Scott V. Adams

Cadmium Exposure and Cancer Mortality in the Third National Health and Nutrition Examination Survey Cohort

Objective This study examined prospective data from the Third National Health and Nutrition Examination Survey (NHANES III) cohort to investigate the relationship between cadmium exposure and cancer mortality, and the specific cancers associated with cadmium exposure, in the general population. Methods Vital status and cause of death through 31 December 2006 were obtained by the National Center for Health Statistics for NHANES III participants. The cadmium concentration of spot urine samples was measured and corrected for urine creatinine (uCd). Weighted Cox proportional hazards regression with age as the time metric was applied to estimate sex-specific adjusted HRs (aHRs) of mortality associated with uCd for all cancers and the cancers responsible for the most deaths in the USA. Estimates were stratified by smoking history and adjusted for education, body mass index and race. Results uCd was associated with cancer mortality (aHR per twofold higher uCd (95% CI), men: 1.26 (1.07 to 1.48); women: 1.21 (1.04 to 1.42)). In men, mortality from lung cancer, pancreatic cancer and non-Hodgkin lymphoma was associated with uCd; an association with leukaemia mortality was suggested. In women, associations were suggested with mortality due to lung cancer, leukaemia, ovarian and uterine cancer, but evidence was weaker than in men. Conclusions Cadmium appears to be associated with overall cancer mortality in men and women, but the specific cancers associated differ between men and women, suggesting avenues for future research. Limitations of the study include the possibility of uncontrolled confounding by cigarette smoking or other factors, and the limited number of deaths due to some cancers.

Differences in Epidemiologic Risk Factors for Colorectal Adenomas and Serrated Polyps by Lesion Severity and Anatomical Site

Using a case-control design, we evaluated differences in risk factors for colorectal polyps according to histological type, anatomical site, and severity. Participants were enrollees in the Group Health Cooperative aged 20-79 years who underwent colonoscopy in Seattle, Washington, between 1998 and 2007 and comprised 628 adenoma cases, 594 serrated polyp cases, 247 cases with both types of polyps, and 1,037 polyp-free controls. Participants completed a structured interview, and polyps were evaluated via standardized pathology review. We used multivariable polytomous logistic regression to compare case groups with controls and with the other case groups. Factors for which the strength of the association varied significantly between adenomas and serrated polyps were sex (P < 0.001), use of estrogen-only postmenopausal hormone therapy (P = 0.01), and smoking status (P < 0.001). For lesion severity, prior endoscopy (P < 0.001) and age (P = 0.05) had significantly stronger associations with advanced adenomas than with nonadvanced adenomas; and higher education was positively correlated with sessile serrated polyps but not with other serrated polyps (P = 0.02). Statistically significant, site-specific associations were observed for current cigarette smoking (P = 0.05 among adenomas and P < 0.001 among serrated polyps), postmenopausal estrogen-only therapy (P = 0.01 among adenomas), and obesity (P = 0.01 among serrated polyps). These findings further illustrate the epidemiologic heterogeneity of colorectal neoplasia and may help elucidate carcinogenic mechanisms for distinct pathways.

Cadmium blood and urine concentrations as measures of exposure: NHANES 1999–2010

Exposure to cadmium, a heavy metal present in cigarettes, can be assessed in both urine and blood. Few studies have compared the properties of concurrent measurements of urine cadmium (uCd) and blood cadmium (bCd) in relation to the duration and timing of a known exposure. In this study, bCd and uCd were modeled with data from the National Health and Nutrition Examination Survey (1999–2010). Adjusted geometric mean bCd and uCd were estimated from regression results. Each 1% higher geometric mean uCd was associated with 0.50% (95% confidence interval: 0.47%–0.54%; R2=0.30) higher bCd. In male never-smokers, bCd was 69% (59%–81%) and uCd was 200% (166%–234%) higher at age ≥70 years versus 20–29 years. Ten pack-years (py) of smoking were associated with 13.7% (10.0%–17.4%) higher bCd and 16.8% (12.6%–21.1%) higher uCd in male smokers. The first year after smoking cessation was associated with 53% (48%–58%) lower bCd and 23% (14%–33%) lower uCd in representative males aged 55 years with 20 py smoking. Smoking in the previous 5 days was associated with 55% (40%–71%) higher bCd and 7% (−3%–18%) higher uCd. Results were similar for women. uCd mainly measures long-term exposure and bCd recent exposure, but with noticeable overlap. Epidemiological studies should base the choice of uCd or bCd on the timing of cadmium exposure relevant to the disease under study.

