Added Value of Serum Hormone Measurements in Risk Prediction Models for Breast Cancer for Women Not Using Exogenous Hormones: Results from the EPIC Cohort

Purpose: Circulating hormone concentrations are associated with breast cancer risk, with well-established associations for postmenopausal women. Biomarkers may represent minimally invasive measures to improve risk prediction models.Experimental Design: We evaluated improvements in discrimination gained by adding serum biomarker concentrations to risk estimates derived from risk prediction models developed by Gail and colleagues and Pfeiffer and colleagues using a nested case-control study within the EPIC cohort, including 1,217 breast cancer cases and 1,976 matched controls. Participants were pre- or postmenopausal at blood collection. Circulating sex steroids, prolactin, insulin-like growth factor (IGF) I, IGF-binding protein 3, and sex hormone-binding globulin (SHBG) were evaluated using backward elimination separately in women pre- and postmenopausal at blood collection. Improvement in discrimination was evaluated as the change in concordance statistic (C-statistic) from a modified Gail or Pfeiffer risk score alone versus models, including the biomarkers and risk score. Internal validation with bootstrapping (1,000-fold) was used to adjust for overfitting.Results: Among women postmenopausal at blood collection, estradiol, testosterone, and SHBG were selected into the prediction models. For breast cancer overall, model discrimination after including biomarkers was 5.3 percentage points higher than the modified Gail model alone, and 3.4 percentage points higher than the Pfeiffer model alone, after accounting for overfitting. Discrimination was more markedly improved for estrogen receptor-positive disease (percentage point change in C-statistic: 7.2, Gail; 4.8, Pfeiffer). We observed no improvement in discrimination among women premenopausal at blood collection.Conclusions: Integration of hormone measurements in clinical risk prediction models may represent a strategy to improve breast cancer risk stratification. Clin Cancer Res; 23(15); 4181-9. ©2017 AACR.

A treelet transform analysis to relate nutrient patterns to the risk of hormonal receptor-defined breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

Pattern analysis has emerged as a tool to depict the role of multiple nutrients/foods in relation to health outcomes. The present study aimed at extracting nutrient patterns with respect to breast cancer (BC) aetiology.

DESIGN

Nutrient patterns were derived with treelet transform (TT) and related to BC risk. TT was applied to twenty-three log-transformed nutrient densities from dietary questionnaires. Hazard ratios (HR) and 95 % confidence intervals computed using Cox proportional hazards models quantified the association between quintiles of nutrient pattern scores and risk of overall BC, and by hormonal receptor and menopausal status. Principal component analysis was applied for comparison.

SETTING

The European Prospective Investigation into Cancer and Nutrition (EPIC).

SUBJECTS

Women (n 334 850) from the EPIC study.

RESULTS

The first TT component (TC1) highlighted a pattern rich in nutrients found in animal foods loading on cholesterol, protein, retinol, vitamins B12 and D, while the second TT component (TC2) reflected a diet rich in β-carotene, riboflavin, thiamin, vitamins C and B6, fibre, Fe, Ca, K, Mg, P and folate. While TC1 was not associated with BC risk, TC2 was inversely associated with BC risk overall (HRQ5 v. Q1=0·89, 95 % CI 0·83, 0·95, P trend<0·01) and showed a significantly lower risk in oestrogen receptor-positive (HRQ5 v. Q1=0·89, 95 % CI 0·81, 0·98, P trend=0·02) and progesterone receptor-positive tumours (HRQ5 v. Q1=0·87, 95 % CI 0·77, 0·98, P trend<0·01).

CONCLUSIONS

TT produces readily interpretable sparse components explaining similar amounts of variation as principal component analysis. Our results suggest that participants with a nutrient pattern high in micronutrients found in vegetables, fruits and cereals had a lower risk of BC.

