IGF1 and risk of additional breast cancer in the WHEL study

IGF1, IGF-binding protein-3 (IGFBP-3), IGFBP-1, insulin, leptin, and adiponectin have been inconsistently associated with breast cancer incidence. We explore how these factors are related to breast cancer recurrence and how tamoxifen treatment is related to IGF1 levels among breast cancer survivors in the Women's Healthy Eating and Living (WHEL) study. A nested case-control design was used to match breast cancer cases (who had an additional breast cancer event) to controls. Baseline blood samples from 510 matched cases and controls were analyzed for IGF1 levels; a subset of 188 pairs were analyzed for five other hormones and binding proteins. Median follow-up was 7.3 years. Matching was on recruitment site, cancer stage, age at cancer diagnosis, dates of cancer diagnosis, and randomization. Cox proportional hazards regression models, stratified on case-control pair, were used to assess the associations. Insulin, IGFBP-1, IGFBP-3, leptin, and adiponectin did not significantly predict recurrence of breast cancer. IGF1 was positively, but not significantly, associated with recurrence (hazard ratio (HR): 1.33 (95% confidence interval (CI) 0.98-1.81)) in the unadjusted analyses. Adjusting for menopausal status and tamoxifen use attenuated the HR to 1.07 (95% CI 0.76-1.40). Analyses of case-control pairs with discordant tamoxifen use show opposing HR: IGF1 predicts higher risk of recurrence if cases did not receive tamoxifen treatment. In conclusion, no significant association was found between IGF1 levels, or other related factors, and risk of additional breast cancer among breast cancer survivors. Tamoxifen can confound analysis of IGF1 and recurrence. This supports re-evaluating significance of IGF1 to breast cancer recurrence.     

Increasing hookah use in California

Hookah use is gaining popularity nationwide. We determined the correlates and trends for hookah use from the California Tobacco Survey. Between 2005 and 2008 hookah use increased more than 40%, and in 2008, 24.5% of young men reported ever using a hookah. Hookah use was more common among the young (18-24 years), the educated, the non-Hispanic Whites, and the cigarette smokers. Hookah use is increasing in California, especially among young adults, and in 2008 reached the highest prevalence ever reported for both genders.     

Plasma carotenoids as biomarkers of intake of fruits and vegetables: ecological-level correlations in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE: The aim of this study was to assess the ability of a single 24-h dietary recall (24HDR) and food questionnaires (FQ) to predict plasma carotenoid levels at the ecological level by assessing the relationship between mean plasma carotenoid levels and mean intake of fruit and vegetables measured by 24HDR and FQ across 16 European regions. DESIGN: A random subsample of 3089 subjects was included, stratified by age and gender. They provided blood samples and dietary information between 1992 and 2000 as part of the European Prospective Investigation into Cancer and Nutrition. RESULTS: Using Spearman's correlation coefficients, the correlations between mean regional 24HDR fruit and vegetable variables and corresponding mean plasma carotenoid levels were generally higher than the correlations using FQ means. The highest correlation was between the 24HDR citrus fruit variable and beta-cryptoxanthin (r = 0.90). For 24HDR, total fruits and vegetables were highly correlated with lutein, zeaxanthin, and beta-cryptoxanthin (r = 0.83-0.87), while vegetables were more closely related with lutein (r = 0.69) and zeaxanthin (r = 0.68), and fruits correlated with zeaxanthin (r = 0.87) and beta-cryptoxanthin (r = 0.84). Root vegetables (r = 0.81) and total carrots (r = 0.71) were well correlated with alpha-carotene. In the multivariate models adjusting for age, body mass index, and season, and using observations of means stratified by sex and region, the association was generally higher for 24HDR compared to FQ. CONCLUSION: Mean regional intakes of fruits and vegetables in several European countries were closely correlated with corresponding mean plasma levels of individual carotenoids. Fruits and vegetables measured by 24HDR were generally better able to predict plasma carotenoids at the ecological level.     

Passive Smoking in Children: Effect of Avoidance Strategies at Home as Measured by Hair Nicotine Levels

Hair nicotine levels were studied among children, relative to their caregivers' reported exposure to environmental tobacco smoke. A total of 117 children, aged 3 months to 10 years, were recruited consecutively from hospital inpatients, and their respective parents or caregivers were interviewed. Degree of exposure to environmental tobacco smoke was assessed via questionnaire. Scalp hair samples were collected from children and were assayed for nicotine. Levels of nicotine in hair among children reportedly exposed to smokers were higher than levels among unexposed children (χ² = 26.46, p < .0001). In addition, hair nicotine levels were higher among children with mothers who smoked, compared with those whose mothers did not smoke. Whether household members smoked outside or inside the house had no significant effect on hair nicotine levels of children. Hair nicotine levels differed between children who were reportedly unexposed to environmental tobacco smoke at home and those who were exposed. Smoking outside the home, as reported by parents, did not cause a reduction in nicotine levels in the hair of children.     

