Compliance with indoor tanning bans for minors among businesses in the USA

Indoor tanning is a known risk factor for skin cancer and is especially dangerous for adolescents. Some states have passed indoor tanning bans for minors, but business compliance with the bans is not well understood. Thus far, studies have assessed ban compliance in one or two states at a time. This study aimed to assess compliance with indoor tanning bans for minors and knowledge of dangers and benefits of tanning among indoor tanning businesses. Female research assistants posing as minors telephoned a convenience sample of 412 businesses in 14 states with tanning bans for minors under age 17 or 18. We evaluated differences in compliance by census region and years since ban was implemented and differences in reported dangers and benefits by compliance. Most (80.1%) businesses told the "minor" caller she could not use the tanning facilities. Businesses in the south and in states with more recent bans were less compliant. Among those (n = 368) that completed the full interview, 52.2% identified burning and 20.1% mentioned skin cancer as potential dangers. However, 21.7% said dangers were no worse than the sun and 10.3% denied any dangers. Stated benefits included vitamin D (27.7%), social/cosmetic (27.2%), and treats skin diseases (26.4%), with only 4.9% reporting no benefits. While most businesses followed the indoor tanning ban when a minor called, one-fifth did not. Many stated inaccurate health claims. Additional enforcement or education might increase compliance with indoor tanning bans and action is needed to prevent businesses from stating false health information.

Abstract 5321: Metabolomics and body mass index among breast cancer survivors in The Lifestyle, Exercise, and Nutrition (LEAN) Study

Background: While there is a growing body of literature on metabolomics and body mass index (BMI), there are limited studies in relation to weight change in overweight and obese individuals, and to our knowledge, no such studies in breast cancer survivors.

Methods: The Lifestyle, Exercise and Nutrition (LEAN) randomized diet- and exercise-induced weight loss trial in breast cancer survivors enrolled overweight or obese breast cancer survivors (Stage 0-III) identified via the Yale-New Haven Hospital tumor registry or self-referral. Participants were randomized to either usual care group (n=33) or the 6-month lifestyle intervention (11 sessions with a registered dietitian) (n=67). Height and weight were measured by study staff at baseline and 6 months, and a fasting (≥ 12 hours) blood draw was also performed at these time points. Paired (baseline and 6-month) serum metabolomics data were available for 83 women. Only those metabolites consistently detected in >80% of quality control samples with a coefficient of variation <30% were included in data analysis. We evaluated partial Pearson correlations between the ratio of metabolites at baseline versus 6-months and change in BMI adjusted for age and intervention group. We also assessed mean changes in metabolites from baseline to 6-months by randomization group using the general estimating equation in linear regression. Adjustment for multiple comparisons was based on the False Discovery Rate (FDR) with a threshold of 0.1.

Results: Overall, a total of 307 metabolites were analyzed; 168 were quantitated by LC-MS and 139 were semi-quantitated by GC-TOF/MS. For BMI change from baseline to 6-months, we observed correlations with 16 metabolites (isocitric acid, 3-hydroxybutyric acid, serine, L-cysteine, petroselinic acid, aminomalonic acid, palmitoleic acid, linoleic acid, 2-hydroxybutyric acid, and seven unidentified metabolites, p <0.05), however FDR correction for multiple comparisons yielded no statistically significant results. We also observed differences by randomization group for L-alanine, dopamine, serotonin, PCaaC36:1, 3-hydroxyoleoylcarnitine, and PCaeC36:1 in bivariate analyses, but in models adjusted for age and BMI only L-alanine remained significant (p<0.05). After correction for FDR, there were no significant differences by randomization group.

Conclusions: There were no clear associations between metabolites and change in BMI or randomization group among overweight and obese breast cancer survivors enrolled in a weight loss trial. Larger sample sizes would help to clarify if any of the potential signals observed in this population may be associated with BMI or other lifestyle changes, such as diet quality.

Citation Format: Leah M. Ferrucci, Brenda Cartmel, Maura Harrigan, Tara Sanft, Mary Playdon, Wei Jia, Herbert Yu, Caroline H. Johnson, Lajos Pusztai, Anees B. Chagpar, Melinda L. Irwin. Metabolomics and body mass index among breast cancer survivors in The Lifestyle, Exercise, and Nutrition (LEAN) Study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5321. doi:10.1158/1538-7445.AM2017-5321

Pre-diagnosis diet and survival after a diagnosis of ovarian cancer

Background:

The relationship between diet and survival after ovarian cancer diagnosis is unclear as a result of a limited number of studies and inconsistent findings.

