Baseline Oral Microbiome and All-cancer Incidence in a Cohort of Nonsmoking Mexican American Women

Given the increasing evidence that the oral microbiome is involved in obesity, diabetes, and cancer risk, we investigated baseline oral microbiota profiles in relation to all-cancer incidence among nonsmoking women enrolled in a Texas cohort of first- and second-generation immigrants of Mexican origin. We characterized the 16Sv4 rDNA microbiome in oral mouthwash samples collected at baseline from a representative subset of 305 nonsmoking women, ages 20-75 years. We evaluated within- (alpha) and between-sample (beta) diversity by incident cancer status and applied linear discriminant analysis (LDA) effect size analysis to assess differentially abundant taxa. Diversity and candidate taxa in relation to all-cancer incidence were evaluated in multivariable-adjusted Cox regression models. Over 8.8 median years of follow-up, 31 incident cancer cases were identified and verified. Advanced age, greater acculturation, and cardiometabolic risk factors were associated with all-cancer incidence. Higher alpha diversity (age-adjusted P _difference < 0.01) and distinct biological communities (P _difference = 0.002) were observed by incident cancer status. Each unit increase in the Shannon diversity index yielded >8-fold increase in all-cancer and obesity-related cancer risk [multivariable-adjusted HR (95% confidence interval), 8.11 (3.14-20.94) and 10.72 (3.30-34.84), respectively] with similar findings for the inverse Simpson index. Streptococcus was enriched among women who did not develop cancer, while Fusobacterium, Prevotella, Mogibacterium, Campylobacter, Lachnoanaerobaculum, Dialister, and Atopobium were higher among women who developed cancer (LDA score ≥ 3; q-value < 0.01). This initial study of oral microbiota and overall cancer risk in nonsmoking Mexican American women suggests the readily accessible oral microbiota as a promising biomarker. PREVENTION RELEVANCE: Mexican American women suffer a disproportionate burden of chronic health conditions that increase cancer risk. Few investigations of the microbiome, a key determinant of host health, have been conducted among this group. Oral microbiota profiles may provide early and accessible cancer biomarker data on invasive bacteria or community disruptions.

Abstract 1121: Baseline oral microbiota profiles associated with all-cancer incidence in a cohort of non-smoking Mexican American women

Background: We previously demonstrated an association of age and acculturation with oral microbiota among non-smoking women enrolled in a Texas cohort of first and second generation immigrants of Mexican origin. Given the increasing evidence that the oral microbiome is involved in obesity, diabetes and cancer risk, as well as the lack of data in Mexican Americans, we prospectively investigated baseline oral microbiota profiles in relation to all-cancer incidence.

Methods: We characterized the 16Sv4 rDNA microbiome in oral mouthwash samples collected at baseline from a representative subset of 369 non-smoking women, aged 20-78 years, enrolled in the MD Anderson Mano a Mano Mexican American (MA) cohort study. Using Dirichlet multinomial mixtures (DMM) modeling, we previously identified three microbial communities or clusters in our sample uniquely characterized by Streptococcus, Fusobacterium and Prevotella. We evaluated within (alpha) and between sample (beta) diversity by incident cancer status and applied Linear Discriminant Analysis (LDA) Effect Size analysis (LEfSe) to assess differentially abundant taxa.

Results: Over 8.9 median years of follow-up, 31 incident cancer cases were identified and verified with the Texas Cancer Registry. In addition to advanced age and higher acculturation, a prior history of cardiovascular disease and multiple cardiometabolic risk factors (obesity, diabetes, high cholesterol, hypertension) were associated with higher all-cancer incidence in this subset of non-smoking women. With the exception of country of birth and following adjustment for age, none of these were strongly associated with the oral microbiome. Higher overall diversity of the oral microbiota, as assessed by Shannon diversity index, was observed among women diagnosed with cancer over follow-up, as compared to those who were not (age-adjusted Pdiff=0.0003). We observed potentially distinct biological communities, as measured by weighted UniFrac distance (Pdiff =0.001), and several differentially abundant taxa by incident cancer status. Fusobacterium, Campylobacter, Prevotella, Dialister and Atopobium were higher among women who developed cancer, while Streptococcus was enriched among women who did not develop cancer (LDA&gt;=3, P&lt;0.01). Moreover, we observed increased odds of developing cancer among women in the Prevotella vs. Streptococcus cluster (age-adjusted OR=3.08, 95%CI=1.14, 8.35, P=0.02).

Conclusions: To our knowledge, this is the first look at oral microbiota and cancer risk in Mexican American women. Our findings support the potential of the more readily accessible oral microbiota as a promising biomarker of cancer risk in non-smoking women.

Citation Format: Xiaotao Zhang, Kristi L. Hoffman, Qiong Dong, Kplola Y. Elhor Gbito, Shine Chang, Joseph Petrosino, Carrie R. Daniel-MacDougall. Baseline oral microbiota profiles associated with all-cancer incidence in a cohort of non-smoking Mexican American women [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1121.

Acculturation and Diabetes Risk in the Mexican American Mano a Mano Cohort

OBJECTIVES

To investigate the association between acculturation and diabetes risk in the Mexican American Mano a Mano (hand to hand) Cohort.

