R.A. Goldbohm

Familial breast cancer: collaborative reanalysis of individual data from 52 epidemiological studies including 58,209 women with breast cancer and 101,986 women without the disease

BACKGROUND Women with a family history of breast cancer are at increased risk of the disease, but no study has been large enough to characterise reliably how, over womens lives, this risk is influenced by particular familial patterns of breast cancer. This report, on the relevance of breast cancer in first-degree relatives, is based on combined data from 52 epidemiological studies. METHODS Individual data on breast cancer in first-degree relatives (mothers, sisters, and daughters) of 58209 women with breast cancer and of 101986 controls were collected, checked, and analysed centrally. Risk ratios for breast cancer were calculated by conditional logistic regression, stratified by study, age, menopausal status, number of sisters, parity, and age when the first child was born. Breast-cancer incidence and mortality rates for particular family histories were calculated by applying age-specific risk ratios to breast-cancer rates typical for more-developed countries. FINDINGS Altogether 7496 (12.9%) women with breast cancer and 7438 (7.3%) controls reported that one or more first-degree relatives had a history of breast cancer: 12% of women with breast cancer had one affected relative and 1% had two or more. Risk ratios for breast cancer increased with increasing numbers of affected first-degree relatives: compared with women who had no affected relative, the ratios were 1.80 (99% CI 1.69-1.91), 2.93 (2.36-3.64), and 3.90 (2.03-7.49), respectively, for one, two, and three or more affected first-degree relatives (p<0.0001 each). The risk ratios were greatest at young ages, and for women of a given age, were greater the younger the relative was when diagnosed. The results did not differ substantially between women reporting an affected mother (9104) or sister (6386). Other factors, such as childbearing history, did not significantly alter the risk ratios associated with a family history of breast cancer. For women in more-developed countries with zero, one, or two affected first-degree relatives, the estimated cumulative incidence of breast cancer up to age 50 was 1.7%, 3.7%, and 8.0%, respectively; corresponding estimates for incidence up to age 80 were 7.8%, 13.3%, and 21.1%. Corresponding estimates for death from breast cancer up to age 80 were 2.3%, 4.2%, and 7.6%. The age when the relative was diagnosed had only a moderate effect on these estimates. INTERPRETATION Eight out of nine women who develop breast cancer do not have an affected mother, sister, or daughter. Although women who have first-degree relatives with a history of breast cancer are at increased risk of the disease, most will never develop breast cancer, and most who do will be aged over 50 when their cancer is diagnosed. In countries where breast cancer is common, the lifetime excess incidence of breast cancer is 5.5% for women with one affected first-degree relative and 13.3% for women with two.Familial breast cancer: collaborative reanalysis of individual data from 52 epidemiological studies including 58,209 women with breast cancer and 101,986 women without the disease. Collaborative Group on Hormonal Factors in Breast Cancer. BACKGROUND: Women with a family history of breast cancer are at increased risk of the disease, but no study has been large enough to characterise reliably how, over womens lives, this risk is influenced by particular familial patterns of breast cancer. This report, on the relevance of breast cancer in first-degree relatives, is based on combined data from 52 epidemiological studies. METHODS: Individual data on breast cancer in first-degree relatives (mothers, sisters, and daughters) of 58209 women with breast cancer and of 101986 controls were collected, checked, and analysed centrally. Risk ratios for breast cancer were calculated by conditional logistic regression, stratified by study, age, menopausal status, number of sisters, parity, and age when the first child was born. Breast-cancer incidence and mortality rates for particular family histories were calculated by applying age-specific risk ratios to breast-cancer rates typical for more-developed countries. FINDINGS: Altogether 7496 (12.9%) women with breast cancer and 7438 (7.3%) controls reported that one or more first-degree relatives had a history of breast cancer: 12% of women with breast cancer had one affected relative and 1% had two or more. Risk ratios for breast cancer increased with increasing numbers of affected first-degree relatives: compared with women who had no affected relative, the ratios were 1.80 (99% CI 1.69-1.91), 2.93 (2.36-3.64), and 3.90 (2.03-7.49), respectively, for one, two, and three or more affected first-degree relatives (p<0.0001 each). The risk ratios were greatest at young ages, and for women of a given age, were greater the younger the relative was when diagnosed. The results did not differ substantially between women reporting an affected mother (9104) or sister (6386). Other factors, such as childbearing history, did not significantly alter the risk ratios associated with a family history of breast cancer. For women in more-developed countries with zero, one, or two affected first-degree relatives, the estimated cumulative incidence of breast cancer up to age 50 was 1.7%, 3.7%, and 8.0%, respectively; corresponding estimates for incidence up to age 80 were 7.8%, 13.3%, and 21.1%. Corresponding estimates for death from breast cancer up to age 80 were 2.3%, 4.2%, and 7.6%. The age when the relative was diagnosed had only a moderate effect on these estimates. INTERPRETATION: Eight out of nine women who develop breast cancer do not have an affected mother, sister, or daughter. Although women who have first-degree relatives with a history of breast cancer are at increased risk of the disease, most will never develop breast cancer, and most who do will be aged over 50 when their cancer is diagnosed. In countries where breast cancer is common, the lifetime excess incidence of breast cancer is 5.5% for women with one affected first-degree relative and 13.3% for women with two