Polymorphisms of Helicobacter pylori signaling pathway genes and gastric cancer risk in the European Prospective Investigation into Cancer-Eurgast cohort

Helicobacter pylori is a recognized causal factor of noncardia gastric cancer (GC). Lipopolysaccharide and peptidoglycan of this bacterium are recognized by CD14, TLR4 and NOD2 human proteins, while NFKB1 activates the transcription of pro-inflammatory cytokines to elicit an immune response. Single nucleotide polymorphisms (SNPs) in these genes have been associated with GC in different populations. We genotyped 30 SNPs of these genes, in 365 gastric adenocarcinomas and 1,284 matched controls from the European Prospective Investigation into Cancer cohort. The association with GC and its histological and anatomical subtypes was analyzed by logistic regression and corrected for multiple comparisons. Using a log-additive model, we found a significant association between SNPs in CD14, NOD2 and TLR4 with GC risk. However, after applying the multiple comparisons tests only the NOD2 region remained significant (p = 0.009). Analysis according to anatomical subtypes revealed NOD2 and NFKB1 SNPs associated with noncardia GC and CD14 SNPs associated with cardia GC, while analysis according to histological subtypes showed that CD14 was associated with intestinal but not diffuse GC. The multiple comparisons tests confirmed the association of NOD2 with noncardia GC (p = 0.0003) and CD14 with cardia GC (p = 0.01). Haplotype analysis was in agreement with single SNP results for NOD2 and CD14 genes. From these results, we conclude that genetic variation in NOD2 associates with noncardia GC while variation in CD14 is associated with cardia GC.

Abstract LB-448: Genome-wide association study identifies new prostate cancer susceptibility loci

Prostate cancer (PrCa) is the most common non-skin cancer diagnosed among males in developed countries and the second leading cause of cancer mortality, yet little is known regarding etiology or factors influencing clinical outcome. Although PrCa genome-wide association studies (GWAS) have identified at least 30 distinct susceptibility loci for overall risk, the critical clinical question is determining who will develop advanced as opposed to indolent disease. To identify additional PrCa susceptibility loci, particularly for advanced PrCa, we conducted a GWAS of 2,782 prospectively ascertained advanced PrCa cases (Gleason grade 8+ or tumor stage C/D) and 4,458 matched controls of European ancestry from the NCI Breast & Prostate Cancer Cohort Consortium (BPC3). Case and control genotype frequencies were compared using a 1-df trend test within each cohort, and then combined using fixed effect meta-analysis for 571,243 single nucleotide polymorphisms (SNPs). In our Stage 1 GWAS, we found associations (P&lt;0.05) and consistent per-allele odds ratios (OR) with advanced PrCa for a majority of previously reported PrCa loci associated with overall risk. We did not observe associations with the proposed advanced-only region 17p12 or 22q13.1 after excluding overlapping subjects in the initial report (P=0.39). The advanced-only marker on chromosome 9q33.2 was nominally associated with advanced PrCa (rs1571801, P=1.4×10−3), but previous results in BPC3 (10,501 cases and 10,831 controls) found no evidence of difference between advanced and non-advanced PrCa (case-only test for heterogeneity P=0.50). No novel regions were detected at genome-wide significance in Stage 1 (P&lt;5×10−8). In Stage 2 we performed in silico replication for 4,679 of the most promising novel markers (P&lt;=0.02) identified in Stage 1 using data from two previous GWAS conducted in the UK and Australia (5,504 PrCa cases/5,834 controls) and the Cancer of the Prostate in Sweden Study (CAPS; 1,854 PrCa cases/898 controls). We identified a new susceptibility locus associated with overall PrCa risk at 2q37.3 (rs2292884: OR=1.14, P=4.3 × 10−8) and confirmed a suggested locus at 12q13 (rs902774: OR=1.17, P=8.6×10−9). The estimated per-allele OR between advanced and non-advanced PrCa did not differ (case-only test for heterogeneity P&gt;0.60). Furthermore, we identified several genome-wide significant markers (P&lt;5×10−8) in known PrCa loci while conditioning on the index signal, suggesting multiple risk markers may exist. Although our Stage 1 GWAS was adequately powered (&gt;90%) to detect a marker with a per-allele OR of 1.18 and minor allele frequency of 40%, we identified no loci primarily associated with advanced PrCa. This suggests that-unlike unique breast cancer markers associated with estrogen-receptor positive and negative tumors-there are very few, if any, common markers with moderate effects differentially associated with advanced or non-advanced PrCa.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-448. doi:10.1158/1538-7445.AM2011-LB-448

Anthropometry, physical activity and hip fractures in the elderly

INTRODUCTION

Hip fractures constitute a major and growing public health problem amongst the elderly worldwide. We examined the association of anthropometry and physical activity with hip fracture incidence in a cohort of elderly Europeans, participants in the European Prospective Investigation into Cancer and nutrition (EPIC) study.

