re: How should we define light or intermittent smoking? Does it matter?

BMJ in 2005 published data looking at roughly 43,000 people who smoked 1-4 cigarettes a day from 1970-2002. All cause mortality and ischemic heart disease (heart attacks) were significantly higher in the smoking group.

No significant difference in the general term "cancer," across men/women. When looking at lung cancer only, there was a statistically significant increased risk in women that seemed present but didn't quite reach significance in men (trends that way though, but relative risk crosses 1 at the 95% confidence interval)


Can't answer your question directly with data but can be reasonably sure that it's worse than smoking none.