THE ASSOCIATION BETWEEN CAFFEINE INTAKE AND CARDIOVASCULAR MORTALITY: AN ANALYSIS OF THE NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY (NHANES) 1999-2014 DATABASE

Abstract

Sixty-four percent of adults in America drink coffee daily and 71% of caffeine intake comes from coffee in the United States (US) diet. Cardiovascular disease (CVD) is the number one cause of death in the US. The purpose of this study was to examine the association between caffeine intake and CVD mortality in a nationally representative sample of the US civilian non-institutionalized population. The association between caffeine intake and CVD mortality among 21,938 participants (age ranging from 20 to 85 years) in the NHANES 1999-2014 database was examined by multivariate Cox’s proportional hazards regression model. Daily caffeine intake was assessed once at enrollment. Mortality data came from the 2015 Public-use Linked Mortality Files (LMF). A total of 2,206 deaths occurred, including 394 cases of CVD death. Compared with those with a caffeine intake of < 100 mg/day (1 cup/8 oz/240 ml of coffee contains about 100 mg caffeine), the hazard ratios (HRs) for CVD mortality were significantly lower in the participants with a caffeine intake of 100-200 mg/day (HR, 0.63; 95% CI, 0.45-0.88; p = 0.008), and those with a caffeine intake of > 200 mg/day (HR, 0.70; 95% CI, 0.53-0.94; p = 0.02), after adjusting for age, race, gender, education, income, body mass index (BMI), smoking status, total daily intake of energy, carbohydrates, protein, and fat, and presence of diabetes, hypertension (HTN), CVD (excluding HTN), and cancer at enrollment. Higher caffeine intake (compared to < 100 mg/day as the reference group) was associated with lower CVD mortality. Further research is needed to figure out the mechanism of this inverse association. The current study cannot prove cause-effect relationship.