Oral contraceptives, reproductive history and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

Background:

Oral contraceptive use and reproductive factors may initiate long-term changes to the hormonal milieu and thereby, possibly influence colorectal cancer risk.

Methods:

We examined the association of hormonal and reproductive factors with risk of colorectal cancer among 337 802 women in the European Prospective Investigation into Cancer and Nutrition, of whom 1878 developed colorectal cancer.

Results:

After stratification for center and age, and adjustment for body mass index, smoking, diabetes mellitus, physical activity and alcohol consumption, ever use of oral contraceptives was marginally inversely associated with colorectal cancer risk (hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.83–1.02), although this association was stronger among post-menopausal women (HR, 0.84; 95% CI: 0.74–0.95). Duration of oral contraceptive use and reproductive factors, including age at menarche, age at menopause, type of menopause, ever having an abortion, parity, age at first full-term pregnancy and breastfeeding, were not associated with colorectal cancer risk.

Conclusion:

Our findings provide limited support for a potential inverse association between oral contraceptives and colorectal cancer risk.     

Dietary fat intake and risk of ovarian cancer in the NIH-AARP Diet and Health Study

Background:

Fat intake has been postulated to increase risk of ovarian cancer, but previous studies have reported inconsistent results.

Methods:

The NIH-AARP Diet and Health Study, a large prospective cohort, assessed diet using a food frequency questionnaire at baseline in 1995–1996. During an average of 9 years of follow-up, 695 ovarian cancer cases were ascertained through the state cancer registry database. The relative risks (RRs) and 95% confidence interval (CI) were estimated using a Cox proportional hazard model.

Results:

Women in the highest vs the lowest quintile of total fat intake had a 28% increased risk of ovarian cancer (RR_{Q5 vs Q1}=1.28, 95% CI: 1.01–1.63). Fat intake from animal sources (RR_{Q5 vs Q1}=1.30; 95% CI: 1.02–1.66), but not from plant sources, was positively associated with ovarian cancer risk. Saturated and monounsaturated fat intakes were not related to risk of ovarian cancer, but polyunsaturated fat intake showed a weak positive association. The association between total fat intake and ovarian cancer was stronger in women who were nulliparous or never used oral contraceptives.

Conclusion:

Fat intake, especially from animal sources, was related to an increased risk of ovarian cancer. The association may be modified by parity and oral contraceptive use, which warrants further investigation.     

Fish consumption and the risk of colorectal cancer: the Ohsaki Cohort Study

Background:

Evidence from laboratory and animal studies suggests that high fish consumption may reduce the risk of colorectal cancer, but the results of studies in humans have been inconsistent. The objective of this study was to prospectively examine the association between fish consumption and the risk of colorectal cancer incidence in Japan, where fish is widely consumed.

Methods:

We analysed data from 39 498 men and women registered in the Ohsaki National Health Insurance Cohort Study who were 40–79 years old and free of cancer at the baseline. Fish consumption was assessed at the baseline using a self-administered food frequency questionnaire.

Results:

During 9 years of follow-up, we identified 566 incident cases of colorectal cancer (379 men and 187 women). The hazard ratios and 95% confidence intervals (CIs) for colorectal cancer incidence in the highest quartile of fish consumption compared with the lowest quartile were 1.07 (95% CIs; 0.78–1.46, P-trend=0.43) for men, and 0.96 (95% CIs; 0.61–1.53, P-trend=0.69) for women.

Conclusion:

The results of this prospective cohort study revealed no association between fish consumption and the risk of colorectal cancer.     

Concentrations of IGF-I and IGFBP-3 and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition

Background:

Insulin-like growth factors (IGFs) and their binding proteins (BPs) regulate cell differentiation, proliferation and apoptosis, and may have a role in the aetiology of various cancers. Information on their role in pancreatic cancer is limited and was examined here in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition.

Methods:

Serum concentrations of IGF-I and IGFBP-3 were measured using enzyme-linked immunosorbent assays in 422 cases and 422 controls matched on age, sex, study centre, recruitment date, and time since last meal. Conditional logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI) adjusted for confounding variables.

