observed, cigarette smoking was significantly associated with hyperplastic polyp development, except for those in the proximal colon. This prospective study confirms that cigarette smoking has a significant effect on the development of hyperplastic colorectal polyps.

Prevalence of colorectal neoplasia in smokers

OBJECTIVES

Smoking has been linked with colorectal neoplasia. Previous colonoscopy screening studies have omitted smoking and have examined only gender, age, and family history. Our aim was to use a screening population to measure the prevalence of neoplasia in smokers, the anatomic location of these lesions, and the strength of this association relative to other risk factors.

METHODS

Data collected from the charts of 1988 screening colonoscopy patients included colonic findings, histology, risk factors for colorectal neoplasia, and smoking pattern. Current smokers were defined as those who had smoked more than 10 pack-years and were currently smoking or who had quit within the past 10 yr. Our outcomes were any adenomatous lesion and significant colonic neoplasia, which included adenocarcinoma, high grade dysplasia, villous tissue, large (>1 cm) adenomas, and multiple (more than two) adenomas.

RESULTS

Multivariate analysis revealed that current smokers were more likely to have any adenomatous lesion (odds ratio [OR] = 1.89; 95% CI = 1.42-2.51; p < 0.001) as well as significant neoplasia (OR = 2.26; 95% CI = 1.56-3.27; p < 0.001) than those who had never smoked. The increased risk for smokers was predominantly for left-sided neoplasia. The risk for significant neoplasia was greater for smokers than for patients with a family history of colorectal cancer (OR = 1.20; 95% CI = 0.75-1.92; p > 0.05).

CONCLUSIONS

Smoking is a significant risk factor for colorectal neoplasia in a screening population, especially for significant left-sided lesions. In our sample population, smoking posed a greater risk than family history of colorectal cancer.

Effect ofSULT1A1 andNAT2 genetic polymorphism on the association between cigarette smoking and colorectal adenomas

Cigarette smoke contains polycyclic hydrocarbons and arylamines that may both be activated by sulfotransferase, encoded by SULT1A1. A genetic polymorphism leads to an Arg213His substitution, thereby decreasing enzyme activity and stability and might thus modify the association between smoking and colorectal adenomas. We investigated this in a Dutch case-control study. Additionally, we evaluated potential roles of epoxide hydrolase (EPHX), N-acetyltransferases (NAT1 and NAT2) and glutathione S-transferases (GSTM1 and GSTT1). The data analysis included 431 adenoma cases and 432 polyp-free controls (54% women; mean age, 54.6 years) enrolled at endoscopy in 8 Dutch hospitals between 1997 and 2000. All participants provided data on smoking habits and blood for DNA isolation. Genotyping was performed using appropriate polymerase chain reaction-restriction fragment length polymorphism procedures. Multivariate models included age, sex, endoscopy indication, consumption of snacks and alcohol and, if appropriate, daily smoking dose or smoking duration. Smoking increased colorectal adenoma risk, most importantly by duration. Smoking for more than 25 years more than doubled adenoma risk (OR = 2.4, 95% CI = 1.4-4.1) compared to never smoking. Combinations of SULT1A1 fast sulfation (*1/*1) and of NAT2 slow acetylation with smoking resulted in a 4 times higher risk of adenomas compared to never smokers with other inherited gene variants, although there was no statistically significant effect modification. We found no clear effects of the other genetic polymorphisms on the association between smoking and adenomas. We conclude that smoking increases risk of colorectal adenomas and that SULT1A1 and NAT2 only modestly modify this association.

Cigarette and alcohol consumption and the risk of colorectal cancer in Shanghai, China

The relation of cigarette smoking and alcohol drinking to colorectal cancer risk has been inconsistent in the epidemiological literature. In a population-based case-control study of colorectal cancer in Shanghai, China, where the incidence rates are rising sharply, we examined the association with tobacco and alcohol use. Cases were aged 30-74 years and newly diagnosed with cancers of the colon (N = 931) or rectum (N = 874) between 1990 and 1992. Controls (N = 1552) were randomly selected among Shanghai residents, frequency-matched to cases by gender and age. Information on lifetime consumption of tobacco and alcohol, as well as demographic and other risk factors, was obtained through in-person interviews. Associations with cigarette smoking and alcohol use were estimated by odds ratios (ORs) and 95% confidence intervals (CIs). Among women, the prevalence of smoking and alcohol drinking was low, and no significant association with colon or rectal cancer was observed. Although cigarette smoking among men was not related overall to colon or rectal cancer risk, there was a 50% excess risk of rectal cancer (OR 1.5, 95% CI 0.9-2.5) among those who smoked 55 or more pack-years. Among men, former alcohol drinkers had an increased risk of colon cancer (OR 2.3, 95% CI 1.4-3.7) but not rectal cancer, while current drinkers had a 30-50% excess risk of colon cancer only among those with long-term (30+ years) and heavy (>560 g ethanol/week) consumption. The excess risks were mainly associated with hard liquor consumption, with no material difference in risk between proximal and distal colon cancer. Although cigarette smoking and alcohol drinking in general were not risk factors for colorectal cancers in Shanghai, there were small excess risks for rectal cancer among heavy smokers and colon cancer among heavy drinkers.

