Association of Diet Quality with Risk of Incident Rheumatoid Arthritis in the Women's Health Initiative.

BACKGROUND: Various foods and nutrients are linked with higher or lower risk of rheumatoid arthritis (RA), yet these associations are inconsistent across studies. Limited research has been done evaluating the association between diet quality and RA in a larger scale prospective study on postmenopausal women. OBJECTIVE: The objective of this study was to evaluate the association between dietary quality and risk of incident RA in postmenopausal women. DESIGN: This is a prospective cohort study as part of the Women's Health Initiative (WHI) with an average follow-up time of 8.1 years. Baseline diet was measured using a food frequency questionnaire (FFQ). Diet quality was evaluated by the Healthy Eating Index (HEI) - 2015 total score. In addition, intake of food groups/nutrients that align with HEI-2015 components was assessed. PARTICIPANTS/SETTING: 109,591 postmenopausal women were included in this study, which was conducted at various clinical centers across the US with recruitment from 1993 to 1998. WHI participants who were missing outcome data, had unreliable/missing FFQ data, or had RA at baseline were excluded. MAIN OUTCOME MEASURES: The primary outcome measure is incident RA. STATISTICAL ANALYSES PERFORMED: Multivariable Cox proportional regression analysis was performed evaluating the association of diet quality with self-reported physician-diagnosed RA after adjusting for age, race, ethnicity, education status, income, and body mass index (BMI). RESULTS: During 857,517 person-years of follow-up, 5,823 incident RA cases were identified. After adjustment for multiple comparisons, compared to quartile 1, quartiles 2, 3, and 4 of the HEI-2015 total scores were associated with a lower RA risk of 1%, 10%, and 19%, respectively (p-trend < 0.001). Greater consumption of total fruits (p-trend=0.014), whole fruits (p-trend<0.0002), total vegetables (p-trend=0.008), greens and beans (p-trend<0.0002), whole grains (p-trend=0.008), and dairy (p-trend=0.018) were significantly associated with lower rates of incident RA. Conversely, higher consumption of saturated fat (p-trend=0.002) was significantly associated with higher rates of incident RA. CONCLUSION: A higher quality diet reflected by higher HEI-2015 total scores was inversely associated with incident rheumatoid arthritis in post-menopausal women.

Use of non-steroidal anti-inflammatory drugs and pancreatic cancer risk in the Women's Health Initiative.

BACKGROUND: Pancreatic cancer is among the most fatal human cancers and the fourth leading cause of cancer death in the United States. Evidence suggests that chronic inflammation may play a role in pancreatic carcinogenesis, and its inhibition through non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pancreatic cancer incidence. METHODS: We examined associations of total and individual NSAIDs with pancreatic cancer risk among postmenopausal women participating in the Women's Health Initiative observational study and clinical trials cohorts. Among 117,452 women, ages 55-79 years, 727 incident pancreatic cancer cases were reported over 18 years of follow-up. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between NSAIDs and pancreatic cancer risk. RESULTS: Relative to non-use, consistent use of any NSAID was inversely associated with pancreatic cancer risk (HR 0.71, 95% CI: 0.59-0.87), primarily driven by strong associations for aspirin use (HR 0.67, 95% CI: 0.52-0.86). Use of total or individual non-aspirin NSAIDs were not associated with pancreatic cancer. Upon stratified analysis, we observed stronger associations for NSAIDs among participants with prevalent diabetes (HR 0.28, 95% CI: 0.10-0.75) relative to those without (HR 0.75, 95% CI: 0.61-0.92; P-interaction=0.03). CONCLUSIONS: Additional large prospective studies with careful measurement of NSAID type, dose, and frequency are needed to further investigate the possibility of added benefit among individuals diagnosed with diabetes. IMPACT: This study adds to existing evidence from prospective studies and clinical trials suggesting that use of aspirin may provide moderate benefit for pancreatic cancer prevention.

Testing the feasibility of mobile ecological momentary assessment for symptom burden and management among metastatic cancer patients.

