Environmental Factor, October 2005, National Institute of Environmental Health Sciences
What Follows Fruit Fiber Benefits to Second-Hand Smoke Effects?
By Blondell Peterson
Through a study of 35,000 adult non-smokers in Singapore, researchers found that early life exposure to second-hand smoke can create life-long respiratory problems. Subjects who ate more fruit and soy fiber in adulthood seemed to be protected against some of the negative effects associated with early tobacco exposure.
"We found that the harmful effects were found predominantly in people who had a less fiber rich diet.-not to say that fiber is a cure-all," said Stephanie London, a senior investigator in the Epidemiology branch. "The message is that environmental tobacco smoke can have long lasting effects and diet can have some beneficial effects on respiratory health. London developed collaboration to the Singapore Chinese Health Study, and added the respiratory assessment to the cancer cohort study.
"What really made this study possible was the meticulous attention to detail of my collaborators," said London. She credits Mimi C. Yu, principal investigator of the cohort study, which was sponsored by the National Cancer Institute. Yu, now at the Univ. of Minnesota Cancer Center, also directed the study team in Singapore. The Singapore collaborators were Hin-Peng Lee and Woon-Pyay Koh, researchers at the National University of Singapore. "It's really a great resource largely because of their efforts," London said. The paper was written by London's former post doctoral fellow, Gloria David, a researcher at Rho Inc. in Chapel Hill.
What follows the fruit fiber finding?
The immediate goal, according to London, is to keep the cohort going and complete another round of follow up. That will take four to five years because it is such a large cohort.
London is also putting together a proposal to do objective tests of pulmonary function on a sample of members of the cohort. The big thrust in the next five years is to look at gene environment interaction with respiratory disease, said London.
London noted that about half of the subjects in the cohort gave blood samples for further studies. "We'll look at genetic polymorphisms that may influence adult asthma risk, and we'll be able to look at interaction with environmental tobacco smoke and active smoking," she said. "That's the next wave."
Another work in progress is a paper in which her former postdoctoral fellow, Lesley Butler, now at the University of California at Davis is using principal components analysis to analyze dietary patterns in the cohort in relation to respiratory symptoms and illness. London explained that the analysis of dietary patterns can help make sense of findings based on individual foods and nutrients.