TUESDAY, June 8 (HealthDay News) -- Secondhand smoke (SHS) exposure among healthy adults is associated with psychological distress and risk of future psychiatric illness, according to a cross-sectional and longitudinal study published online June 7 in the Archives of General Psychiatry.
Mark Hamer, Ph.D., of the University College London, and colleagues evaluated 5,560 nonsmoking and 2,595 smoking individuals without a history of mental illness from the Scottish Health Survey in 1998 and 2003. Study participants with cotinine values of 15.00 µg/L or higher were considered smokers. The researchers used a score greater than three on the 12-item General Health Questionnaire as an indicator of psychological distress.
The researchers found psychological distress in 14.5 percent of the sample population, with high SHS exposure among nonsmoking individuals (cotinine level >0.70 and <15.00 µg/L) linked to a higher odds of psychological distress (odds ratio, 1.49) compared to those with cotinine levels below the limit of detection (≤0.05 µg/L). Over six years of follow-up, the researchers also showed in prospective analyses that the risk of a psychiatric hospital admission was related to high SHS exposure (hazard ratio, 2.84) and active smoking (multivariate hazard ratio, 3.74).
"In summary, we found a robust dose-response association between objectively assessed nicotine exposure and psychological distress, which was apparent at low levels of SHS exposure and was strongest in current smokers," the authors write. "This association was replicated in prospective analyses that demonstrated an association between SHS exposure, active smoking, and risk of psychiatric episodes over six years of follow-up."
