Secondhand smoke exposure in Mexican discotheques.

Area of Science:

• Environmental Health
• Toxicology
• Public Health

Background:

• Secondhand smoke (SHS) exposure is a significant public health concern.
• Discotheques are environments where SHS exposure can be high due to smoking prevalence.
• Assessing SHS exposure through biomarkers is crucial for understanding health risks.

Purpose of the Study:

• To quantify the impact of SHS exposure in discotheques on nonsmokers.
• To compare pre- and post-exposure urinary cotinine levels in discotheque patrons.
• To evaluate the effectiveness of discotheques as indicators of SHS exposure.

Main Methods:

• Recruitment of 100 nonsmoking volunteers in central Mexico.
• Collection of paired urine samples: pre-exposure and post-exposure (average 6 hours after).
• Quantification of urinary cotinine and trans-3'-hydroxycotinine using liquid chromatography-mass spectrometry.

Main Results:

• Significantly increased urinary cotinine levels post-exposure in both females (2.2 to 15.7 ng/ml) and males (3.7 to 49.1 ng/ml).
• Highest post-exposure cotinine levels observed in males under 22 years old (469.5 ng/ml).
• High concentrations of cotinine and its metabolite indicate substantial SHS absorption.

Conclusions:

• Discotheque environments lead to significant SHS exposure for nonsmokers.
• Urinary cotinine is a reliable biomarker for assessing SHS exposure in such settings.
• Prohibiting smoking in discotheques is essential to safeguard nonsmokers' health.