Background: Individuals who have metastatic cancer experience substantial physical and psychological distress (e.g., pain, depression, anxiety) from their disease and its treatment compared to patients with less advanced disease. As the burden of symptoms varies over time, ecological momentary assessment (EMA) may be used to better understand patients' symptom trajectories, complimenting traditional longitudinal data collection methods. However, few have used EMA in patients with metastatic disease. The current study adds to the existing literature by exploring interrelated, common cancer-related symptoms of pain, anxiety, and depression and use of cannabis-based products, opioid medications, other (nonopioid) pain medications, and medications for anxiety or depression. Methods: An eight-day prospective observational feasibility study was conducted among 50 patients with metastatic cancer recruited from seven solid cancer clinics at The Ohio State University Comprehensive Cancer Center. Participants completed a week of interval-contingent mobile EMA, administered daily at 9 a.m., 3 p.m., and 8 p.m., and a comprehensive interviewer-administered questionnaire on Day 8. Participants were queried on their symptom burden and management strategies (i.e., use of medications and cannabis). We considered EMA to be feasible if a priori retention (80%) and adherence goals (75%) were met. Results: Seventy-nine percent of eligible patients contacted enrolled in the study (n = 50 of 63). Among those enrolled, 92% were retained through Day 8 and 80% completed >90% of EMAs, exceeding a priori objectives. Participants' average pain, anxiety, and depressive symptoms across the week of EMA ranged from 1.7 to 1.8 (1 to 5 scale). Symptoms varied little by day or time of administration. On Day 8, significant proportions of participants reported past-week use of medications and cannabis for symptom management. Conclusions: Participants exceeded a priori adherence and retention objectives, indicating that mobile EMA is feasible among metastatic cancer patients, addressing a gap in the existing literature and informing future research. Restricting eligibility to participants with a minimum cutoff of symptom burden may be warranted to increase observations of symptom variability and provide opportunities for future health interventions. Future research is needed to test the acceptability and quality of data over a longer study period in this patient population.

Current cannabis use and pain management among US cancer patients.

BACKGROUND: National studies reporting the prevalence of cannabis use have focused on individuals with a history of cancer without distinction by their treatment status, which can impact symptom burden. While pain is a primary motivation to use cannabis in cancer, the magnitude of its association with cannabis use remains understudied. METHODS: We examined cannabis use and pain management among 5523 respondents of the Behavioral Risk Factor Surveillance System with a cancer history. Survey-weighted prevalence proportions of respondents' cannabis use are reported, stratified on cancer treatment status. Regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs) of cancer-related pain and cannabis use. RESULTS: Cannabis use was slightly more prevalent in those undergoing active treatment relative to those who were not undergoing active treatment (9.3% vs. 6.2%; P=0.05). Those under active treatment were more likely to use cannabis medicinally (71.6% vs. 50.0%; P=0.03). Relative to those without cancer-related pain, persons with pain under medical control (OR 2.1, 95% CI, 1.4-3.2) or uncontrolled pain were twice as likely to use cannabis (OR 2.0, 95% CI, 1.1-3.5). CONCLUSIONS: Use of cannabis among cancer patients may be related to their treatment and is positively associated with cancer-related pain. Future research should investigate the associations of cannabis use, symptom burden, and treatment regimens across the treatment spectrum to facilitate interventions.

Associations of Cancer Patients' Demographic and Clinical Characteristics With Cannabis-Related Interest and Behaviors.

Background: Cannabis interest and use is increasing in the United States, yet research on its use among cancer patients is limited. Methods: Individuals with cancer completed an anonymous cross-sectional questionnaire. Multivariable logistic regressions estimated odds ratios (OR) between patients' demographic and clinical characteristics with cannabis-related interest, current use, and provider recommendation. Results: Participants (n = 943) were, on average, 61.7 years old. Older patients were less likely to use cannabis products (OR = 0.42, confidence interval [95% CI]: 0.26-0.69) and less likely to be interested in cannabis (OR = 0.60, 95% CI: 0.44-0.84) than younger patients. Those with higher education were less likely to be using cannabis (OR = 0.41, 95% CI: 0.25-0.67) and less likely to have received a provider recommendation of cannabis use than the least educated (OR = 0.38, 95% CI: 0.19-0.76). Cancer spread and type were significant correlates of provider recommendation of cannabis use. Conclusions: Additional research is warranted to better understand cancer patients' motivations for cannabis use and interest.