MATERIALS AND METHODS

The study population consisted of 27 982 volunteers (10 553 men and 17 429 women) aged 60 years and above from five European countries. Information on anthropometry, physical activity, medical history and other characteristics was collected at baseline. During a median follow-up of 8 years, 261 incident hip fractures (203 women and 58 men) were recorded. Data were analysed through Cox proportional hazard regression with adjustment for potential confounders.

RESULTS

A higher body mass index (BMI) was associated with lower hip fracture risk (hazard ratio (HR)per increasing sex-specific-quintile: 0.85, 95% confidence interval (95% CI): 0.77–0.94). Body height was associated with increased hip fracture risk (HR per 5 cm: 1.13, 95% CI: 1.01–1.25). Waist-to-hip ratio was not related to hip fracture risk. Increasing levels of leisure-time physical activity were related to lower risk (HR per increasing tertile: 0.84, 95% CI: 0.70–0.99, p for trend: 0.039).

CONCLUSIONS

In a prospective cohort study of elderly Europeans, we found evidence that high body stature increased and high BMI decreased the incidence of hip fractures. After adjustment for BMI,waist to-hip ratio was not associated with hip fracture risk. Leisure-time physical activity appears to play a beneficial role in the prevention of hip fractures.

CagA+ Helicobacter pylori infection and gastric cancer risk in the EPIC-EURGAST study

Helicobacter pylori (H. pylori), atrophic gastritis, dietary and life-style factors have been associated with gastric cancer (GC). These factors have been evaluated in a large case-control study nested in the European Prospective Investigation into Cancer and Nutrition carried out in 9 countries, including the Mediterranean area. Participants, enrolled in 1992-1998, provided life-style and dietary information and a blood sample (360,000; mean follow-up: 6.1 years). For 233 GC cases diagnosed after enrolment and their 910 controls individually-matched by center, gender, age and blood donation date H. pylori antibodies (antilysate and antiCagA) and plasma Pepsinogen A (PGA) were measured by ELISA methods. Severe chronic atrophic gastritis (SCAG) was defined as PGA circulating levels <22 microg/l. Overall, in a conditional logistic regression analysis adjusted for education, smoke, weight and consumption of total vegetables, fruit, red and preserved meat, H. pylori seropositivity was associated with GC risk. Subjects showing only antibodies anti-H. pylori lysate, however, were not at increased risk, while those with antiCagA antibodies had a 3.4-fold increased risk. Overall, the odds ratio associated with SCAG was 3.3 (95% CI 2.2-5.2). According to site, the risk of noncardia GC associated with CagA seropositivity showed a further increase (OR 6.5; 95% CI 3.3-12.6); on the other hand, a ten-fold increased risk of cardia GC was associated with SCAG (OR 11.0; 95% CI 3.0-40.9). These results support the causal relationship between H. pylori CagA+ strains infection, and GC in these European populations even after taking into account dietary habits. This association was limited to distal GC, while serologically defined SCAG was strongly associated with cardia GC, thus suggesting a divergent risk pattern for these 2 sites.

Serum sex steroids in premenopausal women and breast cancer risk within the European Prospective Investigation into Cancer and Nutrition (EPIC)

BACKGROUND

Contrasting etiologic hypotheses about the role of endogenous sex steroids in breast cancer development among premenopausal women implicate ovarian androgen excess and progesterone deficiency, estrogen excess, estrogen and progesterone excess, and both an excess or lack of adrenal androgens (dehydroepiandrosterone [DHEA] or its sulfate [DHEAS]) as risk factors. We conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort to examine associations among premenopausal serum concentrations of sex steroids and subsequent breast cancer risk.

METHODS

Levels of DHEAS, (Delta4-)androstenedione, testosterone, and sex hormone binding globulin (SHBG) were measured in single prediagnostic serum samples from 370 premenopausal women who subsequently developed breast cancer (case patients) and from 726 matched cancer-free control subjects. Levels of progesterone, estrone, and estradiol were also measured for the 285 case patients and 555 matched control subjects who had provided information about the day of menstrual cycle at blood donation. Conditional logistic regression models were used to estimate relative risks of breast cancer by quartiles of hormone concentrations. All statistical tests were two-sided.

