COFFEE AND THE HEART. HAVE A CUPPA. ANOTHER J CURVE PHENOMENA

Much has been written about coffee drinking and the heart as coffee is probably the most common imbibed beverage. many of us drink coffee routinely in the morning and sometimes another cup through the day. There were some earlier data to suggest that coffee may increase the risk of cardiovascular disease. However, more and more data is now emerging to suggest that drinking coffee in moderation ( as usual ) may protect the heart. That then begs the question of how much is too much?
Well, Dr Elizabeth Mostofsky and colleague at Beth Israel Hospital, Boston, looked into this issue for us and published their findings in the June 26th issue of Circulation : Heart failure. They did a meta-analysis of coffee consumption and heart failure, taking data from 5 large clinical trial. These were people without pre-existing heart disease, drinking coffee and followed them up. The study cohort was a large 140,220 subjects with 10 years of follow-up ( the data base search was from 1996 - 2011 ). There were 6522 cases of CCF. When they related these cases of CCF to coffee consumption, they found that drinking 2-4 cups of coffee ( using the American cup, which is probably twice the size of a European cup ) protects you from heart failure and if one drinks 5 or more cups a day, the incidence of heart failure goes up ( the protection is loss ). Again, this shows the J curve again.

I am also quite intrigue that many illnesses and body responses to them exhibit the J curve phenomenon. Adequate is good and too much is bad. I will keep observing and see how much more we can uncover.

Relative risk (RR) of incident heart failure* by daily cups of coffee (Northern-European style) in a five-study meta-analysis

Cups/day	RR (95% CI)
1-2	0.96 (0.90-0.99)
2-3	0.93 (0.86-0.99)
3-4	0.90 (0.82-0.99)
4-5	0.89 (0.81-0.99)
5-6	0.91 (0.83-1.01)
6-7	0.93 (0.85-1.02)
7-8	0.95 (0.87-1.05)
8-9	0.97 (0.89-1.07)
9-10	0.99 (0.90-1.10)
10-11	1.01 (0.90-1.14)
>11	1.03 (0.89-1.19)

*p =0.02 for nonlinearity and for overall significance of curve

The analysis is fairly well done by the Boston group and this adds to the growing number of studies that concluded that moderate consumption of coffee is good for the heart.
So lets go and have a cuppa, but not more than 4 a day please.