Several studies have suggested an inverse association between use of combined oral contraceptives (OC) and the risk of colorectal cancer and here we present a meta-analysis of published studies. Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on OC use. The pooled relative risks (RR) of colorectal cancer for ever OC use from the 8 case-control studies was 0.81 (95% confidence interval (CI): 0.69-0.94), and the pooled estimate from the 4 cohort studies was 0.84 (95% CI: 0.72-0.97). The pooled estimate from all studies combined was 0.82 (95% CI: 0.74-0.92), without apparent heterogeneity. Duration of use was not associated with a decrease in risk, but there was some indication that the apparent protection was stronger for women who had used OCs more recently (RR = 0.46; 95% CI: 0.30-0.71). A better understanding of this potential relation may help informed choice of contraception.

Several studies have evaluated the possible association between intakes of retinoids and carotenoids and the risk of prostate cancer, but the evidence is still inconsistent. Further, only a few studies have investigated the role of specific carotenoids other than beta-carotene. We have thus considered the association between retinol and various carotenoids using data from a multicentric case-control study conducted in Italy between 1991 and 2002. This included 1,294 incident, histologically confirmed prostate cancer cases below age 75 years admitted to major teaching and general hospitals in the areas under study, and 1,451 controls below age 75 years selected among patients admitted to the same hospitals as cases for a wide spectrum of acute nonneoplastic conditions not related to long-term modifications of diet. Subjects' usual diet was investigated by means of a validated food-frequency questionnaire. Multivariate odds ratios and the corresponding 95% confidence intervals were estimated using unconditional logistic regression models. The risk of prostate cancer tended to decrease with increasing intake of retinol (OR=0.79 for the highest versus the lowest quintile of intake), carotene (OR=0.70), alpha-carotene (OR=0.85) and beta-carotene (OR=0.72), although the estimates were significant for carotene and beta-carotene only. No meaningful associations emerged for nonprovitamin A carotenoids, such as lycopene (OR=0.94) and lutein/zeaxanthin (OR=0.91). No systematic heterogeneity was observed across strata of age, education and body mass index. Thus, our study supports the hypothesis of a weak protective effect of carotene, particularly beta-carotene, on the risk of prostate cancer, while it indicates that other carotenoids, including lycopene, and retinol are not appreciably related to the risk of this neoplasm.

Several epidemiologic studies have reported a protective effect of oral contraceptives (OCs) on ovarian cancer. However, there remain open issues, including better quantification of time-related factors such as time since last use, age at first use and time since first use. We performed a collaborative reanalysis of 6 case-control studies conducted between 1978 and 1999 in the United Kingdom, Greece and Italy, including a total of 2,768 incident, histologically confirmed cases of epithelial ovarian cancer and 6,274 hospital controls under age 70 years. A reduced risk of ovarian cancer was found for ever- compared to never-users [odds ratio (OR) = 0.66, 95% confidence interval (CI) 0.56-0.79], and a stronger reduction was observed for women who had used OCs for > or =5 years (OR = 0.50, 95% CI 0.33-0.76) compared to those who had used them for <5 years. The protective effect of OCs on ovarian cancer was consistent across strata of age, parity, menopausal status and family history of breast or ovarian cancer. After allowance for duration of use, no other time factor was related to ovarian cancer risk: the reduced risk was similar for women who stopped OC use > or =20 years before compared to <10 years; likewise, no significant modification of risk reduction was observed for age at first OC use and time since first OC use. The present analysis indicates that, after taking into account duration of OC use, the OC protection from ovarian cancer persists for a long time after stopping use.

Intake of flavonoids has been inversely related to the risk of various common neoplasms, but limited data exist on renal cell carcinoma (RCC). We used data from a case-control study conducted between 1994 and 2002 in four Italian areas to study the relation between major flavonoid classes and RCC. The study included 767 cases with incident, histologically confirmed RCC and 1,534 hospital controls admitted for acute, nonneoplastic conditions and matched with cases by study center, sex, and quinquennia of age. We applied published data on food and beverage content of six major classes of flavonoids to dietary information collected through a validated food frequency questionnaire. After adjustment for major recognized confounding factors and total energy intake, the odds ratios for subjects in the highest versus the lowest quintile of intake were 0.80 [95% confidence interval (95% CI), 0.58-1.11] for total flavonoids, 0.76 (95% CI, 0.56-1.03) for isoflavones, 0.94 (95% CI, 0.60-1.47) for anthocyanidins, 0.77 (95% CI, 0.56-1.06) for flavan-3-ols, 0.90 (95% CI, 0.67-1.21) for flavanones, 0.68 (95% CI, 0.50-0.93) for flavones, and 0.69 (95% CI, 0.50-0.95) for flavonols. Allowance for vegetable and fruit consumption only partly explained these inverse relations. Thus, flavonoids, and particularly flavones and flavonols, may account, at least in part, for the favorable role of plant foods on RCC.