A REVIEW OF MECHANISMS UNDERLYING ANTICARCINOGENICITY BY BRASSICA VEGETABLES

The mechanisms by which brassica vegetables might decrease the risk of cancer are reviewed in this paper. Brassicas, including all types of cabbages, broccoli, cauliflower and Brussels sprouts, may be protective against cancer due to their relatively high glucosinolate content. Glucosinolates are usually broken down through hydrolysis catalyzed by myrosinase, an enzyme that is released from damaged plant cells. Some of the hydrolysis products, viz. indoles and isothiocyanates, are able to influence phase 1 and phase 2 biotransformation enzyme activities, thereby possibly influencing several processes related to chemical carcinogenesis, e.g. the metabolism, DNA-binding and mutagenic activity of promutagens. A reducing effect on tumor formation has been shown in rats and mice. The anticarcinogenic action of isothiocyanates and indoles depends upon many factors, such as the test system, the target tissue, the type of carcinogen challenge and the anticarcinogenic compound, their dosage, as well as the timing of the treatment. Most evidence concerning anticarcinogenic effects of glucosinolate hydrolysis products and brassica vegetables has come from studies in animals. Animal studies are invaluable in identifying and testing potential anticarcinogens. In addition, studies carried out in humans using high but still realistic human consumption levels of indoles and brassica vegetables have shown putative positive effects on health.

Intake of butylated hydroxyanisole and butylated hydroxytoluene and stomach cancer risk: results from analyses in the Netherlands Cohort Study.

Both carcinogenic and anticarcinogenic properties have been reported for the synthetic antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). The association between dietary intake of BHA and BHT and stomach cancer risk was investigated in the Netherlands Cohort Study (NLCS) that started in 1986 among 120,852 men and women aged 55 to 69 years. A semi-quantitative food frequency questionnaire was used to assess food consumption. Information on BHA or BHT content of cooking fats, oils, mayonnaise and other creamy salad dressings and dried soups was obtained by chemical analysis, a Dutch database of food additives (ALBA) and the Dutch Compendium of Foods and Diet Products. After 6.3 years of follow-up, complete data on BHA and BHT intake of 192 incident stomach cancer cases and 2035 subcohort members were available for case-cohort analysis. Mean intake of BHA or BHT among subcohort members was 105 and 351 microg/day, respectively. For consumption of mayonnaise and other creamy salad dressings with BHA or BHT no association with stomach cancer risk was observed. A statistically non-significant decrease in stomach cancer risk was observed with increasing BHA and BHT intake [rate ratio (RR) highest/lowest intake of BHA = 0.57 (95% confidence interval (CI): 0.25-1.30] and BHT = 0.74 (95% CI: 0.38-1.43). In this study, no significant association with stomach cancer risk was found for usual intake of low levels of BHA and BHT.

A Prospective Study of Dietary Acrylamide Intake and the Risk of Endometrial, Ovarian, and Breast Cancer

Background: Acrylamide, a probable human carcinogen, was detected in various heat-treated carbohydrate-rich foods in 2002. The few epidemiologic studies done thus far have not shown a relationship with cancer. Our aim was to investigate the association between acrylamide intake and endometrial, ovarian, and breast cancer risk. Methods: The Netherlands Cohort Study on diet and cancer includes 62,573 women, aged 55-69 years. At baseline (1986), a random subcohort of 2,589 women was selected using a case cohort analysis approach for analysis. The acrylamide intake of subcohort members and cases was assessed with a food frequency questionnaire and was based on chemical analysis of all relevant Dutch foods. Subgroup analyses were done for never-smokers to eliminate the influence of smoking; an important source of acrylamide. Results: After 11.3 years of follow-up, 327, 300, and 1,835 cases of endometrial, ovarian, and breast cancer, respectively, were documented. Compared with the lowest quintile of acrylamide intake (mean intake, 8.9 μg/day), multivariable-adjusted hazard rate ratios (HR) for endometrial, ovarian, and breast cancer in the highest quintile (mean intake, 40.2 μg/day) were 1.29 [95% confidence interval (95% CI), 0.81-2.07; Ptrend = 0.18], 1.78 (95% CI, 1.10-2.88; Ptrend = 0.02), and 0.93 (95% CI, 0.73-1.19; Ptrend = 0.79), respectively. For never-smokers, the corresponding HRs were 1.99 (95% CI, 1.12-3.52; Ptrend = 0.03), 2.22 (95% CI, 1.20-4.08; Ptrend = 0.01), and 1.10 (95% CI, 0.80-1.52; Ptrend = 0.55). Conclusions: We observed increased risks of postmenopausal endometrial and ovarian cancer with increasing dietary acrylamide intake, particularly among never-smokers. Risk of breast cancer was not associated with acrylamide intake. (Cancer Epidemiol Biomarkers Prev 2007;16(11):2304–13)

