Cruciferous vegetables and cancer risk in a network of case-control studies

BACKGROUND

Cruciferous vegetables have been suggested to protect against various cancers, though the issue is open to discussion. To further understand their role, we analyzed data from a network of case-control studies conducted in Italy and Switzerland.

PATIENTS AND METHODS

The studies included a total of 1468 cancers of the oral cavity/pharynx, 505 of the esophagus, 230 of the stomach, 2390 of the colorectum, 185 of the liver, 326 of the pancreas, 852 of the larynx, 3034 of the breast, 367 of the endometrium, 1031 of the ovary, 1294 of the prostate, 767 of the kidney, and 11,492 controls. All cancers were incident, histologically confirmed; controls were subjects admitted to the same network of hospitals as cases for a wide spectrum of acute nonneoplastic conditions.

RESULTS

The multivariate odds ratio (OR) for consumption of cruciferous vegetables at least once a week as compared with no/occasional consumption was significantly reduced for cancer of the oral cavity/pharynx (OR=0.83), esophagus (OR=0.72), colorectum (OR=0.83), breast (OR=0.83), and kidney (OR=0.68). The OR was below unity, but not significant, for stomach (OR=0.90), liver (OR=0.72), pancreatic (OR=0.90), laryngeal (OR=0.84), endometrial (OR=0.93), ovarian (OR=0.91), and prostate (OR=0.87) cancer.

CONCLUSION

This large series of studies provides additional evidence of a favorable effect of cruciferous vegetables on several common cancers.

Dietary patterns and the risk of esophageal cancer

BACKGROUND

The role of dietary habits on esophageal cancer risk has been rarely considered in terms of dietary patterns.

PATIENTS AND METHODS

We analyzed data from an Italian case-control study, including 304 cases with squamous cell carcinoma of the esophagus and 743 hospital controls. Dietary habits were evaluated using a food frequency questionnaire. A posteriori dietary patterns were identified through principal component factor analysis performed on 28 selected nutrients. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained from multiple logistic regression models applied on quartiles of factor scores, adjusting for potential confounding variables.

RESULTS

We identified five major dietary patterns, named 'animal products and related components', 'vitamins and fiber', 'starch-rich', 'other polyunsaturated fatty acids and vitamin D', and 'other fats'. The 'animal products and related components' pattern was positively related to esophageal cancer (OR = 1.64, 95% CI:1.06-2.55, for the highest versus the lowest quartile of factor scores category). The 'vitamins and fiber' (OR = 0.50, 95% CI: 0.32-0.78) and the 'other polyunsaturated fatty acids and vitamin D' (OR = 0.48, 95% CI: 0.31-0.74) were inversely related to esophageal cancer. No significant association was observed for the other patterns.

CONCLUSION

Our findings suggest that a diet rich in foods from animal origin and poor in foods containing vitamins and fiber increase esophageal cancer risk.

Fiber intake and pancreatic cancer risk: a case-control study

BACKGROUND

Scanty and inconsistent studies are available on the relation between dietary fiber intake and pancreatic cancer. A case-control study was carried out in northern Italy to further investigate the role of various types of dietary fibers in the etiology of pancreatic cancer.

PATIENTS AND METHODS

Cases were 326 patients with incident pancreatic cancer, excluding neuroendocrine tumors, admitted to major teaching and general hospitals during 1991-2008. Controls were 652 patients admitted for acute, nonneoplastic conditions to the same hospital network of cases. Information was elicited using a validated food frequency questionnaire. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were estimated for intake quintiles of different types of fiber after allowance for total energy intake and other potential confounding factors.

RESULTS

Total fiber intake was inversely related to risk of pancreatic cancer (OR=0.4 for highest versus lowest quintile of intake; 95% CI 0.2-0.7). An inverse association emerged between pancreatic cancer and both soluble (OR=0.4; 95% CI 0.2-0.7) and total insoluble fiber (OR=0.5; 95% CI 0.3-0.8), particularly cellulose (OR=0.4; 95% CI 0.3-0.7) and lignin (OR=0.5; 95% CI 0.3-0.9). Fruit fiber intake was inversely associated with pancreatic cancer (OR=0.5; 95% CI 0.3-0.8), whereas grain fiber was not (OR=1.2; 95% CI 0.7-2.0).