A high prevalence of hepatitis C virus (HCV) infection in patients with B-cell non-Hodgkin's lymphoma (B-NHL) has been reported in some, but not all, studies, and the association showed a strong regional variation. We conducted a systematic review of the prevalence of HCV infection in case series of B-NHL and, when an appropriate control group was available, of the odds ratio of B-NHL associated with HCV infection. A high HCV prevalence in B-NHL was found in southern and eastern Europe, Japan and the southern United States, but not in central and northern Europe, Canada, northern United States, or a few Asian countries. Possible sources of heterogeneity and bias are discussed. The odds ratio of B-NHL for HCV infection was relatively weak, ranging from 2 to 4 in most studies. Thus, even if the observed association were causal, the percentage of cases of B-NHL attributable to HCV infection would be relatively low (10%) also in countries with a high prevalence of HCV infection in the general population, and extremely low in other countries. This may explain apparent inconsistencies between studies. Potential mechanisms of action are also discussed.

These results confirm and provide convincing evidence that, after allowance for selected covariates including total energy intake, a protein-rich diet is not inversely related to BMI, and a carbohydrate-rich diet is not directly related to BMI.

A cohort of 889 men and 1077 women employed for at least 1 month between 1946 and 1984 by a former Italian leading asbestos (mainly textile) company, characterised by extremely heavy exposures often for short durations, was followed up to 1996, for a total of 53,024 person-years of observation. Employment data were obtained from factory personnel records, while vital status and causes of death were ascertained through municipality registers and local health units. We observed 222 cancer deaths compared with 116.4 expected (standardized mortality ratio, SMR=191). The highest ratios were found for pleural (SMR=4105), peritoneal (SMR=1817) and lung (SMR=282) cancers. We observed direct relationships with duration of employment for lung and peritoneal cancer, and with time since first employment for lung cancer and mesothelioma. Pleural cancer risk was independent from duration (SMR=3428 for employment <1 year, 7659 for 1-4 years, 2979 for 5-9 years and 2130 for > or =10 years). Corresponding SMRs for lung cancer were 139, 251, 233 and 531. Nonsignificantly increased ratios were found for ovarian (SMR=261), laryngeal (SMR=238) and oro-pharyngeal (SMR=226) cancers. This study confirms and further quantifies the central role of latency in pleural mesothelioma and of cumulative exposure in lung cancer.

Tobacco smoking is a well-documented risk factor for several cancers, but the role of cigarette smoking in the etiology of non-Hodgkin lymphoma (NHL) is inadequately understood. Hepatitis C virus (HCV) has been associated with NHL, but the interaction between HCV and smoking habits has not yet been studied. Between 1999 and 2002, we conducted a case-control study on the association of HCV, smoking habits and NHL in 2 areas of northern and southern Italy. Cases were 225 consecutive patients (median age, 59 years) with a new diagnosis of NHL that were admitted to reference and general hospitals. Controls were 504 patients (median age, 63 years) admitted to the same hospitals as cases, for a wide spectrum of acute, nonneoplastic, nonimmune-, nor tobacco-related conditions. Current, heavy smokers (> or = 20 cigarettes/day) had an odds ratio (OR) of NHL of 2.10 (95% confidence interval, CI: 1.07-4.12) compared to never smokers. The association between smoking and NHL was consistent across strata of sex and age. Compared to never smokers, current smokers of > or = 20 cigarettes/day had ORs of 1.14 (95% CI: 0.37-3.56) for B-cell-low-grade, 2.10 (95% CI: 0.94-4.67) for B-cell-intermediate and high-grade, and 25.84 (95% CI: 1.95-342.17) for T-cell NHL. The effect of tobacco smoking and HCV were independent on the relative risk, leading a 4-fold elevated risk in current smokers HCV positive subjects. Tobacco smoking and hepatitis C virus (HCV) have been associated to non-Hodgkin lymphoma (NHL), but the interaction between HCV and smoking habits has not yet been studied. Our study confirms that tobacco is related to NHL, and reports on the combined effect of tobacco smoking and HCV. Infection acted together according to a multiplicative model, leading to a 4-fold elevated risk in current smokers HCV positive subjects.

The authors considered the incidence of second neoplasms among 1,672 oesophageal cancers diagnosed between 1974 and 2004 in the Cancer Registries of the Swiss Cantons of Vaud and Neuchâtel, and followed-up to 2004. A total of 141 second neoplasms were observed versus 38.5 expected, corresponding to a standardized incidence ratio (SIR) of 3.7 (95% confidence interval: 3.1-4.3). The SIRs were statistically significant for cancers of the oral cavity and pharynx (57.3), larynx (24.3), lung (6.6) and intestines (2.6). The SIRs were higher in subjects diagnosed below age 50 and in the first year after diagnosis. The SIR of upper digestive and respiratory tract neoplasms was higher for oesophageal cancers diagnosed in the upper (87.5) and middle (68.1), as compared with the lower third (19.4). There was no rise of second oral, pharyngeal and laryngeal cancer with advancing age, and their incidence tended indeed to decline from 100/1,000 at age 40-49 to 25/1,000 at age 70-79. There was no tendency to rise with age in the incidence of first oesophageal cancer in subjects who subsequently developed another upper digestive or respiratory tract neoplasm. The excess risks of upper digestive and respiratory tract neoplasms are attributable to increased diagnosis and registration of second neoplasms following a diagnosis of oesophageal cancer, as well as to heavy tobacco and alcohol consumption in oesophageal cancer cases. The absence of rise in incidence with age is also compatible with the existence of a subset of the population of susceptible individuals.

For the first time since the 1950s the overall smoking prevalence in Italian adults fell below 30%, but the figure is now higher than in most Western countries. Also for females the smoking prevalence in Italy is now higher than in the USA. This reflects the absence of any comprehensive policy and legislation against smoking in Italy.