Accelerated epigenetic age, inflammation, and gene expression in lung: comparisons of smokers and vapers with non-smokers.

BACKGROUND: Cigarette smoking and aging are the main risk factors for pulmonary diseases, including cancer. Epigenetic aging may explain the relationship between smoking, electronic cigarette vaping, and pulmonary health. No study has examined smoking and vaping-related epigenetic aging in relation to lung biomarkers. METHODS: Lung epigenetic aging measured by DNA methylation (mAge) and its acceleration (mAA) was assessed in young (age 21-30) electronic cigarette vapers (EC, n = 14, including 3 never-smoking EC), smokers (SM, n = 16), and non-EC/non-SM (NS, n = 39). We investigated relationships of mAge estimates with chronological age (Horvath-mAge), lifespan/mortality (Grim-mAge), telomere length (TL-mAge), smoking/EC history, urinary biomarkers, lung cytokines, and transcriptome. RESULTS: Compared to NS, EC and SM had significantly older Grim-mAge, shorter TL-mAge, significantly accelerated Grim-mAge and decelerated TL-mAge. Among SM, Grim-mAA was associated with nicotine intake and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). For EC, Horvath-mAA was significantly correlated with puffs per day. Overall, cytokines (IL-1ß, IL-6, and IL-8) and 759 transcripts (651 unique genes) were significantly associated with Grim-mAA. Grim-mAA-associated genes were highly enriched in immune-related pathways and genes that play a role in the morphology and structures of cells/tissues. CONCLUSIONS: Faster lung mAge for SM is consistent with prior studies of blood. Faster lung mAge for EC compared to NS indicates possible adverse pulmonary effects of EC on biological aging. Our findings support further research, particularly on epigenetic markers, on effects of smoking and vaping on pulmonary health. Given that most EC are former smokers, further study is needed to understand unique effects of electronic cigarettes on biological aging.

Marijuana and Cannabidiol Use Prevalence and Symptom Management Among Patients with Cancer.

Symptoms such as pain, nausea, and anxiety are common in individuals with cancer. Treatment of these issues is often challenging. Cannabis products may be helpful in reducing the severity of these symptoms. While some studies include data on the prevalence of cannabis use among patients with cancer, detailed data remain limited, and none have reported the prevalence of cannabidiol (CBD) use in this population. Adult patients with cancer attending eight clinics at a large, NCI-designated Comprehensive Cancer Center completed a detailed, cannabis-focused questionnaire between 2021 and 2022. Eligible participants were diagnosed with invasive cancer and treated in the past 12 months. Summary statistics were calculated to describe the sample regarding cannabis use. Approximately 15% (n = 142) of consented patients (n = 934) reported current cannabis use (defined as use within the past 12 months). Among which, 75% reported cannabis use in the past week. Among current cannabis users, 39% (n = 56; 6% overall) used CBD products. Current users reported using cannabis a median of 4.5 (interquartile range: 0.6­7.0) days/week, 2.0 (1.0­3.0) times per use/day, and for 3 years (0.8­30.0). Use patterns varied by route of administration. Patients reported moderate to high relief of symptoms with cannabis use. This study is the most detailed to date in terms of cannabis measurement and provides information about the current state of cannabis use in active cancer. Future studies should include complete assessments of cannabis product use, multiple recruitment sites, and diverse patient populations. SIGNIFICANCE: Clinicians should be aware that patients are using cannabis products and perceive symptom relief with its use.

Pre-diagnosis lipid levels and mortality after obesity-related cancer diagnosis in the Women's Health Initiative cardiovascular disease biomarker cohort.