Results:

Neither circulating levels of IGF-I (OR=1.21, 95% CI 0.75–1.93 for top vs bottom quartile, P-trend 0.301), IGFBP-3 (OR=1.00, 95% CI 0.66–1.51, P-trend 0.79), nor the molar IGF-I/IGFBP-3 ratio, an indicator of free IGF-I level (OR=1.22, 95% CI 0.75–1.97, P-trend 0.27), were statistically significantly associated with the risk of pancreatic cancer. In a cross-classification, however, a high concentration of IGF-I with concurrently low levels of IGFBP-3 was related to an increased risk of pancreatic cancer (OR=1.72, 95% CI 1.05–2.83; P-interaction=0.154).

Conclusion:

On the basis of these results, circulating levels of components of the IGF axis do not appear to be the risk factors for pancreatic cancer. However, on the basis of the results of a subanalysis, it cannot be excluded that a relatively large amount of IGF-1 together with very low levels of IGFBP-3 might still be associated with an increase in pancreatic cancer risk.     

Menopausal symptoms and bone health in women undertaking risk reducing bilateral salpingo-oophorectomy: significant bone health issues in those not taking HRT

Background:

Women at high ovarian cancer risk, especially those with mutations in BRCA1/BRCA2, are encouraged to undergo bilateral risk-reducing salpingo-oophorectomy (BRRSPO) prior to the natural menopause. The decision to use HRT to cover the period of oestrogen deprivation up to 50 years of age is difficult because of balancing the considerations of breast cancer risk, bone and cardiovascular health.

Methods:

We reviewed by questionnaire 289 women after BRRSPO aged ⩽48 years because of high ovarian cancer risk; 212 (73%) of women responded.

Results:

Previous HRT users (n=67) had significantly worse endocrine symptom scores than 67 current users (P=0.006). A total of 123 (58%) of women had ⩾24 months of oestrogen deprivation <50 years with 78 (37%) never taking HRT. Bone density (DXA) evaluations were available on 119 (56%) women: bone loss with a T score of ⩽−1.0 was present in 5 out of 31 (16%) women with no period of oestrogen deprivation <50 years compared with 37 out of 78 (47%) of those with ⩾24 months of oestrogen deprivation (P=0.03).

Interpretation:

Women undergoing BRRSPO <50 years should be counselled concerning the risks/benefits of HRT, taking into consideration the benefits on symptoms, bone health and cardiovascular health, and that the risks of breast cancer from oestrogen-only HRT appear to be relatively small.     

Alcohol intake and risk of thyroid cancer in the NIH-AARP Diet and Health Study

Background:

Certain studies suggest that alcohol may reduce the risk of thyroid cancer in women, but the effect in men remains unclear.

Methods:

We analysed the association between alcohol and thyroid cancer in a large (n=490 159) prospective NIH-AARP Diet and Health Study with self-reported beer, wine, and liquor intakes.

Results:

Over 7.5 years of follow-up (median), 170 men and 200 women developed thyroid cancer. Overall, the thyroid cancer risk decreased with greater alcohol consumption (⩾2 drinks per day vs none, relative risk=0.57, 95% CI 0.36–0.89, P-trend=0.01).

Conclusions:

These results suggest a potential protective role for alcohol consumption in thyroid cancer.     

Uptake of risk-reducing salpingo-oophorectomy in women carrying a BRCA1 or BRCA2 mutation: evidence for lower uptake in women affected by breast cancer and older women

Background:

Bilateral risk-reducing salpingo-oophorectomy (BRRSO) is the only effective way of reducing mortality from ovarian cancer. This study investigates uptake of BRRSO in 700 BRCA1/2 mutation carriers from Greater Manchester.

Methods:

Dates of last follow-up and BRRSO were obtained, and the following variables were investigated: ovarian cancer risk/gene, age and breast cancer history. The date of the genetic mutation report was the initiation for Kaplan–Meier analysis.