Methods:

We examined the association between pre-diagnostic diet and overall survival in a population-based cohort (n=811) of Australian women diagnosed with invasive epithelial ovarian cancer between 2002 and 2005. Diet was measured by validated food frequency questionnaire. Deaths were ascertained up to 31 August 2014 via medical record review and Australian National Death Index linkage. We conducted Cox proportional hazards regression analysis, controlling for diagnosis age, tumour stage, grade and subtype, residual disease, smoking status, body mass index, physical activity, marital status, and energy intake.

Results:

We observed improved survival with highest compared with lowest quartile of fibre intake (hazard ratio (HR)=0.69, 95% CI: 0.53–0.90, P-trend=0.002). There was a suggestion of better survival for women with highest compared with lowest intake category of green leafy vegetables (HR=0.79, 95% CI: 0.62–0.99), fish (HR=0.74, 95% CI: 0.57–0.95), poly- to mono-unsaturated fat ratio (HR=0.76, 95% CI: 0.59–0.98), and worse survival with higher glycaemic index (HR=1.28, 95% CI: 1.01–1.65, P-trend=0.03).

Conclusions:

The associations we observed between healthy components of diet pre-diagnosis and ovarian cancer survival raise the possibility that dietary choices after diagnosis may improve survival.

Predictors of tanning dependence in white non-Hispanic females and males

BACKGROUND

Growing evidence suggests that some individuals may exhibit symptoms of dependence on ultraviolet (UV) light, a known carcinogen, in the context of tanning; however, few studies have investigated predictors of tanning dependence (TD).

OBJECTIVE

To identify predictors of TD.

METHODS

Non-Hispanics of European ancestry who had previously participated in a case-control study of early-onset basal cell carcinoma completed an online survey to ascertain TD and other behaviours (alcohol dependence, nicotine dependence, seasonal affective disorder (SAD), exercise 'addiction' and depression). Information on host factors, such as skin and eye colour and history of sunbathing and indoor tanning, was obtained from a study in which the participants were previously enrolled. Lifetime TD was assessed using the modified Cut down, Annoyed, Guilty, Eye-opener (mCAGE) and the modified Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (mDSM-IV-TR) questionnaires. Participants were classified as 'TD' if positive on both questionnaires and not TD if negative on both questionnaires.

RESULTS

In total, 499 individuals completed the online survey (81.9% participation rate), and 24.4% were classified as 'TD'. In the multivariate model, women were more likely to be TD [odds ratio (OR) 6.93; 95% confidence intervals (95% CI) (3.36-14.27)] than men. Alcohol dependence (OR 6.55: 95% CI 3.19-13.42), SAD (OR 2.77; 95% CI 1.26-6.09) and exercise 'addiction' (OR 5.47; 95% CI 1.15-26.06) were all significant predictors for TD.

CONCLUSION

Increased knowledge of those at risk for TD will allow appropriate interventions to be designed.

Body mass index, height and early-onset basal cell carcinoma in a case-control study

INTRODUCTION

Basal cell carcinoma (BCC) is the most common malignancy in the US. Body mass index (BMI) and height have been associated with a variety of cancer types, yet the evidence regarding BCC is limited. Therefore, we evaluated BMI and height in relation to early-onset BCC (under age 40) and explored the potential role of ultraviolet (UV) radiation exposure and estrogen-related exposures in the BMI-BCC relationship.

METHODS

BCC cases (n=377) were identified through a central dermatopathology facility in Connecticut. Control subjects (n=389) with benign skin conditions were randomly sampled from the same database and frequency matched to cases on age (median=36, interquartile range 33-39), gender, and biopsy site. Participants reported weight (usual adult and at age 18), adult height, sociodemographic, phenotypic, and medical characteristics, and prior UV exposures. We calculated multivariate odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression models.

