Association between environmental tobacco smoke exposure of children and parental socioeconomic status: a cross-sectional study in Korea

Association between glycated haemoglobin and the risk of chronic obstructive pulmonary disease: A prospective cohort study in UK biobank

AIMS

To investigate the association between glycated haemoglobin (HbA1c) levels and chronic obstructive pulmonary disease (COPD) incidents in the general population, and the association between HbA1c levels and mortality in patients with COPD.

MATERIALS AND METHODS

We investigated the association of HbA1c levels with COPD risk in the general population in the UK Biobank, using data from 420 065 participants. Survival analysis was conducted for 18 854 patients with COPD. We used restricted cubic spline analysis to assess the dose-response relationship between HbA1c levels and COPD risk and survival. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 12.3 years, 11 556 COPD cases were recorded. HbA1c had a non-linear relationship with COPD risk (p for non-linearity < .05). Compared with the quintile 2 (32.2-<34.3 mmol/mol), those with HbA1c levels above 38.7 mmol/mol (quintile 5) had a 22% (HR, 1.22, 95% CI: 1.15-1.30) higher risk of COPD. Compared with the HbA1c decile 2 (30.5-<32.2 mmol/mol), the HRs (95% CI) of COPD risk were 1.16 (1.03-1.30) and 1.36 (1.24-1.50) in the lowest HbA1c decile (<30.5 mmol/mol) and highest decile (≥41.0 mmol/mol), respectively. The increased COPD risk associated with HbA1c was more pronounced in younger, current smokers, passive smokers, and participants with a higher Townsend deprivation index (all p for interaction < .05). Among patients with COPD, 4569 COPD cases died (488 because of COPD) during a median follow-up of 5.4 years. Regarding COPD survival, HbA1c had a non-linear relationship with all-cause death (p for non-linearity < .05). Those with HbA1c quintile 5 (≥38.7 mmol/mol) had a 23% (HR, 1.23, 95% CI: 1.10-1.37) higher risk of all-cause death compared with the quintile 2 (32.2-<34.3 mmol/mol). Compared with the HbA1c decile 4 (33.3-<34.3 mmol/mol), those in the lowest HbA1c decile (<30.5 mmol/mol) and highest HbA1c decile (≥41.0 mmol/mol) had 22% (HR, 1.22; 95% CI: 1.01-1.47) and 28% (HR, 1.28; 95% CI: 1.11-1.48) higher risk for overall death. However, no significant association was observed between HbA1c levels and the risk of COPD-specific death.

CONCLUSIONS

Our findings indicated that lower and higher HbA1c levels were associated with a higher risk of COPD. In COPD cases, lower and higher HbA1c levels were associated with a higher COPD all-cause death risk.

Trend of passive smoking and associated factors in Iranian children and adolescents: the CASPIAN studies

Background

It is well documented that, similar to active smokers, passive smokers are also at an increased risk of developing non-communicable diseases, and it could impose high financial costs on the healthcare system. This study aimed to evaluate the trend of passive smoking and related determinants during the three phases of a school-based surveillance program.

Methods

This is a secondary study using the national data obtained from three phases of the surveillance program entitled The Childhood and Adolescence Surveillance and Prevention of Adult Noncommunicable Disease (CASPIAN) study, conducted from 2008 to 2014 on Iranian children and adolescents living in urban and rural areas of 30 provinces in Iran. Participants were selected by cluster multistage sampling method.

Results

Overall, the study participants consisted of 33,288 students (50.5% boys) with a mean (± SD) age of 12.8 ± 3.2 years. The passive smoking rate was significantly increased from 35.6% in 2008 to 43.2% in 2015 among children and adolescents. According to the multivariate logistic regression, father’s university education, mother’s employment, life satisfaction, and socioeconomic status had a protective role regarding second-hand smoke exposure. In contrast, the father’s self-employment had a positive role in increasing the rate of passive smoking.

Conclusion

Considering the increasing trend of passive smoking and its considerable adverse health effects, it is necessary to implement large-scale public interventions to reduce the rate and hazards of exposure to tobacco smoke.

