Reproductive factors,exogenous female hormones,and colorectal cancer by subsite

The associations between reproductive factors, exogenous hormones, and colorectal cancer were examined among female subjects in a population-based case-control study in Sweden. The study was performed in Stockholm in 1986–88, and included 299 cases and 276 controls. There was little evidence that age at first birth, number of months of breast feeding, age at menarche, or age at menopause influenced the risk of colon or rectal cancer. However, the results indicate that postmenopausal hormone-replacement therapy might reduce the risk of colorectal cancer (age-adjusted relative risk [RR]=0.4, 95 percent confidence interval [CI]=0.2–0.9). Compared with nulliparous women, women with at least four births were at reduced risk for colon cancer (RR=0.5, CI=0.2–1.2) but not rectal cancer (RR=1.0, CI=0.4–2.6). However, no trend across increasing parity was observed. Adjustments for diet, body mass, and physical activity had little influence on the results.The authors are with the Department of Preventive Medicine, University of Southern California School of Medicine. Dr Gerhardsson de Verdier is also in the Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. Address correspondence to Dr London, University of Southern California School of Medicine, Department of Preventive Medicine, PMB B306, 1420 San Pablo Street, Los Angeles, CA 90033, USA. The study was supported by two grants (2228-B86-013XA; 2228-B87-02XA) from the Swedish National Cancer Society.     

A case-control study of occupational and dietary factors in colorectal cancer in young men by subsite

With the hope that exposures responsible for colorectal cancer might be especially obvious among those in whom it develops early, 147 men with colorectal carcinomas first diagnosed between the ages of 25 and 44 years were compared to neighborhood controls. Physical activity on the job was protective for tumors located in the transverse and descending portions of the colon. Rectal cancer and to a lesser extent sigmoid cancers were associated with jobs in which dusts or fumes were inhaled, especially if those jobs were held for long periods in young adulthood. While risk for rectal cancer did not seem to be limited to any particular type of dust or fume, the excess risk was strongest for wood and metal dusts. Consumption of fruits and vegetables and a preference for whole grain breads were protective for colon but not rectal cancers, while consumption of deep fried foods and barbecued/smoked meats increased risk at specific subsites. Beef intake, alcohol consumption, and cigarette smoking appeared to play little or no role at any subsite.     

Nutritional factors in colorectal cancer risk: a case-control study in Majorca.

The relationship between energy intake, selected nutrients and colorectal cancer was investigated in the population of Majorca, a Spanish island in the Mediterranean basin. A population-based case-control study using food frequency questionnaires was conducted during the period 1984-1988 and included 286 cases of colorectal cancer, 295 population controls and 203 hospital controls. Food composition tables and ad-hoc estimates of portion sizes were used to derive intake estimates of 29 nutrients and of total calories. Relative risks were calculated for quartiles of consumption of each specific nutrient after adjustment for total calorie intake. Colorectal cancer was found associated with dietary intake of total calories (RRs = 1.0, 1.6, 1.6, 2.6) and cholesterol (RRs = 1.0, 0.9, 1.7, 1.7) and a protective effect was associated with the intake of fibre from legumes (pulses) and folic acid. The associations and the trends were statistically significant. Among the main energy-supplying nutrients, after adjustment for calories from other sources, increased risks were found for protein (RRs = 1.0, 1.1, 1.7, 2.5), notably animal protein, and carbohydrates (RRs = 1.0, 1.5, 1.4, 2.2), whereas no effects were found for increased consumption of lipids or saturated fats.     

Dietary patterns and subsequent colorectal cancer risk by subsite: a prospective cohort study

In order to investigate the associations between dietary patterns and the risk of colorectal cancer by subsite in Japan, the baseline data from a population-based cohort study of 20,300 men and 21,812 women were analyzed. We conducted factor analysis and identified 3 major dietary patterns, "healthy," "traditional" and "Western," and calculated the factor scores of each pattern for individuals. During 10 years of follow-up, 370 colorectal cancer cases were identified. We found a positive association between the traditional pattern and colon cancer risk in women [rate ratio for highest quartile (RR) = 2.06; 95% CI = 1.10-3.84; p for trend = 0.11], but not in men. This positive association was slightly stronger for proximal colon cancer (RR = 2.07; 95% CI = 0.84-5.12) than for distal colon cancer (RR = 1.84; 95% CI = 0.75-4.50). After multivariate adjustment, the Western dietary pattern was also positively associated with colon cancer risk in females (RR = 2.21; 95% CI = 1.10-4.45), with the strongest associations being observed for females with distal colon cancer (RR = 3.48; 95% CI = 1.25-9.65). We did not observe any significant association between the healthy dietary pattern and colon cancer risk. For rectal cancer, no significant associations were found for the 3 dietary patterns. In conclusion, we found that the traditional and the Western dietary patterns were positively associated with colon cancer risk in females.     