METHODS

We recruited 15 975 men and women in the Houston, Texas, area from 2001 to 2014. We used language use, birth country, and duration of US residence (among Mexico-born) to assess acculturation. Participants self-reported a physician's diagnosis of diabetes during annual follow-up over an average of 5.4 (range = 1-13) years. Self-reported diabetes status was validated in medical records for a subset of 235 participants with 98% agreement.

RESULTS

Diabetes risk was higher among immigrants with 15 to 19, 20 to 24, and 25 or more years (relative risk = 1.47; 95% confidence interval = 1.07, 2.01) of US residence, relative to those with less than 5 years. Neither language acculturation nor birth country was significantly associated with diabetes risk.

CONCLUSIONS

Among participants born in Mexico, diabetes risk increased with longer duration of US residence.

Dietary intake of vegetables, fruits, and meats/beans as potential risk factors of acute myeloid leukemia: a Texas case-control study

Diet has been identified as a risk factor for some cancers, but its role in adult de novo acute myeloid leukemia (AML) is unclear. This study was conducted at the University of Texas MD Anderson Cancer Center to evaluate associations between consumption of vegetables, fruits, and meats with AML risk among Texas residents. All participants, 323 adult de novo AML cases and 380 frequency-matched controls, completed demographic and food frequency questionnaires. Overall, AML risk was significantly decreased among those who consumed the most dark green vegetables, seafood, and nuts/seeds; and it was significantly increased among greatest consumers of red meat. Among men, AML risk was lowest among those whose consumption was in the highest quartile for fruits [odds ratio (OR) = 0.25, 95% confidence interval (CI) = 0.10-0.69], poultry (OR = 0.28, 95%CI = 0.10-0.78), and seafood (OR = 0.39, 95%CI = 0.16-0.96) compared to those in the lowest. Among women, risk was lowest among those whose consumption was in the highest quartile of dark-green vegetables (OR = 0.28, 95%CI = 0.12-.68), orange vegetables (OR = 0.40, 95%CI = 0.17-.96) and nuts/beans (OR = 0.26, 95%CI = 0.11-0.60). Based on these findings, interventions can be developed to modify intake of specific dietary components to reduce cancer risk.

De novo acute myeloid leukemia risk factors: a Texas case-control study

BACKGROUND

Acute myeloid leukemia (AML) is comprised of several bone marrow-based cancers and is the most common type of leukemia in the United States. The etiology of AML is not well understood. A case-control study was conducted at The University of Texas M. D. Anderson Cancer Center to investigate associations between lifestyle characteristics and the risk of AML in Texas.

METHODS

This study included 638 adult patients with de novo AML (cases) and a group of 636 matched controls. Interviewer-administered questionnaires were used to collect demographic and occupational data. The distribution of cases by World Health Organization (WHO) subtype was 71 patients (11%) with recurrent cytogenetic abnormalities (AML-RCA), 134 patients (21%) with multilineage dysplasia (AML-MD), and 389 patients (61%) with AML not otherwise categorized (AML-NOC). Multivariate logistic regression analyses were performed among all AML cases and among both sexes and each WHO subgroup.

RESULTS

Among men, heavy smoking (≥30 pack-years; odds ratio [OR], 1.86) and occupational solvent exposure at low levels (OR, 2.87) or moderate/high levels (OR, 4.13) statistically significantly increased the risk of AML. Among women, obesity (OR, 1.62) and solvent exposure to low levels (OR, 2.73) or moderate/high levels (OR, 3.90) increased the risk of AML. Across WHO subtypes, obesity was associated with a statistically significantly increased risk of AML-RCA (OR, 3.15), whereas solvent exposure increased the risk in all subtypes at low levels (AML-RCA: OR, 4.11; AML-MD: OR, 2.54) and moderate/high levels (AML-RCA: OR, 5.13; AML-MD: OR, 3.02). A joint effect between smoking and solvent exposure was observed, and the highest risk was observed among smokers who had solvent exposure (OR, 4.51).

CONCLUSIONS

The current results suggested that several factors play a role in AML predisposition with possible joint effects. Risk profiles for AML differed by sex and WHO subtype.

Automated system to identify Clostridium difficile infection among hospitalised patients

The purpose of this study was to assess whether data on stool frequency collected electronically could identify patients at high risk for Clostridium difficile infection (CDI). All patients with reports of diarrhoea were assessed prospectively for number of stools per day and number of diarrhoea days. C. difficile testing was requested independently from study investigators. Number of days with diarrhoea and maximum number of unformed stools was assessed as a CDI predictor. A total of 605 patients were identified with active diarrhoea of whom 64 (10.6%) were diagnosed with CDI. In univariate analysis, the maximum number of stools and number of diarrhoea days was associated with increased risk of CDI. Compared to patients with three diarrhoea stools per day (CDI incidence: 6.3%), CDI increased to 13.4% in patients with four or more diarrhoea stools per day [odds ratio (OR): 2.3; 95% confidence interval (CI): 1.3-4.2; P=0.0054]. Compared to patients with one day of diarrhoea (CDI incidence: 6.3%), CDI increased to 17.4% in patients with two diarrhoea days (OR: 3.1; 95% CI: 1.7-5.6) and to 27.1% in patients with three or more diarrhoea days (OR: 5.5; 95% CI: 2.6-11.7). These results were validated using logistic regression with number of days with diarrhoea identified as the most important predictor. Using an electronic data capture technique, number of days of diarrhoea and maximum number of diarrhoea stools in a 24h time period were able to identify a patient population at high risk for CDI.