Colorectal cancer: molecules and populations

The epidemiology and molecular biology of colorectal cancer are reviewed with a view to understanding their interrelationship. Risk factors for colorectal neoplasia include a positive family history, meat consumption, smoking, and alcohol consumption. Important inverse associations exist with vegetables, nonsteroidal anti-inflammatory drugs (NSAIDs), hormone replacement therapy, and physical activity. There are several molecular pathways to colorectal cancer, especially the APC (adenomatous polyposis coli)-beta-catenin-Tcf (T-cell factor; a transcriptional activator) pathway and the pathway involving abnormalities of DNA mismatch repair. These are important, both in inherited syndromes (familial adenomatous polyposis [FAP] and hereditary nonpolyposis colorectal cancer [HNPCC], respectively) and in sporadic cancers. Other less well defined pathways exist. Expression of key genes in any of these pathways may be lost by inherited or acquired mutation or by hypermethylation. The roles of several of the environmental exposures in the molecular pathways either are established (e.g., inhibition of cyclooxygenase-2 by NSAIDs) or are suggested (e.g., meat and tobacco smoke as sources of specific blood-borne carcinogens; vegetables as a source of folate, antioxidants, and inducers of detoxifying enzymes). The roles of other factors (e.g., physical activity) remain obscure even when the epidemiology is quite consistent. There is also evidence that some metabolic pathways, e.g., those involving folate and heterocyclic amines, may be modified by polymorphisms in relevant genes, e.g., MTHFR (methylenetetrahydrofolate reductase) and NAT1 (N-acetyltransferase 1) and NAT2. There is at least some evidence that the general host metabolic state can provide a milieu that enhances or reduces the likelihood of cancer progression. Understanding the roles of environmental exposures and host susceptibilities in molecular pathways has implications for screening, treatment, surveillance, and prevention.

Cigarette smoking, alcohol use, and colorectal adenoma in Japanese men and women

PURPOSE

The aim of this study was to examine the relationships between smoking and alcohol use and risk of colorectal adenoma.

METHODS

Information about smoking, alcohol use, and other lifestyle variables were obtained prospectively from 14,427 male and 17,125 female residents in a city of Gifu Prefecture, Japan, by a self-administered questionnaire in September, 1992. Colorectal adenomas were newly diagnosed in 181 men and 78 women in this cohort between January, 1993 and December, 1995 by colonoscopic examination at two major hospitals of the city. Gender-specific and site-specific relative risks and 95 percent confidence intervals adjusted for age and for age plus other potential confounding factors were calculated by using logistic regression models.

RESULTS

Thirty or more years of smoking was significantly associated with risk of adenoma in general compared with never having smoked in both men and women (relative risk, 1.60; 95 percent confidence interval, 1.02-2.62 and relative risk, 4.54; 95 percent confidence interval, 2.04-9.08, respectively). Effect of smoking was stronger in the proximal colon. After adjusting for age and carbohydrate intake, total alcohol intake was not associated with risk of adenoma in any site in the colon in men. Sake drinkers were at significantly increased risk of adenoma in general, but the dose-response relationship was not statistically significant. Risk of adenoma in the rectum was not significantly increased for those who consumed >30.3 g/day of ethanol (relative risk, 5.7).

CONCLUSION

These data suggest that smoking is a risk factor of adenoma in Japanese men and women. The role of alcohol, however, is less clear.