Results:

The uptake of BRRSO in BRCA1 mutation carriers was 54.5% (standard error 3.6%) at 5 years post testing compared with 45.5% (standard error 3.2%) in BRCA2 mutation carriers (P=0.045). The 40–59 years category showed the greatest uptake for BRRSO and uptake was significantly lower in the over 60 s (P<0.0001). Of the unaffected BRCA1 mutation carriers, 65% (standard error 5.1%) opted for surgery at 5 years post-testing compared with 41.1% (standard error 5.1%) in affected BRCA1 mutation carriers (P=0.045).

Conclusion:

The uptake of BRRSO is lower in women previously affected by breast cancer and in older women. As there is no efficient method for early detection of ovarian cancer, uptake should ideally be greater. Counselling should be offered to ensure BRCA1/2 mutation carriers make an informed decision about managing their ovarian cancer risk.     

Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry

Background:

Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry.

Methods:

We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls).

Results:

In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only.

Conclusion:

We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.     

Mammographic density and its interaction with other breast cancer risk factors in an Asian population

Background:

Joint effects of mammographic density and other risk factors on breast cancer risk remain unclear.

Methods:

From The Singapore Breast Screening Project, we selected 491 cases and 982 controls. Mammographic density was measured quantitatively. Data analysis was by conditional logistic regression.

Results:

Density was a significant risk factor, adjusting for other factors. Density of 76–100% had an odds ratio of 5.54 (95% CI 2.38–12.90) compared with 0–10%. Density had significant interactions with body mass index and oral contraceptive use (P=0.02).

Conclusions:

Percent density increases breast cancer risk in addition to effects of other risk factors, and modifies the effects of BMI and OCs.     

Height and risk of prostate cancer in the prostate, lung, colorectal, and ovarian cancer screening trial

Background:

The relationship between prostate cancer and height is uncertain.

Methods:

We prospectively examined the association of height with prostate cancer among 34268 men in the prostate, lung, colorectal, and ovarian cancer trial. Anthropometry was assessed at baseline and 2144 incident prostate cancer cases were identified upto 8.9 years of follow-up.

Results:

Overall, tallness was not associated with the risk of prostate cancer or with the risk of non-aggressive disease, but the risk for aggressive prostate cancer tended to be greater in taller men (Gleason score ⩾7 or stage ⩾III; P trend=0.05; relative risk (RR) for 190 cm+ vs ⩽170 cm=1.39, 95% confidence interval (95% CI): 0.96–2.01). This association was largely limited to men below the age of 65 years (P trend=0.008; RR for 190 cm+ vs ⩽170 cm=1.76, 95% CI: 1.06–2.93; P for interaction=0.009), although the number of cases was small and risk estimates were somewhat unstable.

Conclusion:

The results of this large prospective prostate cancer screening trial suggest that tallness is associated with increased risk for younger onset aggressive prostate cancer.     

Postmenopausal endometrial cancer risk and body size in early life and middle age: prospective cohort study

Background:

Greater adiposity in early life has been linked to increased endometrial cancer risk in later life, but the extent to which this association is mediated through adiposity in later life is unclear.

Methods:

Among postmenopausal women who had never used menopausal hormone therapies and reported not having had a hysterectomy, adjusted relative risks (RRs) of endometrial cancer were estimated using Cox regression.

Results:

Among 249 791 postmenopausal women with 7.3 years of follow-up on average (1.8 million person-years), endometrial cancer risk (n=1410 cases) was strongly associated with current body mass index (BMI) at baseline (RR=1.87 per 5 kg m⁻² increase in BMI, 95% confidence interval (CI): 1.77–1.96). Compared with women thinner than average at age 10, the increased risk among women plumper at age 10 (RR=1.27, 95% CI: 1.09–1.49) disappeared after adjustment for current BMI (RR=0.90, 95% CI: 0.77–1.06). Similarly, compared with women with clothes size 12 or less at age 20, the increased risk among women with clothes size 16 or larger (RR=1.87, 95% CI: 1.61–2.18) was not significant after adjustment for current BMI (RR=1.03, 95% CI: 0.88–1.22).

Conclusion:

Among women who have never used hormone therapy for menopause, the association between body size in early life and endometrial cancer risk in postmenopausal women can be largely explained by women''s current BMI.     