RESULTS

Adult BMI was inversely associated with early-onset BCC (obese vs. normal OR=0.43, 95% CI=0.26-0.71). A similar inverse association was present for BMI at age 18 (OR=0.54, 95% CI=0.34-0.85). Excluding UV exposures from the BMI models and including estrogen-related exposures among women only did not alter the association between BMI and BCC, indicating limited mediation or confounding. We did not observe an association between adult height and BCC (OR per cm=1.00, 95% CI=0.98-1.02).

CONCLUSIONS

We found a significant inverse association between BMI and early-onset BCC, but no association between height and BCC. This association was not explained by UV exposures or estrogen-related exposures in women.

Health information needs and preferences in relation to survivorship care plans of long-term cancer survivors in the American Cancer Society's Study of Cancer Survivors-I

PURPOSE

Survivorship care plans (SCPs) provide cancer patients and health care providers with a treatment summary and outline of recommended medical follow-up. Few studies have investigated the information needs and preferred sources among long-term cancer survivors.

METHODS

Cancer survivors of the ten most common cancers enrolled in the longitudinal Study of Cancer Survivors-I (SCS-I) completed a survey 9 years post-diagnosis (n = 3138); at time of diagnosis of the SCS-I cohort, SCPs were not considered usual care. We assessed participants' current desire and preferred sources for information across ten SCP items and evaluated factors associated with information need 9 years after diagnosis.

RESULTS

The proportion of long-term cancer survivors endorsing a need for cancer and health information 9 years post-diagnosis ranged from 43 % (cancer screening) to 9 % (consequences of cancer on ability to work). Print media and personalized reading materials were the most preferred information sources. Younger age, higher education, race other than non-Hispanic white, later cancer stage, having breast cancer, having ≥2 comorbidities, and self-reporting poor health were associated with greater informational need (p < 0.05).

CONCLUSIONS/IMPLICATIONS FOR CANCER SURVIVORS

Long-term cancer survivors continue to report health information needs for most SCP items and would prefer a print format; however, level of need differs by socio-demographic and cancer characteristics. Cancer survivors who did not previously receive a SCP may still benefit from receiving SCP content, and strategies for enabling dissemination to long-term survivors warrant further investigation.

Novel gene identified in an exome-wide association study of tanning dependence

Growing evidence suggests that some individuals may exhibit symptoms of dependence to ultraviolet light, a known carcinogen, in the context of tanning. Genetic associations with tanning dependence (TD) have not yet been explored. We conducted an exome-wide association study in 79 individuals who exhibited symptoms of TD and 213 individuals with volitional exposure to ultraviolet light, but who were not TD based on three TD scales. A total of 300 000 mostly exomic single nucleotide polymorphisms primarily in coding regions were assessed using an Affymetrix Axiom array. We performed a gene burden test with Bonferroni correction for the number of genes examined (P < 0.05/14 904 = 3.36 × 10(-6) ). One gene, patched domain containing 2 (PTCHD2), yielded a statistically significant P-value of 2.5 × 10(-6) (OR = 0.27) with fewer individuals classified as TD having a minor allele at this locus. These results require replication, but are the first to support a specific genetic association with TD.

Abstract A50: Impact of indoor tanning and MC1R genotype on basal cell carcinoma risk in young people

Background: The incidence of basal cell carcinoma (BCC), which accounts for the majority of non-melanoma skin cancer (NMSC), is increasing, particularly in young people. While BCC is treatable, it can be associated with significant morbidity and health care costs. The ability to identify individuals at the highest risk of early-onset BCC could help focus public health efforts and mitigate the increasing incidence. However, to date, few risk prediction models exist for BCC. To identify individuals at risk of BCC at young ages, we assessed the utility of existing skin cancer risk prediction models (for melanoma or overall skin cancer) in the setting of early-onset BCC and built a novel risk prediction model, with a focus on indoor tanning and melanocortin 1 receptor (MC1R) genotype.

Methods: We evaluated unconditional multivariate logistic regression models among 759 (376 cases, 383 controls) non-Hispanic whites from the Yale Study of Skin Health, a case-control study of early-onset BCC conducted in Connecticut among individuals under age 40. BCC cases and randomly sampled controls with minor benign skin conditions diagnosed between July 2006 and September 2010 were identified through Yale University's Dermatopathology database. Participants completed a structured in-person interview, self-administered questionnaires, and provided a saliva sample. We gathered self-reported eye color, skin color (inner upper arm), hair color (natural color), freckling on the arms (based on images), number of moles on the back ≥ 5 mm (clear acetate size template), mole removal, skin reaction to sunlight for the first time in the summer for one hour without sunscreen, skin reaction after repeated and prolonged exposure to sunlight, family history of melanoma and NMSC, and indoor and outdoor ultraviolet (UV) radiation exposure.

