Smoking one a day can’t hurt, can it?

We know that smoking 20 cigarettes a day increases your risk of CHD and stroke - but what happens if you cut down to 1, do you have 1/20th of that risk? Allan Hackshaw, professor of epidemiology at UCL joins us to discuss a new systematic review and meta analysis published on bmj.com, examining the risk of smoking just one or two cigarettes a day. Read the full review: http://www.bmj.com/content/360/bmj.j5855