Diet and lifestyle in the prevention of colorectal cancer: an overview

Numerous lifestyle factors have been implicated in colorectal carcinogenesis. These include diet, inadequate physical activity, obesity, alcohol consumption, and smoking. Epidemiologic studies, animal experiments, and randomized clinical trials have shown that dietary factors can influence all stages of colorectal carcinogenesis, from cell proliferation to transformation to cancer. Defining the precise role of diet and other lifestyle factors in colorectal carcinogenesis may require the elucidation of genetic susceptibility and genetic-environmental interactions. Despite the preoccupation with nutrition by the public and the media in the United States, trends in food consumption have not been favorable. The average U.S. diet is still too high in calories and fat and too low in fiber, cereals, fruits, and vegetables. Dietary modifications along with secondary prevention measures may have a major impact on reducing the mortality from colorectal cancer.

Epidemiologic panorama of colorectal cancer in Mexico, 1980-1993

INTRODUCTION

Colorectal cancer is the third cause of cancer-related death in the world, with 468,000 estimated deaths in 1993. In some countries mortality rates have started to decline, and survival rates have increased. In this study performed in Mexico, information is presented on the increase in mortality from this form of cancer, especially in more economically developed areas.

METHODS

The mortality trend for colorectal cancer was evaluated and standardized by five-year age groups in the period 1980 to 1993. Also, the standardized mortality ratio was calculated for Mexico's 32 states, as was the possible association between mortality and indicators of rurality level and fertility rates in the different regions of Mexico.

RESULTS

In the period studied, 18,962 deaths were officially reported. The average age of death was 66 years. The mortality rate among women (1.8) was significantly higher than among men (1.55 per 100,000 inhabitants). Mortality from colorectal cancer grew by 100 percent in both genders (beta = 0.089; P < 0.001), especially in the age group 34 and younger, in the 45 to 49 age group, and in the older than 75 age group (P < 0.05). The standardized mortality ratio was greater in the states in the north of Mexico. Finally, an inverse correlation was observed throughout Mexico between the rurality index (r = -0.60; P < 0.001) and the fertility rates (r = -0.43; P < 0.05) and mortality from colorectal cancer.

CONCLUSIONS

In this study, there is evidence that mortality from this cancer is higher in geographic areas with greater socioeconomic development, similar to regional patterns observed in other countries. In Mexico, the coming years will see a serious epidemic in mortality from this disease; therefore, immediate attention must be given to identifying the profile of high-risk subjects and implementing early cancer detection measures.

Folate intake, alcohol consumption, cigarette smoking, and risk of colorectal adenomas

BACKGROUND

Recent evidence suggests that folic acid (and derivatives) could contribute to the protective effect of fruits and vegetables against the risk of large-bowel cancer. Other evidence indicates that alcohol drinking and cigarette smoking may impair the biologic actions of folate. We used data from an adenoma prevention trial to investigate the occurrence of colorectal adenomas (possible precursors of colorectal cancer) in association with folate intake, alcohol consumption, and cigarette smoking.

METHODS

Patients with at least one recent large-bowel adenoma were followed with colonoscopy 1 year and 4 years after their qualifying colon examinations. Adenomas detected after the year 1 examination were used as end points. A food-frequency questionnaire was administered at study entry and at study completion; nutrient intake at study entry was used in this analysis. All statistical tests were two-sided.

RESULTS

After adjustment for caloric intake, dietary folate had a significant protective association with the risk of recurrence of large-bowel adenoma (P for trend = .04). However, this inverse association was attenuated by further adjustment for intake of dietary fiber and fat. Use of folate supplements was not associated with a reduction in risk. Alcohol intake (seven or more drinks/week) was associated with increased risk (odds ratio = 2.04; 95% confidence interval = 1.28-3.26). Cigarette smoking, even smoking for long duration, was not related to adenoma recurrence.

CONCLUSIONS

These data provide only modest support for previous findings suggesting beneficial effects of folate on colorectal adenoma risk. We find no evidence that cigarette smoking increases risk. These findings do suggest a substantial increase in risk with alcohol consumption.

Tobacco use and colon cancer

Smoking cigarettes has been consistently associated with adenomatous polyps. However, only a few studies have reported associations between smoking cigarettes or using other forms of tobacco and colon cancer. A population-based case-control study of colon cancer was conducted in 3 areas in the United States: northern California, Utah and Minnesota. We observed approximately a 50% increase in colon cancer risk from smoking over a pack of cigarettes per day among both men and women. Those who stopped smoking remained at increased risk, even if they stopped over 10 years ago. Our data suggest that the amount smoked may be a more important factor than the total number of years smoked. Smoking neither cigars nor pipes was associated with an increased risk of colon cancer. Among female participants only, those who smoked over 20 cigarettes per day and had a large body mass index were at greater risk of colon cancer than participants who smoked the same amount but were smaller (p for interaction among women = 0.04).

