ABSTRACT
Background:
The association between coffee consumption and incident hypertension remained inconsistent.
Objective:
This study aimed to examine the association of consumption of coffee, including different types (instant, ground) and with different additives, with new-onset hypertension, and evaluate whether genetic variation in caffeine metabolism and inflammation may modify the association.
Design:
This study utilized a prospective cohort design.
Participants/setting:
A total of 98,765 participants free of hypertension enrolled in the UK Biobank between 2006 and 2010 were included. Dietary coffee consumption was collected using 24-hour dietary recall questionnaires.
Main outcome measures:
The study outcome was new-onset hypertension, ascertained by self-reported medical conditions, hospital inpatient records, death registers, and primary care records.
Statistical analyses performed:
Cox proportional hazards models were used to estimate hazard ratio (HR) and 95% confidence interval (CI). Potential modifying effects were assessed by likelihood ratio testing.
Results:
During a median follow-up of 12.1 years, 7,090 (7.2%) new-onset cases of hypertension were documented. Overall, regardless of coffee type (instant, ground) and whether adding milk to coffee, there was a U-shaped association between unsweetened coffee consumption and new-onset hypertension, with a 14-18% reduction of hypertension risk at >1- ≤ 4 drinks/d; while a null association was observed between sweetened coffee consumption and the risk of new-onset hypertension. Relative to coffee nonconsumers, the adjusted HRs (95%CIs) of new-onset hypertension for participants who drinking unsweetened coffee 1 or fewer, >1 to 2, >2 to 3, >3 to 4, and >4 drinks/d were 0.92 (0.85-1.00), 0.82 (0.76-0.89), 0.86 (0.79-0.96), 0.86 (0.77-0.96), and 0.88 (0.78-0.99), respectively. Moreover, a stronger inverse association between moderate consumption of unsweetened coffee and new-onset hypertension was found in participants with higher C-reactive protein levels (P-interaction =0.012), while individual's genetic variation in caffeine metabolism did not significantly modify the association (P-interaction =0.453).
Conclusions:
Regardless of the type of coffee (instant, ground) or the addition of milk to coffee, moderate consumption of unsweetened coffee (>1- ≤ 4 drinks/d), but not sweetened coffee, was associated with a lower risk of new-onset hypertension.
