Health effects of very light cigarette smoking over the long term

March 16, 2009 8:12 AM

What are the health effects of very light cigarette smoking (1-3 per week) over the long term?

The highly dangerous effects of cigarette smoking are well known, however (from my understanding) this is based on studies that have considered the difference between non-smokers and 1+ pack/day smokers.

So, what are the health effects of very light cigarette smoking? Define very light as being 1-3 cigarettes per week, perhaps less.

Are the effects at that dosage negligible or almost the same? Obviously I would expect it to be somewhere in between, but are there any studies that demonstrate this? One might expect that the effect of smoking is exponential, and there is a tipping point where the impact starts becoming much more pronounced with additional use. Or, one might expect that any exposure is detrimental.

I've googled it using the search terms that I could think of, but found nothing. Can anyone point to any research on this topic?

Anecdotal evidence, although interesting, would probably not be helpful in this circumstance.

posted by Simon Barclay to health & fitness (14 comments total)

From a California EPA study on secondhand smoke health effects:

Part B of the report includes information on the health effects of secondhand smoke and concludes that the following health effects are causally associated iwth ETS exposure:

Developmental Effects: Fetal growth: Low birth weight and decrease in birth weight, Sudden Infant Death Syndrome (SIDS), Pre-term Delivery

Respiratory Effects: Acute lower respiratory tract infections in children (e.g., bronchitis and pneumonia), Asthma induction and exacerbation in children and adults, Chronic respiratory symptoms in children, Eye and nasal irritation in adults, Middle ear infections in children,

Carcinogenic Effects: Lung cancer, Nasal sinus cancer, Breast cancer in younger, primarily premenopausal women

Cardiovascular Effects: Heart disease mortality, Acute and chronic coronary heart disease morbidity, Altered vascular properties

It seems a safe assumption that light smoking would be as bad or worse than secondhand smoke, which is already pretty bad.
posted by scottreynen at 8:44 AM on March 16

It seems a safe assumption that light smoking would be as bad or worse than secondhand smoke, which is already pretty bad.

Disagreed. I'd assume in these studies that secondhand smoke is "always on," like someone living with a pack-a-day smoker, but in this situation the body is being given time to recuperate between cigarettes.
posted by soma lkzx at 8:53 AM on March 16

Here's an article talking about the dangers of smoking 1-4 cigarettes a day (which is still more than what you're asking about, but not a LOT more).
posted by cider at 8:53 AM on March 16

This is the article you want. And Pack Years.

In summary, our analysis of a large case-control study of lung cancer using a novel exposure and exposure-rate model reveals a direct intensity effect at low smoking intensities; i.e., an intensity enhancement effect, resulting in an increasing EOR/pack-year, and an inverse intensity-rate effect (i.e., reduced potency or wasted exposure effect), resulting in a decreasing EOR/pack-year at higher intensities.

I don't think you want to play this game. There does seem to be a link to the amount you smoke to the risk, but the risk is still WAY higher than a non-smoker. As smoking is responsible for 90% of the lung cancer deaths, you will in the 90% category.
posted by lamby at 8:59 AM on March 16

This question has been brought up more than once (there's a link to an earlier question in that one as well).

The bottom line is that there isn't hard data on very light smoking (less than one a day). It just hasn't been subjected to large-scale study. The health impacts of smoking correlate closely to frequency and duration of use, so the less frequently and less overall time you smoke the less effects you risk. These effects have been demonstrated and studied at levels much lower than a pack a day, incidentally. The effects are roughly cumulative, which is to say smoking a third of a pack a day for 3 years is putting you in the ballpark of smoking a pack a day for a year.

For many of the effects of smoking there may be a lower threshold where there is no impact for light smoking - if your lungs can recover from the damage of the volume of smoking you do, you're not going to get emphysema (presuming you wouldn't have gotten it anyway from some other causes). On the other hand, every time you smoke you are exposing your lungs to carcinogens. Those chemicals don't magically become carcinogenic at some magic amount of smoking. They represent a cancer-causing risk at any level. It is a game of odds. Obviously with heavier exposure your odds are worse (and probably further worsened by smoking damaging your lung's capacity to maintain their health in other ways, making them more susceptible to the carcinogenic effects). The majority of heavy smokers don't get lung cancer. People with no environmental risk factors get lung cancer. Here's an article on relative lung cancer risk just for context.

