A comparative analysis of risk factor associations with interval and screen-detected breast cancers: A large UK prospective study.

The associations of certain factors, such as age and menopausal hormone therapy, with breast cancer risk are known to differ for interval and screen-detected cancers. However, the extent to which associations of other established breast cancer risk factors differ by mode of detection is unclear. We investigated associations of a wide range of risk factors using data from a large UK cohort with linkage to the National Health Service Breast Screening Programme, cancer registration, and other health records. We used Cox regression to estimate adjusted relative risks (RRs) and 95% confidence intervals (CIs) for associations between risk factors and breast cancer risk. A total of 9421 screen-detected and 5166 interval cancers were diagnosed in 517,555 women who were followed for an average of 9.72 years. We observed the following differences in risk factor associations by mode of detection: greater body mass index (BMI) was associated with a smaller increased risk of interval (RR per 5 unit increase 1.07, 95% CI 1.03-1.11) than screen-detected cancer (RR 1.27, 1.23-1.30); having a first-degree family history was associated with a greater increased risk of interval (RR 1.81, 1.68-1.95) than screen-detected cancer (RR 1.52, 1.43-1.61); and having had previous breast surgery was associated with a greater increased risk of interval (RR 1.85, 1.72-1.99) than screen-detected cancer (RR 1.34, 1.26-1.42). As these differences in associations were relatively unchanged after adjustment for tumour grade, and are in line with the effects of these factors on mammographic density, they are likely to reflect the effects of these risk factors on screening sensitivity.

Ovarian cancer survival by stage, histotype, and pre-diagnostic lifestyle factors, in the prospective UK Million Women Study.

BACKGROUND: Ovarian cancer is the fifth leading cause of cancer mortality in UK women. Ovarian cancer survival varies by disease stage at diagnosis, but evidence is mixed on the effect of tumour histological type (histotype) and other factors. METHODS: 1.3 million UK women completed a detailed health questionnaire in 1996-2001 and were followed for incident cancers and deaths via linkage to national databases. Using Cox regression models, we estimated adjusted relative risks (RRs) of death from ovarian cancer, by stage at diagnosis, tumour histotype, and 16 other personal characteristics of the women. RESULTS: During 17.7 years' average follow-up, 13,222 women were diagnosed with ovarian cancer, and 8697 of them died from the disease. Stage at diagnosis was a major determinant of survival (stage IV vs I, RR=10.54, 95% CI: 9.16-12.13). Histotype remained a significant predictor after adjustment for stage and other factors, but associations varied over the follow-up period. Histotype-specific survival was worse for high-grade than low-grade tumours. Survival appeared worse with older age at diagnosis (per 5 years: RR=1.19, 95% CI: 1.15-1.22), higher BMI (per 5-unit increase: RR=1.06, 95% CI: 1.02-1.11), and smoking (current vs never: RR=1.17, 95% CI: 1.07-1.27), but there was little association with 13 other pre-diagnostic reproductive, anthropometric, and lifestyle factors. CONCLUSION: Stage at diagnosis is a strong predictor of ovarian cancer survival, but tumour histotype and grade remain predictors of survival even after adjustment for stage and other factors, contributing further evidence of biological dissimilarity between the ovarian cancer histotypes. Obesity and smoking represent potentially-modifiable determinants of survival, but the stronger association with stage suggests that improving earlier diagnosis would have a greater impact on increasing ovarian cancer survival.

Ethnicity and the tumour characteristics of invasive breast cancer in over 116,500 women in England.

BACKGROUND: Ethnic minority women are commonly reported to have more aggressive breast cancer than White women, but there is little contemporary national evidence available. METHODS: We analysed data from the National Cancer Registration and Analysis Service on women diagnosed with invasive breast cancer during 2013-2018. Multivariable logistic regression yielded adjusted odds ratios (and 95% confidence intervals) of less favourable tumour characteristics (high stage, high grade, ER negative, Her2 positive) by ethnicity (black African, black Caribbean, Indian, Pakistani and white) in younger (30-46 years) and older (53-70 years) women. RESULTS: In 24,022 women aged 30-46 at diagnosis, all ethnic minority groups apart from Indian women had a significantly greater odds of certain less favourable tumour characteristics compared to white women in fully adjusted models. In 92,555 women aged 53-70, all ethnic minorities had a significantly greater adjusted odds of several of the less favourable tumour characteristics. These differences were most marked in black African and black Caribbean women. CONCLUSIONS: Ethnic minority women are at greater risk of breast cancers with less favourable characteristics, even after allowing for age and other potential confounders. These differences are greater in older than younger women, and in the Black rather than South Asian ethnic groups.

