MedWire News: Reassuring study findings suggest passive smoking has no appreciable effect on the risk for esophageal or gastric adenocarcinomas (EGAs).
Smoking is a well-established cause of esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EA), say Leslie Bernstein (University of Southern California, Los Angeles, USA) and co-workers.
They investigated the impact of passive smoking in 938 patients first-incident EA, gastric cardia adenocarcinoma (GCA), or distal gastric adenocarcinoma (DGA) diagnosed between 1992 and 1997 in Los Angeles county.
The mean age at diagnosis was 62.2 years for the 220 patients with EA, 58.7 years in the 277 with GCA, and 58.0 years for the 441 DGA patients. An additional 1356 control participants were recruited, with a mean age of 57.0 years at identification.
Among all 2294 participants, 33.5% never smoked, 45.8% were ex-smokers, and 20.7% were current smokers.
Current smokers were at significantly increased risk for EA, GCA, and DGA compared with never smokers who had no passive smoke exposure, with adjusted odds ratios of risk 3.27, 2.07, and 1.83, respectively.
However, never smokers exposed to passive smoking during childhood were not at significantly increased risk for adenocarcinomas of the esophagus, gastric cardia, or distal stomach compared with those who had no passive smoke exposure.
Those exposed to at least one smoker during adulthood showed a trend toward an elevated EA risk, but the confidence intervals crossed 1. A similar trend for EA and DGA was observed for passive smoking exposure of more or less than 12 years.
Reporting in the British Journal of Cancer, the authors conclude: “We found no evidence that exposure of persons who have never actively smoked to passive smoke during their childhood years or during their adult years strongly influences their risk for EGA.”
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