Thursday, August 30, 2012

Pipe Smoking and Health

Health risks associated with cigar smoking are lower than those for cigarette smoking, reflecting a lower exposure to smoke toxicants (see my earlier post here).  The same holds true for pipe smoking, as a 2004 American Cancer Society study documented (abstract here).

Dr. S. Jane Henley and colleagues examined data from the Cancer Society’s Second Cancer Prevention Survey, which enrolled participants in 1982.  They compared deaths among exclusive men pipe smokers with those among never tobacco users over the next 18 years.  They also considered the number of pipes smoked each day, duration of smoking, and how much smokers inhaled.  The results are expressed as hazard ratios (HRs, similar to relative risks); a confidence interval spanning 1.0 means the risk elevation was not statistically significant.

The table shows that pipe smokers had small to moderate elevations for several smoking-related diseases, with the risk for laryngeal cancer remarkably high.

The Health Risks of Pipe Smoking
Disease Hazard Ratio (95% Confidence Interval)
Oral cavity and pharynx3.9 (2.2 – 7.1)
Esophagus2.4 (1.5 – 4.0)
Stomach1.2 (0.7 – 1.9)
Colon Rectum1.4 (1.2 – 1.7)
Pancreas1.6 (1.2 – 2.1)
Larynx13.1 (5.2 – 33)
Lung5.0 (4.2 – 6.0)
Bladder1.5 (0.9 – 2.4)
Kidney0.9 (0.8 – 1.6)
Heart Disease 1.3 (1.2 – 1.4)
Stroke1.3 (1.1 – 1.5)
Emphysema3.0 (2.2 – 4.1)

The Cancer Society’s analysis of pipe smoking was thorough (in stark contrast to its consideration of smokeless tobacco, discussed here), producing a wealth of insights.  For example, the overall HR for lung cancer among pipe smokers was 5.0, but there was a distinct gradient related to the number of pipes smoked per day.  The HR was 2.0 with one to three pipes, but it increased to 7.7 for 11+ pipes per day.  There was a similar trend with longer duration of smoking, and inhalation played a major role.  The lung cancer HR was 2.9 for pipe smokers who didn’t inhale, but 11.1 for those reporting moderate or deep inhalation. 

Other diseases showed similar trends with dose, duration and inhalation, although some  results weren’t statistically significant.

Dr. Henley also illustrated that alcohol is a powerful risk factor for cancers of the oral cavity, pharynx, larynx and esophagus.  Pipe smokers who consumed less than one alcoholic drink per day had no increased risk for these cancers.  Those consuming 1-3 drinks had an HR of 4.7 (CI = 1.8 – 11.9), while those consuming 4+ drinks had much higher risk (HR = 15, CI = 5.9 – 39).  Never smokers consuming 4+ drinks also had elevated risk for these cancers (HR = 2.3, CI = 1.2 – 4.3). 

“These risks,” according to the researchers, “were generally smaller than those associated with cigarette smoking and similar to or larger than those associated with cigar smoking.”  This confirms one of the tenets of tobacco harm reduction: it’s the smoke that kills, and the risk is proportionate to how much, how long and how deeply smoke is inhaled.  

1 comment:

jredheadgirl said...

" with the risk for laryngeal cancer remarkably high."

I wonder why that is....

Is the risk relative to TSNA content?