Social isolation and risk of heart disease and stroke: analysis of two large UK prospective studies.

BACKGROUND: Social isolation has been associated with increased risk of coronary heart disease and stroke. However, it is unclear whether the associations differ between fatal and non-fatal events or by the type of isolation (living alone or having few social contacts). We aimed to examine these associations in two large UK prospective cohorts. METHODS: Million Women Study and UK Biobank participants without previous coronary heart disease or stroke who provided data in median year 2010 (IQR 2009-2011) on social contacts were included in this prospective analysis. Participants were followed up to median year 2017 (2017-2017) by electronic linkage to national hospital and death records. Risk ratios (RRs) were calculated using Cox regression for first coronary heart disease and stroke event (overall, and separately for hospital admission as the first event and for death without an associated hospital admission as the first event) by three levels of social isolation (based on living alone, contact with family or friends, and group participation) adjusted for age, sex, study, region, deprivation, smoking, alcohol intake, body-mass index, physical activity, and self-rated health. FINDINGS: 938 558 participants were included in our analyses (mean age 63 years [SD 9]): 481 946 participants from the Million Women Study (mean age 68 years [5]) and 456 612 participants (mean age 57 years [8]) from UK Biobank. During a mean follow-up period of 7 years (2), 42 402 first coronary heart disease events (of which 1834 were fatal without an associated hospital admission) and 19 999 first stroke events (of which 529 were fatal without an associated hospital admission) occurred. Little, if any, association was found between social isolation and hospital admission for a first coronary heart disease or stroke event (combined RR for both studies 1·01 [95% CI 0·98-1·04] for coronary heart disease and 1·13 [1·08-1·18] for stroke, when comparing the most isolated group with the least isolated group). However, the risk of death without an associated hospital admission was substantially higher in the most isolated group than the least isolated group for coronary heart disease (1·86 [1·63-2·12]) and stroke (1·91 [1·48-2·46]). For coronary heart disease or stroke death as the first event, RRs were substantially higher (test for heterogeneity, p=0·002) for participants living alone versus those not living alone (1·60 [1·46-1·75]) than for those with fewer versus more contact with family, friends, or groups (1·27 [1·16-1·38]). These findings did not differ greatly between studies, or by self-rated health. INTERPRETATION: Social isolation seems to have little direct effect on the risk of developing a first coronary heart disease or stroke. By contrast, social isolation substantially increases the risk that the first such event is fatal before reaching hospital, particularly among people who live alone, perhaps because of the absence of immediate help in responding to an acute heart attack or stroke. FUNDING: UK Medical Research Council, Cancer Research UK.

Social influences on smoking cessation in mid-life: Prospective cohort of UK women.

INTRODUCTION: Decisions to quit smoking are thought to be influenced by social factors such as friends, family and social groups, but there have been few attempts to examine comprehensively the influence of a range of social factors on smoking cessation. In the largest study to date, we examined whether smoking cessation was associated with marital status and the smoking habits of a partner, socio-economic status and social participation. METHODS: In the prospective Million Women Study, 53,650 current smokers in 2001 (mean age 58.3, SD 4.4) reported their smoking status 4 years later; and reported on social factors on both occasions. Logistic regression yielded odds ratios (ORs) and 99% confidence intervals (CIs) for stopping smoking in the next 4 years by marital status, whether their partner smoked, deprivation, education, and participation in social activities. RESULTS: 31% (16,692) of the current smokers at baseline had stopped after 4 years. Smokers who were partnered at baseline were more likely to quit than those who were not partnered (OR 1.13, 99% CI 1.06-1.19). Compared to having a partner who smoked throughout, those who had a non-smoking partner throughout were more likely to quit (OR 2.01, 99% CI 1.86-2.17), and those who had a partner who smoked at baseline but stopped smoking in the next 4 years were even more likely to quit (OR 6.00, 5.41-6.67). There was no association with cessation for education or deprivation. The association with social participation varied by type of activity but was null overall. CONCLUSION: Women who were partnered were most likely to stop smoking if their partner also stopped smoking. There was little evidence of a strong influence of either socio-economic status or social participation on smoking cessation. These results emphasise the importance of a spouse's smoking habits on the likelihood of a smoker successfully quitting smoking.