BACKGROUND: Published studies have demonstrated inconclusive relationships between serum lipid levels and mortality after cancer. METHODS: The primary objective was to evaluate the relationship between fasting lipid levels and mortality after cancer. Data were obtained on baseline lipids and outcomes after cancer from 1263 postmenopausal women diagnosed with 13 obesity-related cancers who were part of the Women's Health Initiative (WHI) lipid biomarkers cohort. Obesity-related cancers included incident invasive cancers of the breast, colorectum, endometrium, esophagus (adenocarcinoma), kidney, liver, gallbladder, pancreas, ovaries, small intestine, thyroid, stomach, as well as multiple myeloma. Baseline lipid measurements included high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, and non-HDL-cholesterol. Outcomes were all cause, cancer-specific, and CVD mortality. Multivariable Cox proportional hazards models were used to measure associations between lipid levels and mortality (all cause, cancer, and CVD) after a cancer diagnosis, with lipids analyzed as continuous variables. RESULTS: Among women with obesity-related cancer, there were 707 deaths, of which 379 (54%) were due to cancer and 113 (16%) were due to CVD. Mean time from blood draw to cancer diagnosis was 5.1 years (range: 0.05-10 years). LDL-C values above the 95th percentile were associated with higher risk of all-cause mortality (p < 0.001), and cancer-specific mortality (p < 0.001), but not mortality due to CVD. Non-HDL-C values above the 65th percentile were associated with higher risk of all-cause mortality (p = 0.01) and mortality due to CVD (p = 0.003), but not cancer-specific mortality (p = 0.37). HDL-C values above the 95th percentile were associated with lower all-cause mortality (p = 0.002), and above the 65th percentile with lower cancer-specific mortality (p = 0.003), but no significant relationship with mortality due to CVD was observed. CONCLUSIONS: The relationship between pre-diagnosis fasting lipid levels and mortality after cancer diagnosis is complex. These results suggest that improved lipid control through lifestyle and anti-lipid medications could have a meaningful impact on outcomes after cancer.

A Pilot Cross-Sectional Study of Immunological and Microbiome Profiling Reveals Distinct Inflammatory Profiles for Smokers, Electronic Cigarette Users, and Never-Smokers.

Smokers (SM) have increased lung immune cell counts and inflammatory gene expression compared to electronic cigarette (EC) users and never-smokers (NS). The objective of this study is to further assess associations for SM and EC lung microbiomes with immune cell subtypes and inflammatory gene expression in samples obtained by bronchoscopy and bronchoalveolar lavage (n = 28). RNASeq with the CIBERSORT computational algorithm were used to determine immune cell subtypes, along with inflammatory gene expression and microbiome metatranscriptomics. Macrophage subtypes revealed a two-fold increase in M0 (undifferentiated) macrophages for SM and EC users relative to NS, with a concordant decrease in M2 (anti-inflammatory) macrophages. There were 68, 19, and 1 significantly differentially expressed inflammatory genes (DEG) between SM/NS, SM/EC users, and EC users/NS, respectively. CSF-1 and GATA3 expression correlated positively and inversely with M0 and M2 macrophages, respectively. Correlation profiling for DEG showed distinct lung profiles for each participant group. There were three bacteria genera-DEG correlations and three bacteria genera-macrophage subtype correlations. In this pilot study, SM and EC use were associated with an increase in undifferentiated M0 macrophages, but SM differed from EC users and NS for inflammatory gene expression. The data support the hypothesis that SM and EC have toxic lung effects influencing inflammatory responses, but this may not be via changes in the microbiome.

Dietary omega-3 fatty acids and endometrial cancer risk in the Epidemiology of Endometrial Cancer Consortium: An individual-participant meta-analysis.