Subsite-specific risk factors for colorectal cancer: a hospital-based case-control study in Japan

To investigate the subsite-specific risk factors for colorectal cancer, we conducted a case-control study, using a common questionnaire which inquired about general lifestyles over the past five years (1988–92), at the Aichi Cancer Center Hospital, Nagoya, Japan. This study compared 432 patients with histopathologically diagnosed colorectal cancer (94 proximal colon [cecum, ascending colon, transverse colon]; 137 distal colon [descending colon, sigmoid colon]; 201 rectum [rectosigmoid, rectum]); and 31,782 first-visit outpatient controls who were free from cancer. In both genders, habitual smoking selectively increased the risk for rectum cancer. Soft or loose feces increased the risk for all subsites of colorectal cancer, particularly in female cancer (odds ratio [OR]=4.5). Among female dietary habits, Japanese-style foods decreased the risk factors for distal colon cancer, but increased the risk for proximal colon cancer. These results suggested that the risk factors for colorectal cancer differ by subsite among such a low-risk population as the Japanese. It is suggested also that irritable bowel (soft or loose feces) might be associated with distal subsites of colorectal cancer, independently or combined with habitual smoking. Cancer Causes and Control 1995, 6, 14–22.Drs Inoue and Tajima, Ms Hirose, and Drs Hamajima and Takezaki are with the Division of Epidemiology, Aichi Cancer Center Research Institute, Nagoya, Japan. Authors are also affiliated with the Department of Gastroenterological Surgery, Aichi Cancer Center Hospital, Nagoya, Japan (Drs Hirai and Kato), and the Department of Preventive Medicine, Nagoya University School of Medicine, Nagoya, Japan (Drs Inoue and Ohno). Address correspondence to Dr Inoue, Division of Epidemiology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, Japan, 464. This study was funded in part by a Grant-in-Aid for Cancer Research (4-2) and the Comprehensive 10-year Strategy for Cancer Control from the Ministry of Health and Welfare, Japan.     

Reproductive factors and colorectal cancer risk among Chinese females

We report results from a population-based case-control study of colorectal cancer among Chinese women in western North America (NA) and the People's Republic of China (China). A common protocol was used to assess reproductive characteristics and hormone use of 395 Chinese women (189 from NA and 206 from China) with cancer of the colon or rectum and of 1112 age-matched Chinese controls (494 from NA and 618 from China). In NA, risks for cancers of both the colon and rectum were lower among parous compared to nulliparous women (odds ratio for colorectal cancer, 0.6, P = 0.08), but the trend in risk was not smooth with increasing number of livebirths. This association with parity was absent for both cancer sites in China. There were no consistent patterns in the relationships between other reproductive factors (including age at menarche, age at first livebirth, menopausal status) and risk of colon and rectal cancer on either continent.     

Colorectal polypectomy and risk of colorectal cancer by subsite: the Fukuoka Colorectal Cancer study

BACKGROUND: Colorectal adenomas are well-established precursor lesions for colorectal cancer and removal of polyps is deemed to reduce the risk of colorectal cancer. However, benefit of colorectal polypectomy in routine practice is still uncertain. We therefore investigated subsite-specific risks of colorectal cancer in relation to history of colorectal polypectomy in a case-control study. METHODS: Both case patients and control subjects were residents aged 20-74 years in Fukuoka City and three adjacent areas. The case group comprised 840 patients undergoing surgery for a first diagnosis of colorectal cancer, while the control subjects were 833 residents who were selected in the community by two-stage random sampling. Past history of selected diseases, surgery and lifestyle factors were ascertained by in-person interview. Statistical adjustment was made for sex, 5-year age class, residence, smoking, alcohol drinking, physical activity, body mass index and parental history of colorectal cancer. RESULTS: Overall, 74 case patients (9%) and 85 control subjects (10%) reported a prior history of colorectal polyps, and 50 cases (6%) and 64 controls (8%) had a history of colorectal polypectomy. The adjusted odds ratio associated with colorectal polypectomy was 0.71 (95% confidence interval [CI] 0.48-1.06) for the overall risk of colorectal cancer. The corresponding values for cancer of the proximal colon, distal colon, and rectum were 1.68 (95% CI 0.98-2.88), 0.71 (95% CI 0.41-1.26) and 0.24 (95% CI 0.11-0.52), respectively. CONCLUSIONS: The findings indicate that colorectal polypectomy in current practice confers a decreased risk of rectal cancer and possibly of distal colon cancer.     