RESULTS

Increased risks of breast cancer were associated with elevated serum concentrations of testosterone (odds ratio [OR] for highest versus lowest quartile = 1.73, 95% confidence interval [CI] = 1.16 to 2.57; P(trend) = .01), androstenedione (OR for highest versus lowest quartile = 1.56, 95% CI = 1.05 to 2.32; P(trend) = .01), and DHEAS (OR for highest versus lowest quartile = 1.48, 95% CI = 1.02 to 2.14; P(trend) = .10) but not SHBG. Elevated serum progesterone concentrations were associated with a statistically significant reduction in breast cancer risk (OR for highest versus lowest quartile = 0.61, 95% CI = 0.38 to 0.98; P(trend) = .06). The absolute risk of breast cancer for women younger than 40 followed up for 10 years was estimated at 2.6% for those in the highest quartile of serum testosterone versus 1.5% for those in the lowest quartile; for the highest and lowest quartiles of progesterone, these estimates were 1.7% and 2.6%, respectively. Breast cancer risk was not statistically significantly associated with serum levels of the other hormones.

CONCLUSIONS

Our results support the hypothesis that elevated blood concentrations of androgens are associated with an increased risk of breast cancer in premenopausal women.

Intake of the Plant Lignans Secoisolariciresinol, Matairesinol, Lariciresinol, and Pinoresinol in Dutch Men and Women

Enterolignans (enterolactone and enterodiol) are phytoestrogens that are formed by the colonic microflora from plant lignans. They may reduce the risk of certain types of cancer and cardiovascular diseases. Initially, only secoisolariciresinol and matairesinol were considered to be enterolignan precursors, but recently, new precursors such as lariciresinol and pinoresinol were identified. We recently developed a lignan database including 4 major enterolignan precursors. We used this database to estimate lignan intake in a representative sample of Dutch men and women participating in the Dutch Food Consumption Survey, carried out in 1997-1998. Median total lignan intake among 4660 adults (19-97 y old) was 979 microg/d. Total lignan intake did not differ between men and women; thus, the lignan density of the diet was significantly higher (P < 0.001) in women than in men. Lignan intake was strongly skewed toward higher values (range 43-77584 microg/d, mean 1241 microg/d). Lariciresinol and pinoresinol contributed 75% to lignan intake, whereas secoisolariciresinol and matairesinol contributed only 25%. The major food sources of lignans were beverages (37%), vegetables (24%), nuts and seeds (14%), bread (9%), and fruits (7%). Lignan intake was significantly (P < 0.001) correlated with intake of dietary fiber (r = 0.46), folate (r = 0.39), and vitamin C (r = 0.44). Older persons, nonsmokers, vegetarians, and persons with a low BMI or a high socioeconomic status had higher lignan intakes than their counterparts. In brief, this study shows that the amount of enterolignan precursors in the diet has previously been largely underestimated.

Dietary determinants of circulating insulin-like growth factor (IGF)-I and IGF binding proteins 1, -2 and -3 in women in the Netherlands

OBJECTIVE

Epidemiological studies suggest that individuals with elevated plasma concentrations of insulin-like growth factor (IGF-I) are at increased risk of developing cancer. We assessed whether dietary intake of total energy, protein, alcohol, phytoestrogens and related foods, and tomatoes and lycopene was associated with plasma levels of IGF-I and IGF binding proteins (IGFBPs) in Dutch women.

METHODS

A cross-sectional study was conducted in 224 premenopausal and 162 postmenopausal women, aged 49-69, participating in the Prospect-EPIC study in the Netherlands. Diet was assessed using a food frequency questionnaire.

RESULTS

In postmenopausal women, higher alcohol intake was associated with lower plasma IGFBP-1 concentrations (alcohol 1.4 to 20 g/day: 20% decrease in IGFBP-1; p = 0.04), and higher intake of plant lignans was associated with higher IGFBP-1 concentrations (plant lignans 0 to 1 mg/day: 59% increase in IGFBP-1; p =0.02). Higher soy intake was associated with higher plasma IGFBP-2 concentrations in premenopausal women (soy 0 to 2.5 g/day: 3% increase in IGFBP-2; p = 0.04). No independent associations of dietary factors with IGF-I or IGFBP-3 concentrations were observed. However, in premenopausal women alcohol intake was inversely associated with IGF-I and positively associated with IGFBP-3 after mutual adjustment.