Reproductive factors and risk of oesophageal and gastric cancer in the Million Women Study cohort

Background:

Hormonal factors may influence risk for upper gastrointestinal cancers in women. We examined risk of oesophageal and gastric cancers in relation to reproductive factors in a large UK cohort, the Million Women Study.

Methods:

Among 1 319 409 women aged on average 56 years at recruitment, 1186 incident cancers of the oesophagus and 1194 of the stomach were registered during 11.9 million person-years'' observation. Adjusted relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

Results:

Risks of both oesophageal and gastric cancer were significantly higher in postmenopausal than in pre- or peri-menopausal women (RRs 1.46, 1.07–2.00 and 1.59, 1.15–2.20, respectively; P⩽0.01 for both); and, among postmenopausal women, risk was higher the younger women were at menopause (RR, 95% CI per 5 years younger at menopause 1.18, 1.05–1.34 for oesophageal cancer and 1.18, 1.04–1.34 for stomach cancer, P_trend=0.01 for both). For factors relating to childbearing, including women''s age at first birth, their number of children, and breastfeeding history, the only significant association was a higher risk of oesophageal cancer in nulliparous, compared with parous, women (RR 1.31, 1.11–1.55; P=0.002). When risks for squamous cell and adenocarcinomas of the oesophagus were compared, most did not differ significantly, but statistical power was limited.

Conclusion:

Both oesophageal and gastric cancer risks appeared to be related to menopausal status and age at menopause, but there was little consistent evidence for associations with factors related to childbearing.     

An epidemiologic risk prediction model for ovarian cancer in Europe: the EPIC study

Background:

Ovarian cancer has a high case-fatality ratio, largely due to late diagnosis. Epidemiologic risk prediction models could help identify women at increased risk who may benefit from targeted prevention measures, such as screening or chemopreventive agents.

Methods:

We built an ovarian cancer risk prediction model with epidemiologic risk factors from 202 206 women in the European Prospective Investigation into Cancer and Nutrition study.

Results:

Older age at menopause, longer duration of hormone replacement therapy, and higher body mass index were included as increasing ovarian cancer risk, whereas unilateral ovariectomy, longer duration of oral contraceptive use, and higher number of full-term pregnancies were decreasing risk. The discriminatory power (overall concordance index) of this model, as examined with five-fold cross-validation, was 0.64 (95% confidence interval (CI): 0.57, 0.70). The ratio of the expected to observed number of ovarian cancer cases occurring in the first 5 years of follow-up was 0.90 (293 out of 324, 95% CI: 0.81–1.01), in general there was no evidence for miscalibration.

Conclusion:

Our ovarian cancer risk model containing only epidemiological data showed modest discriminatory power for a Western European population. Future studies should consider adding informative biomarkers to possibly improve the predictive ability of the model.     

Red and processed meat consumption and risk of ovarian cancer: a dose-response meta-analysis of prospective studies

Background:

During the last decade, the epidemiological evidence on consumption of meat and risk of ovarian cancer has accumulated.

Methods:

We assessed the relationship between red and processed meat consumption and risk of ovarian cancer with a dose-response meta-analysis. Relevant prospective cohort studies were identified by searching the PubMed and EMBASE databases through 21 January 2011, and by reviewing the reference lists of retrieved articles. Study-specific relative risk (RR) estimates were combined using a random-effects model.

Results:

Eight cohort studies were included in the meta-analysis. The summary RR for an intake increment of 100 g per week was 1.02 (95% confidence interval (CI), 0.99–1.04) for red meat and 1.05 (95% CI, 0.98–1.14) for processed meat. For an intake increment of four servings per week, the summary RR of ovarian cancer was 1.07 (95% CI, 0.97–1.19) for red meat (100 g per serving) and 1.07 (95% CI, 0.97–1.17) for processed meat (30 g per serving).

Conclusion:

Results from this dose-response meta-analysis suggest that red and processed meat consumption is not associated with risk of ovarian cancer. Although a lower consumption of red and processed meat may offer protection against other types of cancer, other interventions are needed to reduce the risk of ovarian cancer.     