Pooled analysis of 3 European case-control studies: I. Reproductive factors and risk of epithelial ovarian cancer

The role of reproductive factors in the aetiology of epithelial ovarian cancer has been re-assessed in a meta-analysis of 3 hospital-based case-control studies conducted in Europe (i.e. Italy, the United Kingdom and Greece), providing a total dataset of 1,140 cases and 2,724 controls. Multiple logistic regression models were used to obtain relative risk (RR) estimates adjusted for study centre, age, socio-cultural indicators, age at menopause, and oral contraceptive use. The risk decreased with increasing number of births and the trend in risk was significant (chi 2(1) = 7.50, p less than 0.01). In comparison to nulliparous women, those who reported 4 or more births had a 40% reduction in risk of ovarian cancer (RR = 0.6, 95% confidence interval, CI: 0.4-0.8). An RR estimate of 1.4 (95% CI: 1.1-1.7) as found, overall, for age of 35 or more at first birth compared to age of 25 or less at first birth. In each stratum and overall, nulliparous women did not appear to be at increased risk compared to those who delayed birth of their first child until age 35 or more. In each study, as well as in the overall dataset, an inverse association between number of abortions and ovarian cancer risk emerged. Overall, the inverse relationship was highly significant, RR estimates for 1 and 2 or more abortions, as compared to none, being 0.9 (95% CI: 0.8 and 1.1) and 0.7 (95% CI: 0.6-0.9) respectively. The effects of parity, age at first birth and number of abortions emerged consistently in various strata of study centre and age.     

Reproductive factors and risk of oesophageal cancer, a population-based nested case-control study in Sweden

Background:

The role of sex hormonal influence in explaining the strong male predominance in oesophageal adenocarcinoma (EA) needs attention.

Methods:

A nation-wide nested case–control study was initiated from the Swedish Multi-Generation Register with subjects born since 1932. The study exposures were the number of children and age at having the first child. Cases of EA, gastroesophageal junctional adenocarcinoma (EJA), and oesophageal squamous cell carcinoma (SCC) were identified. Ten age- and sex-matched controls were randomly selected for each case. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results:

In women, 115 EA, 246 EJA, and 363 SCC were identified. Comparing parous with non-parous women, a decreased risk of EA was indicated (OR=0.66, 95% CI 0.38–1.14), which became statistically significant when EA and EJA were combined (OR=0.73, 95% CI 0.53–0.99). All these associations were, however, at least as strong in men. Age at first birth did not show significant risk in women, but showed risk in men. In addition, the results were similar for SCC in both sexes.

Conclusion:

These findings indicate that associations between the reproductive factors parity and age at first birth, and risk of EA might not be explained by sex hormonal influence.     

Reproductive and other factors and risk of epithelial ovarian cancer: An australian case-control study

Of the few factors known to be associated with epithelial ovarian cancer, the most consistently observed relate to women's reproductive function, although even here uncertainties remain. We have undertaken a case-control study involving personal interviews with over 1,600 women, the largest of its kind to date, to investigate further the associations between women's reproductive histories and other factors and the development of ovarian cancer. Cases were drawn from women diagnosed with epithelial ovarian cancer in 3 Australian states, Queensland, New South Wales and Victoria, between August 1990 and December 1993, and controls were drawn at random from the electoral roll, stratified by age and geographic region. Trained interviewers administered standard questionnaires to obtain detailed information about women's reproductive and contraceptive histories and other factors of interest, such as smoking and family history of ovarian or other cancer. Findings were based on data from 824 cases and 860 controls and confirmed the reduced risk of ovarian cancer associated with increasing parity and duration of use of the oral contraceptive pill (OCP), hysterectomy and tubal ligation. The strongest association of all was seen with use of the OCP for 10 years or more. An inverse association between ovarian cancer and age at first birth was observed, but this was not statistically significant. There were no associations between development of ovarian cancer and number of incomplete pregnancies, use of hormone replacement therapy or menstrual history. Among other factors considered, education after leaving school was negatively associated and high body mass index, family history of ovarian cancer, use of talc in the abdominal or perineal region and smoking were positively associated with occurrence of ovarian cancer. © 1995 Wiley-Liss, Inc.     

Foods as risk factors for colorectal cancer: a case-control study in Burgundy (France).