We assessed the predictive performance of our novel risk prediction model and two models in the literature via summary measures of calibration, misclassification, and discrimination. We employed bootstrapping to better reflect the area under the receiver operating characteristic curve (AUC) expected when the model is tested on an independent, but similar set of patients. To investigate if indoor tanning and MC1R improved prediction performance over our early-onset BCC base model, we evaluated the regression coefficients for the markers in the expanded risk model and the corresponding likelihood ratio test statistic. All statistical tests were two-sided and analyses were performed in the statistical software R (Version 3.0.2).

Results: An existing model by Han et al. (2006) included seven MC1R variants and in our data the bootstrapped AUC for this model was 0.72 (95% CI, 0.66-0.78). Another existing model by Smith et al. (2012) with MC1R and indoor tanning resulted in a bootstrapped AUC of 0.69 (95% CI 0.63-0.75) in our population. Our base model, which included hair color, skin color, skin reaction with prolonged sun exposure, education, freckles on arm, family history of NMSC, and outdoor sun exposure in warm months, had greater predictive ability (bootstrapped AUC=0.75, 95% CI=0.72-0.79) than the existing models we evaluated. We also found that our model was significantly improved when we added ever indoor tanning, burns from indoor tanning, and the R151C MC1R variant (bootstrapped AUC=0.77, 95% CI, 0.74-0.81).

Conclusions: Our risk prediction model incorporating both MC1R and indoor tanning in the risk of early-onset BCC, validates and extends the work of other skin cancer risk prediction models and emphasizes the value of considering both genotype and indoor tanning in skin cancer risk prediction in young people. Therefore, in addition to the typical skin cancer characteristics clinicians rely on, assessing and counseling young people to reduce both indoor and outdoor UV exposure is needed to reduce BCC risk.

Citation Format: Annette M. Molinaro, Leah M. Ferrucci, Brenda Cartmel, Erikka Loftfield, David J. Leffell, Allen E. Bale, Susan T. Mayne. Impact of indoor tanning and MC1R genotype on basal cell carcinoma risk in young people. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A50.

Indoor tanning and the MC1R genotype: risk prediction for basal cell carcinoma risk in young people

Basal cell carcinoma (BCC) incidence is increasing, particularly in young people, and can be associated with significant morbidity and treatment costs. To identify young individuals at risk of BCC, we assessed existing melanoma or overall skin cancer risk prediction models and built a novel risk prediction model, with a focus on indoor tanning and the melanocortin 1 receptor gene, MC1R. We evaluated logistic regression models among 759 non-Hispanic whites from a case-control study of patients seen between 2006 and 2010 in New Haven, Connecticut. In our data, the adjusted area under the receiver operating characteristic curve (AUC) for a model by Han et al. (Int J Cancer. 2006;119(8):1976-1984) with 7 MC1R variants was 0.72 (95% confidence interval (CI): 0.66, 0.78), while that by Smith et al. (J Clin Oncol. 2012;30(15 suppl):8574) with MC1R and indoor tanning had an AUC of 0.69 (95% CI: 0.63, 0.75). Our base model had greater predictive ability than existing models and was significantly improved when we added ever-indoor tanning, burns from indoor tanning, and MC1R (AUC = 0.77, 95% CI: 0.74, 0.81). Our early-onset BCC risk prediction model incorporating MC1R and indoor tanning extends the work of other skin cancer risk prediction models, emphasizes the value of both genotype and indoor tanning in skin cancer risk prediction in young people, and should be validated with an independent cohort.

Alcohol intake and early-onset basal cell carcinoma in a case-control study

BACKGROUND

Previous epidemiological studies of overall alcohol intake and basal cell carcinoma (BCC) are inconsistent, with some evidence for differences by type of alcoholic beverage. While alcohol may enhance the carcinogenicity of ultraviolet (UV) radiation, this has not been evaluated in existing epidemiological studies.

OBJECTIVES

To evaluate alcohol intake in relation to early-onset BCC, and explore potential interactions with UV exposure.