The relationship between smoking exposure and p53 overexpression in colorectal cancer

Although epidemiological studies of the relationship between cigarette smoking and colorectal cancer risk have been equivocal, a positive association is consistently found for colorectal adenoma development. We performed an epidemiological study to determine whether p53 protein overexpression, in tumours obtained at the time of resection, is associated with cigarette exposure in colorectal cancer. A total of 163 colorectal cancer cases and 326 healthy controls responded to a standardised questionnaire on colorectal cancer risk factors including detailed information on their history of cigarette smoking. All patients' tumours were analysed immunohistochemically for p53 overexpression using an avidin-biotin immunoperoxidase procedure and polyclonal anti-p53 antibody CM1. Comparison of colorectal cases with controls revealed an elevated risk for ex-smokers (OR = 1.34, 95% CI 0.85-2.12) and current smokers (OR = 1.13, 95% CI 0.63-2.02) when compared with non-smokers. No dose-response relationship was found for total pack-years of smoking (trend test: P = 0.19). However, a trend for total pack-years of smoking was found when p53-positive cases were compared with p53-negative cases suggesting aetiological, heterogeneity (trend test: P = 0.06). Estimating the individual relative risk of developing a p53-positive tumour relative to controls showed no associations for smoking status or total pack-years of smoking. However, when p53-negative cases were compared with controls, an elevated risk was found for ex-smokers (OR = 1.84, 95% CI 1.00-3.37) and current years of smoking (trend test: P = 0.03). Colorectal tumours developing through p53-positive dependent pathways were not associated with smoking exposure. A significant increase in risk was observed for the p53-negative independent pathway with smoking. p53 overexpression appears to be associated with smoking exposure in colorectal cancer.

Relationship of cigarette smoking, alcohol use, and dietary habits with sigmoid colon adenomas

The relationship between cigarette smoking, alcohol use, and dietary factors and the risk of adenomas of the sigmoid colon was examined in male self-defense officials who received a preretirement health examination at three Self-Defense Forces hospitals in Japan. In the comparison between 228 patients with sigmoid adenomas and 1484 control subjects with normal colonoscopy findings (> or = 60 cm from the anus), a clear dose-response relationship was observed between cigarette smoking and risk of adenoma. After adjustment for rank, body mass index, alcohol use, and physical activity as well as for hospital and survey season, the odds ratios (and 95% confidence intervals (CIs)) for the categories of 0, 1 to 399, 400 to 799, and 800 or more cigarette-years were 1.0, 2.1 (1.2 to 3.5), 2.8 (1.8 to 4.3), and 3.5 (2.1 to 5.8), respectively. Current alcohol drinkers tended to have an increased risk, but without a dose-response relation. Among four types of alcoholic beverages (shochu, sake, beer, and whiskey), only whiskey showed a weak association with risk of adenoma. None of the 13 dietary items studied (including meat and rice consumption) was measurably associated with adenoma risk. The present findings provide additional evidence that cigarette smoking is a risk factor for colon adenomas. It is inconclusive regarding alcohol intake's association with adenoma risk.

The relation of smoking, alcohol use and obesity to risk of sigmoid colon and rectal adenomas

We conducted a case-control study, using 429 cases with histologically confirmed sigmoid adenoma, 75 cases with rectal adenoma, and 3101 controls showing normal colonoscopy at least up to 60 cm from the anus. The subjects were male Self-Defense Forces personnel aged 48-56 who received a retirement health examination including a routine sigmoid- or colonoscopy. Lifestyle characteristics were ascertained by a self-administered questionnaire. Smoking in the recent past (< or = 10 years preceding the colonoscopy) and smoking in the remote past (> 10 years before the colonoscopy) were both significantly associated with risk of sigmoid adenoma but not with rectal adenoma as a whole. After reciprocal adjustment for smoking in the two periods, only smoking in the recent past was associated with both sigmoid colon and rectal adenomas. Odds ratios (OR) of sigmoid adenoma (and 95% confidence interval) for the categories of 0, 1-150, 151-250 and > or = 251 cigarette-years were 1.0 (reference), 1.9 (1.3-2.8), 2.1 (1.4-3.0) and 3.0 (1.9-4.7), respectively (P for trend < 0.01), and those for rectal adenoma were 1.0 (reference), 1.2 (0.4 3.2), 3.5 (1.4-8.5) and 2.0 (0.6 6.7), respectively (P for trend = 0.03). Alcohol use was significantly positively associated with sigmoid adenoma, and insignificantly associated with rectal adenoma. Body mass index was significantly positively associated with sigmoid adenoma, especially large ones. No such association was found for rectal adenoma. These findings suggest that smoking, especially in the recent past, and alcohol use are common risk factors for sigmoid colon and rectal adenomas while obesity may be exclusively related to the growth of sigmoid adenoma.