Although the high meat-low vegetable diet is considered the reference high-risk diet for colorectal cancer, particularly in USA communities, other at-risk dietary patterns, such as high intakes of processed meat and refined carbohydrates are emerging. Little is known about risk factors for colorectal cancer in France, a country at high risk of rectal cancer and moderately high risk of colon cancer. We compared diet of colorectal cancer cases (n = 171) and general population controls (n = 309) in Burgundy (France). Categories of intake were established by sex and based on the distributions of food intakes in controls. Odds ratios for the fourth vs first quartile of intake (OR4) were 2.0 (1.1-3.6) for refined cereal products (rice, pasta and pastry), 2.4 (1.3-4.5) for delicatessen, 2.3 (1.2-4.2) for patés, 1.7 (1.1-2.8) for offal and 2.1 (1.1-4.0) for butter, lard and cream. There was no association with consumption of fresh meat (OR4 = 1.2), fish (OR4 = 1.5), egg (OR4 = 1.1) or dairy products (OR4 = 1.0). A protective effect of vegetables was only observed for left colon cancer (OR3 = 0.3; 0.1-0.6). In men, the most significant risk factors were refined cereal products, seasoning animal fats, chocolate and coffee, whereas risk factors were delicatessen, fat meat, pasta, rice, and chocolate in women. The strong association with refined cereal products is consistent with the hypothesis of a role of hyperinsulinism in colorectal carcinogenesis. The association with processed but not fresh meat suggests the importance of exogenous carcinogenesis in that area.     

Association between mitochondrial DNA content in leukocytes and colorectal cancer risk: a case-control analysis

BACKGROUND:

Compelling epidemiological evidence indicated that alterations of mitochondrial DNA (mtDNA), including mutations and abnormal content of mtDNA, were implicated in the tumorigenesis of several malignancies in a tumor‐specific manner, such as lung cancer, breast cancer, and non‐Hodgkin lymphoma. This study was undertaken to investigate whether mtDNA content in peripheral blood lymphocytes (PBLs) could be used as a risk predictor for colorectal cancer (CRC).

METHODS:

The mtDNA content was measured by using quantitative real‐time polymerase chain reaction in PBLs from 320 CRC patients and 320 matched controls.

RESULTS:

The authors found that CRC patients exhibited statistically significantly higher mtDNA content than matched controls (median, 1.03 vs .86; P < .001). They further assessed the association between mtDNA content and CRC risk using multivariate logistic regression. By using the median value in controls as the cutoff point, they found that, compared with low mtDNA content, high mtDNA content was associated with a significantly increased CRC risk (adjusted odds ratio, 2.03; 95% confidence interval, 1.41‐2.81). In a trend analysis, they found a statistically significant dose‐response relationship between higher mtDNA content and increased CRC risk (P for trend <.001). Stratified analysis showed that the association between mtDNA content and CRC risk was not modulated by major host characteristics.

CONCLUSIONS:

These findings provide the first epidemiological evidence linking the high mtDNA content in PBLs to elevated CRC risk. Cancer 2011. © 2011 American Cancer Society.     

Non-occupational risk factors for bladder cancer: a case-control study

AIMS: The aim of this study was to determine non-occupational risk factors for bladder cancer in Serbia. METHODS AND DESIGN: A hospital-based, case-control study included 130 newly diagnosed bladder cancer patients and the same number of individually matched controls with respect to sex, age (+/- 2 years) and type of residence (rural or urban), from the Clinical Center of Serbia in Belgrade and from the Clinical Center in Kragujevac in central Serbia. The study took place from June 1997 to March 1999. RESULTS: According to multivariate logistic regression analysis, there was an association between: frequency of daily urination (OR = 0.18; 95% CI = 0.08-0.39); consumption of liver (OR = 13.81; 95% CI = 2.49-76.69), canned meat (OR = 8.38; 95% CI = 1.74-40.36), fruit juices (OR = 0.08; 95% CI = 0.01-0.56); the highest tertile of pork (OR = 4.55; 95% CI = 1.30-15.93), cabbage (OR = 0.25; 95% CI = 0.06-1.01) and vinegar (OR = 4.41; 95% CI = 1.18-16.50) intake and risk for bladder cancer. CONCLUSIONS: Consumption of liver, canned meat, pork (h vs l tertile) and vinegar (m vs l tertile) was indicated as a risk factor for bladder cancer, whereas frequent daily urination, consumption of fruit juices and cabbage (h vs l tertile) were indicated as protective factors.     