CONCLUSIONS

In this study population, with limited variation in dietary intake, total energy, protein, phytoestrogens and lycopene were not associated with IGF-I and IGFBP-3. Alcohol was inversely, and some measures of phytoestrogen intake were positively associated with plasma IGFBP-1 or -2 concentrations. The roles of IGFBP-1 and -2 in relation to IGF-I bioactivity and cancer deserve further investigation.

GSTM1 Null Genotype, Red Meat Consumption and Breast Cancer Risk (The Netherlands)

OBJECTIVE

We studied whether polymorphisms in N-acetyltransferase 1 and 2 and Glutathione S-transferase M1 and T1 genes modify the association between meat consumption and breast cancer.

METHODS

A nested case control was conducted in a Dutch prospective cohort. Breast cancer cases (229) and controls (264) were frequency matched on age, town and menopausal status.

RESULTS

There is no relation between any type of meat consumption ( i.e., total meat, processed meat, fresh meat, red meat and white meat) and breast cancer risk. Neither presence of NAT1 or NAT2 rapid genotype, or GSTT1 null genotype, alone or in combination with meat consumption affects breast cancer risk. Absence of GSTM1 shows 46% increased breast cancer risk (OR = 1.46 (95% confidence interval, 95% CI = 1.02-2.09)). When stratifying according to combined 'GSTM1 genotype-meat consumption' categories, breast cancer risk is slightly increased with consumption of red meat both in women with genotype GSTM1 presence (OR = 1.49 and 1.75 for intermediate and high versus low consumption) and in GSTM1 null genotype (OR = 1.18 and 1.02). These increases are statistically not significant. In postmenopausal women a suggestion of an effect of red meat consumption is observed: effects are slightly stronger, although still not statistically significant and without a clear dose-response relation: OR = 1.79 (95% CI = 0.92-3.50) and 1.46 (1.46 (95% CI = 0.76-2.82) for intermediate and high compared to low red meat consumption respectively. Reliable evaluation of interaction is not possible due to the small number of cancers.

CONCLUSION

GSTM1 null genotype increases breast cancer risk. Red meat consumption slightly increases breast cancer risk, but the relation is not statistically significant and GSTM1, NAT1, NAT2 and GSTT1 polymorphisms do not modify this relation.

Modelling future mortality reduction through smoking cessation in the European Union

BACKGROUND

To assess public health relevance of targets on tobacco smoking, information is needed on the decline in future mortality following smoking cessation. WHO's Health for All (HFA) and other targets on tobacco smoking in the European Union (EU) were therefore simulated.

METHODS

A computer simulation model, Markov multi-state type, was developed using published age- and sex-specific information on population sizes, smoking prevalences, total and cause-specific mortality rates and corresponding relative risks for ex- and current smokers. The probabilities to start and quit smoking (transition rates) were estimated. Targets on smoking cessation included WHO's HFA target (country-specific smoking prevalence is reduced to 20% by 2015), and a theoretical maximum target (all smokers quit instantly). Simulation of these targets was based on changes in transition rates for smoking behaviour. For each target, the cumulated number of all-cause and cause-specific deaths between 1994 and 2015 was estimated for each EU member state. Then, the absolute and relative reduction in the number of deaths compared to a reference scenario, in which transition rates for smoking behaviour remained constant, were estimated for the EU as a whole.

RESULTS

WHO's HFA target was expected to give a total mortality reduction by 2015 of 2.5% (around 1.1 million deaths) among men and 0.8% (almost 350,000 deaths) among women in the EU. Overall, the expected mortality declines in the HFA target were about 40-50% (men) and 30% (women) of the expected declines in the maximum target. The largest impact of the HFA target would be reached for lung cancer mortality.

CONCLUSIONS

These results emphasize the need for policymakers in each EU member state to put strong effort into encouraging smokers to quit smoking.