As far as anecdote goes, all I can say is that among my friends who were light smokers the majority either quit completely or fell into heavier daily smoking that they consequently struggle with giving up. Lots of light smokers who think there is no chance they will pick up the habit do so even after years. A sudden period of high stress is all it takes.

It seems a safe assumption that light smoking would be as bad or worse than secondhand smoke

No, that doesn't follow.
posted by nanojath at 9:17 AM on March 16 [1 favorite has favorites]

Disagreed. I'd assume in these studies that secondhand smoke is "always on," like someone living with a pack-a-day smoker, but in this situation the body is being given time to recuperate between cigarettes.

Yeah, the study lamby pointed to seems to confirm soma lkzx's assumption (and disprove mine):

Reduced effects of smoking at higher intensities are also consistent with enhancement of DNA repair capacities.

However, toward the end of that study, they explicitly avoid any conclusions about the low frequency you're asking about:

Thus, any conclusion about whether the estimated EOR/pack-year approaches zero remains constant or, indeed, increases for intensities below 5 to 8 cigarettes per day must be made cautiously.
posted by scottreynen at 9:22 AM on March 16

I second nanojath. The biggest risk is becoming a heavier smoker.
posted by Frasermoo at 9:34 AM on March 16 [1 favorite has favorites]

I was a light smoker from college through the beginning of this year (I'm 35), ranging from perhaps two smokes a week to about a pack a week at the most, then tapering back down to less than a pack a month.

I'l leave the posters above to explain the relatively scant literature that exists on cancer, emphysema, other smoking-related illnesses.

But anecdotally, I'll offer this: If you're in your twenties, smoking this little will produce pretty much zero noticeable negative effects. But in your thirties, when the little aging things start to pop up, the smoking takes a greater toll, even at low doses. A little bit more hungover if you've been drinking. A little longer to get over a cold. If you're prone to allergies or asthma, a little bit more prone. A little less energy the day after indulging. A little more dehydrated overall.

My attachment to the psychological habit was a little sad to give up, but these annoyances were finally not worth it, and so I'm done.
posted by desuetude at 9:55 AM on March 16

Anecdotally, I once consulted a pulmonologist about chronic bronchitis. I told him I was a smoker, but that I was smoking about 4 cigarettes a day, which was true, at that time. I asked him if I should stop, he said (I paraphrase): "Whatever, at that level of smoking the risks aren't the same, it doesn't matter much."

I was about 23.
posted by bunnycup at 4:39 PM on March 16

As some have noted, you are at a point now where you probably could quit relatively easily but if you don't you are quite likely to fall in to heavier smoking. Ozzy Ozborn said that cigarets we the most addictive thing he had ever tried, and if anybody would know, it would be him, right?

Regarding desuetude's statement "But anecdotally, I'll offer this: If you're in your twenties, smoking this little will produce pretty much zero noticeable negative effects." Well sure, but the key word is noticeable. You can do a lot of things to your body with out any immediately noticeable effects. That does not mean they are good for you.

Quit now while you still can.
posted by d4nj450n at 8:18 AM on March 17

Simon Barclay: "So, what are the health effects of very light cigarette smoking? ... Are the effects at that dosage negligible or almost the same?"

Does stinking count as a health effect? [Anecdote warning] I have a co-worker who smokes once or twice a week, and I can always tell which days she smokes.
posted by Plutor at 9:31 AM on March 17

Well, far be it to trust a former light smoker discussing how she quit in her mid-30s, when OZZY SEZ.

d4nj450n, the snippet of my comment to which you replied was specifically referencing everyday noticeable effects, with the acknowledgment that this is a separate issue from long-term health risks.
posted by desuetude at 1:05 PM on March 17

Thanks for the answers, everyone.
posted by Simon Barclay at 6:37 PM on March 19

Hem, I am a little bit late in responding to you desuetude, but if you read this... I was not trying to disagree with you or even reference your post with the bit about the Oz. Just noting that they can be very addictive. Some people, I understand, can be quite immune to the addiction and quit when they want, some are not so lucky.

The part of your post that I did refer to was not to disagree, but I thought it worthwhile to point out that long term effects are something to be considered. ONE exposure to a carcinogen can cause cancer, though the likelyhood of that is extremely small.
posted by d4nj450n at 12:13 PM on April 7