A new study about erectile dysfunction suggests — and also does not suggest — that drinking decaffeinated coffee ups a person’s risk of having erectile dysfunction, especially if the person is a male. The study is:
“Coffee Intake and Incidence of Erectile Dysfunction,” David S. Lopez, Lydia Liu, Eric B. Rimm, Konstantinos K. Tsilidis, Marcia de Oliveira Otto, Run Wang, Steven Canfield, and Edward Giovannucci [pictured here], American Journal of Epidemiology, epub 2017).
The authors explain: “We investigated the association of coffee intake with incidence of ED [erectile dysfunction].”
The authors tell how they did that: “A prospective analysis of 21,403 men aged 40-75 years old was conducted… Total coffee, regular and decaffeinated coffee intakes were self-reported on food-frequency questionnaires. ED was assessed by means of questionnaires in 2000, 2004 and 2008….”
Then the authors tell what they identified: “No significant differences were identified for incident ED after comparing highest (≥ 4 cups/day) with lowest category (0 cups/day) of total and regular- coffee intakes.”
The study includes, also, an observation that non-expert readers might find disturbing: “For decaffeinated coffee intake, after comparing the highest category with lowest category, we found a 37% increased risk of ED…”
But those same non-expert readers, if they have taken worry, might find some comfort in a sentence that occurs farther down in the paper: “Overall, long-term coffee intake was not associated with risk of ED in a prospective cohort study.”
CAUTION: One should remember the maxim that “correlation does not imply causation.” In the case of this study, it is possible to conclude, if one is incautious, that erectile dysfunction causes men to drink decaffeinated coffee.