CONCLUSIONS

This study suggests that selected types of fiber and total fiber are inversely related to pancreatic cancer.

Incidence of thyroid cancer in Italy, 1991-2005: time trends and age-period-cohort effects

BACKGROUND

In Italy, some of the highest incidence rates (IRs) of thyroid cancer (TC) worldwide have been reported.

PATIENTS AND METHODS

TC cases <85 years of age reported to Italian cancer registries during 1991-2005 were included. Age-standardized IRs were computed for all TC and age-period-cohort effects were estimated for papillary TC.

RESULTS

IRs of TC were twofold higher in 2001-2005 than in 1991-1995 (18 and 8 per 100,000 women, 6 and 3 per 100,000 men, respectively). Increases were similar in the two sexes and nearly exclusively due to papillary TC. Increases of papillary TC by birth cohort were found in both sexes and among all age groups between 20 and 79 years. Age-period-cohort models showed a strong period effect in both sexes (rate ratio for 2001-2009 versus 1991-1995 = 2.5 in women and 2.3 in men), although IRs peaked at an earlier age in women (45-49 years) than men (65-69 years).

CONCLUSION

The strength of the period effect in both sexes and the earlier onset in women than men strongly implicated increased medical surveillance in the upward trends of papillary TC incidence in Italy. The consequences of the current intense search for TC on morbidity and possible overtreatment, especially among young women, should be carefully evaluated.

Metabolic syndrome and endometrial cancer risk

BACKGROUND

Various studies reported direct associations between endometrial cancer risk and individual components of the metabolic syndrome (MetS), i.e. obesity, diabetes, hypertension, and dyslipidemia, but only a few epidemiological studies considered the association with MetS overall.

METHODS

We analyzed data from a case-control study including 454 women with incident endometrial cancer and 798 controls admitted to the same hospitals as cases for acute conditions. Different definitions of MetS were considered, including a combination of self-reported history of diabetes, drug-treated hypertension, drug-treated hyperlipidemia, and various measures of (central) obesity. Odds ratios (ORs) were computed from unconditional logistic regression models, adjusted for major confounding factors.

RESULTS

The multivariate ORs of endometrial cancer were 2.18 for type 2 diabetes, 1.77 for hypertension, 1.20 for hyperlipidemia, between 1.62 and 2.23 for various definitions of central obesity, and 3.83 for women with a body mass index (BMI) >30 kg/m(2). The risk of endometrial cancer was significantly increased for subjects with MetS, the ORs ranging between 1.67 and 2.77 when waist circumference was included in MetS definition, and 8.40 when BMI was considered instead.

CONCLUSIONS

This study indicates a direct association between various MetS components, besides overweight, with the risk of endometrial cancer.

Changing patterns of cancer incidence in the early- and late-HAART periods: the Swiss HIV Cohort Study

Background:

The advent of highly active antiretroviral therapy (HAART) in 1996 led to a decrease in the incidence of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma (NHL), but not of other cancers, among people with HIV or AIDS (PWHA). It also led to marked increases in their life expectancy.

Methods:

We conducted a record-linkage study between the Swiss HIV Cohort Study and nine Swiss cantonal cancer registries. In total, 9429 PWHA provided 20 615, 17 690, and 15 410 person-years in the pre-, early-, and late-HAART periods, respectively. Standardised incidence ratios in PWHA vs the general population, as well as age-standardised, and age-specific incidence rates were computed for different periods.

Results:

Incidence of KS and NHL decreased by several fold between the pre- and early-HAART periods, and additionally declined from the early- to the late-HAART period. Incidence of cancers of the anus, liver, non-melanomatous skin, and Hodgkin's lymphoma increased in the early- compared with the pre-HAART period, but not during the late-HAART period. The incidence of all non-AIDS-defining cancers (NADCs) combined was similar in all periods, and approximately double that in the general population.

