Background: Determining the factors associated with secondhand smoke (SHS) exposure in children provides valuable information for smoking control strategies. This study aimed to assess factors related to SHS exposure in infants based on urinary cotinine measures.Materials and Methods: A cross-sectional analysis of the data that were collected as part of the randomized controlled trial was conducted. Participants were 130 smoking households with children under the age of 1 year attending a health care center in southern Tehran. Eligible parents consented to participate in this study and completed a questionnaire including demographic data, questions regarding smoking at home, smoking status and Fagerström test through face-to-face interview. The Infants’ urinary cotinine level was measured using gas chromatography, adjusted with urinary creatinine level and reported as cotinine (ng)/ creatinine (mg). Factors related to infants’ SHS exposure were assessed using the multivariate logistic regression model based on standard cut-point (30 ng of urinary cotinine/mg creatinine). Results: The final multivariate logistic regression model showed that social status (p=0.002), home smoking restriction (p=0.05) and the infant's age (p=0.01) were associated with the infants’ SHS exposure determined based on urinary cotinine levels.Conclusion: These results support the influence of social status, home smoking restriction and infant's age on the exposure of infants to SHS.

Objectives: Exposure to secondhand smoke (SHS) constitutes major health problems that threaten human health around the world; its adverse effects can lead to serious illnesses in both the pregnant women and the growing fetus. The purpose of this study was to determine the prevalence of SHS among Saudi pregnant women in King Khalid University Hospital (KKUH) and to determine the association between the socioeconomic characteristics of the pregnant women and exposure to SHS.Materials and Methods: This was a cross-sectional study conducted in the antenatal clinic, KKUH. Data were collected from consecutive women using a predesigned questionnaire addressing the participants’ demographics and exposure to SHS status.Results: The prevalence of SHS exposure among pregnant women was 24%. Low maternal education level and being unemployed were associated with more exposure to SHS (P=0.039) and (P=0.02), respectively. There was no association between maternal age, parity and monthly income and exposure to SHS (P=0.697), (P=0.420) and (P=0.543), respectively.Conclusion: Maternal educational levels and unemployment are associated risk factors for SHS exposure during pregnancy.

Background: Secondhand Smoke (SHS) exposure has been reported to cause a number of adverse health effects. Although studies have been conducted to identify the link between SHS exposure and cognitive functioning of children, its relationship is still unclear. This study aimed to identify the association of prenatal and postnatal SHS exposure with cognitive ability among adolescents.Methods: A total of 370 adolescents aged 13-14 years old in two states in Malaysia participated in this study. A modified Global Youth Tobacco Survey questionnaire was used to assess exposure to SHS. Parental-administered questionnaire was used to obtain information on parental smoking and prenatal SHS exposure. Cognitive ability was objectively measured using Wechsler Nonverbal Scale of Ability.Results: 75.4% and 24.6% adolescents were identified to have cognitive ability categorized as high (>90 marks) and low (£90 marks), respectively. From the logistic analysis adjusting for confounders, adolescents with SHS exposure in toddlerhood (£2 years old) were three times more likely to have lower cognitive ability compared to those without exposure (Adjusted Odds Ratio (AOR), 2.89; 95% Confidence Interval (CI), 1.21-6.83). School absenteeism was associated with lower cognitive ability.Conclusion: Exposure to SHS during toddlerhood was linked to lower cognitive ability among adolescents. The findings of this study emphasize the need for preventing involuntary toddlerhood SHS exposure from parents and indirectly encourage home smoking restriction practices among Malaysian citizens.

Mother’s and infant exposure to cigarette smoke is one of the most important public health problems. There is no study in Iran evaluating the impact of cigarette smoke on infant growth and development. The purpose of this study was to determine the effects of cigarette. This prospective cohort study was conducted on 51 cigarette smoke-exposed infants (exposed group) and 51 non-exposed infants (non-exposed group). They were evaluated for weight, height and head circumference three times; five to seven days, two months and four months after birth. Urine samples were also collected in each turn. Exposure to secondhand smoke was assessed through questionnaires and urinary cotinine levels. The analysis was performed using an independent t-test, Mann-Whitney U test, chi-square and Fisher’s exact and Kappa tests.Mean urinary cotinine level in the exposed group was 38.57±2.85 ng/mg creatinine at baseline, 86.95±1.16 at two months and 63.32±2.08 at four months of age. These indicated a gradual reduction of exposure from two to four months. The weight and height of the exposed group were significantly lower than the non-exposed group (P<0.001) at two and four months after birth. The results of the present study showed that the exposure to secondhand smoke during infancy may lead to weight and height growth reduction in the first four months of life.

Tobacco smoking has become one of the greatest sources of indoor inhalable particles. Tobacco smoke changes chemically and physically after it is released into indoor air; these changes can increase secondhand smoke (SHS) toxicity. The SHS as assessed by indoor particulate matter with an aerodynamic diameter of less than 2.5 mm (PM2.5) was investigated experimentally and computationally. Test house experiment was performed to study the PM2.5 concentration under controlled conditions coupled with mathematical model of continuity equation. PM2.5 was measured using a DustTrak personal sampler. Two-dimensional flow and dispersion of cigarette smoke were modeled using computational fluids dynamics model which were solved using Reynolds-averaged Navier-Stokes equations. The effect of air purifier in reducing SHS and thirdhand smoke (THS) was analyzed and evaluated. The results demonstrated that the air purifier cannot control the indoor PM2.5 levels. Furthermore, amount of smoke from main stream of SHS is more compared to side stream and THS can be evaluated by calculating the adsorption term of continuity equation.

DEAR EDITOR, Globally, tobacco kills half of its users accounting for close to 6 million deaths each year, of which more than 80% occur due to direct tobacco consumption whereas another 0.6 million nonsmokers die due to exposure to secondhand smoke.Furthermore, almost four-fifths of the world’s smoker are from low- and middle- income nations, which are already struggling to meet the welfare needs of the general population.