Association between parents' smoking status and tobacco exposure in school-age children: assessment using major urine biomarkers

Children are at risk of exposure to secondhand smoke. We aimed to evaluate the extent of their exposure to it in relation to their parents' smoking status by using biomarkers relevant to smoking. We evaluated 847 school-age children (6-12 years) who lived with their parents, using data from the Korea National Health and Nutrition Examination Survey 2016-2018. Secondhand smoke exposure in children of non-smoking and smoking parents was assessed by measuring urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and cotinine concentrations. Overall, the parents of 482 (55.1%) children smoked and those of 392 (44.9%) children did not smoke. After adjusting for covariates, significantly higher concentrations of NNAL (β = 0.482, standard error [S.E.] = 0.065, P < 0.001) and cotinine (β = 0.472, S.E. = 0.06, P < 0.001) were found in children of smoking parents than in children of non-smoking parents. Children of parents who smoked a higher number of cigarettes showed higher NNAL and cotinine concentrations than children of non-smoking parents. Children with both parents who smoked showed the highest NNAL and cotinine concentrations. Children of smoking parents are at a higher risk of exposure to secondhand smoke. A smoke-free environment must be maintained to protect children from the harmful effects of secondhand smoke. Therefore, comprehensive national anti-smoking policies are required.

Longitudinal association between environmental tobacco smoke exposure and behavioral problems in children from ages 5 to 9

Few studies have assessed the cumulative effects of exposure to environmental tobacco smoke (ETS¹) in relation to children's neurobehavioral problems over time. We assessed the longitudinal associations between ETS exposure at age 5 and behavioral problems at ages 5, 7, and 9 using the Ewha Birth and Growth Cohort, in Seoul, Korea. Children with available urinary cotinine levels at age 5 and one or more behavioral problem scores measured with the Korean Version of Child Behavior Checklist (CBCL²) at age 5, 7, and 9 were included in the study. Those whose mothers smoked during pregnancy were excluded, and a total of 179 children were included in the analysis. A linear mixed-model analysis using a REPEATED statement was conducted to assess whether ETS exposure was associated with the total, internalizing, and externalizing behavioral problem scores of the CBCL. The group with higher levels of cotinine showed continuously higher total and external behavioral problem scores from ages 5 to 9, which was seen after adjusting for preterm birth, father's education level, and television watching time. In addition, the difference in the total and external behavioral problem scores between the higher and lower cotinine groups at age 5 was statistically significant after a Bonferroni correction (p = 0.02 and 0.04, respectively), even though the fixed effect of cotinine level was almost but not statistically significant (p = 0.07 and 0.08, respectively). The results of this longitudinal cohort study provide evidence regarding the negative effects of ETS exposure in early childhood and their behavioral problems over time. This study supports the strengthening of anti-smoking policies used in educational interventions for parents, in order to reduce early ETS exposure in children.

Exposure to indoor air pollution across socio-economic groups in high-income countries: A scoping review of the literature and a modelling methodology

Disparities in outdoor air pollution exposure between individuals of differing socio-economic status is a growing area of research, widely explored in the environmental health literature. However, in developed countries, around 80% of time is spent indoors, meaning indoor air pollution may be a better proxy for personal exposure. Building characteristics - such as build quality, volume and ventilation - and occupant behaviour, mean indoor air pollution may also vary across socio-economic groups, leading to health inequalities. Much of the existing literature has focused on inequalities in exposure to outdoor air pollution, and there is thus a lack of an evidence base reviewing data for indoor environments. In this study, a scoping review of the literature on indoor air pollution exposures across different socio-economic groups is performed, examining evidence from both monitoring and modelling studies in the developed world. The literature was reviewed, identifying different indoor pollutants, definitions for socio-economic status and pre- and post- housing interventions. Based on the review, the study proposes a modelling methodology for evaluating the effects of environmental policies on different socio-economic populations. Using a sample size calculation, obstacles in obtaining sufficiently large samples of monitored data are demonstrated. A modelling framework for the rapid quantification of daily home exposure is then outlined as a proof of concept. While significant additional research is required to examine inequalities in indoor exposures, modelling approaches may provide opportunities to quantify exposure disparities due to housing and behaviours across populations of different socio-economic status.

Prevalence of secondhand smoke exposure at home and associated factors among middle school students in Northern Thailand

INTRODUCTION

One-third of youths in Thailand will be exposed to secondhand smoke (SHS) from family members who are smokers. This research aims to study the prevalence of and factors associated with SHS exposure at home among middle school students in Northern Thailand.

METHODS

This study used a cross-sectional survey. The sample was 780 middle school students in Northern Thailand. A self-administered questionnaire was used for data collection and analyses were performed using a chi-squared test and multiple logistic regression.

