What do we know already about smoking and drinking coffee?

We know that smoking is a risk factor for heart disease. In fact, smokers are twice as likely to have a heart attack than non-smokers are.2

There is some evidence to suggest that drinking coffee may increase blood pressure, which increases the risk of a heart attack, but a confirmed link is yet to be shown.3

What did the study show?

The study showed that when people drank coffee and smoked cigarettes at the same time, the combined effect this had on the heart was worse than the effects of the two vices added together.1

What did the study look at?

The study looked at the short-term and long-term effects of smoking and drinking coffee - separately and combined - on the stiffness of the aorta.

The aorta is the body's main artery leading from the heart. Aortic stiffness is a good indicator of risk for heart disease.1

How was the study carried out?

The researchers split the study up into two parts to look at the immediate and long-term effects of smoking and caffeine.

-- Immediate effects
The first part of the study looked at the immediate effects of smoking and drinking coffee, in 24 healthy men and women, who regularly smoked and drank caffeine-containing drinks. The participants either smoked one cigarette alone, or one cigarette after taking two coffee cups' worth of caffeine. To make the study fair, the researchers used real and fake cigarettes and real and fake caffeine tablets. Participants did not know whether they were taking real or fake cigarettes and caffeine

-- Long-term effects
The second part of the study looked at the long-term effects of smoking and drinking coffee in 160 healthy men and women.1

What effects did smoking and caffeine have on the stiffness of the aorta?

In both parts of the study, the researchers showed that smoking and drinking coffee separately increased the stiffness of the aorta.

In the first part of the study, the researchers showed that smoking a cigarette while drinking two cups of coffee temporarily increased the stiffness of the aorta more than either smoking or caffeine alone did.

In the second part of the study, the people who regularly smoked and drank coffee had stiffer aortas than those who did one or the other, or neither.1

Why did caffeine and smoking affect the stiffness of the aorta?

The researchers think that the instant effects that caffeine and smoking had on the aorta may be linked to the release of certain hormones and chemicals in the body that affect blood pressure, heart rate and how the arteries function.

They are less clear about the long-term effects of caffeine and smoking on the heart because they are not sure how regular caffeine intake affects health and the function of your arteries over time.1

How is the stiffness of the aorta linked to heart disease?

The aorta is the largest artery in the body and the stiffness in the aorta contributes to high blood pressure. High blood pressure in the arteries means that the heart has to work harder to pump blood around the body. High blood pressure puts you at greater risk of having heart problems.4

What causes stiffness of the aorta?

In the long term, stiffness of the aorta is caused by atherosclerosis, which is the build-up of plaque - cholesterol and fat - in the arteries. This causes them to become narrower and to lose their elasticity. The amount of blood that is able to travel through the artery is reduced, making the heart work harder to pump blood around the body. Atherosclerosis puts you at greater risk of having heart problems.4

What causes atherosclerosis?

The exact cause of atherosclerosis is unknown, but there are several factors that put you at risk of developing atherosclerosis, including smoking, high blood pressure, high cholesterol levels and being overweight.5

What did the study conclude?

The researchers think that smoking and caffeine may interact with each other to harm the arteries and damage the heart over time………………