Campaign awareness and oral cancer knowledge in UK resident adult Bangladeshi: a cross-sectional study

Background:

This study reports awareness of the ‘Open up to Mouth Cancer'' campaign materials and oral cancer knowledge among two UK adult Bangladeshi communities, both at high risk for oral cancer.

Methods:

Differences in the outcomes of campaign awareness and knowledge of oral cancer risk factors and early signs were compared between campaign and comparison areas. Home-based interviews were conducted with representative samples from both areas by bilingual interviewers. Data collected included a modified 36-item Humphris Oral Cancer Knowledge Scale and socio-demographic information. The data were collected 4 weeks after the campaign completion and analysed using χ²-tests and binary logistic regressions.

Results:

The response rate was 77%. Both awareness of the campaign materials (29.99% (95% confidence interval (CI) 15.82, 46.99) vs 8.12% (95% CI 6.16, 10.62)) and the mean Humphris Oral Cancer Knowledge Scale scores (13.32 (95% CI 11.06, 15.57) vs 8.27 (95% CI 6.59, 9.94)) were higher in the campaign area. The campaign area sample was significantly more likely to be aware of the materials (odds ratio (OR)=6.03, 95% CI 3.00, 12.1).

Conclusion:

Superior awareness and oral cancer knowledge was identified in the community with access to the campaign materials. Further evaluation to identify long-term campaign impact is required.     

Polygenic susceptibility to prostate and breast cancer: implications for personalised screening

Background:

We modelled the efficiency of a personalised approach to screening for prostate and breast cancer based on age and polygenic risk-profile compared with the standard approach based on age alone.

Methods:

We compared the number of cases potentially detectable by screening in a population undergoing personalised screening with a population undergoing screening based on age alone. Polygenic disease risk was assumed to have a log-normal relative risk distribution predicted for the currently known prostate or breast cancer susceptibility variants (N=31 and N=18, respectively).

Results:

Compared with screening men based on age alone (aged 55–79: 10-year absolute risk ⩾2%), personalised screening of men age 45–79 at the same risk threshold would result in 16% fewer men being eligible for screening at a cost of 3% fewer screen-detectable cases, but with added benefit of detecting additional cases in younger men at high risk. Similarly, compared with screening women based on age alone (aged 47–79: 10-year absolute risk ⩾2.5%), personalised screening of women age 35–79 at the same risk threshold would result in 24% fewer women being eligible for screening at a cost of 14% fewer screen-detectable cases.

Conclusion:

Personalised screening approach could improve the efficiency of screening programmes. This has potential implications on informing public health policy on cancer screening.     

Association of obesity with prostate cancer: a case-control study within the population-based PSA testing phase of the ProtecT study

Background:

Obesity has been inconsistently linked to prostate cancer, mainly with mortality rather than incidence. Few large-scale studies exist assessing obesity in relation to prostate-specific antigen (PSA)-detected prostate cancer.

Methods:

We used cases and stratum-matched controls from the population-based PSA-testing phase of the Prostate testing for cancer and Treatment study to examine the hypothesis that obesity as measured by body mass index (BMI), waist circumference and waist-to-hip ratio (WHR) is associated with increased prostate cancer risk, and with higher tumour stage and grade. In all, 2167 eligible cases and 11 638 randomly selected eligible controls with PSA values were recruited between 2001 and 2008. A maximum of 960 cases and 4156 controls had measurement data, and also complete data on age and family history, and were included in the final analysis. BMI was categorised as <25.0, 25.0–29.9, ⩾30.0 in kg m⁻².

Results:

Following adjustment for age and family history of prostate cancer, we found little evidence that BMI was associated with total prostate cancer (odds ratio (OR): 0.83, 95% confidence interval (CI): 0.67, 1.03; highest vs lowest tertile; P-trend 0.1). A weak inverse association was evident for low-grade (OR: 0.76, 95% CI: 0.59, 0.97; highest vs lowest tertile; P-trend 0.045) prostate cancer. We found no association of either waist circumference (OR: 0.94, 95% CI: 0.80, 1.12; highest vs lowest tertile) or waist-to-hip ratio (WHR; OR: 0.93, 95% CI: 0.77, 1.11; highest vs lowest tertile) with total prostate cancer, and in analyses stratified by disease stage (all P-trend>0.35) or grade (all P-trend>0.16).