Prediagnostic non-steroidal anti-inflammatory drug use and survival after diagnosis of colorectal cancer

Objective Non-steroidal anti-inflammatory drug (NSAID) use decreases both the incidence of colorectal cancer and recurrence of adenomas among patients with prior colorectal neoplasia. However, few studies have investigated the association between NSAID use and colorectal cancer-specific survival. The role of prediagnostic NSAID use was therefore examined in relation to colorectal cancer-specific survival among cases from the Seattle Colon Cancer Family Registry (Seattle Colon CFR). Methods This was a follow-up study that included incident cases of colorectal cancer from the Seattle Colon CFR. Cases were aged 20–74, diagnosed from 1997 to 2002, and were identified using the population-based Puget Sound SEER registry. Detailed information on history of NSAID use, including type, recency and duration, was collected through an interviewer-administered questionnaire. Follow-up for mortality was completed through linkages to the National Death Index. The main outcome measure was death due to colorectal cancer after diagnosis. Cox proportional hazards regression was used to investigate the relationship between prediagnostic NSAID use and colorectal cancer-specific mortality among cases. Results NSAID use prior to colorectal cancer diagnosis was associated with an ∼20% lower rate of colorectal cancer mortality after diagnosis compared with never use (HR 0.79; 95% CI 0.65 to 0.97). This relationship appeared to be duration dependent, with longer reported use prior to diagnosis associated with lower rates of colorectal cancer mortality among cases. The most pronounced reductions in mortality were observed among cases diagnosed with proximal disease (HR 0.55; 95% CI 0.37 to 0.82), whereas no association was observed between NSAID use prior to diagnosis and colorectal cancer-specific mortality among cases diagnosed with distal or rectal disease. Conclusions The findings suggest that regular use of NSAIDs prior to diagnosis is associated with improved colorectal cancer survival, particularly among cases diagnosed with proximal disease and in longer term NSAID users.

Dietary cadmium exposure and risk of breast, endometrial, and ovarian cancer in the Women's Health Initiative.

Background: In vitro and animal data suggest that cadmium, a heavy metal that contaminates some foods and tobacco plants, is an estrogenic endocrine disruptor. Elevated estrogen exposure is associated with breast, endometrial, and ovarian cancer risk. Objectives: We examined the association between dietary cadmium intake and risk of these cancers in the large, well-characterized Women’s Health Initiative (WHI). Methods: A total of 155,069 postmenopausal women, 50–79 years of age, who were enrolled in the WHI clinical trials or observational study, participated in this study. We estimated dietary cadmium consumption by combining baseline food frequency questionnaire responses with U.S. Food and Drug Administration data on food cadmium content. Participants reported incident invasive breast, endometrial, or ovarian cancer, and WHI centrally adjudicated all cases through August 2009. We applied Cox regression to estimate adjusted hazard ratios (HRs) and 95% CIs for each cancer, comparing quintiles of energy-adjusted dietary cadmium intake. Results: Over an average of 10.5 years, 6,658 invasive breast cancers, 1,198 endometrial cancers, and 735 ovarian cancers were reported. We observed no statistically significant associations between dietary cadmium and risk of any of these cancers after adjustment for potential confounders including total dietary energy intake. Results did not differ in any subgroup of women examined. Conclusions: We found little evidence that dietary cadmium is a risk factor for breast, endometrial, or ovarian cancers in postmenopausal women. Misclassification in dietary cadmium assessment may have attenuated observed associations. Citation: Adams SV, Quraishi SM, Shafer MM, Passarelli MN, Freney EP, Chlebowski RT, Luo J, Meliker JR, Mu L, Neuhouser ML, Newcomb PA. 2014. Dietary cadmium exposure and risk of breast, endometrial, and ovarian cancer in the Women’s Health Initiative. Environ Health Perspect 122:594–600; http://dx.doi.org/10.1289/ehp.1307054

