Martin Blaser and colleagues find evidence linking early-life social environment and microbe-induced gastric cancer
Early-Life Family Structure and Microbially Induced Cancer Risk
Martin J. Blaser1,2,3*, Abraham Nomura4, James Lee4, Grant N. Stemmerman4,5, Guillermo I. Perez-Perez1
1. Department of Medicine, New York University School of Medicine, New York, New York, USA, 2. Department of Microbiology, New York University School of Medicine, New York, New York, USA, 3. Veterans Administration Medical Center, New York, New York, USA, 4. Kuakini Medical Center and University of Hawaii, Honolulu, Hawaii, USA, 5. University of Cincinnati, Cincinnati, Ohio, USA
Background
Cancer may follow exposure to an environmental agent after many decades. The bacterium Helicobacter pylori, known to be acquired early in life, increases risk for gastric adenocarcinoma, but other factors are also important. In this study, we considered whether early-life family structure affects the risk of later developing gastric cancer among H. pylori+ men.
Methods and Findings
We examined a long-term cohort of Japanese-American men followed for 28 y, and performed a nested case-control study among those carrying H. pylori or the subset carrying the most virulent cagA+ H. pylori strains to address whether family structure predicted cancer development. We found that among the men who were H. pylori+ and/or cagA+ (it is possible to be cagA+ and H. pylori− if the H. pylori test is falsely negative), belonging to a large sibship or higher birth order was associated with a significantly increased risk of developing gastric adenocarcinoma late in life. For those with cagA+ strains, the risk of developing gastric cancer was more than twice as high (odds ratio 2.2; 95% confidence interval 1.2–4.0) among those in a sibship of seven or more individuals than in a sibship of between one and three persons.
Conclusions
These results provide evidence that early-life social environment plays a significant role in risk of microbially induced malignancies expressing five to eight decades later, and these findings lead to new models to explain these interactions.
*Address correspondence to: martin.blaser@med.nyu.edu