BACKGROUND: Limited data from prospective studies suggest that higher dietary intake of long-chain omega-3 polyunsaturated fatty acids (LCn3PUFA), which hold anti-inflammatory properties, may reduce endometrial cancer risk; particularly among certain subgroups characterized by body mass and tumor pathology. MATERIALS AND METHODS: Data from 12 prospective cohort studies participating in the Epidemiology of Endometrial Cancer Consortium were harmonized as nested case-control studies, including 7268 endometrial cancer cases and 26,133 controls. Habitual diet was assessed by food frequency questionnaire, from which fatty acid intakes were estimated. Two-stage individual-participant data mixed effects meta-analysis estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) through logistic regression for associations between study-specific energy-adjusted quartiles of LCn3PUFA and endometrial cancer risk. RESULTS: Women with the highest versus lowest estimated dietary intakes of docosahexaenoic acid, the most abundant LCn3PUFA in diet, had a 9% increased endometrial cancer risk (Quartile 4 vs. Quartile 1: OR 1.09, 95% CI: 1.01-1.19; P trend = 0.04). Similar elevated risks were observed for the summary measure of total LCn3PUFA (OR 1.07, 95% CI: 0.99-1.16; P trend = 0.06). Stratified by body mass index, higher intakes of LCn3PUFA were associated with 12-19% increased endometrial cancer risk among overweight/obese women and no increased risk among normal-weight women. Higher associations appeared restricted to White women. The results did not differ by cancer grade. CONCLUSION: Higher dietary intakes of LCn3PUFA are unlikely to reduce endometrial cancer incidence; rather, they may be associated with small to moderate increases in risk in some subgroups of women, particularly overweight/obese women.

Supplemental B-Vitamins and Risk of Upper Gastrointestinal Cancers in the Women's Health Initiative.

B-vitamins contribute to DNA synthesis, maintenance, and regulation. Few studies have examined associations of supplemental sources of B-vitamins with the incidence of upper gastrointestinal (GI) cancers [including gastric (GCA) and esophageal (ECA) cancers]; the only prior study to comprehensively examine such intakes reported potential elevated risks of ECA. We examined 159,401 postmenopausal women, ages 50-79 years at baseline, including 302 incident GCA and 183 incident ECA cases, over 19 years of follow-up within the Women's Health Initiative observational study and clinic trials. Adjusted Cox regression models estimated hazard ratios (HR) and 95% confidence intervals (CI) for associations of supplemental B-vitamins [riboflavin (B2), pyridoxine (B6), folic acid (B9), or cobalamin (B12)] with GCA and ECA risk, respectively. Although HRs were generally below 1.0, we observed no statistically significant associations between supplemental intakes of any of the evaluated B-vitamins with the risk of GCA or ECA. As the first prospective study to comprehensively assess these associations, our findings do not corroborate prior research indicating potential harm from supplemental B-vitamin intake for upper GI cancer risk. This study adds evidence that supplemental intakes of B-vitamins may be used by postmenopausal women without regard to their relationship with upper GI cancer risk.

Proton Pump Inhibitor Use and Obesity-Associated Cancer in the Women's Health Initiative.

Proton pump inhibitors (PPIs) have off-target activity on fatty acid synthase (FASN), a critical enzyme in energy balance and cancer growth. We evaluated risk of common obesity-related cancers: breast, colorectal (CRC), and endometrial, with use of PPI and histamine-2 receptor antagonists (H2RA) in 124,931 postmenopausal women enrolled in the Women's Health Initiative. Incident cancer cases were physician-adjudicated. Cox proportional hazards models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for cancer incidence after year 3. There were 7956 PPI ever users and 9398 H2RA only users. Ever use of either PPI or H2RA was not associated with risk of breast cancer (n = 9186) nor risk of endometrial cancer (n = 1231). The risk of CRC (n = 2280) was significantly lower in PPI users (HR = 0.75, 95% CI = 0.61-0.92), but not in H2RA users (HR = 1.13, 95% CI = 0.97-1.31). The association of PPI use with CRC was apparent regardless of BMI or NSAID use, and was stronger with longer PPI duration (p = 0.006) and potency (p = 0.005). The findings that PPI use, but not H2RA use, demonstrate an inverse dose-response relationship with risk of CRC is consistent with preclinical data showing FASN inhibition prevents colon cancer progression and supports a role of PPI in CRC prevention.

Lung mitochondrial DNA copy number, inflammatory biomarkers, gene transcription and gene methylation in vapers and smokers.