RESULTS

Of the respondents, 46.8% reported that they had been exposed to SHS at home. The main SHS sources were from fathers (45.4%), relatives (24.1%), siblings (12.4%), mothers (3.3%), and neighbours and guests (14.8%). The factors associated with SHS exposure at home included: household members who were smokers (OR=7.43; 95% CI: 5.17–10.68; p<0.001), home without a smoke-free rule (OR=3.40; 95% CI: 1.85–6.24; p<0.001), household members who were alcohol drinkers (OR=2.29; 95% CI: 1.59–3.30; p<0.001), and living in homes with ≤3 rooms (OR=1.79; 95% CI: 1.21–2.63; p=0.003).

CONCLUSIONS

Thai student’s exposure to SHS at home is high, especially when household members smoke and they live in a home without a smoke-free rule. Our findings highlight the need for policies and interventions to establish smoke-free homes.

Household environmental tobacco smoke exposure in healthy young children in Hong Kong: Prevalence and risk factors

Background

Environmental tobacco smoke (ETS) exposure attributable respiratory illness burden is huge in paediatric population. Understanding the epidemiology of ETS exposure is important to guide health promotion planning. Therefore, we designed this study to determine the prevalence of household ETS exposure in healthy young children under 2 years of age in Hong Kong, and to explore risk factors associated with the exposure. Our secondary goal was to characterise children’s exposure profile to maternal smoking.

Methods

A secondary analysis was performed based on the data collected from our 2013–2014 territory-wide cross-sectional pneumococcal carriage surveillance study, with a sample size of 1541. We conducted descriptive analysis for exposure prevalence, univariate and multivariate analysis for identification of risk factors.

Results

1541 children (mean age: 11.2 ± 6.4 months, male: 50.7%) were included in the analysis. The overall prevalence of current household ETS exposure was 31.5%, prevalence of prenatal and postnatal maternal smoking was 3.5% and 1.6% respectively. Independent factors associated with children’s ETS exposure were: never breastfed (AOR: 1.48, 95% CI: 1.13–1.93, p = 0.004); prenatal maternal smoking (AOR: 7.46, 95% CI: 2.73–20.39, p< 0.001); overcrowding of household living place (AOR: 3.17, 95% CI: 2.02–4.96, P< 0.001); lower household income (AOR: 1.34, 95% CI: 1.04–1.72, p = 0.02). Interestingly, children residing in Kowloon (AOR: 1.66, 95% CI: 1.19–2.33, p = 0.003) and New Territories West (AOR: 1.54, 95% CI: 1.11–2.15, p = 0.01) were associated with exposure compared with children residing in Hong Kong Island.

Conclusion

Exposure to household ETS is prevalent among Hong Kong young children, particularly in children with maternal unfavourable behaviour and lower socioeconomic status. The identified risk factors should be considered while tobacco control interventions and legislations are planned.

Second-hand smoke prevalence in 252 regions of South Korea in three exposure locations

PURPOSE

The association between regional contextual factors and second-hand smoke (SHS) prevalence is important, but is unclear. This study investigated the changes of SHS prevalence from 2011 to 2013 and explored the correlations of SHS prevalence and regional contextual factors by exposure location.

METHODS

The data were obtained from the 2011 and 2013 Korean Community Health Survey and the Development of Health Indicators for Community Health Ranking report. A t-test was used to examine and compare the SHS prevalence in 2011 and 2013 by exposure location (home, workplace, and public places). A correlation analysis and linear regression were used to investigate the impacts of the regional variables on SHS prevalence by location.

RESULTS

The prevalence of SHS in all three locations had a decreased trend overall, but remained high in public locales. There were clear differences in the prevalence of SHS and its change by region between 2011 and 2013. The SHS prevalence in the workplace and public places had increased in the high social and economic characteristic regions, compared to the other regions in 2 years. The SHS had an increased trend in regions featuring a high level of socioeconomic development. It was observed that regional factors affecting SHS prevalence differed in the three locations.

CONCLUSION

The differences and changes of regional SHS prevalence by location were influenced by specific social contextual factors of the particular region. Local government initiatives regarding special SHS protective measures or tailored regulations, according to specific regional status and location, are recommended, with attention to high socioeconomic regions in particular.

Impact of Presence of Children on Indoor Tobacco Restrictions in Households of Urban and Rural Adult Tobacco Users

OBJECTIVES

Secondhand smoke exposure in children is changing as a result of new public policy and electronic nicotine products (e-cigarettes). We examined factors related to self-imposed indoor household tobacco restrictions, with emphasis on children in the household and associations with combustible and noncombustible product use.

