Moderate Alcohol Intake and Cancer Incidence in Women Naomi E
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ARTICLE Moderate Alcohol Intake and Cancer Incidence in Women Naomi E. Allen , Valerie Beral , Delphine Casabonne , Sau Wan Kan , Gillian K. Reeves , Anna Brown , Jane Green ; on behalf of the Million Women Study Collaborators Background With the exception of breast cancer, little is known about the effect of moderate intakes of alcohol, or of particular types of alcohol, on cancer risk in women. Methods A total of 1 280 296 middle-aged women in the United Kingdom enrolled in the Million Women Study were routinely followed for incident cancer. Cox regression models were used to calculate adjusted relative risks and 95% confidence intervals (CIs) for 21 site-specific cancers according to amount and type of alco- holic beverage consumed. All statistical tests were two-sided. Results A quarter of the cohort reported drinking no alcohol; 98% of drinkers consumed fewer than 21 drinks per week, Downloaded from with drinkers consuming an average of 10 g alcohol (1 drink) per day. During an average 7.2 years of follow-up per woman 68 775 invasive cancers occurred. Increasing alcohol consumption was associated with increased risks of cancers of the oral cavity and pharynx (increase per 10 g/d = 29%, 95% CI = 14% to 45%, Ptrend < .001), esophagus (22%, 95% CI = 8% to 38%, Ptrend = .002), larynx (44%, 95% CI = 10% to 88%, Ptrend = .008), http://jnci.oxfordjournals.org/ rectum (10%, 95% CI = 2% to 18%, Ptrend = .02), liver (24%, 95% CI = 2% to 51%, Ptrend = .03), breast (12%, 95% CI = 9% to 14%, Ptrend < .001), and total cancer (6%, 95% CI = 4% to 7%, P trend < .001). The trends were similar in women who drank wine exclusively and other consumers of alcohol. For cancers of the upper aerodigestive tract, the alcohol-associated risk was confined to current smokers, with little or no effect of alcohol among never and past smokers ( Pheterogeneity < .001). Increasing levels of alcohol consumption were associated with a decreased risk of thyroid cancer ( Ptrend = .005), non – Hodgkin lymphoma ( Ptrend = .001), and renal cell carcinoma ( Ptrend = .03). Conclusions Low to moderate alcohol consumption in women increases the risk of certain cancers. For every additional drink regularly consumed per day, the increase in incidence up to age 75 years per 1000 for women in by guest on May 17, 2013 developed countries is estimated to be about 11 for breast cancer, 1 for cancers of the oral cavity and pharynx, 1 for cancer of the rectum, and 0.7 each for cancers of the esophagus, larynx and liver, giving a total excess of about 15 cancers per 1000 women up to age 75. J Natl Cancer Inst 2009;101: 296 – 305 Many epidemiological studies have investigated the relationship of women in the United Kingdom. A secondary aim is to examine between drinking alcohol and the risk of cancer. In 2007, the the associations found by the type of alcoholic drink and to determine International Agency for Research on Cancer concluded that there whether they are modifi ed by other major risk factors for cancer. is sufficient evidence that alcohol causes cancer of the oral cavity, pharynx, esophagus, larynx, colorectum, liver, and female breast ( 1 ). Results from some previous studies suggested that alcohol may Participants and Methods reduce the risk of non – Hodgkin lymphoma, thyroid cancer, and Data Collection, Follow-up, and Definitions renal cell carcinoma, but the findings are inconsistent ( 2 – 4 ). Most The Million Women Study has been described previously (6 ). In of the evidence for an association of alcohol with cancer risk comes 1996 – 2001 a total of 1.3 million middle-aged women who attended from studies of men with high intakes and, with the exception of breast cancer screening clinics in the United Kingdom completed breast cancer (5 ), little is known about the risk of cancer associated with more moderate intakes typically consumed by women. Even Affiliation of authors: Cancer Epidemiology Unit, University of Oxford, for breast cancer, little is known about the effects of particular types Oxford, UK . of alcohol or whether the association differs according to other Correspondence to: Dr Naomi E. Allen, Cancer Epidemiology Unit, University of Oxford, Richard Doll Building, Oxford OX3 7LF, UK (e-mail: naomi.allen@ lifestyle factors such as use of hormone replacement therapy. ceu.ox.ac.uk ). The main aim of this report is to describe the relationship of low See “Funding” and “Notes” following “References.” to moderate levels of alcohol intake, mostly below 21 drinks per week DOI: 10.1093/jnci/djn514 (i.e fewer than 3 drinks per day or 30 g alcohol per day), with subse- © The Author 2009. Published by Oxford University Press. All rights reserved. quent risk of cancer, overall and at particular sites, in a large cohort For Permissions, please e-mail: [email protected]. 