BACKGROUND: Mitochondrial DNA copy number (mtCN) maintains cellular function and homeostasis, and is linked to nuclear DNA methylation and gene expression. Increased mtCN in the blood is associated with smoking and respiratory disease, but has received little attention for target organ effects for smoking or electronic cigarette (EC) use. METHODS: Bronchoscopy biospecimens from healthy EC users, smokers (SM), and never-smokers (NS) were assessed for associations of mtCN with mtDNA point mutations, immune responses, nuclear DNA methylation and gene expression using linear regression. Ingenuity pathway analysis was used for enriched pathways. GEO and TCGA respiratory disease datasets were used to explore the involvement of mtCN-associated signatures. FINDINGS: mtCN was higher in SM than NS, but EC was not statistically different from either. Overall there was a negative association of mtCN with a point mutation in the D-loop but no difference within groups. Positive associations of mtCN with IL-2 and IL-4 were found in EC only. mtCN was significantly associated with 71,487 CpGs and 321 transcripts. 263 CpGs were correlated with nearby transcripts for genes enriched in the immune system. EC-specific mtCN-associated-CpGs and genes were differentially expressed in respiratory diseases compared to controls, including genes involved in cellular movement, inflammation, metabolism, and airway hyperresponsiveness. INTERPRETATION: Smoking may elicit a lung toxic effect through mtCN. While the impact of EC is less clear, EC-specific associations of mtCN with nuclear biomarkers suggest exposure may not be harmless. Further research is needed to understand the role of smoking and EC-related mtCN on lung disease risks. FUNDING: The National Cancer Institute, the National Heart, Lung, and Blood Institute, the Food and Drug Administration Center for Tobacco Products, the National Center For Advancing Translational Sciences, and Pelotonia Intramural Research Funds.

Saliva and Lung Microbiome Associations with Electronic Cigarette Use and Smoking.

The microbiome has increasingly been linked to cancer. Little is known about the lung and oral cavity microbiomes in smokers, and even less for electronic cigarette (EC) users, compared with never-smokers. In a cross-sectional study (n = 28) of smokers, EC users, and never-smokers, bronchoalveolar lavage and saliva samples underwent metatranscriptome profiling to examine associations with lung and oral microbiomes. Pairwise comparisons assessed differentially abundant bacteria species. Total bacterial load was similar between groups, with no differences in bacterial diversity across lung microbiomes. In lungs, 44 bacteria species differed significantly (FDR < 0.1) between smokers/never-smokers, with most decreased in smokers. Twelve species differed between smokers/EC users, all decreased in smokers of which Neisseria sp. KEM232 and Curvibacter sp. AEP1-3 were observed. Among the top five decreased species in both comparisons, Neisseria elongata, Neisseria sicca, and Haemophilus parainfluenzae were observed. In the oral microbiome, 152 species were differentially abundant for smokers/never-smokers, and 17 between smokers/electronic cigarette users, but only 21 species were differentially abundant in both the lung and oral cavity. EC use is not associated with changes in the lung microbiome compared with never-smokers, indicating EC toxicity does not affect microbiota. Statistically different bacteria in smokers compared with EC users and never-smokers were almost all decreased, potentially due to toxic effects of cigarette smoke. The low numbers of overlapping oral and lung microbes suggest that the oral microbiome is not a surrogate for analyzing smoking-related effects in the lung. PREVENTION RELEVANCE: The microbiome affects cancer and other disease risk. The effects of e-cig usage on the lung microbiome are essentially unknown. Given the importance of lung microbiome dysbiosis populated by oral species which have been observed to drive lung cancer progression, it is important to study effects of e-cig use on microbiome.

The Associations between Dietary Supplement Use, Diet Quality, and Health-Related Quality of Life among Older Female Cancer Survivors.

Evidence-based guidelines for cancer survivorship do not recommend dietary supplementation, yet older cancer survivors report high prevalence of dietary supplement use, specifically multivitamin (MVM), calcium, and vitamin D. Female cancer survivors (≥65 years) who were ≤5 years post-cancer diagnosis completed questionnaires assessing health-related quality of life (HRQoL), diet quality, and supplement intake. Intakes of MVM, calcium, and vitamin D supplementation were 61.4%, 76.9%, and 35.3%, respectively. Women who used MVM supplements had significantly higher dietary quality mean scores for total vegetables (4.5 ± 0.9 to 4.1 ± 1.1), greens and beans (4.1 ± 1.3 to 3.6 ± 1.6), whole fruit (4.7 ± 0.8 to 4.3 ± 1.3), and whole grains (2.9 ± 1.8 to 2.3 ± 1.6) than those who did not use these supplements. After controlling for demographic and clinical variables, the odds of MVM use was 1.07 times greater among those women who had higher total HEI scores. Participants with lower HRQoL were 4% more likely to take an MVM. Understanding the prevalence of supplementation, associations with diet quality, and perceived benefits of supplementation may help healthcare providers in educating survivors and promoting adherence to the evidence-based guidelines.