Screen-detected and interval colorectal cancers in England: Associations with lifestyle and other factors in women in a large UK prospective cohort.

Faecal occult blood (FOB) - based screening programmes for colorectal cancer detect about half of all cancers. Little is known about individual health behavioural characteristics which may be associated with screen-detected and interval cancers. Electronic linkage between the UK National Health Service Bowel Cancer Screening Programme (BCSP) in England, cancer registration and other national health records, and a large on-going UK cohort, the Million Women Study, provided data on 628,976 women screened using a guaiac-FOB test (gFOBt) between 2006 and 2012. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated by logistic and Cox regression for associations between individual lifestyle factors and risk of colorectal tumours. Among screened women, 766 were diagnosed with screen-detected colorectal cancer registered within 2 years after a positive gFOBt result, and 749 with interval colorectal cancers registered within 2 years after a negative gFOBt result. Current smoking was significantly associated with risk of interval cancer (RR 1.64, 95%CI 1.35-1.99) but not with risk of screen-detected cancer (RR 1.03, 0.84-1.28), and was the only factor of eight examined to show a significant difference in risk between interval and screen-detected cancers (p for difference, 0.003). Compared to screen-detected cancers, interval cancers tended to be sited in the proximal colon or rectum, to be of non-adenocarcinoma morphology, and to be of higher stage.

Regulation between personality traits: individual social tendencies modulate whether boldness and leadership are correlated.

Although consistent behavioural differences between individuals (i.e. personality variation) are now well established in animals, these differences are not always expressed when individuals interact in social groups. This can be key in important social dynamics such as leadership, which is often positively related to personality traits such as boldness. Individuals consistently differ in how social they are (their sociability), so if other axes of personality variation, such as boldness, can be suppressed during social interactions, this suppression should be stronger in more sociable individuals. We measured boldness (latency to leave a refuge when alone) and sociability (time spent with a conspecific) in three-spined sticklebacks (Gasterosteus aculeatus) and tested the boldness-leadership association in pairs of these fish. Both boldness and sociability were repeatable, but were not correlated. When splitting the data between the 50% most sociable and 50% less sociable fish, boldness was more strongly associated with leadership in less rather than more sociable individuals. This is consistent with more sociable fish conforming to their partner's behaviour due to their greater social tendency. One axis of personality variation (sociability) can thus modulate the relationship between others (boldness and leadership), with potential implications for selection on personality variation in social animals.

Histological subtypes of ovarian cancer associated with parity and breastfeeding in the prospective Million Women Study.

Ovarian cancer risk is known to be reduced amongst women who have had children, but reported associations with breastfeeding are varied. Few studies have had sufficient power to explore reliably these associations by tumour histotype. In a prospective study of 1.1 million UK women, 8719 developed ovarian cancer during follow-up. Cox regression yielded adjusted relative risks (RRs) overall and by tumour histotype amongst women with different childbearing patterns. Nulliparous women had a 24% greater ovarian cancer risk than women with one child, with significant heterogeneity by histotype (p = 0.01). There was no significant increase in serous tumours, a modest increase in mucinous tumours, but a substantial increase in endometrioid (RR = 1.49, 95% CI: 1.18-1.89) and clear-cell tumours (RR = 1.68, 1.29-2.20). Among parous women, each additional birth was associated with an overall 6% reduction in ovarian cancer risk; this association also varied by histotype (p = 0.0006), with the largest reduction in risk for clear-cell tumours (RR per birth = 0.75, 0.65-0.85, p < 0.001) and weak, if any, effect for endometrioid, high-grade serous, or mucinous tumours. We found little association with age at first or last birth. There was about a 10% risk reduction per 12-months breastfeeding (RR = 0.89, 0.84-0.94, p < 0.001), with no significant heterogeneity by histotype, but statistical power was limited. In this large prospective study, ovarian cancer risk associated with parity varied substantially by tumour histotype. Nulliparity was associated with a substantially greater overall risk than expected from the effect of a single birth, especially for clear cell and endometrioid tumours, perhaps suggesting that infertility is associated with these histotypes.

