Both active smokers and those exposed to high levels of secondhand smoke
had lower levels of folate in their blood than nonsmokers, according to the
report
in the journal Nicotine & Tobacco Research.
“Overall, we found that red blood cell folate levels in current smokers
were 20 percent lower than those in our entire group of nonsmokers,” say
David M. Mannino, M.D., of the Centers for Disease Control and Prevention
and colleagues.
Nonsmokers exposed to heavy amounts of secondhand smoke also had decreased
folate levels, but their folate loss was only 60 percent of the amount leeched
from active smokers.
Previous studies have linked low folate levels to several different diseases,
and Mannino and colleagues suggest that the association between folate and
smoke exposure might help explain the increased risk of these diseases among
active smokers.
“The finding provides biological support for recent studies linking
tobacco smoke exposure to heart disease and breast cancer and provides biological
plausibility to examine the role of tobacco smoke exposure in other folate-related
diseases such as neural tube defects and colon cancer,” Mannino and
colleagues say.
The study included 15,564 adults ages 17 and older who received blood tests
for cotinine, a nicotine byproduct, and folate. The people were also asked
about their eating and smoking habits. Older individuals in study, those ages
50 and older, were less likely to be active smokers or to be exposed to high
levels of secondhand smoke.
The researchers measured folate in both red blood cells and blood serum
to determine each person’s overall folate levels. Levels in serum reflect
recent folate intake, while levels in red blood cells reflect long-term intake
and tend to be a more stable indicator of how the body is processing the
vitamin. In both cases, folate levels dipped with smoke exposure.
The study was supported by the Centers for Disease Control and Prevention.
