Adherence to the WHO’s Healthy Diet Indicator and Overall Cancer Risk in the EPIC-NL Cohort

et al. (2013) Adherence to the WHO's Healthy Diet Indicator and Overall Cancer Risk in the EPIC-NL Cohort. PLoS ONE 8(8): e70535. doi:10.1371/journal.pone.0070535 Adherence to the WHO's Healthy Diet Indicator and Overall Cancer Risk in the EPIC-NL Cohort Nina E. Berentzen 0 Joline W. Beulens 0 Marieke P. Hoevenaar-Blom 0 Ellen Kampman 0 H. Bas Bueno- 0 de-Mesquita 0 Dora Romaguera-Bosch 0 Petra H. M. Peeters 0 Anne M. May 0 Olga Y. Gorlova, The University of Texas M. D. Anderson Cancer Center, United States of America 0 1 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht , Utrecht , The Netherlands , 2 Center for Nutrition, Prevention, and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands, 3 Division of Human Nutrition, Wageningen University , Wageningen , The Netherlands , 4 National Institute for Public Health and the Environment, Bilthoven, The Netherlands, 5 Department of Gastroenterology and Hepatology, University Medical Center Utrecht , Utrecht , The Netherlands , 6 Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London , United Kingdom , 7 Department of Epidemiology and Public Health, Imperial College London , London , United Kingdom Background: A healthy dietary pattern defined by international recommendations of the World Health Organisation (WHO) has been shown to reduce overall mortality risk. It is unknown whether this healthy dietary pattern is associated with overall cancer incidence. Design: In total 35,355 men and women within the Dutch European Prospective Investigation into Cancer and Nutritioncohort were followed for cancer occurrence. Diet was assessed through a validated food-frequency questionnaire. We computed a dietary score for all participants based on the seven WHO dietary guidelines for the prevention of chronic diseases (Healthy Diet Indicator (HDI)). We used the existing HDI score based on the 1990 WHO guidelines, and adapted it to meet with the 2002 WHO guidelines. Multivariate-adjusted Cox proportional hazards analysis was used to examine the association between adherence to the HDI and subsequent overall cancer risk. Results: A number of 3,007 new cancers were identified during a mean follow-up of 12.7 years. Adherence to the HDI was not associated with a reduced overall cancer risk. The hazard ratio (HR) of overall cancer associated with a one-point increment of the HDI was 0.96 (95% CI 0.89-1.03) in men, and 1.00 (95% CI 0.96-1.04) in women. Adherence to the HDI was not associated with smoking-related cancer ((HR men: 0.94 (95% CI 0.84-1.04); HR women: 1.00 (95% CI 0.94-1.07)), or alcohol-related cancer ((HR men: 1.02 (95% CI 0.87-1.20); HR women: 1.03 (95% CI 0.98-1.08)). Conclusions: Greater adherence to the WHO's Healthy Diet Indicator, a dietary pattern for prevention of chronic diseases, was not associated with reduced overall, smoking-related or alcohol-related cancer risk in men or women. - Funding: This work was supported by Europe against Cancer Programme of the European Commission (SANCO), the Dutch Ministry of Health, Welfare and Sports, the Dutch Cancer Society, the Netherlands Organisation for Health Research and Development (ZonMW), the World Cancer Research Fund (WCRF) and by a grant of the Dutch Research Council (NWO-ZonMw; grant no 40-00812-98-10040). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. The Netherlands has the 12th highest cancer rates in the world. Every year 286.8 people out of every 100,000 develop cancer [1] and the disease accounts for nearly one third of total annual mortality in the Netherlands [2]. Dietary habits are recognized to be important modifiable factors influencing cancer risk [3,4] and have been estimated, together with overweight/obesity and physical activity, to account for approximately 3538% of 12 common cancers in high-income countries, according to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) [5]. Dietary patterns examine effects of overall diet and allow for underlying synergistic effects between the individual dietary components [6]. Most of the studies that relate dietary patterns to health outcomes use either a priori (researcherdriven) diet scores, or a posteriori (data-driven) scores derived from factor- or cluster analysis. A priori dietary scores can be further grouped into three categories; (a) scores that assess dietary variety or diversity, (b) scores that assess concordance with dietary guidelines and (c) scores that assess specific dietary patterns (e.g. the Mediterranean diet) [7]. The Mediterranean dietary pattern has been found to reduce risk for cancer morbidity and mortality for some countries (especially the Mediterranean countries), but not for other, more Northern countries such as the Netherlands [8,9]. In 1990, the World Health Organisation (WHO) published international dietary guidelines for prevention of chronic diseases. Successively, the Healthy Diet Indicator (HDI) was developed by Huijbregts et al. [10] to quantify adherence to these guidelines. Previous studies have related the HDI to overall- and cancerspecific mortality. The HDI was found to be inversely related to all-cause mortality in elderly men of three European countries (RR for high versus low HDI adherence: 0.87, 95% CI: 0.770.98) [10]. This study also found risk of death from cardiovascular disease and cancer to be respectively 18% and 15% lower in the highest HDI group than in the lowest group, but specific estimates were not provided. In another cohort of elderly European men and women, a higher HDI was related to lower all-cause mortality (HR: 0.89 with 95% CI: 0.810.98), however, cancer mortality was not investigated [11]. In addition, the HDI was studied in relation to breast cancer risk in British women; however, no association was found (HR for maximal adherence to the HDI compared with minimal adherence: 0.94 with 95% CI: 0.671.32) [12]. As far as we know, no prospective study has related adherence to this dietary pattern to the occurrence of overall cancer. We aimed to investigate the association between adherence to the HDI and risk of overall cancer incidence, as well as alcohol- and smoking-related cancer. We examined associations separately for men and women participating in the Dutch part of the European Prospective Investigation into Cancer and Nutrition (EPIC-NL) cohort study. Subjects and Methods Study Population The EPIC-NL study consists of the two Dutch contributions to the EPIC cohort: Prospect and MORGEN cohorts [13]. The study design has been described elsewhere [14]. In brief, Prospect is a prospective cohort study of 17,357 women, aged 4970, who participated in breast cancer screening between 1993 and 1997 [15]. The M (...truncated)