296 Articles | JNCI Vol. 101, Issue 5 | March 4, 2009 a questionnaire that asked for sociodemographic and other per- CONTEXT AND CAVEATS sonal information, including how much wine, beer, and spirits they drank on average each week. Information on whether the line Prior knowledge consumed was red, white or both was also recorded. In a follow- With the exception of breast cancer, there was little information on up survey, done about 3 years after recruitment, study participants the cancer risks conferred by alcohol consumption in women. were again asked to report the usual number of alcoholic drinks Study design consumed per week. The study questionnaires are available on the Prospective cohort study with alcohol consumption determined on study web site (www.millionwomenstudy.org ). All participants the basis of a questionnaire and information on incidence of spe- gave written informed consent to take part in the study, and cific cancers obtained from a national registry. Cox regression approval was provided by the Oxford and Anglia Multi-Centre models were used to estimate cancer risks associated with alcohol Research and Ethics Committee. consumption after adjustment for other risk factors. All study participants were “fl agged” on the National Health Contribution Service (NHS) Central Registers, which routinely provide the Increasing but moderate alcohol consumption in women was deter- investigators with information on deaths and incident cancers, and mined to be associated with an increased risk of cancers of the oral code the cause of death and cancer site according to the the cavity and pharynx, esophagus, larynx, rectum, breast, and liver, and International Classifi cation of Diseases, 10th Revision (ICD-10) with a decreased risk for thyroid cancer, non – Hodgkin lymphoma, and ( 7 ). For this analysis, we examined the 21 most common cancer renal cell carcinoma. No differences in cancer risks were observed sites: oral cavity and pharynx (C00 – C14); esophagus (C15); stom- between drinkers of wine only and other consumers of alcohol. ach (C16); colon (C18); rectum (C19– C20); liver (C22); pancreas Implications Downloaded from (C25); larynx (C32); lung (C34); malignant melanoma (C43); In middle-aged women, moderate alcohol consumption increases breast (C50); cervix (C53); endometrium (C54); ovary (C56); renal the risk of cancer overall; each additional drink regularly consumed cell carcinoma (C64); bladder (C67); brain (C71); thyroid (C73); per day may account for approximately 15 excess cancers per 1000 non – Hodgkin lymphoma (C82 – C85); multiple myeloma (C90); women up to age 75 in this age group in developed countries. and leukemia (C91 – C93, C95). Cancers of the esophagus were Limitations http://jnci.oxfordjournals.org/ classifi ed according to histological subtype and defi ned as adeno- The study could not address the risk conferred by heavy sustained carcinoma (ICD-10-0 morphology codes under ICD-10 C15: drinking due to the composition of the cohort. 81903, 81453, 81403, 81443, 82113, 82603, 84803, and 84813) or From the Editors nonadenocarcinoma (all other morphology codes). Statistical Analysis intake using the regression dilution approach ( 9 , 10 ), whereby Of the 1 332 425 women potentially eligible for these analyses, we women were categorized into fi ve levels of alcohol intake, based on excluded 42 408 who had a cancer (except nonmelanoma skin cancer consumption reported at recruitment, but the average intake of by guest on May 17, 2013 [ICD-10 C44]) registered before recruitment and a further 9721 alcohol (expressed as g/d) in each category was taken to be that who had missing information on alcohol intake, leaving 1 280 296 reported in the follow-up survey, about 3 years later, using data for the main analyses. The analyses of endometrial and cervical from 708 265 women. It was assumed that each drink contains 10 g cancer were restricted to women who reported at recruitment not alcohol, and for women who reported at resurvey drinking less having had a hysterectomy (n = 954 450), and analyses of ovarian than one drink per week, daily consumption was taken to be zero. cancer were restricted to women who reported not having had a Woman-years were calculated from the date of recruitment to bilateral oophorectomy (n = 1 116 460). the date of any cancer registration (other than nonmelanoma skin Women were categorized into fi ve groups according to the total cancer), death, or the last date of follow-up, whichever came fi rst. number of alcoholic drinks that contained about 10 g alcohol The last date of follow-up in most areas was December 31, 2006; consumed per week, as reported in the recruitment questionnaire but in the West Midlands and the Thames region it was June 30, (ie, 1 glass of wine, half a pint of beer, or 1 measure of spirits). For 2006; in the North Yorkshire and North West Merseyside regions wine, a standard glass volume is 125 mL and standard alcohol con- it was December 31, 2005; and in Scotland it was December 31, tent is 8.8 g/100 mL for white wine and 9.5 g/100 mL for red wine, 2002.