METHODS

Basal cell carcinoma cases (n = 380) and controls with benign skin conditions (n = 390) under 40 years of age were identified through Yale Dermatopathology. Participants provided information on lifetime alcohol intake, including type of beverage, during an in-person interview. Self-reported data on indoor tanning and outdoor sunbathing were used to categorize UV exposure. We calculated odds ratios (OR) and 95% confidence intervals (CIs) using unconditional multivariate logistic regression in the full sample and in women only.

RESULTS

There was no statistically significant association between lifetime alcohol intake and early-onset BCC overall [above median intake vs. no regular alcohol intake (OR 1·10, 95% CI 0·69-1·73)] or in women only (OR 1·21, 95% CI 0·73-2·01). Similarly, intake of red wine, white wine, beer or spirits and mixed drinks was not associated with early-onset BCC. In exploratory analyses, we saw limited evidence for an interaction (P(interaction) = 0·003), with highest risk for high alcohol and high UV exposures, especially in women, but subgroup risk estimates had wide and overlapping CIs.

CONCLUSIONS

Overall, we did not observe any clear association between lifetime alcohol intake and early-onset BCC.

Indoor tanning in businesses and homes and risk of melanoma and nonmelanoma skin cancer in 2 US case-control studies

BACKGROUND

Indoor tanning increases skin cancer risk. Beyond early research describing melanoma and sun lamps, few recent reports describe where individuals indoor tan and whether skin cancer risk varies by location (business, home-based).

OBJECTIVE

We sought to assess where individuals tanned indoors and skin cancer risk by tanning device location.

METHODS

Multivariate logistic regression was conducted in 2 US case-control studies of melanoma (1161 cases, 1083 controls, ages 25-59 years) and early-onset basal cell carcinoma (375 cases, 382 controls, age<40 years) conducted between 2004 and 2010.

RESULTS

Most indoor tanners (86.4%-95.1%), especially younger individuals, tanned exclusively in businesses. Persons who used indoor tanning exclusively in businesses were at increased risk of melanoma (odds ratio 1.82, 95% confidence interval 1.47-2.26) and basal cell carcinoma (odds ratio 1.69, 95% confidence interval 1.15-2.48) compared with non-users. Melanoma risk was also increased in the small number who reported tanning indoors only at home relative to non-users (odds ratio 4.14, 95% confidence interval 1.75-9.78); 67.6% used sun lamps.

LIMITATIONS

Self-reported tanning and potential recall bias are limitations.

CONCLUSION

Business-only tanning, despite claims of "safe" tanning, was positively associated with a significant risk of melanoma and basal cell carcinoma. Home tanning was uncommon and mostly from sun lamps, which were rarely used by younger participants. Regardless of location, indoor tanning was associated with increased risk of skin cancer.

Dietary iron, iron homeostatic gene polymorphisms and the risk of advanced colorectal adenoma and cancer

Dietary iron intake and variation in iron homeostasis genes may affect colorectal neoplasia risk. We conducted two nested case-control studies within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial: one of advanced colorectal adenoma (1205 cases; 1387 controls) and one of colorectal cancer (370 cases; 401 controls). Iron intake was estimated with a food frequency questionnaire and genotyping was performed for 21 genes. Unconditional logistic regression was used to estimate odds ratio (OR) and 95% confidence intervals (95% CIs) for colorectal neoplasia risk within quartiles of intake. Several single nucleotide polymorphisms (SNPs) modified the association between iron intake and the risk of adenoma or cancer. Dietary iron was positively associated with colorectal adenoma among three SNPs of HEPHL1, including carriers of the AA genotype at rs7946162 (ORQ4-Q1 = 2.22, 95% CI 1.15-4.27, Ptrend = 0.03; Pinteraction = 0.10), the TT genotype at rs2460063 (ORQ4-Q1 = 2.39, 95% CI 1.26-4.54, Ptrend = 0.02; Pinteraction = 0.04) and the GG genotype at rs7127348 (ORQ4-Q1 = 2.40, 95% CI 1.23-4.67, Ptrend = 0.02; Pinteraction = 0.09). Heme iron was positively associated with colorectal cancer among those with GG genotypes for ACO1 rs10970985 (ORQ4-Q 1 = 2.45, 95% CI 3.40-8.06, Ptrend = 0.004; Pinteraction = 0.05). However, none of the associations were statistically significant after adjustment for multiple comparisons. Future studies should target the specific genes and SNPs for which the association was significant prior to multiple comparison correction.