NAT2 slow acetylation and GSTM1 null genotypes may increase postmenopausal breast cancer risk in long-term smoking women

N-acetyltransferase (NAT) 1 and 2 and glutathione S-transferase (GST) M1 and T1 are phase II enzymes that are important for activation and detoxification of carcinogenic heterocyclic and aromatic amines, as present in cigarette smoke. We studied whether genetic polymorphisms in these genes modifies the relationship between smoking and breast cancer. A nested case-control study was conducted among participants in a Dutch prospective cohort. Breast cancer cases (n=229) and controls (n=264) were frequency-matched on age, menopausal status and residence. Compared to never smoking, smoking 20 cigarettes or more per day increased breast cancer risk statistically significant only in postmenopausal women [odds ratio (OR)=2.17; 95% confidence interval (CI) 1.04-4.51]. Neither NAT1 slow genotype, or GSTT1 null genotype, alone or in combination with smoking, affected breast cancer risk. However, compared to individuals with rapid NAT2 genotype, women with the very slow acetylator genotype (NAT2*5), who smoked for 20 years showed an increased breast cancer risk (OR=2.29; 95% CI 1.06-4.95). Similarly, the presence of GSTM1 null genotype combined with high levels of cigarette smoking (OR=3.00; 95% CI 1.46-6.15) or long duration (OR=2.53; 95% CI 1.24-5.16), increased rates of breast cancer. The combined effect of GSTM1 null genotype and smoking high doses was most pronounced in postmenopausal women (OR=6.78; 95% CI 2.31-19.89). In conclusion, our results provide support for the view that women who smoke and who have a genetically determined reduced inactivation of carcinogens (GSTM1 null genotype or slow NAT2 genotype (especially very slow NAT2 genotype)) are at increased risk of breast cancer.

Rapid N-acetyltransferase 2 imputed phenotype and smoking may increase risk of colorectal cancer in women (Netherlands)

OBJECTIVE

The relationship between smoking and colorectal cancer risk and whether such effect is modified by variations in the NAT2 genotype is investigated.

METHODS

In the prospective DOM (Diagnostisch Onderzoek Mammacarcinoom; 27,722 women) cohort follow-up from 1976 until 1987 revealed 54 deaths due to colon or rectal cancer, and follow-up from 1987 to 01-01-1996 revealed 204 incident colorectal cancer cases. A random sample (n = 857) from the baseline cohort was used as controls. Four NAT2 restriction fragment length polymorphisms (RFLPs) were analysed using DNA extracted from urine samples. Rapid or slow acetylator phenotype status was attributed to individuals.

RESULTS

Smoking may increase the risk for colon cancer (RR = 1.36, 95% CI 0.97-1.92) as well as for rectal cancer (RR = 1.31, 95% CI 0.76-2.25), although not statistically significant. Rapid NAT2 acetylation did not increase colorectal cancer risk, but in combination with smoking the risk was statistically significant increased, compared to women who had a slow NAT2 imputed phenotype and never smoked (RR = 1.56, 95% CI 1.03-2.37). For colon cancer, but not for rectal cancer the increased risk was statistically significant (RR = 1.67, 95% CI, 1.05-2.67 versus RR = 1.30 95% CI 0.63-2.68).

CONCLUSIONS

Our study points to smoking as a risk factor for colon and rectal cancer and, in addition, especially in women with rapid NAT2 imputed phenotype.

Quality of NAT2 genotyping with restriction fragment length polymorphism using DNA isolated from frozen urine

In large studies and under field conditions common to epidemiological research, factors outside of and inside the laboratory can introduce misclassification of genetic susceptibility markers. Few reports have been made on the accuracy of genotyping individuals using DNA extracted from frozen urine that was stored for approximately 20 years. This study was performed to determine the reproducibility and accuracy of N-acetyltransferase 2 (NAT2) genotyping by RFLP analysis using DNA from stored urine. To obtain long-term frozen urine and blood samples from the same person, the databases of two large prospective studies were linked by name and date of birth. Six polymorphisms within the coding region of NAT2 were determined in 65 urine and blood samples after which, genotypes and imputed phenotypes (rapid, slow) were derived. To test reproducibility, all of the six polymorphisms were determined twice in 47 urine-blood pairs. Reproducibility of imputed phenotypes was 91.5% in urine samples and 97.9% in blood samples. To test accuracy, results for all six polymorphisms were compared between urine and blood DNA. All of the kappa's were at least 0.85 except one. Identical results for all six polymorphisms were seen in 78.5% of urine-blood pairs. Taking blood samples as a reference standard, rapid acetylators were classified as rapid in 97% of subjects (95% confidence interval, 90-100%), and slow acetylators were classified as slow also in 97% of subjects (95% confidence interval, 91-100%), when using urine. This study shows that stored urine samples can be used for DNA genotyping in large cohort studies, when blood samples are not available.