Urinary lead concentration and composition of the adult gut microbiota in a cross-sectional population-based sample

BACKGROUND

Lead (Pb) is a ubiquitous environmental contaminant with an array of detrimental health effects in children and adults, including neurological and immune dysfunction. Emerging evidence suggests that Pb exposure may alter the composition of the gut microbiota, however few studies have examined this association in human populations. The purpose of this study was to examine the association between urinary Pb concentration and the composition of the adult gut microbiota in a population-based sample of adults.

METHODS

Data used in this study were collected as part of the Survey of the Health of Wisconsin (SHOW) and its ancillary microbiome study. The SHOW is a household-based health examination survey of Wisconsin residents, collecting a variety of survey data on health determinants and outcomes, as well as objective measurements of body habitus, and biological specimens including urine. The ancillary microbiome study added additional questions and biological specimen collection, including stool, from participants age 18+. Pb concentration was analyzed in urine samples, and gut microbiota composition was assessed using DNA sequencing of the 16S rRNA V4 region, extracted from stool samples. Data processing and statistical analyses were performed in mothur, Python, R, and SAS.

RESULTS

Of 696 participants, urinary Pb concentration was highest in those age 70+, females, those with a high school diploma or lower, current and former smokers, and those without indoor pets. In adjusted models, increasing urinary Pb levels were associated with increases in microbial α-diversity (p = 0.071) and richness (p = 0.005). Differences in microbial β-diversity were significantly associated (p = 0.003) with differences in urinary Pb level. Presence of Proteobacteria, including members of the Burkholderiales, was significantly associated with increased urinary Pb.

CONCLUSION

These results suggest that Pb exposure is associated with differences in the composition of the adult gut microbiota in a population-based human sample. Further investigation of this association is warranted.

Abstract B74: Behavioral and social science: Recruitment/retention/adherence research

Background: Enrollment in interventional therapeutic clinical trials is a small fraction of all patients who might participate given reasonable access. A case series of new prostate cancer cases are evaluated for their participation in a clinical trial.

Methods: A hierarchical approach is utilized in measuring staged participation from trial availability to patient enrollment. Our framework suggests that concern for justice comes in the design and eligibility criteria for clinical trials; attention to beneficence is given in the eligibility and physician triage stages. The remaining four stages (doctor discussion with the patient, patient interest, patient consent, patient enrolled) rely on respect for persons.

Reasons for nonparticipation or barriers to participation in prostate cancer clinical trials are examined within the seven step framework. Ninety-seven medical oncology patients with an initial six month consultation are tracked from one stage to the next to assess comparability of participation by race.

Results: We illustrated seven transitions from being a patient to enrollment in a clinical trial in a case series of prostate cancer cases who consulted medical oncology in early 2010 (n=97). Pilot data suggest transition probabilities as follows for patients 65% had trial availability, of those 84% were eligible, of those 92% were triaged, of those 100% have trials discussion, of those 51% were interested, of those 71% consented, and of those 94% enrolled. The average transition probability was 77.7%. Trial availability, patient interest and patient consented were three transitions that were below average; none were statistically significant however. We combined steps to obtain the probability of a patient-trial-fit, 50%; the probability of opportunity, 51%; and the probability of acceptance, 66.7%. there were no differences in enrollments by race.

Conclusions: The framework may serve to streamline comprehensive and improved reporting of clinical trial participation to the benefit of patients and toward the ethical conduct of clinical trials. The seven step framework may aid trouble shooting of flagging trial enrollment.

Citation Format: Norma F. Kanarek, Marty Kanarek, Dare Olatoye, Michael Carducci. Behavioral and social science: Recruitment/retention/adherence research. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B74.

The role of sport-fish consumption advisories in mercury risk communication: a 1998-1999 12-state survey of women age 18-45

BACKGROUND

In 2002, in the United States, 48 states issued advisories for sport-fish consumers that included 39 chemical contaminants. The most commonly identified chemical was methyl mercury, which is linked to reproductive and developmental effects. Advisories to reduce consumption of contaminated fish have been issued by states since the early 1970s. Advisories are being integrated to include both sport and commercial fish.

METHODS

As part of a comprehensive risk-communication project, from December 1998 through August 1999 the Wisconsin Division of Public Health and the State of Maine Bureau of Health conducted a 12-state random-digit-dial telephone survey of 3015 women of childbearing age (ages 18-45). The goal was to assess the prevalence of fish consumption, understanding of mercury toxicity, and awareness of state sport-fish consumption advisories for mercury. We gathered information concerning respondents' demographic characteristics, understanding of mercury toxicity, fish consumption during the preceding 12 months, and sport-fish consumption advisory awareness.

RESULTS

The overall survey completion rate was 57% with a Council of American Survey Research Organizations (CASRO)-calculated response rate of 50%. Completion rates varied from 37% in New Jersey to 73% in Minnesota. Fish consumption during the previous 12 months was reported by 87% of respondents (range by state of 82-90%). Nearly 10% of women reported consuming two or more fish-meals per week over the prior 12 months. Twenty-nine percent reported sport-fish consumption during the same time period, with a greater state-to-state variability (14-43%). Most women (71%) were aware of mercury's toxicity to a developing child (87% among those aware of an advisory and 67% among those unaware of an advisory). However, awareness of state advisories was only 20%, ranging by state from 8% to 32%. Women who were older, had more than a high school education, and had a household member with a fishing license were the most informed about mercury and fish-consumption advisories.

CONCLUSIONS

Most women of childbearing age consume commercial fish and a substantial number also consume sport-caught fish. Despite this potential exposure to dietary mercury, most are unfamiliar with their state's mercury fish-consumption advisory. Most women were aware of the most toxic effects of mercury but less informed about mercury and its relationship to types of fish and fish characteristics. Minorities, women over age 30, family incomes above 25,000 US dollars, and those with some collage education were more likely to be consuming two or more fish-meals per week. Until source control and environmental remediation efforts can reduce the environmental burden of mercury below levels of concern, combined sport and commercial fish consumption advisories will remain the primary means of reducing human exposure to methylmercury. Assuring and assessing the effectiveness of such advisories is paramount. Our survey documents that current efforts to inform vulnerable populations are far from optimal.