Retrospective studies only select for those criteria that meet the study
measures. There's no control on the data, ie...no
cohorts from 'outside' of the study parameters to act as a baseline measure.
So the data is generally poor at best. And 12 cases
doesn't power the analysis enough to statistically challenge the results.
But I'm no expert....I've only been a medical/biological scientist since
1977.

bill

"David Hakala" wrote in message
...
Well, I'll go with the experts on this:


WOODD-DUST-EXPOSURE
NASAL-CANCER

WOOD DUST AND SINO-NASAL CANCER: POOLED REANALYSIS OF TWELVE CASE-CONTROL
STUDIES
Data from 12 case control studies conducted in seven countries were pooled
and reanalyzed in an effort to examine the relationship between wood dust
and sino/nasal cancer. There was a high risk of adenocarcinoma among male
employees in wood related occupations, with the greatest risk found for
those in jobs with the highest wood dust exposure and increased duration
of exposure. The risk of adenocarcinoma was also greater among women
employed in wood related jobs. An excess of squamous cell carcinoma
appeared in women in dust exposed jobs, which increased with the duration
of exposure, but only men employed for 30 or more years showed an
increased risk of squamous cell carcinoma. The authors conclude that the
study provides strong support to the link between wood dust exposure with
various occupations and the risk of sino/nasal adenocarcinoma, but the
evidence with regard to squamous cell carcinomas is ambiguous.

American Journal of Industrial Medicine, 28(2):151-166, 1995. (36
references)

http://infoventures.com/osh/abs/wood0002.html