The Association of Caffeine Metabolite with Obesity and Glycohemoglobin Level
Abstract Objectives To examine the mediating effect of central obesity (measured by waist circumference [WC]) on the relationship between caffeine metabolite (1, 7-dimethylxanthine) and glycohemoglobin level, adjusting for covariates of age, gender, race/ethnicity, smoking, and alcohol intake. Methods Design: Publicly available data from the 2009–2010 National Health and Examination Surveys (NHANES) were used to conduct this secondary data analysis. NHANES collected data from respondents using in-home surveys and mobile examination centers. Subjects: For the current study, 1976 respondents were included. Respondents were included if they participated in data collection for caffeine consumption and ≥20 years of age. Respondents were excluded if a proxy was required for data collection or had pregnancy confirmation during the physical examination portion of data collection. Outcome Measures: Original NHANES variables, 1, 7-dimethylxanthine level, glycohemoglobin level, WC, age and gender, were used. Race/ethnicity, smoking, and alcohol were recoded to better address the aim of this study. Results Structural equation modeling showed that WC mediated the relationship between 1, 7-dimethylxanthine and glycohemoglobin level, adjusting for covariates. The total effect of 1, 7-dimethylxanthine on glycohemoglobin level was -.001 (indirect effect [.029 x .013] + direct effect [–.001]), adjusting for covariates, which suggests that the total effect was minimal. Age (β = .014, P < .001), non-White race (non-Hispanic Blacks: β = .28, P < .001; Hispanics: β = .29, P < .001, other ethnicities: β = .41, P = .003), smoking (β = .10, P = .014, ), and heavy drinking (β = –.24, P < .001, ) had significant effects on the relationship between 1, 7-dimethylxanthine and glycohemoglobin level. Conclusions Although WC mediated the relationship between 1, 7-dimethlyxanthine and glycohemoglobin level, minimal effects suggest that caffeine consumption should only be considered as part of a treatment regimen in combination with other interventions to reduce glycohemoglobin levels. Funding Sources None.