Epidemiologic evidence for beta-carotene and cancer prevention.

In 1981 it was hypothesized that a high dietary intake of beta-carotene might reduce human cancer rates. Since then, several observational epidemiologic studies have addressed this topic. The results of both case-control and cohort studies show a remarkable consistency for the association of increased lung cancer risk with low amounts of dietary beta-carotene or low plasma beta-carotene concentrations. For stomach cancer, the evidence is also consistent, although the number of studies is more modest. For breast and prostate cancer, the studies indicate no consistent association of plasma or dietary beta-carotene and reduced cancer risk. For colorectal cancer, the effect will be moderate, if existent. For several other cancer sites, the numbers of cases in prospective studies are often small, implying that only strong associations can be detected. For some of these sites, results from retrospective studies are promising. The epidemiologic studies should be carefully interpreted because dietary habits may be misclassified and smoking may reduce plasma beta-carotene concentrations. Observational epidemiology cannot definitively resolve whether associations are indeed due to beta-carotene, or to other components of fruit and vegetables that are rich in beta-carotene. However, overall results are promising and several plausible cancer preventive mechanisms have been reported for beta-carotene. The ongoing human intervention studies will provide more answers regarding cancer prevention by beta-carotene but may need long follow-ups to be conclusive.

Vitamins C and E, retinol, beta-carotene and dietary fibre in relation to breast cancer risk: a prospective cohort study

Association between breast cancer risk and the intake of vitamins C and E, retinol, beta (beta)-carotene, dietary fibre, vegetables, fruit and potatoes was examined in The Netherlands Cohort Study, for 62,573 women aged 55-69 years. After 4.3 years of follow-up, 650 incident breast cancer cases were identified. After adjusting for traditional risk factors, breast cancer risk was not influenced by the intake of beta-carotene, vitamin E, dietary fibre, supplements with vitamin C, vegetables or potatoes. Fruit consumption showed a non-significant inverse association with breast cancer risk (RR highest/lowest quintile = 0.76, 95% CI 0.54-1.08). A small reduction in risk was also observed with increasing intake of dietary vitamin C (RR highest/lowest quintile = 0.77, 95% CI 0.55-1.08). For retinol, a weak positive association was observed (RR highest/lowest quintile = 1.24, 95% CI 0.83-1.83). Among subjects with a high intake of polyunsaturated fatty acids (PUFAs), both beta-carotene and vitamin C intake showed a non-significant inverse association with breast cancer risk (P-trend = 0.15 and 0.16 respectively). Our findings do not suggest a strong role, if any, for intake of vitamins C and E, beta-carotene, retinol, dietary fibre, vegetables, fruit and potatoes in the aetiology of breast cancer.

Vegetable and fruit consumption and lung cancer risk in the Netherlands Cohort Study on diet and cancer

AbstractObjective: The purpose was to study the association between vegetable and fruit consumption and lung cancer incidence using 1074 cases after 6.3 years of follow-up in the Netherlands Cohort Study. Methods: Dietary intake was assessed using a 150-item food-frequency questionnaire. Multivariate models were used including age, sex, family history of lung cancer, highest educational level attained, and smoking history. Results: Statistically significant inverse associations were found with total vegetables and most vegetable groups. Rate ratios (RRs) based on consumption frequency showed the strongest effect of vegetables from the Brassica group (RR 0.5, 95% confidence interval (95% CI) 0.3–0.9, for consumption ≥3 times per week versus ≤ once a month). RR of highest versus lowest quintile of total vegetable consumption was 0.7 (95% CI 0.5–1.0, p-trend 0.001). Statistically significant inverse associations were found for all fruits listed in the questionnaire. RRs for quintiles of total fruit intake were 1.0, 0.7, 0.6, 0.6 and 0.8 respectively (p-trend < 0.0001). Protective effects of fruits and vegetables were stronger in current than in former smokers, and weaker for adenocarcinomas than for other types of tumors. Conclusions: Inverse associations with lung cancer are found for both vegetable and fruit intake, but no specific type of vegetable or fruit seems to be particularly responsible.