Conclusion:

General adiposity, as measured by BMI, was associated with a decreased risk of low-grade PSA-detected prostate cancer. However, effects were small and the confidence intervals had limits very close to one. Abdominal obesity (as measured by WHR/waist circumference) was not associated with PSA-detected prostate cancer.     

Hand pattern indicates prostate cancer risk

Background:

The ratio of digit lengths is fixed in utero, and may be a proxy indicator for prenatal testosterone levels.

Methods:

We analysed the right-hand pattern and prostate cancer risk in 1524 prostate cancer cases and 3044 population-based controls.

Results:

Compared with index finger shorter than ring finger (low 2D : 4D), men with index finger longer than ring finger (high 2D : 4D) showed a negative association, suggesting a protective effect with a 33% risk reduction (odds ratio (OR) 0.67, 95% confidence interval (CI) 0.57–0.80). Risk reduction was even greater (87%) in age group <60 (OR 0.13, 95% CI 0.09–0.21).

Conclusion:

Pattern of finger lengths may be a simple marker of prostate cancer risk, with length of 2D greater than 4D suggestive of lower risk.     

Breast, ovarian, and endometrial malignancies in systemic lupus erythematosus: a meta-analysis

Background:

An increased lymphoma risk is well documented in systemic lupus (SLE). Less attention has been focused on women''s cancers, even though SLE affects mostly females. Our objective was to estimate the risk of breast, ovarian, and endometrial cancers in SLE, relative to the general population.

Methods:

Data were included from five recent studies of large SLE cohorts. The number of cancers observed was determined for each cancer type. The expected number of malignancies was ascertained from general population data. The parameter of interest was the standardised incidence ratio (SIR), the ratio of observed to expected malignancies.

Results:

The five studies included 47 325 SLE patients (42 171 females) observed for 282 553 patient years. There were 376 breast cancers, 66 endometrial cancers, and 44 ovarian cancers. The total number of cancers observed was less than that expected, with SIRs of 0.76 (95% CI: 0.69, 0.85) for breast cancer, 0.71 (95% CI: 0.55, 0.91) for endometrial cancer, and 0.66 (95% CI: 0.49, 0.90) for ovarian cancer.

Conclusions:

Data strongly support a decreased risk of breast, ovarian, and endometrial cancers in SLE. This may be due to inherent differences in women in SLE (vs the general population) regarding endogenous oestrogen, other medications, and/or genetic make-up.     

Dietary cadmium exposure and risk of epithelial ovarian cancer in a prospective cohort of Swedish women

Background:

The proposed cadmium-induced oestrogen mimicking effects in reproductive tissues, suggest a role of this widespread food contaminant in the development of hormone-dependent malignancies.

Methods:

We prospectively evaluated the association between tertiles of dietary cadmium exposure and epithelial ovarian cancer in 60 889 women from the population-based Swedish Mammography Cohort. Dietary cadmium was estimated using a food-frequency questionnaire at baseline (1987–1990) and in 1997. Multivariable-adjusted rate ratios (RR) were evaluated using Cox proportional hazards models.

Results:

During a mean follow-up of 18.9 years (1 149 470 person-years), we identified 409 incident cases of epithelial ovarian cancer, including 215 serous, 27 mucinous, 62 endometrioid and 12 clear cell tumours. We found no association between dietary cadmium exposure and the risk of ovarian cancer. Compared with the lowest tertile of cadmium exposure, the multivariable-adjusted RR for the highest tertile was 0.90 (95% confidence interval (CI): 0.71–1.15) for total epithelial ovarian cancer. Likewise, no association was observed in subtypes modelled with continuous dietary cadmium exposure; multivariable RR for each 1 μg per day increment of cadmium: 0.97 (95% CI: 0.93–1.02) for serous tumours, 0.94 (95% CI: 0.82–1.07) for mucinous tumours and 1.00 (95% CI: 0.92–1.08) for endometrioid and clear cell tumours.

Conclusion:

Our study suggests that dietary cadmium exposure is not likely to have a substantial role in ovarian cancer development.