Conclusions:

Increases in the incidence of selected NADCs after the introduction of HAART were largely accounted for by the ageing of PWHA.

Tobacco smoking, alcohol consumption and pancreatic cancer risk: a case-control study in Italy

In Italy, pancreatic cancer accounts for approximately 5% of cancer-related deaths. Tobacco smoking is the major established risk factor for this cancer, whereas the role of alcohol consumption is open to debate. Between 1991 and 2008, we conducted a hospital-based case-control study on pancreatic cancer in northern Italy. Cases were 326 patients (median age 63 years) with incident pancreatic cancer admitted to major general hospitals. Controls were 652 patients (median age 63 years) with acute non-neoplastic conditions admitted to the same hospital network of cases. Multiple logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI). Pancreatic cancer was associated to current smoking (OR=1.68; 95% CI: 1.13-2.48), and the risk rose with increasing number of cigarettes/day (OR=2.04; 95% CI: 1.14-3.66 for > or = 20 cigarettes/day). No association emerged for former smokers (OR=0.98; 95% CI: 0.66-1.45). Alcohol consumption was associated to increased pancreatic cancer risk, but ORs were significant only among heavy drinkers (ORs: 2.03 and 3.42 for 21-34 and > or = 35 drinks/week, respectively). Pancreatic cancer risk was 4.3-fold higher in heavy smokers (> or = 20 cigarettes/day) and heavy drinkers (> or = 21 drinks/week) in comparison with never smokers who drunk < 7 drinks/week, which is compatible with an additive effect of these exposures. In conclusion, we found that tobacco smoking and alcohol drinking are two independent risk factors for pancreatic cancer which may be responsible for approximately one third of these cancers in our population.

Differences in the risk of cervical cancer and human papillomavirus infection by education level

BACKGROUND

Cervical cancer risk is associated with low education even in an unscreened population, but it is not clear whether human papillomavirus (HPV) infection follows the same pattern.

METHODS

Two large multicentric studies (case-control studies of cervical cancer and HPV prevalence survey) including nearly 20 000 women. GP5+/GP6+ PCR was used to detect HPV.

RESULTS

Education level was consistently associated with cervical cancer risk (odds ratio (OR) for 0 and >5 years vs 1-5 years=1.50, 95% confidence interval (CI): 1.25-1.80 and 0.69, 95% CI: 0.57-0.82, respectively, P for trend <0.0001). In contrast, no association emerged between education level and HPV infection in either of the two IARC studies. A majority of the women studied had never had a Pap smear. The association between low education level and cervical cancer was most strongly attenuated by adjustment for age at first sexual intercourse and first pregnancy. Parity and screening history (but not lifetime number of sexual partners, husband's extramarital sexual relationships, and smoking) also seemed to be important confounding factors.

CONCLUSION

The excess of cervical cancer found in women with a low socio-economic status seems, therefore, not to be explained by a concomitant excess of HPV prevalence, but rather by early events in a woman's sexually active life that may modify the cancer-causing potential of HPV infection.

HPV infection in women with and without cervical cancer in Conakry, Guinea

BACKGROUND

Cervical cancer incidence in western Africa is among the highest in the world.

METHODS

To investigate human papillomavirus (HPV) infection in Guinea, we obtained cervical specimens from 831 women aged 18-64 years from the general population of the capital Conakry and from 77 locally diagnosed invasive cervical cancers (ICC). Human papillomavirus was detected using a GP5+/6+ PCR-based assay.

RESULTS

Among the general population, the prevalence of cervical abnormalities was 2.6% by visual inspection and 9.5% by liquid-based cytology. Fourteen of 15 high-grade squamous intraepithelial lesions were visual inspection-negative. Human papillomavirus prevalence was 50.8% (32.1% for high-risk types) and relatively constant across all age groups. Being single or reporting > or =3 sexual partners was significantly associated with HPV positivity. HPV16 was the most common type, both among the general population (7.3%) and, notably in ICC (48.6%). HPV45 (18.6%) and HPV18 (14.3%), the next most common types in ICC, were also more common in ICC than in HPV-positive women with normal cytology from the general population.