Childhood cancer incidence by ethnic group in England, 2001-2007: a descriptive epidemiological study.

BACKGROUND: After the first year of life, cancers are the commonest cause of death in children. Incidence rates vary between ethnic groups, and recent advances in data linkage allow for a more accurate estimation of these variations. Identifying such differences may help identify potential risk or protective factors for certain childhood cancers. This study thus aims to ascertain whether such differences do indeed exist using nationwide data across seven years, as have previously been described in adult cancers. METHODS: We obtained data for all cancer registrations for children (aged 0-14) in England from January 2001 to December 2007. Ethnicity (self-assigned) was established through record linkage to the Hospital Episodes Statistics database or cancer registry data. Cancers were classified morphologically according to the International Classification of Childhood Cancer into four groups - leukaemias; lymphomas; central nervous system; and other solid tumours. Age standardised incidence rates were estimated for each ethnic group, as well as incidence rate ratios comparing each individual ethnic group (Indian, Pakistani, Bangladeshi, Black African, Black Carribean, Chinese) to Whites, adjusting for sex, age and deprivation. RESULTS: The majority of children in the study are UK born. Black children (RR = 1.18, 99% CI: 1.01-1.39), and amongst South Asians, Pakistani children (RR = 1.19, 99% CI: 1.02-1.39) appear to have an increased risk of all cancers. There is an increased risk of leukaemia in South Asians (RR = 1.31, 99% CI: 1.08-1.58), and of lymphoma in Black (RR = 1.72, 99% CI: 1.13-2.63) and South Asian children (RR = 1.51, 99% CI: 1.10-2.06). South Asians appear to have a decreased risk of CNS cancers (RR = 0.71, 99% CI: 0.54-0.95). CONCLUSIONS: In the tradition of past migrant studies, such descriptive studies within ethnic minority groups permit a better understanding of disease incidence within the population, but also allow for the generation of hypotheses to begin to understand why such differences might exist. Though a major cause of mortality in this age group, childhood cancer remains a relatively rare disease; however, the methods used here have permitted the first nationwide estimation of childhood cancer by individual ethnic group.

Lifelong vegetarianism and breast cancer risk: a large multicentre case control study in India.

BACKGROUND: The lower incidence of breast cancer in Asian populations where the intake of animal products is lower than that of Western populations has led some to suggest that a vegetarian diet might reduce breast cancer risk. METHODS: Between 2011 and 2014 we conducted a multicentre hospital based case-control study in eight cancer centres in India. Eligible cases were women aged 30-70 years, with newly diagnosed invasive breast cancer (ICD10 C50). Controls were frequency matched to the cases by age and region of residence and chosen from the accompanying attendants of the patients with cancer or those patients in the general hospital without cancer. Information about dietary, lifestyle, reproductive and socio-demographic factors were collected using an interviewer administered structured questionnaire. Multivariate logistic regression models were used to estimate the odds ratio (OR) and 95% confidence intervals for the risk of breast cancer in relation to lifelong vegetarianism, adjusting for known risk factors for the disease. RESULTS: The study included 2101 cases and 2255 controls. The mean age at recruitment was similar in cases (49.7 years (SE 9.7)) and controls (49.8 years (SE 9.1)). About a quarter of the population were lifelong vegetarians and the rates varied significantly by region. On multivariate analysis, with adjustment for known risk factors for the disease, the risk of breast cancer was not decreased in lifelong vegetarians (OR 1.09 (95% CI 0.93-1.29)). CONCLUSIONS: Lifelong exposure to a vegetarian diet appears to have little, if any effect on the risk of breast cancer.

Heterogeneity of colorectal cancer risk by tumour characteristics: Large prospective study of UK women.