Coronary artery disease and colorectal neoplasia

PURPOSE

This study was designed to determine whether patients with coronary artery disease are at elevated risk for colorectal neoplasia.

METHODS

A case-control study was conducted among consecutive patients in three colonoscopy practices in New York City from 1986 to 1988. All study participants completed an interview questionnaire covering demographics, diet, environmental and behavioral exposures, family and personal medical history, and other variables. For the present study, 298 newly diagnosed colorectal adenoma cases and 107 incident cancer cases were compared with 507 colonoscoped controls without colorectal neoplasia or other significant findings on colonoscopy. Data on history of coronary artery disease (angina and/or heart attack) were obtained solely from the study participants' questionnaire responses.

RESULTS

No association was observed between angina, heart attack, or either and colorectal adenomas in males. However, prior coronary artery disease was found to be associated with colorectal cancer in males more than 60 years of age and with colorectal adenomas in females aged 50 years or younger.

CONCLUSION

Men with coronary artery disease may be at elevated risk for subsequent colorectal cancer. Young women with coronary artery disease also may be at elevated risk for colorectal neoplasia.

Increased risk of colorectal cancer among smokers: results of a 26-year follow-up of US veterans and a review

To clarify the relationship between tobacco use and risk of colorectal cancer, we evaluated a cohort of 248,046 American veterans followed prospectively for 26 years. In comparison with veterans who had never used tobacco, the risk of death was significantly increased for colon cancer and rectal cancer among current and former cigarette smokers and among pipe or cigar smokers, controlling for social class and occupational physical activity. Rectal-cancer risk was also significantly elevated among users of chewing tobacco or snuff. For both sites, risk increased significantly with pack-years, earlier age at first use, and number of cigarettes. These results reinforce 2 recent reports of the association of cigarette smoking and colorectal cancer in men and women. Inconsistencies in the findings of earlier epidemiologic studies appear to be due in large part to differences in length of follow-up or in choice of controls. Studies with at least 20 years of follow-up or population-based controls have tended to find elevated risk with tobacco smoking, while those with shorter follow-up or hospital controls have not. This, plus the strength and consistency of the association of smoking and colon polyps, suggest that smoking may primarily affect an early stage in the development of colon cancer. If this association is causal, tobacco use may be responsible for 16% of colon-cancer and 22% of rectal-cancer deaths among these veterans.

Cigarette smoking and other behavioral risk factors for recurrence of colorectal adenomatous polyps (New York City, NY, USA)

Adenomatous polyps (hereinafter referred to as adenomas) are known precursors of colorectal cancer. Cigarette smoking has been associated with adenomas but not with colorectal cancer, while alcohol and fat intake have been associated with both adenomas and cancer in some studies. Approximately 30 percent of patients with resected adenomas develop another adenoma within three years. This case-control study explores the association of cigarette smoking with adenoma recurrence. Between April 1986 and March 1988, we administered a questionnaire to colonoscoped patients aged 35 to 84 years in three New York City (NY, USA) practices. We compared 186 recurrent polyp cases (130 males, 56 females) and 330 controls (187 males, 143 females) who had a history of polypectomy but normal follow-up colonoscopy, by cigarette-smoking pack-years adjusted for possible confounders. Risk for a metachronous or recurrent adenoma was significantly greater in the highest quartile of smokers than in never-smokers among both men (odds ratio [OR] = 1.8, 95 percent confidence interval [CI] = 1.0-3.4) and women (OR = 3.6, CI = 1.7-7.6). Adjustment for time since smoking cessation reduced risk only slightly, as did adjustment for dietary fat intake, which itself remained significant. No association was found between alcohol intake and risk of recurrence. Cigarette smokers appear to have an elevated risk of adenoma recurrence that is not eliminated entirely by smoking cessation. Intervention trials that use adenoma recurrence as an endpoint should take smoking into account.

Cigarette smoking, alcohol, and the risk of colorectal adenomas

BACKGROUND

The present study was designed to further assess the reported association between cigarette smoking, alcohol, and colorectal adenomas.