Sources of cadmium exposure among healthy premenopausal women

BACKGROUND Cadmium, a persistent and widespread environmental pollutant, has been associated with kidney function impairment and several diseases. Cigarettes are the dominant source of cadmium exposure among smokers; the primary source of cadmium in non-smokers is food. We investigated sources of cadmium exposure in a sample of healthy women. METHODS In a cross-sectional study, 191 premenopausal women completed a health questionnaire and a food frequency questionnaire. The cadmium content of spot urine samples was measured with inductively-coupled plasma mass spectrometry and normalized to urine creatinine content. Multivariable linear regression was used to estimate the strength of association between smoking habits and, among non-smokers, usual foods consumed and urinary cadmium, adjusted for age, race, multivitamin and supplement use, education, estimated total energy intake, and parity. RESULTS Geometric mean urine creatinine-normalized cadmium concentration (uCd) of women with any history of cigarette smoking was 0.43 μg/g (95% confidence interval (CI): 0.38-0.48 μg/g) and 0.30 μg/g (0.27-0.33 μg/g) among never-smokers, and increased with pack-years of smoking. Analysis of dietary data among women with no reported history of smoking suggested that regular consumption of eggs, hot cereals, organ meats, tofu, vegetable soups, leafy greens, green salad, and yams was associated with uCd. Consumption of tofu products showed the most robust association with uCd; each weekly serving of tofu was associated with a 22% (95% CI: 11-33%) increase in uCd. Thus, uCd was estimated to be 0.11 μg/g (95% CI: 0.06-0.15 μg/g) higher among women who consumed any tofu than among those who consumed none. CONCLUSIONS Cigarette smoking is likely the most important source of cadmium exposure among smokers. Among non-smokers, consumption of specific foods, notably tofu, is associated with increased urine cadmium concentration.

Sex Differences in Hospitalizations with Maintenance Hemodialysis

Hospitalization is a major source of morbidity among patients with ESRD undergoing maintenance hemodialysis and is a significant contributor to health care costs. To identify subgroups at the highest risk of hospitalization, we analyzed by sex, age, and race, adjusting for demographic and clinical characteristics, the hospitalization rates, and 30-day readmissions for 333,756 hospitalizations among 111,653 patients undergoing maintenance hemodialysis in facilities operated by a large dialysis organization in the United States (2007-2011). The overall hospitalization rate was 1.85 hospitalizations per person-year and was much higher among women than among men (2.08 versus 1.68 hospitalizations per year for women versus men, P<0.001). Age group-specific hospitalization rates were consistently higher for women than for men of the same race, and the differences were greatest in younger age groups (for example, women aged 18-34 years and ≥75 years had 54% [95% confidence interval, 42% to 67%] and 14% [95% confidence interval, 11% to 18%] higher hospitalization rates, respectively, than did men of respective ages). Women also had substantially higher risk for 30-day readmission, with the largest differences at younger ages. Women had a significantly lower serum albumin level than men, and stratification by serum albumin level attenuated sex differences in the age group-specific hospitalization and 30-day readmission rates. These findings suggest that women undergoing maintenance hemodialysis have substantially higher risks for hospitalization and 30-day readmission than men. In this cohort, the sex differences were greatest in the younger age groups and were attenuated by accounting for differences in health status reflected by serum albumin level.

Racial Patterns of Peripheral T-Cell Lymphoma Incidence and Survival in the United States

PURPOSE To compare incidence and survival of peripheral T-cell lymphoma (PTCL) subtypes among US racial/ethnic groups. METHODS Patients with PTCL (age ≥ 15 years; 2000 to 2012) were identified in the Surveillance, Epidemiology, and End Results (SEER) registries. Race/ethnicity was categorized as non-Hispanic white, black, Asian/Pacific Islander, Hispanic white, or American Indian/Alaskan native. Age-standardized annual incidence rates and incidence rate ratios were estimated with 95% CIs, and case-case odds ratios were estimated by race/ethnicity using polytomous regression. Survival was estimated from SEER follow-up data with Cox regression. RESULTS Thirteen thousand one hundred seven patients with PTCL were identified. Annual PTCL incidence was highest in blacks and lowest in Native Americans. Compared with non-Hispanic whites, blacks had a higher incidence of PTCL not otherwise specified (PTCL-NOS), anaplastic large-cell lymphoma, and adult T-cell leukemia/lymphoma (ATLL) and a lower incidence of angioimmunoblastic T-cell lymphoma (AITL); Asians/Pacific Islanders had a higher incidence of AITL, extranodal nasal-type natural killer/T-cell lymphoma and NK-cell leukemia (ENKCL), and ATLL and a lower incidence of anaplastic large-cell lymphoma; Hispanics had a higher incidence of AITL and ENKCL; and Native Americans had a lower incidence of PTCL-NOS (all P < .05). The ratio of ENKCL to PCTL-NOS among Native Americans, Asians/Pacific Islanders, and Hispanic whites was approximately three- to four-fold the same ratio among non-Hispanic whites. Survival varied significantly by race/ethnicity (P < .001), with blacks in particular experiencing shorter survival for most subtypes. CONCLUSION Striking variation in incidence, proportions of PTCL subtypes, and survival was observed. Aspects of these PTCL subtype patterns, such as for ENKCL and ATLL, were similar to corresponding global populations. Despite the small population size and limited number of Native American patients, PTCL subtype frequencies in this group were distinct but most similar to Hispanic whites. Survival disparities were evident, especially for blacks compared with non-Hispanic whites.