Adiposity and breast, endometrial, and colorectal cancer risk in postmenopausal women: Quantification of the mediating effects of leptin, C-reactive protein, fasting insulin, and estradiol.

BACKGROUND: Mechanisms underlying the adiposity-cancer relationship are incompletely understood. We quantified the mediating roles of C-reactive protein (CRP), leptin, fasting insulin, and estradiol in the effect of adiposity on estrogen receptor (ER)-positive breast, endometrial, and colorectal cancer risk in postmenopausal women. METHODS: We used a case-cohort study within the Women's Health Initiative Observational Study, analyzed as a cumulative sampling case-control study. The study included 188 breast cancer cases, 98 endometrial cancer cases, 193 colorectal cancer cases, and 285 controls. Interventional indirect and direct effects on the risk ratio (RR) scale were estimated using causal mediation analysis. RESULTS: For breast cancer, the total effect RR for BMI ≥30 versus ≥18.5-<25 kg/m2 was 1.87 (95%CI,1.11-3.13). The indirect effect RRs were 1.38 (0.79-2.33) through leptin and CRP, 1.58 (1.17-2.43) through insulin, and 1.11 (0.98-1.30) through estradiol. The direct effect RR was 0.82 (0.39-1.68). For endometrial cancer, the total effect RR was 2.12 (1.12-4.00). The indirect effect RRs were 1.72 (0.85-3.98) through leptin and CRP, 1.42 (0.96-2.26) through insulin, and 1.24 (1.03-1.65) through estradiol. The direct effect RR was 0.70 (0.23-2.04). For colorectal cancer, the total effect RR was 1.70 (1.03-2.79). The indirect effect RRs were 1.04 (0.61-1.72) through leptin and CRP, 1.36 (1.00-1.88) through insulin, and 1.02 (0.88-1.17) through estradiol. The direct effect RR was 1.16 (0.58-2.43). CONCLUSION: Leptin, CRP, fasting insulin, and estradiol appear to mediate the effect of high BMI on cancer risk to different extents, with likely varying degrees of importance between cancers. These insights might be important in developing interventions to modify obesity-associated cancer risk in postmenopausal women.

Vitamin B12 Supplementation and Vitamin B12 Blood Serum Levels: Evaluation of Effect Modification by Gender and Smoking Status.

Research suggests that high intake of supplemental vitamin B12 may be associated with increased risk of cancer, with some evidence that this association may vary by gender and smoking status. This investigation evaluates if similar patterns in association are observed for data for 11,757 adults from the National Health and Nutrition Examination Survey (1999-2006). Survey-weighted multivariable-adjusted linear regression was used to evaluate the association between regular B12 supplement use and log-transformed serum B12 levels. Persons taking vitamin B12 through a multivitamin/multimineral (MVMM) had a median supplemental intake of 12 mcg/day (Q1: 6, Q3: 25), compared to 100 mcg/day (Q1: 22, Q3: 500) for persons reporting supplemental B12 intake through a MVMM-exclusive source. MVMM users had a geometric mean serum B12 26% (95% CI: 23%-30%) higher than nonusers, whereas MVMM-exclusive users' geometric mean was 61% (95% CI: 53%-70%) higher than nonusers (p-trend < 0.001). Although a positive trend (p-trend < 0.001) was observed for both men and women, the association was stronger among women (p-interaction < 0.001). No interaction was observed for smoking status (p-interaction = 0.45). B12 supplementation is associated with higher levels of serum B12, with significant interaction by gender but not smoking. Further work is needed to better understand the interplay of B12 and gender.