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Secondhand smoke is a
mixture of the smoke given off by the burning end of a cigarette, pipe, or
cigar, and the smoke exhaled by smokers.
Children are
particularly vulnerable to the effects of secondhand smoke because they are
still developing physically, have higher breathing rates than adults, and have
little control over their indoor environments. Exposure to secondhand smoke can cause
asthma in children who have not previously exhibited symptoms. Infants and
children younger than 6 who are regularly exposed to secondhand smoke are at
increased risk of lower respiratory track infections, such as pneumonia and
bronchitis and while teens are at increased risk of middle ear infections.
Exposure to secondhand smoke increases the risk for Sudden Infant Death
Syndrome.
Secondhand Smoke is
Linked to Type 2 Diabetes and Obesity in Adults
A new study has shown that adults who are exposed to
secondhand smoke have higher rates of obesity and Type 2 diabetes than do
nonsmokers without environmental exposure to tobacco smoke.
“More effort needs to be made to reduce exposure of
individuals to secondhand smoke,” said study co-author Theodore C. Friedman,
MD, PhD, chairman of the Department of Internal Medicine at Charles R. Drew University,
Los Angeles.
Cotinine is a metabolite of nicotine, and serum cotinine
measures a person’s exposure to tobacco smoke.
In their current study, Friedman and his fellow researchers
used serum cotinine levels to verify passive smoking. They examined data from
more than 6,300 adults who participated from 2001 to 2006 in the National
Health and Nutrition Examination Survey (NHANES), a nationally representative
sample of the U.S.
population.
The investigators defined current smokers, which made up 25
percent of the sample, as survey participants who reported that they smoke
cigarettes and who had a measured serum cotinine level greater than 3 nanograms
per milliliter (ng/mL). Nonsmokers (41 percent of the sample) were those who
answered “no” to the question “Do you smoke cigarettes?” and who had a cotinine
level below 0.05 ng/mL. Participants who answered “no” to this question but
whose cotinine level was above 0.05 ng/mL were defined as secondhand “smokers”
(34 percent).
In analyzing these groups, the researchers controlled for
age, sex, race, alcohol consumption and physical activity. They found that,
compared with nonsmokers, secondhand smokers had a higher measure of insulin
resistance, a condition that can lead to Type 2 diabetes; higher levels of
fasting blood glucose, or blood sugar; and a higher hemoglobin A1c, a measure
of blood sugar control over the past three months.
Secondhand smokers also had a higher rate of Type 2
diabetes, as defined by a hemoglobin A1c greater than 6.5 percent. Secondhand
smokers had a similar rate of diabetes to that of current smokers, according to
Friedman.
Secondhand smokers also had a higher body mass index (BMI),
a measure of body fat, compared with nonsmokers, Friedman reported. Current
smokers had a lower BMI than nonsmokers but a higher hemoglobin A1c. When the
researchers controlled for BMI, they found that secondhand smokers and current
smokers still had a higher hemoglobin A1c than did nonsmokers.
“This finding shows that the association between secondhand
smoke and Type 2 diabetes was not due to obesity,” Friedman said. “More studies
are needed to show whether secondhand smoke is a cause of diabetes.”
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The A1C test is a common blood test used to
diagnose type 1 and type 2 diabetes and then to gauge how well you're managing
your diabetes. The A1C test goes by many other names, including glycated
hemoglobin, glycosylated hemoglobin, hemoglobin A1C and HbA1c.
The A1C test result
reflects your average blood sugar level for the past two to three months.
Specifically, the A1C test measures what percentage of your hemoglobin — a
protein in red blood cells that carries oxygen — is coated with sugar
(glycated). The higher your A1C level, the poorer your blood sugar control. And
if you have previously diagnosed diabetes, the higher the A1C level, the higher
your risk of diabetes complications. Source: Mayo Clinic
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