Colorectal Polyp Type and the Association With Charred Meat Consumption, Smoking, and Microsomal Epoxide Hydrolase Polymorphisms

We determined the association between charred meat consumption, cigarette smoking, microsomal epoxide hydrolase (mEH) polymorphisms (rs1051740 and rs2234922), and colorectal adenomas and hyperplastic polyps (HPs) and explored gene–environment interactions. Men and women with colorectal adenomas (n = 519), HPs (n = 691), or concurrently with both types of polyps (n = 227) and polyp-free controls (n = 772) receiving a colonoscopy from December 2004 to September 2007 were recruited. Participants completed telephone interviews and provided buccal cell samples; genotyping of mEH was completed using Taqman assays. We conducted polytomous regression and calculated odd ratios (OR) and 95% confidence intervals. Interactions were evaluated using Wald chi-square tests. Consumption of >3 servings of charred meat per week was associated with distal HPs (OR = 2.0, 1.2–3.4) but not adenomas nor either type of proximal polyp. Heavy cigarette smoking (≥ 22 pack-years) was associated with an increased risk for colorectal adenomas (OR = 1.7, 95% CI: 1.2–2.4), HPs (OR = 2.4, 95% CI: 1.7–3.3), and both types (OR = 2.8, 95% CI: 1.8–4.3) with the strongest association for distal polyps. There was no association between mEH genotype and colorectal polyps, nor were any statistically significant gene–environment interactions identified. Future investigation of BaP exposure and colorectal neoplasia should analyze whether associations are dependent upon anatomic location.

No association between maternal pre-pregnancy obesity and risk of hypospadias or cryptorchidism in male newborns.

BACKGROUND Hypospadias and cryptorchidism, two relatively common male genital anomalies, may be caused by altered maternal hormone levels, blood glucose levels, or nutritional deficiencies. Maternal obesity, which increases risk of diabetes and could influence hormone levels, may, therefore, be associated with risk of hypospadias and cryptorchidism. The purpose of this study was to assess the association between pre-pregnancy maternal obesity and hypospadias and cryptorchidism. METHODS We conducted a case-control study of hypospadias and cryptorchidism in male singleton newborns using Washington State birth records from 1992 to 2008 linked to birth-hospitalization discharge records. Maternal pre-pregnancy body mass index (BMI) was calculated from pre-pregnancy weight and height. Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) for hypospadias or cryptorchidism were estimated by fitting multivariable logistic regression models adjusted for year of birth, and maternal age, education, parity, race, and cigarette smoking during pregnancy. RESULTS The complete-case analysis included 2219 hypospadias cases, 2563 cryptorchidism cases, and 32,734 controls. Maternal obesity (BMI ≥30 kg/m(2) ) was not associated with risk of hypospadias or cryptorchidism in male offspring: hypospadias (aOR, 1.07; 95% CI, 0.95-1.21); cryptorchidism (aOR, 0.99; 95% CI, 0.89-1.11), and no trend in risk with increasing maternal BMI was found. There was little indication of risk associated with BMI among any subgroup of mothers examined, including women with pre-existing diabetes or hypertension, women who developed preeclampsia, non-Hispanic white women, first-time mothers, or mothers aged ≥30 years. CONCLUSIONS The results of this study do not support the hypothesis that pre-pregnancy maternal obesity is a cause of hypospadias or cryptorchidism in male infants.