METHODS

A number of environmental and life-style risk factors were examined in 236 patients with histologically proven adenomas and 409 controls with no adenomas.

RESULTS

Age, sex, race, and indication for procedure were similar in cases and controls. Those who had ever smoked were not at increased risk for adenomas compared with those who had never smoked. Years of smoking, cigarettes per day, and total pack-years showed no dose-response effect. Results for men and women were similar. Alcohol was a significant risk factor for men but not for women. Men in the highest quartile of daily caloric intake from alcohol were more than four times more likely than nondrinkers to develop adenomas, with a statistically significant trend in risk from the lowest to the highest quartile. These findings persisted after controlling for other potential risk factors for adenomas. The risk for colon and rectal polyps were similar. Men in the highest tertile of beer consumption were nearly six times more likely to develop adenomas than nondrinkers.

CONCLUSIONS

Beer drinking is a risk factor for colorectal adenomas in this population.

Cigarettes, alcohol, coffee, and caffeine as risk factors for colorectal adenomatous polyps

The possible association of colorectal adenomatous polyps, a precursor lesion for colorectal cancer, with cigarette smoking, alcohol consumption, and coffee and caffeine consumption was investigated in a case-control study. Between April 1986 and March 1988, 271 cases of patients with pathologically confirmed incident colorectal adenomatous polyps and 457 control subjects were collected from three colonoscopy practices in New York City. Information on exposure was obtained by structured interviews. After adjustment of age, statistically significant odds ratios (highest-lowest quartile) were found for cigarette smoking in males (2.2; 95% confidence interval (CI), 1.2 to 3.8) and coffee consumption in females (2.0%; 95% CI, 1.0 to 3.9). No significant associations were obtained for cigarette smoking in females, for coffee consumption in males, or for alcohol or caffeine consumption. After adjustments for alcohol, coffee, and caffeine consumption, the association of adenomas with cigarette smoking remained in males and significant associations were also observed in subcategory analysis for both left-side and right-side adenomatous polyps. Adjustment for cigarette smoking eliminated the association between colorectal adenomatous polyps and coffee consumption in females. Cigarette smoking appears to be a significant risk factor for colorectal adenomatous polyps in males.

Risk factors for small intestine cancer

Small intestine cancer is relatively rare. Clinical reports have suggested that several medical conditions may predispose to increased occurrence of this cancer, but otherwise its etiology is unknown. In one of the first case-control studies of this cancer, we compared questionnaire responses provided by next-of-kin of 430 persons who died of small intestine cancer cf921 controls who died of other causes. Subjects were identified from decedents included in the 1986 United States National Mortality Followback Survey. The questionnaires sought information on demographic and lifestyle characteristics, including diet and use of tobacco and alcohol. Tobacco and alcohol consumption were unrelated to risk of small intestine cancer, but weekly or more frequent consumption of red meat and monthly or more frequent intake of salt-cured/smoked foods were associated with two- to three fold increases in risk. The findings suggest that dietary factors probably are involved in risk of small intestine cancer, but additional research in other settings is required to clarify the determinants of these rare cancers.

Cigarette smoking, alcohol use and adenomatous polyps of the sigmoid colon

The relationship of adenomatous polyps of the sigmoid colon with cigarette smoking and alcohol use was investigated in male self-defense officials in Japan. In the comparison between 116 cases and 930 controls, total ethanol intake was not at all associated with the risk of adenomatous polyps, but cigarette smoking was strongly related to adenomatous polyps. After adjustment for total ethanol intake, body mass index and rank, odds ratios (and 95% confidence interval) for the categories of 0, 1-399, 400-799, and 800 or more cigarette-years were 1.0 (referent), 2.3 (1.1-4.6), 2.9 (1.5-5.4) and 3.2 (1.6-6.5), respectively. Among five alcoholic beverages (sake, shochu, beer, whiskey including brandy, and wine), only whiskey consumption was weakly related to the risk of adenomatous polyps. Because the present findings disagree with an earlier observation on self-defense officials, we examined the association with smoking and alcohol use separately for small (less than 5 mm) and large (greater than or equal to 5 mm) adenomas, combining data from these two studies. Cigarette smoking was more strongly associated with small adenomas while the positive association with certain alcoholic beverages were largely confined to large adenomas. These findings suggest that cigarette smoking and alcohol use may be linked with the development of adenoma at different stages of colon tumorigenesis.