Moving toward precision: Understanding the heterogeneity of obesity.

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12054 Background: Obesity is a global health epidemic and has been linked to detrimental impact on cancer incidence, recurrence, and mortality. Growing evidence have recognized the complex biopsychosocial relationship including microbial phenotypes that undermines the carcinogenic potential and heterogeneity of obesity. A precision understanding on obesity while at its infancy is necessary to accelerate reduction of its impact on cancer outcomes. Methods: With our aim to better understand the biopsychosocial relationship on obesity, we conducted a cross sectional study in healthy and obese individuals. Univariate and multivariate logistic regression models were used to examine obesity and its association with sociodemographic (age, gender, ethnicity, education, income, and marital status), clinical (waist to hip ratio), dietary-behavioral (daily calorie, fat, carbohydrate, protein consumption, and preference on cultural diet), and biological factors (gut microbiome). Parameters were controlled and corrected for multiple hypothesis testing. Gut microbial data using 16S rRNA sequencing were analyzed for alpha diversity, beta diversity, and association of taxa abundance. Results: Among 171 participants between July 2013 and August 2018, individuals were found to have a higher BMI if they were Hispanic [Adjusted Odds Ratio (AOR) 3.36, 95% CI 1.27-8.90], had an obese waist to hip ratio (AOR 8.51, 95% CI 3.45-21.02), and consumed an American diet (AOR 4.82, 95% CI 1.74-13.34). Multivariate permutation analysis controlling for BMI, sociodemographic, clinical, and dietary parameters found that Hispanic have a significantly different microbiome profile than non-Hispanic (p = 0.042). While microbial species richness (Chao1) were similar (p = 0.22), Hispanic had a lower microbial species evenness (Shannon) compared to non-Hispanic (p = 0.029). Differential expression of microbial species revealed a positive correlation of Firmicutes:Bacteroidetes ratio in individuals with higher BMI and consumed an American diet whereas a negative correlation to Hispanic ethnicity. Conclusions: Obesity association to Hispanic ethnicity uniquely expressed through microbial signature despite sociodemographic, clinical, and dietary differences. Microbial characterization as an emerging predictive marker for oncology therapeutics may also serve as selection biomarker in onco-obesity practices and clinical trials. Addressing ethnic disparities guided by microbial phenotypes may unlock novel understanding of obesity heterogeneity and transform its impact on cancer care.