Associations between behavioural and other personal factors and colorectal cancer risk have been reported to vary by tumour characteristics, but evidence is inconsistent. In a large UK-based prospective study we examined associations of 14 postulated risk factors with colorectal cancer risk overall, and across three anatomical sites and four morphological subtypes. Among 1.3 million women, 18,518 incident colorectal cancers were identified during 13.8 (SD 3.4) years follow-up via record linkage to national cancer registry data. Cox regression yielded adjusted relative risks. Statistical significance was assessed using correction for multiple testing. Overall, colorectal cancer risk was significantly associated with height, body mass index (BMI), smoking, alcohol intake, physical activity, parity and menopausal hormone therapy use. For smoking there was substantial heterogeneity across morphological types; relative risks around two or greater were seen in current smokers both for signet ring cell and for neuroendocrine tumours. Obese women were also at higher risk for signet ring cell tumours. For adenocarcinomas, the large majority of colorectal cancers in the cohort, all risk factor associations were weak. There was little or no heterogeneity in risk between tumours of the right colon, left colon and rectum for any of the 14 factors examined. These epidemiological findings complement an emerging picture from molecular studies of possible different developmental pathways for different tumour types.

Past cervical intraepithelial neoplasia grade 3, obesity, and earlier menopause are associated with an increased risk of vulval cancer in postmenopausal women.

BACKGROUND: Vulval cancer predominantly affects postmenopausal women. A smaller proportion of vulval cancers, particularly at older ages, are now thought to be associated with human papillomavirus infection than previously reported, but other risk factors have not been well examined in prospective cohort studies. METHODS: A total of 1.3 million women aged 49-65 years were followed for incident vulval cancer (ICD-10 C51). Adjusted Cox regression models were used to examine the relationship between reproductive and lifestyle factors and risk of vulval cancer. RESULTS: There were 898 vulval cancers registered in the cohort over an average of 14 years of follow-up; 70% were squamous cell carcinomas. Past registration of cervical carcinoma in situ (RR 2.68; 95% CI 1.71-4.18; P<0.001), obesity (RR 1.71; 95% CI 1.44-2.04; P<0.0001), and menopause before the age of 50 years (RR 1.52; 95% CI 1.22-1.89; P<0.001) were associated with a significantly increased risk of subsequent vulval cancer. CONCLUSION: Past cervical pre-cancer, obesity, and earlier age at menopause are associated with an increased risk of vulval cancer at older ages.

Nervous System and Intracranial Tumour Incidence by Ethnicity in England, 2001-2007: A Descriptive Epidemiological Study.

BACKGROUND: There is substantial variation in nervous system and intracranial tumour incidence worldwide. UK incidence data have limited utility because they group these diverse tumours together and do not provide data for individual ethnic groups within Blacks and South Asians. Our objective was to determine the incidence of individual tumour types for seven individual ethnic groups. METHODS: We used data from the National Cancer Intelligence Network on tumour site, age, sex and deprivation to identify 42,207 tumour cases. Self-reported ethnicity was obtained from the Hospital Episode Statistics database. We used mid-year population estimates from the Office for National Statistics. We analysed tumours by site using Poisson regression to estimate incidence rate ratios comparing non-White ethnicities to Whites after adjustment for sex, age and deprivation. RESULTS: Our study showed differences in tumour incidence by ethnicity for gliomas, meningiomas, pituitary tumours and cranial and paraspinal nerve tumours. Relative to Whites; South Asians, Blacks and Chinese have a lower incidence of gliomas (p<0.01), with respective incidence rate ratios of 0.68 (confidence interval: 0.60-0.77), 0.62 (0.52-0.73) and 0.58 (0.41-0.83). Blacks have a higher incidence of meningioma (p<0.01) with an incidence rate ratio of 1.29 (1.05-1.59) and there is heterogeneity in meningioma incidence between individual South Asian ethnicities. Blacks have a higher incidence of pituitary tumours relative to Whites (p<0.01) with an incidence rate ratio of 2.95 (2.37-3.67). There is heterogeneity in pituitary tumour incidence between individual South Asian ethnicities. CONCLUSIONS: We present incidence data of individual tumour types for seven ethnic groups. Current understanding of the aetiology of these tumours cannot explain our results. These findings suggest avenues for further work.

Tubal ligation and incidence of 26 site-specific cancers in the Million Women Study.