Do nonmelanoma skin cancer survivors use tanning beds more often than the general public?

e20017

Background: Tanning bed use increases the incidence of nonmelanoma skin cancer (NMSC), however utilization of indoor tanning after diagnosis in this population is not well-studied. We sought to determine if tanning bed use among NMSC survivors differed from the general population. Methods: The National Health Interview Survey is an annual population-based survey that is representative of the civilian US population. We utilized the 2010 cancer supplement to evaluate self-reported tanning bed use in the previous 12 months in self-reported NMSC survivors compared to individuals without a history of skin cancer. Results: In 2010, 24,941 people were surveyed, 1.85% of whom had a self-reported history of NMSC. On univariate analysis, NMSC survivors were significantly less likely to use tanning beds in the previous 12 months (2.16 vs. 5.61%, p < 0.001). On multivariate analysis, however, NMSC survivors were equally likely to use tanning beds as those who had never had skin cancer (see Table). Conclusions: When controlling for other sociodemographic factors, NMSC survivors were no less likely to use tanning beds than the general population. These findings suggest a need to better educate NMSC survivors about the increased risk of future skin cancers with ongoing tanning bed use. [Table: see text]

Developing a heme iron database for meats according to meat type, cooking method and doneness level

BACKGROUND

Animal studies have demonstrated that iron may be related to carcinogenesis, and human studies found that heme iron can increase the formation of N-nitroso compounds, which are known carcinogens.

OBJECTIVES

One of the postulated mechanisms linking red meat intake to cancer risk involves iron. Epidemiologic studies attempt to investigate the association between heme iron intake and cancer by applying a standard factor to total iron from meat. However, laboratory studies suggest that heme iron levels in meat vary according to cooking method and doneness level. We measured heme iron in meats cooked by different cooking methods to a range of doneness levels to use in conjunction with a food frequency questionnaire to estimate heme iron intake.

METHODS

Composite meat samples were made to represent each meat type, cooking method and doneness level. Heme iron was measured using atomic absorption spectrometry and inductively coupled plasma-atomic emission spectrometry.

RESULTS

Steak and hamburgers contained the highest levels of heme iron, pork and chicken thigh meat had slightly lower levels, and chicken breast meat had the lowest.

CONCLUSIONS

Although heme iron levels varied, there was no clear effect of cooking method or doneness level. We outline the methods used to create a heme iron database to be used in conjunction with food frequency questionnaires to estimate heme iron intake in relation to disease outcome.

Meat-related mutagen exposure, xenobiotic metabolizing gene polymorphisms and the risk of advanced colorectal adenoma and cancer

Meat mutagens, including heterocyclic amines (HCAs), polycyclic aromatic hydrocarbons (PAHs) and N-nitroso compounds (NOCs), may be involved in colorectal carcinogenesis depending on their activation or detoxification by phase I and II xenobiotic metabolizing enzymes (XME). Using unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), we examined the intake of five meat mutagens and >300 single nucleotide polymorphisms (SNPs) in 18 XME genes in relation to advanced colorectal adenoma (1205 cases and 1387 controls) and colorectal cancer (370 cases and 401 controls) within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Dietary intake of meat mutagens was assessed using a food frequency questionnaire with a detailed meat-cooking module. An interaction was observed between 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) intake and the NAT1 polymorphism rs6586714 in the adenoma study (P(interaction) = 0.001). Among individuals carrying a GG genotype, high MeIQx intake was associated with a 43% increased risk of adenoma (95% CI 1.11-1.85, P(trend) = 0.07), whereas the reverse was observed among carriers of the A variant (OR = 0.50, 95% CI 0.30-0.84, P(trend) = 0.01). In addition, we observed some suggestive (P < 0.05) modifying effects for SNPs in other XME genes (UGT1A, CYP2E1, EPHX1, AHR and GSTM3), but these were not significant after adjustment for multiple testing. This large and comprehensive study of XME genes, meat mutagens and the risk of colorectal tumours found that a NAT1 polymorphism modified the association between MeIQx intake and colorectal adenoma risk.

