Context

The worldwide popularity of coffee combined with its potential to impact health has stimulated public and scientific interest. The 2015 Dietary Guidelines Advisory Committee concluded that moderate coffee drinking (3–5 cups/day) can be incorporated into a healthy diet. This conclusion was based, in part, on consistent evidence from prospective studies that moderate coffee drinking is not associated with increased risk of premature mortality and may, actually, be associated inversely.1 However, whether these modest inverse associations persist at higher levels of coffee intake remains unclear. This is largely because smoking is strongly positively correlated with coffee drinking such that heavy coffee drinkers tend to be smokers.