Comorbidity and colorectal cancer according to subsite and stage: a population-based study

In developed countries the growing proportion of elderly colorectal cancer patients with comorbidity will probably complicate clinical management. The aim of this study was to investigate the prevalence of prognostically relevant comorbidity in unselected colorectal cancer patients diagnosed in the Eindhoven Cancer Registry, according to age, gender and subsite and the association with stage of disease, treatment and short-term survival. Comorbid conditions were recorded, according to Charlson's index. The most common concomitant illnesses were cardiovascular diseases, previous cancers and hypertension. The prevalence of comorbidity, especially of cardiovascular disease, previous cancer and diabetes, was highest in the ascending colon. It was slightly higher in patients with Dukes' stage A, probably due to early detection because of regular monitoring for the comorbid condition. Comorbidity was not associated with the resection rate, but was negatively associated with short-term survival. Elder male colorectal cancer patients particularly suffer from substantial comorbidity, influencing the prognosis.     

Reproductive risk factors for ovarian cancer in carriers of BRCA1 or BRCA2 mutations: a case-control study

BACKGROUND: Several of the known risk factors for ovarian cancer are thought to act through their effects on ovulation and the menstrual cycle, such as parity, breastfeeding, and use of oral contraceptives. We aimed to assess the effect of these three risk factors, and of tubal ligation, on the risk of ovarian cancer in women who carry a mutation in the BRCA1 or BRCA2 genes. METHODS: We did a matched case-control study in women who were found to carry a pathogenetic mutation in BRCA1 or BRCA2. Participants were derived from a population-based study of ovarian cancer in Ontario, Canada, and from an international registry of mutation carriers based in Toronto, ON, Canada. All participants completed a written questionnaire that detailed their reproductive history. Women with invasive ovarian cancer and controls were matched on year of birth, country of residence, mutation (BRCA1 or BRCA2), and history of breast cancer. The odds ratios and 95% CI for ovarian cancer were estimated with respect to use of oral contraceptives, parity, breastfeeding, and tubal ligation. FINDINGS: Questionnaires were completed by 799 women with a history of invasive ovarian cancer (670 with BRCA1 mutations, 128 with BRCA2 mutations, and one with a mutation in both genes), and controls were 2424 women without ovarian cancer (2043 with BRCA1 mutations, 380 with BRCA2 mutations, and one with a mutation in both genes). Use of oral contraceptives reduced the risk of ovarian cancer in carriers of BRCA1 mutations (odds ratio 0.56 [95% CI 0.45-0.71]; p<0.0001) and carriers of BRCA2 mutations (0.39 [0.23-0.66]; p=0.0004). Parity was associated with a reduced risk for carriers of BRCA1 mutations (0.67 [0.46-0.96]; p=0.03), but with an increased risk for those with BRCA2 mutations (2.74 [1.18-6.41]; p=0.02). Breastfeeding was associated with a reduced risk for carriers of BRCA1 mutations (0.74 [0.56-0.97]; p=0.03). An effect of similar magnitude was seen for carriers of BRCA2 mutations (0.72 [0.41-1.29]; p=0.27), but this was not statistically significant. The association with tubal ligation was not significant for carriers of BRCA1 mutations (0.80 [0.59-1.08]; p=0.15), or for carriers of BRCA2 mutations (0.63 [0.34-1.15]; p=0.13). INTERPRETATION: Oral contraceptives could be used as a means to prevent ovarian cancer in carriers of BRCA1 and BRCA2 mutations. The possible adverse effect of parity on ovarian-cancer risk in women with a BRCA2 mutation needs further study.     

An analysis of risk factors for oral cancer in young people: a case-control study

The incidence of oral cancer amongst young adults is increasing in many European and high incidence countries. The aim of this study was to evaluate the major risk factors for oral cancer in young adults using a case-control design. A sample of 116 patients aged 45 years and younger, diagnosed with squamous cell carcinoma of the oral cavity between 1990 and 1997 from the south east of England were included. Two-hundred and seven controls who had never had cancer, matched for age, sex and area of residence, were recruited. The self-completed questionnaire contained items about exposure to the following risk factors: tobacco products, cannabis, alcohol and diet. Conditional logistic analyses were conducted adjusting for social class, ethnicity, tobacco and alcohol habits. All tests for statistical significance were two-sided. The majority of oral cancer patients reported exposure to the major risk factors of tobacco and alcohol even at this younger age. The estimated risks associated with tobacco or alcohol were low (OR range: 0.6-2.5) among both males and females. Only smoking for 21 years or more produced significantly elevated odds ratios (OR=2.1; 95% CI: 1.1-4.0). Exposure associated with other major risk factors did not produce significant risks in this sample. Long term consumption of fresh fruits and vegetables in the diet appeared to be protective for both males and females. The results suggest that although this younger sample exhibit similar behavioural risk factors to older oral cancer patients, the low odds produced in addition to the relatively short duration of exposure, suggest that factors other than tobacco and alcohol may be implicated in the development of oral cancer in these younger patients.