Lessons learned from randomized clinical trials of micronutrient supplementation for cancer prevention

This review discusses the results of randomized clinical trials of supplemental micronutrients for cancer prevention completed over the past 20 years, including trials of beta-carotene and retinol, vitamins C and E, selenium, folic acid, and vitamin D. Some trials observed significant reductions in risk, whereas others observed significant increases in risk of the primary cancer endpoint. In considering these trials, it appears that supplementation targeted to populations with low status of the nutrient of interest may prevent cancer, whereas supplementation in populations with higher status or to achieve pharmacological exposures may promote cancer. Observational epidemiologic evidence coupled with these trial results supports the concept of a U-shaped curve for micronutrients in relation to cancer prevention. Based on these data, nutrient supplements are not currently recommended for cancer prevention in the general population. The hypothesis that groups with low nutrient status may benefit from supplementation has yet to be formally tested.

Lifetime history of indoor tanning in young people: a retrospective assessment of initiation, persistence, and correlates

Background

Despite educational and public health campaigns to convey the risks of indoor tanning, many individuals around the world continue to engage in this behavior. Few descriptive studies of indoor tanning have collected information pertaining to the lifetime history of indoor tanning, thereby limiting our ability to understand indoor tanning patterns and potentially target interventions for individuals who not only initiate, but continue to persistently engage in indoor tanning.

Methods

In-person interviews elicited detailed retrospective information on lifetime history of indoor tanning among white individuals (n = 401) under age 40 seen by a dermatologist for a minor benign skin condition. These individuals were controls in a case-control study of early-onset basal cell carcinoma. Outcomes of interest included ever indoor tanning in both males and females, as well as persistent indoor tanning in females - defined as females over age 31 who tanned indoors at least once in the last three or all four of four specified age periods (ages 11-15, 16-20, 21-30 and 31 or older). Multivariate logistic regression was used to identify sociodemographic and lifestyle correlates of ever and persistent indoor tanning in females.

Results

Approximately three-quarters (73.3%) of females and 38.3% of males ever tanned indoors, with a median age of initiation of 17.0 and 21.5, respectively. Among indoor tanners, 39.3% of females and 21.7% of males reported being burned while indoor tanning. Female ever indoor tanners were younger, had darker color eyes, and sunbathed more frequently than females who never tanned indoors. Using unique lifetime exposure data, 24.7% of female indoor tanners 31 and older persistently tanned indoors starting as teenagers. Female persistent indoor tanners drank significantly more alcohol, were less educated, had skin that tanned with prolonged sun exposure, and sunbathed outdoors more frequently than non-persistent tanners.

Conclusions

Indoor tanning was strikingly common in this population, especially among females. Persistent indoor tanners had other high-risk behaviors (alcohol, sunbathing), suggesting that multi-faceted behavioral interventions aimed at health promotion/disease prevention may be needed in this population.

Meat consumption and the risk of incident distal colon and rectal adenoma

Background:

Most studies of meat and colorectal adenoma have investigated prevalent events from a single screening, thus limiting our understanding of the role of meat and meat-related exposures in early colorectal carcinogenesis.

Methods:

Among participants in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial who underwent baseline and follow-up sigmoidoscopy (n=17 072), we identified 1008 individuals with incident distal colorectal adenoma. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between meat and meat-related components and incident distal colorectal adenoma using multivariate logistic regression.

Results:

We observed suggestive positive associations for red meat, processed meat, haeme iron, and nitrate/nitrite with distal colorectal adenoma. Grilled meat (OR=1.56, 95% CI=1.04–2.36), well or very well-done meat (OR=1.59, 95% CI=1.05–2.43), 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP) (OR=1.75, 95% CI=1.17–2.64), benzo[a]pyrene (OR=1.53, 95% CI=1.06–2.20), and total mutagenic activity (OR=1.57, 95% CI=1.03–2.40) were positively associated with rectal adenoma. Total iron (diet and supplements) (OR=0.69, 95% CI=0.56–0.86) and iron from supplements (OR=0.65, 95% CI=0.44–0.97) were inversely associated with any distal colorectal adenoma.

Conclusion:

Our findings indicate that several meat-related components may be most relevant to early neoplasia in the rectum. In contrast, total iron and iron from supplements were inversely associated with any distal colorectal adenoma.