BACKGROUND: Tubal ligation is known to be associated with a reduction in ovarian cancer risk. Associations with breast, endometrial and cervical cancers have been suggested. We investigated associations for 26 site-specific cancers in a large UK cohort. METHODS: Study participants completed a questionnaire on reproductive and lifestyle factors in 1996-2001, and were followed for cancer and death via national registries. Using Cox regression models, we estimated adjusted relative risks (RRs) for 26 site-specific cancers among women with vs without tubal ligation. RESULTS: In 1 278 783 women without previous cancer, 167 430 incident cancers accrued during 13.8 years' follow-up. Significantly reduced risks were found in women with tubal ligation for cancers of the ovary (RR=0.80, 95% CI: 0.76-0.85; P<0.001; n=8035), peritoneum (RR=0.81, 0.66-0.98; P=0.03; n=730), and fallopian tube (RR=0.60, 0.37-0.96; P=0.04; n=168). No significant associations were found for endometrial, breast, or cervical cancers. CONCLUSIONS: The reduced risks of ovarian, peritoneal and fallopian tube cancers are consistent with hypotheses of a common origin for many tumours at these sites, and with the suggestion that tubal ligation blocks cells, carcinogens or other agents from reaching the ovary, fallopian tubes and peritoneal cavity.

Incidence of prostate and urological cancers in England by ethnic group, 2001-2007: a descriptive study.

BACKGROUND: The aetiology of urological cancers is poorly understood and variations in incidence by ethnic group may provide insights into the relative importance of genetic and environmental risk factors. Our objective was to compare the incidence of four urological cancers (kidney, bladder, prostate and testicular) among six 'non-White' ethnic groups in England (Indian, Pakistani, Bangladeshi, Black African, Black Caribbean and Chinese) to each other and to Whites. METHODS: We obtained Information on ethnicity for all urological cancer registrations from 2001 to 2007 (n = 329,524) by linkage to the Hospital Episodes Statistics database. We calculated incidence rate ratios adjusted for age, sex and income, comparing the six ethnic groups (and combined 'South Asian' and 'Black' groups) to Whites and to each other. RESULTS: There were significant differences in the incidence of all four cancers between the ethnic groups (all p < 0.001). In general, 'non-White' groups had a lower incidence of urological cancers compared to Whites, except prostate cancer, which displayed a higher incidence in Blacks. (IRR 2.55) There was strong evidence of differences in risk between Indians, Pakistanis and Bangladeshis for kidney, bladder and prostate cancer (p < 0.001), and between Black Africans and Black Caribbeans for all four cancers (p < 0.001). CONCLUSIONS: The risk of urological cancers in England varies greatly by ethnicity, including within groups that have traditionally been analysed together (South Asians and Blacks). In general, these differences are not readily explained by known risk factors, although the very high incidence of prostate cancer in both black Africans and Caribbeans suggests increased genetic susceptibility. g.

Incidence of breast and gynaecological cancers by ethnic group in England, 2001-2007: a descriptive study.

BACKGROUND: Although international comparisons reveal large geographical differences in the incidence of breast and gynaecological cancers, incidence data for ethnic groups in England remains scarce. METHODS: We compared the incidence of breast, ovarian, cervical and endometrial cancer in British Indians, Pakistanis, Bangladeshis, Black Africans, Black Caribbeans, Chinese and Whites between 2001 and 2007. We identified 357,476 cancer registrations from which incidence rates were calculated using mid-year population estimates from 2001 to 2007. Ethnicity was obtained through linkage to the Hospital Episodes Statistics database. Incidence rate ratios were calculated, comparing the 6 non-White ethnic groups to Whites, and were adjusted for age and income. RESULTS: We found evidence of differences in the incidence of all 4 cancers by ethnic group (p<0.001). Relative to Whites, South Asians had much lower rates of breast, ovarian and cervical cancer (IRRs of 0.68, 0.66 and 0.33 respectively), Blacks had lower rates of breast, ovarian and cervical cancer but higher rates of endometrial cancer (IRRs of 0.85, 0.62, 0.72 and 1.16 respectively), and Chinese had lower rates of breast and cervical cancer (IRRs of 0.72 and 0.68 respectively). There were also substantial intra-ethnic differences, particularly among South Asians, with Bangladeshis experiencing the lowest rates of all 4 cancers. CONCLUSIONS: Our study provides evidence that the risk of breast and gynaecological cancers varies by ethnic group and that those groups typically grouped together are not homogenous with regards to their cancer risk. Furthermore, several of our findings cannot be readily explained by known risk factors and therefore warrant further investigation.