Validity and systematic error in measuring carotenoid consumption with dietary self-report instruments

Vegetables and fruits are rich in carotenoids, a group of compounds thought to protect against cancer. Studies of diet-disease associations need valid and reliable instruments for measuring dietary intake. The authors present a measurement error model to estimate the validity (defined as correlation between self-reported intake and "true" intake), systematic error, and reliability of two self-report dietary assessment methods. Carotenoid exposure is measured by repeated 24-hour recalls, a food frequency questionnaire (FFQ), and a plasma marker. The model is applied to 1,013 participants assigned between 1995 and 2000 to the nonintervention arm of the Women's Healthy Eating and Living Study, a randomized trial assessing the impact of a low-fat, high-vegetable/fruit/fiber diet on preventing new breast cancer events. Diagnostics including graphs are used to assess the goodness of fit. The validity of the instruments was 0.44 for the 24-hour recalls and 0.39 for the FFQ. Systematic error accounted for over 22% and 50% of measurement error variance for the 24-hour recalls and FFQ, respectively. The use of either self-report method alone in diet-disease studies could lead to substantial bias and error. Multiple methods of dietary assessment may provide more accurate estimates of true dietary intake.     

Is the hair nicotine level a more accurate biomarker of environmental tobacco smoke exposure than urine cotinine?

STUDY OBJECTIVE: The aim of this study was to compare the two biomarkers of exposure to environmental tobacco smoke (ETS); urine cotinine and hair nicotine, using questionnaires as the standard. DESIGN: A cross sectional study of children consecutively admitted to hospital for lower respiratory illnesses during the period of the study. SETTINGS: Three regional hospitals in the larger Wellington area, New Zealand. PARTICIPANTS: Children aged 3-27 months and admitted to the above hospitals during August 1997 to October 1998. A total of 322 children provided 297 hair samples and 158 urine samples. MAIN RESULTS: Hair nicotine levels were better able to discriminate the groups of children according to their household's smoking habits at home (no smokers, smoke only outside the home, smoke inside the house) than urine cotinine (Kruskall-Wallis; chi(2)=142.14, and chi(2)=49.5, respectively (p<0.0001)). Furthermore, hair nicotine levels were more strongly correlated with number of smokers in the house, and the number of cigarettes smoked by parents and other members of the child's households. Hair nicotine was better related to the questionnaire variables of smoking in a multivariate regression model (r(2)=0.55) than urine cotinine (r(2)=0.31). CONCLUSIONS: In this group of young children, hair nicotine was a more precise biomarker of exposure to ETS than urine cotinine levels, using questionnaire reports as the reference. Both biomarkers indicate that smoking outside the house limits ETS exposure of children but does not eliminate it.     

Dietary intake, supplement use, and survival among women diagnosed with early-stage breast cancer

Previous studies examining the relationship between micronutrient intakes and survival following diagnosis of breast cancer have reported mixed results. This may be partly due to considerable variance in amounts of micronutrients consumed from diet and supplements across studies. Early-stage breast cancer survivors (N = 3081) completed four 24-h dietary and supplement recalls at the baseline assessment (1995 to 2000) and were followed for a median of 9.0 yr. Mean micronutrient intakes were compared to dietary reference intakes (DRI) to assess micronutrient adequacy for both users and nonusers of supplements. Cox regressions were performed to assess whether intakes of selected micronutrients were associated with all-cause mortality. Four hundred and twelve deaths occurred between baseline and August 2009. Among these women, more supplement users had adequate micronutrient intakes than nonusers for 15 out of 17 micronutrients. Less than 10% of supplement users (<2% of nonsupplement users) reported levels that exceeded the tolerable upper limit for each micronutrient except magnesium. After adjusting for age, tumor characteristics, and health status variables, micronutrient intakes were not significantly associated with all-cause mortality. Dietary supplements may improve overall micronutrient intakes of breast cancer survivors. However, vitamin and mineral intakes were not associated with all-cause mortality.