Animal products, calcium and protein and prostate cancer risk in The Netherlands Cohort Study.

SummaryProstate cancer risk in relation to consumption of animal products, and intake of calcium and protein was investigated in the Netherlands Cohort Study. At baseline in 1986, 58 279 men aged 55–69 years completed a self-administered 150-item food frequency questionnaire and a questionnaire on other risk factors for cancer. After 6.3 years of follow-up, 642 prostate cancer cases were available for analysis. In multivariate case-cohort analyses adjusted for age, family history of prostate cancer and socioeconomic status, no associations were found for consumption of fresh meat, fish, cheese and eggs. Positive trends in risk were found for consumption of cured meat and milk products (P-values 0.04 and 0.02 respectively). For calcium and protein intake, no associations were observed. The hypothesis that dietary factors might be more strongly related to advanced prostate tumours could not be confirmed in our study. We conclude that, in this study, animal products are not strongly related to prostate cancer risk.

The joint association of air pollution and noise from road traffic with cardiovascular mortality in a cohort study

Objectives: Associations between cardiovascular mortality and air pollution and noise together were investigated. Methods: Data from the ongoing Netherlands Cohort Study on Diet and Cancer (120 852 subjects; follow-up 1987–1996) were used. Cox proportional hazard analyses were conducted for the association between cardiovascular mortality and exposure to black smoke, traffic intensity on the nearest road and road traffic noise at the home address. Results: The correlations between traffic noise and background black smoke, and traffic intensity on the nearest road were moderate at 0.24 and 0.30, respectively. Traffic intensity was associated with cardiovascular mortality, with highest relative risk (95% confidence interval) for ischaemic heart disease (IHD) mortality being 1.11 (1.03 to 1.20) (increment 10 000 motor vehicles/24 h). Relative risks for black smoke concentrations were elevated for cerebrovascular (1.39 (0.99 to 1.94)) and heart failure mortality (1.75 (1.00 to 3.05)) (increment 10 μg/m3). These associations were insensitive to adjustment for traffic noise. There was an excess of cardiovascular mortality in the highest noise category (>65 dB(A)), with elevated risks for IHD (1.15 (0.86 to 1.53)) and heart failure mortality (1.99 (1.05 to 3.79)). After adjustment for black smoke and traffic intensity, noise risk reduced to unity for IHD mortality and was slightly reduced for heart failure mortality. Conclusions: Associations between black smoke concentrations and traffic intensity on the nearest road with specific cardiovascular causes of death were not explained by traffic noise in this study.

Alcohol consumption, cigarette smoking and risk of subtypes of oesophageal and gastric cancer: A prospective cohort study

Objective: Alcohol consumption and cigarette smoking may be differentially associated with oesophageal squamous cell carcinoma (OSCC), oesophageal adenocarcinoma (OAC), gastric cardia adenocarcinoma (GCA) and gastric non-cardia adenocarcinoma (GNCA). However, because this was based on retrospective studies, these hypotheses were examined in a prospective cohort. Methods: The prospective Netherlands Cohort Study consists of 120 852 participants who completed a baseline questionnaire on diet and other cancer risk factors in 1986. After 16.3 years of follow-up, 107 OSCC, 145 OAC, 164 GCA and 491 GNCA cases were available for analysis using Cox proportional hazards models and the case–cohort approach. Results: The multivariable adjusted incidence rate ratio (RR) for OSCC was 4.61 (95% CI 2.24 to 9.50) for ⩾30 g ethanol/day compared with abstainers (p trend <0.001), while no associations with alcohol were found for OAC, GCA or GNCA. Compared with never smokers, current smokers had RRs varying from 1.60 for GCA to 2.63 for OSCC, and were statistically significant or borderline statistically significant. Frequency, duration and pack-years of smoking were independently associated with risk of all four cancers. A positive interaction was found between alcohol consumption and smoking status regarding OSCC risk. The RR for current smokers who consumed >15 g/day of ethanol was 8.05 (95% CI 3.89 to 16.60; p interaction = 0.65), when compared with never smokers who consumed <5 g/day of ethanol. Conclusions: This prospective study found alcohol consumption to be associated with increased risk of only OSCC. Cigarette smoking was associated with risk of all four cancers.