Incidence of haematological malignancies by ethnic group in England, 2001-7.

The aetiology of most haematological malignancies is largely unknown. Studies of migrant populations can provide insights into the relative importance of genetic and environmental risk factors for these diseases. This study compares incidence rates in British Indians, Pakistanis, Bangladeshis, Black Africans, Black Caribbeans, Chinese and Whites in England from 2001 to 2007. We analysed 134,302 haematological cancer registrations with ethnicity obtained by linkage to the Hospital Episodes Statistics database. Mid-year population estimates from 2001 to 2007 were used. Incidence rate ratios adjusted for age, sex and income were calculated, comparing the six ethnic groups to Whites and to each other. Whites had the highest rates for most subtypes. However, Blacks experienced more than double the incidence of plasma cell and mature T-cell neoplasms compared to other ethnic groups. There were also significant differences in incidence between Indians, Pakistanis and Bangladeshis for Hodgkin lymphoma and mature B-cell neoplasms and between Black African and Black Caribbeans for mature B-cell and other lymphoid neoplasms (all P < 0.001). Our results show that the risk of haematological cancers varies greatly by ethnic group, including within those groups that have traditionally been grouped together (South Asians and Blacks) with many of these differences not explicable by known risk factors.

Childhood cancer incidence in British Indians & Whites in Leicester, 1996-2008.

BACKGROUND: South Asians in England have an increased risk of childhood cancer but incidence by their individual ethnicities using self-assigned ethnicity is unknown. Our objective was to compare the incidence of childhood cancer in British Indians and Whites in Leicester, which has virtually complete, self-assigned, ethnicity data and the largest population of Indians in England. METHODS: We obtained data on all cancer registrations from 1996 to 2008 for Leicester with ethnicity obtained by linkage to the Hospital Episodes Statistics database. Age-standardised incidence rates were calculated for childhood cancers in Indians and Whites as well as rate ratios, adjusted for age. RESULTS: There were 33 cancers registered among Indian children and 39 among White children. The incidence rate for Indians was greater compared to Whites for all cancers combined (RR 1.82 (95% CI 1.14 to 2.89); p = 0.01), with some evidence of increased risk of leukaemia (RR 2.20 (0.95 to 5.07); p = 0.07), lymphoma (RR 3.96 (0.99 to 15.84); p = 0.04) and central nervous system tumours (RR 2.70 (1.00 to 7.26); p = 0.05). Rates were also higher in British Indian children compared to children in India. CONCLUSIONS: British Indian children in Leicester had an increased risk of developing cancer compared to White children, largely due to a higher incidence of central nervous system and haematological malignancies.

Incidence of gastrointestinal cancers by ethnic group in England, 2001-2007.

OBJECTIVE: To compare the incidence of six gastrointestinal cancers (colorectal, oesophageal, gastric, liver, gallbladder and pancreatic) among the six main 'non-White' ethnic groups in England (Indian, Pakistani, Bangladeshi, Black African, Black Caribbean and Chinese) to each other and to Whites. METHODS: We analysed all 378 511 gastrointestinal cancer registrations from 2001-2007 in England. Ethnicity was obtained by linkage to the Hospital Episodes Statistics database and we used mid-year population estimates from 2001-2007. Incidence rate ratios adjusted for age, sex and income were calculated, comparing the six ethnic groups (and combined 'South Asian' and 'Black' groups) to Whites and to each other. RESULTS: There were significant differences in the incidence of all six cancers between the ethnic groups (all p<0.001). In general, the 'non-White' groups had a lower incidence of colorectal, oesophageal and pancreatic cancer compared to Whites and a higher incidence of liver and gallbladder cancer. Gastric cancer incidence was lower in South Asians but higher in Blacks and Chinese. There was strong evidence of differences in risk between Indians, Pakistanis and Bangladeshis for cancer of the oesophagus, stomach, liver and gallbladder (all p<0.001) and between Black Africans and Black Caribbeans for liver and gallbladder cancer (both p<0.001). CONCLUSIONS: The risk of gastrointestinal cancers varies greatly by individual ethnic group, including within those groups that have traditionally been grouped together (South Asians and Blacks). Many of these differences are not readily explained by known risk factors and suggest that important, potentially modifiable causes of these cancers are still to be discovered.