CONCLUSION

The heavy burden of HPV infection and severe cervical lesions in Guinean women calls for new effective interventions. Sixty-three per cent of cervical cancers are theoretically preventable by HPV16/18 vaccines in Guinea; perhaps more if some cross-protection exists with HPV45.

Glycemic index, glycemic load and renal cell carcinoma risk

BACKGROUND

The risk of renal cell carcinoma (RCC) has been related to refined cereals and starchy foods, but the association has not been studied in terms of glycemic index (GI) and glycemic load (GL). To provide information on this issue, we analyzed data from an Italian multicentric case-control study.

MATERIALS AND METHODS

Cases were 767 patients with histologically confirmed, incident RCC. Controls were 1534 subjects admitted to the same hospitals as cases for a wide spectrum of acute, non-neoplastic conditions, unrelated to known risk factors for RCC. Information on dietary habits was derived through a food-frequency questionnaire. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) for GI and GL intake were adjusted for major relevant covariates.

RESULTS

Compared with the lowest quintile, the ORs for the highest quintile were 1.43 (95% CI 1.05-1.95) for GI and 2.56 (95% CI 1.78-3.70) for GL, with significant trends in risk. Compared with the lowest quintile, the risk of RCC for all subsequent levels of GL was higher in never drinkers than in ever drinkers.

CONCLUSIONS

We found direct relations between dietary levels of GI and GL and RCC risk. This can be related to mechanisms linked to insulin resistance and sensitivity.

Dietary glycemic load and hepatocellular carcinoma with or without chronic hepatitis infection

BACKGROUND

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the major risk factors for hepatocellular carcinoma (HCC). The association of diabetes mellitus with HCC suggests that dietary glycemic load (GL) may influence HCC risk. We have examined the association between dietary GL and HCC.

PATIENTS AND METHODS

We conducted a hospital-based case-control study in Italy in 1999-2002, including 185 HCC cases and 412 controls who answered a validated food frequency questionnaire and provided blood samples. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed using unconditional multiple logistic regression.

RESULTS

We observed a positive association between GL and HCC overall, with an OR of 3.02 (95% CI 1.49-6.12) for the highest quintile of GL compared with the lowest and a significant trend. The OR among HCC cases with evidence of chronic infection with HBV and/or HCV was 3.25 (95% CI 1.46-7.22), while the OR among those with no evidence of infection was 2.45 (95% CI 0.69-8.64), with no significant trend. The association was not explained by the presence of cirrhosis or diabetes.

CONCLUSIONS

High dietary GL is associated with increased risk for HCC. The positive association was most pronounced among HCC cases with HBV and/or HCV markers.

Dietary vitamin D and cancers of the oral cavity and esophagus

BACKGROUND

Data on the association between vitamin D and upper digestive tract neoplasms are limited.

METHODS

In two case-control studies in Italy, we examined the relation between dietary vitamin D intake and squamous cell carcinoma of the esophagus (SCCE; 304 cases) and oral/pharyngeal cancer (804 cases). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multiple logistic regression.

RESULTS

Adjusted ORs for SCCE and oral/pharyngeal cancer were 0.58 (95% CI 0.39-0.86) and 0.76 (95% CI 0.60-0.94), respectively, for the highest tertile of vitamin D intake. Using a reference group of those in the highest tertile of vitamin D who were never/former smokers, ORs were 8.7 (95% CI 4.1-18.7) for SCCE and 10.4 (95% CI 6.9-15.5) for oral/pharyngeal cancer among heavy smokers in the lowest vitamin D tertile; similarly, compared with those in the highest tertile of vitamin D who drank <3 alcoholic drinks/day, corresponding ORs were 41.9 (95% CI 13.7-128.6) for SCCE and 8.5 (95% CI 5.7-12.5) for oral/pharyngeal cancer, among heavy alcohol drinkers in the lowest vitamin D tertile.

CONCLUSION

We observed inverse associations between dietary vitamin D intake and risk of SCCE and, perhaps, oral/pharyngeal cancer, which were most pronounced among heavy current smokers and heavy consumers of alcohol.

