A brief exposure to moderate passive smoke increases metabolism and thyroid hormone secretion.
BACKGROUND
Active smoking influences normal metabolic status and thyroid function.


OBJECTIVE
The objective was to assess experimentally the effects of 1 h of moderate passive smoking in a controlled simulated bar/restaurant environment on the metabolism and thyroid hormone levels in healthy nonsmokers.


METHODS
Eighteen (nine females, nine males) healthy individuals (mean +/- sd: age, 25.3 +/- 3.1 yr; height, 174.0 +/- 10.1 cm; weight, 65.2 +/- 13.7 kg) participated in the study.


METHODS
In repeated-measures randomized blocks, participants visited the laboratory on 2 consecutive days. In the experimental condition, they were exposed to 1 h of moderate passive smoking at a carbon monoxide concentration of 23 +/- 1 ppm in an environmental chamber, whereas in the control condition participants remained in the same chamber for 1 h breathing normal atmospheric air.


METHODS
In both conditions, cotinine serum and urine levels, resting energy expenditure (REE), as well as concentration of T3, free T4, and TSH were assessed before participants entered the chamber and immediately after their exit. Heart rate and blood pressure were tested in 10-min intervals during all REE assessments.


RESULTS
The mean +/- sd difference of serum and urine cotinine levels (-0.27 +/- 3.94 vs. 14.01 +/- 6.54 and 0.05 +/- 2.07 vs. 7.23 +/- 3.75, respectively), REE (6.73 +/- 98.06 vs. 80.58 +/- 120.91) as well as T3 and free T4 (0.05 +/- 0.11 vs. 0.13 +/- 0.12 and 0.02 +/- 0.15 vs. 0.22 +/- 0.20) were increased in the experimental compared with the control condition at baseline and follow-up (P < 0.05). No statistically significant variation was observed in the mean difference of the remaining parameters (P > 0.05). Serum and urine cotinine values were linearly associated with REE (P < 0.05).


CONCLUSIONS
One hour of passive smoking at bar/restaurant levels is accompanied by significant increases in metabolism and thyroid hormone levels.
Metsios
Giorgos S
GS
Laboratory of Applied Physiology, Department of Sports and Exercise Science, University of Thessaly, Karies, Trikala GR42100, Greece. gm@wlv.ac.uk
Flouris
Andreas D
AD
Jamurtas
Athanasios Z
AZ
Carrillo
Andres E
AE
Kouretas
Demetrios
D
Germenis
Anastasios E
AE
Gourgoulianis
Konstantinos
K
Kiropoulos
Theodoros
T
Tzatzarakis
Manolis N
MN
Tsatsakis
Aristeidis M
AM
Koutedakis
Yiannis
Y
D000328:Adult; D003367:Cotinine / Q000097:blood / Q000652:urine; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D013963:Thyroid Hormones / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014284:Triiodothyronine / Q000097:blood
D013963:Thyroid Hormones; D014028:Tobacco Smoke Pollution; D014284:Triiodothyronine; D003367:Cotinine; D013974:Thyroxine