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Vitamins and lung cancer risk – no link, says meta-analysis
By Stephen Daniells
29/03/2006 - High intake of vitamins A, C, E and folic acid do not reduce the risk of lung cancer, says a pooled analysis of prospective studies.
The link between intakes of the vitamins A, C, and E and folic acid, has been reported by some studies, but not by others. The new analysis, led by Eunyoung Cho from Brigham and Women's Hospital and Harvard Medical School, sought to clarify the situation by pooling eight prospective studies with a total population size of 430,281 participants.
The analysis, published in the International Journal of Cancer (Vol. 118, pp. 970-978), concluded: “This pooled analysis does not suggest that intakes of vitamins A, C and E and folate reduce the risk of lung cancer.”
Eight prospective studies from Canada, Finland, the Netherlands, and the US, were pooled together using baseline data collected by the original study using food frequency questionnaires. Follow-up of the participants ranged from six to sixteen years, but only baseline food intakes were used in the meta-analysis.
When the results were adjusted for age, the researchers calculated that the highest intake of all four nutrients from food only was associated with a 28 per cent reduction in the risk of lung cancer.
This significant association was lost after adjusting for other variables, such as education, body-mass index, alcohol consumption and smoking. However, the associations for intakes of vitamin C and E remained significant.
Further analysis led the researchers to calculate that the vitamin E association was not significant and that vitamin C was only protective in men.
Even this link was eliminated when the researchers accounted for beta-cryptoxanthin, the compound that gives the red colour to red-orange fruits and vegetables.
“The inverse association between vitamin C intake from food-only and lung cancerrisk probably represents the association with either beta-cryptoxanthin intake or some other dietary constituents that are highly correlated with beta-cryptoxanthin in fruits,” said Cho.
When supplement sources of the four micronutrients was examined, not link was found between lung cancer risk and nutrient intake for the entire sample population, but was linked to a “modest increase in lung cancer risk among women.” This was said to be due to chance and did not have biological implications.
This analysis has several important limitations including the use of data only from baseline, and no indication of dietary changes that may have occurred during the six to 16 years of follow-up which may have affected the lung cancer risk.
Also, the meta-analysis design had a limited power to detect associations for high intakes of vitamins and the effects of duration of vitamin supplementation.
Over 1.2m new cases of lung cancer are diagnosed every year worldwide, with the cancer being the most commong form of cancer in Europe.
Supervisors urged state not to file charges in asbestos case
Letter shows county stressed meeting project deadline
By VIRGINIA HENNESSEY
Herald Salinas Bureau
May. 20, 2006 - County supervisors in January asked state prosecutors not to file criminal charges against its contractors for allegedly mishandling asbestos in the Salinas Courthouse, citing concerns about the cost and construction schedule of the renovation project.
In a letter to the state Attorney General's Office, board Chairman Jerry Smith said it was "critical that the county complete the project on schedule" and that the courthouse continue to operate during construction. Smith expressed "serious concerns about your stated intent to initiate a criminal prosecution."
Two weeks later, the Attorney General's Office filed felony charges against Nova Partners Inc.; its project manager, Seth Henderson; Skanska USA Building Inc.; and its project manager, Anthony Jones. The complaint, which was followed by a grand jury indictment, alleges the group was responsible for the release of asbestos into the ventilation system of the court's north wing "in a manner which caused an unreasonable risk of serious injury or death" to the people working and visiting the courthouse.
The grand jury transcript includes testimony by two contractors who told Henderson and Jones their plan to saw-cut and jackhammer concrete on the second story of the building would release dangerous asbestos into the ventilation system.
The transcript indicates the advice was ignored and that Henderson and Jones had another contractor perform the concrete work on two nights without warning him of the presence of asbestos. That contractor, Don Chaney of Thayer Construction, said he completed the job without gear to protect him from asbestos exposure.
Elevated asbestos levels were detected in the courthouse after the second night, March 31, 2005, and the courthouse was closed the next day to allow for cleaning.
Smith's letter to state prosecutors makes clear that, while the county was concerned about public safety, it was also motivated by a concern that the project remain on time and under budget, and that court operations not be disturbed in the meantime.
"Not only is safety a main concern, but so too is the ongoing operation of the courts," Smith wrote. "From the outset of this project the county advised all involved that, due to the financial constraints of that project, the courthouse had to remain occupied during the course of the renovation; the cost to replicate a temporary court facility... would have depleted the budget such that there would not be sufficient funding to complete the renovation project as planned."
Smith said Nova had been diligent in cutting costs for the county and finding "ways to enhance the schedule."
In his testimony before the grand jury, asbestos consultant Glenn Nystrom said Henderson repeatedly tried to get him to approve the plan to cut the concrete without first removing the asbestos. Nystrom said he told Henderson it couldn't safely be done because the courthouse was occupied.
"I kept saying no. And at one point he was so angry... that he basically hung up the phone on me," Nystrom testified. "He felt he had a schedule to keep and we weren't assisting."
In his letter to the state, Smith explained that the county must complete the work on schedule because it is required by state law to turn the building over to the state by June 30, 2007. The transfer is the final step in the 1997 consolidation of the state's courts.
Smith described Nova, the contractor managing the renovation and seismic retrofit of the north wing, as a "can do" company that would not "cut corners when it comes to safety."
"From everything the county has learned of those events and the way that Nova has dealt with safety issues and with hazardous materials throughout its work on the Monterey County Government Center, it is our view that any mistake was inadvertent," he wrote.
Linda Butson, the county's former capital projects director, also wrote to the Attorney General's Office in January, saying her day-to-day contact with Nova found the company's attitude toward safety to be "consistently exemplary."
Defense attorneys have complained that state prosecutors did not present to the grand jury the letters from Smith and Butson, nor testimony making it clear that it was the county's decision to continue courthouse operations during construction.
Deputy Attorney General Janill Richards said Friday she did not fault the Board of Supervisors for its attempt to ward off criminal charges.
"Part of the problem is not everybody always has all of the information," she said. "Our office had done an investigation, so we were convinced the charges we were bringing were supported by evidence. That information was not available to (Smith). He was speaking on the information he had."
But on Friday, Smith and Supervisor Butch Lindley continued to assert that the Attorney General's Office wrongly pursued criminal charges.
"We felt like that the Attorney General's office was grandstanding," Lindley said. "The numbers that the state uses (to identify elevated asbestos levels) you can probably find under your fingernails on a regular basis."
Smith said the asbestos release on March 31 was unintentional.
"We felt as though the Attorney General's Office was pushing this to the limit on an incidental incident. It was totally accidental," he said. "The organization has demonstrated good safety measures."
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