Early age at first sexual intercourse and early pregnancy are risk factors for cervical cancer in developing countries

Early age at first sexual intercourse (AFSI) has long been associated with an increased risk of invasive cervical carcinoma (ICC). Age at first pregnancy (AFP) and ICC have been investigated less, although AFSI and AFP are strongly interrelated in most developing countries. A pooled analysis of case–control studies on ICC from eight developing countries with 1864 cases and 1719 controls investigated the roles of AFSI, AFP, and ICC risk. Age at first sexual intercourse, AFP and age at first marriage (AFM) were highly interrelated and had similar ICC risk estimates. Compared with women with AFSI ⩾21 years, the odds ratio (OR) of ICC was 1.80 (95% CI: 1.50–2.39) among women with AFSI 17–20 years and 2.31 (95% CI: 1.85–2.87) for AFSI ⩽16 years (P-trend <0.001). No statistical interaction was detected between AFSI and any established risk factors for ICC. The ICC risk was 2.4-fold among those who reported AFSI and AFP at ⩽16 years compared with those with AFSI and AFP at ⩾21 years. These data confirm AFSI and AFB as risk factors for ICC in eight developing countries, but any independent effects of these two events could not be distinguished.

Different cervical cancer screening approaches in a Chinese multicentre study

To evaluate alternative cervical cancer screening methods, digital colposcopy and collection of cervical exfoliated cells for liquid-based cytology (LBC) and hybrid capture 2 (HC2) testing were performed among 2562 women aged 15–59 years in three study sites in the People's Republic of China (rural Shanxi province, Shenyang city in Liaoning province and Shenzhen city in Guangdong province). Visual inspection with acetic acid (VIA) was also evaluated independently from colposcopy. A total of 74 cases of histologically confirmed cervical intraepithelial neoplasia grade 2 or worse (CIN2+) were identified, and 16 CIN2+ cases were imputed among unbiopsied women to correct for verification bias. Corrected sensitivity for CIN2+ was 37% for VIA, 54% for colposcopy, 87% for LBC with a threshold of atypical cells of undetermined significance (LBC⩾ASCUS), 90% for HC2, 84% for LBC using HC2 to triage ASCUS and 96% for positivity to LBC⩾ASCUS or HC2. For VIA, sensitivity was much lower among women ⩾40 years (12%) than those aged ⩽39 years (50%). Specificity varied from 77% for positivity to LBC⩾ASCUS or HC2, up to 94% for LBC using HC2 to triage ASCUS. In conclusion, LBC, HC2 and their combinations performed well, whereas VIA missed a majority of CIN2+, particularly in older women. Digital colposcopy performed better than VIA, but still missed nearly half of CIN2+ in this study.

Clustering dietary habits and the risk of breast and ovarian cancers

BACKGROUND

Limited information is available on the relationship between dietary patterns and breast and ovarian cancers.

PATIENTS AND METHODS

Cases were 2569 breast cancers and 1031 ovarian cancers hospitalized in four Italian areas from 1991 to 1999. Controls were 3413 women in hospital for acute non-neoplastic diseases. Dietary habits were investigated through a validated food-frequency questionnaire. Dietary patterns were obtained from a K-means clustering on factor scores from factor analysis. Odds ratios (ORs) for both cancers were estimated using unconditional multiple logistic regression models on clusters of patients. Floating absolute risk method was used for reporting 95% floating confidence intervals (FCIs).

RESULTS

We identified five groups of subjects. The G3 cluster, including subjects with the lowest intakes of any food group, was used as reference. The G5 cluster, including subjects mainly consuming bread and pasta, was unfavorable for both cancers (OR=1.23, 95% FCI=1.08-1.38 for breast cancer, OR=1.21, 95% FCI=1.03-1.42 for ovarian cancer). The G1 group, including subjects mainly consuming fruits and vegetables, was protective against ovarian cancer (OR=0.81, 95% FCI=0.67-0.98).

CONCLUSIONS

A diet mainly based on bread and pasta is unfavorable for breast and ovarian cancers; a diet rich in fruits and vegetables may be associated with a reduced risk of ovarian cancer.