METHODS

A cross-sectional survey of urban and rural Ohio adult tobacco users classified participants as exclusive combustible users, smokeless tobacco (SLT) users, e-cigarette users, or dual users. They were further stratified according to combustible or noncombustible product use and the presence of indoor tobacco use restrictions. Multiple logistic regression determined factors associated with indoor tobacco restrictions.

RESULTS

A total of 1210 tobacco users participated, including 25.7% with children living in the home. Half allowed combustible and two thirds allowed noncombustible tobacco use indoors. Urban location (odds ratio [OR] = 1.58), younger age (OR = 0.88 per 5 year), male sex (OR = 1.40), college education (OR = 1.40), household income of more than $15,000 (OR = 1.78), and being married (OR = 2.43) were associated with a higher likelihood of banning combustible products indoors. SLT (OR = 8.12) and e-cigarette (OR = 5.85) users were more likely to have indoor bans compared to combustible users. Children in the household (OR = 1.89), older age (OR = 1.12 per 5 years), and nonwhite race (OR = 1.68) were associated with a higher likelihood of banning noncombustible products indoors. Combustible (OR = 4.54) and e-cigarette (OR = 3.04) users were more likely than SLT users to have indoor bans.

CONCLUSIONS

Indoor restrictions on tobacco use remain infrequent in homes with children and are associated with user type and socioeconomic factors. Public policy should target modifiable risk factors for in-home secondhand smoke exposure.

Environmental Tobacco Smoke Exposure at Home and High-Sensitivity C-Reactive Protein Levels in Three-to-Five-Year-Old Children

Exposure to harmful environmental factors is particularly detrimental to younger children. We investigated the relationship between environmental tobacco smoke (ETS) exposure in pre-schoolers at home and the level of high-sensitivity C-reactive protein (hs-CRP), a predictive factor for cardiovascular disease. This study was conducted in 2014 and was based on the data of preschool children from the Korean Environmental Health Survey in Children and Adolescents (2012 to 2014), a nationally representative sample. Of 577 children, aged three to five years, 482 were eventually selected for the analysis after excluding those with missing variables, or whose hs-CRP level exceeded the reference value. The proportion of pre-school children exposed to ETS at home was 14.8%. The odd ratios (OR)s of hs-CRP > 1mg/L were 4.90 (95% Confidence Interval (CI) = 1.04-23.17) and 11.66 (95% CI = 1.90-71.65) in the groups exposed to ETS 3-4 times and ≥5 times daily, respectively, compared to the non-exposed group. The risk of elevated levels of hs-CRP showed an increasing trend proportionally to the increase in ETS exposure frequency (p for trend = 0.03). Anti-smoking educational programs for parents and guardians may be helpful to reduce ETS exposure at home.

Effectiveness of government anti-smoking policy on non-smoking youth in Korea: a 4-year trend analysis of national survey data

OBJECTIVES

Since the Health Promotion Act was introduced in Korea in 1995, anti-smoking policies and regulations have undergone numerous revisions, and non-smoking areas have gradually been expanded. The purpose of this study was to examine the impact of a partial legislative ban on adolescent exposure to secondhand smoke using objective urinary cotinine levels in a nationwide representative sample.

METHODS

Urine cotinine levels were measured in the Korea National Health and Nutrition Examination Survey from 2008 to 2011. This study was a trend analysis of 4 years of national survey data from 2197 Korean youth aged 10-18 years. Among non-smokers, the 75th percentile urinary cotinine level was estimated. We also considered the number of household smokers.

RESULTS

The 75th percentile urine cotinine level of non-smokers showed a significant decreasing trend from 2008 to 2011, from 15.47 to 5.37 ng/mL, respectively. Urine cotinine did not decline significantly in non-smokers living with smokers during the study period. The results did not show a statistically significant reduction in smoking rate in adolescents from 2008 to 2011, although there was a trend towards a decrease (p=0.081).

CONCLUSIONS

Based on urine cotinine levels, government-initiated anti-smoking policies have only been effective among highly exposed non-smoking adolescents during the study period. Further study needs to evaluate whether or not the legislative ban affects domestic smoking exposure.

Secondhand Smoke Exposure and Low Blood Lead Levels in Association With Attention-Deficit Hyperactivity Disorder and Its Symptom Domain in Children: A Community-Based Case-Control Study

AIM

Secondhand smoke (SHS) is a major indoor pollutant. We examined the possible association between exposure to both SHS and low levels of lead and attention-deficit-hyperactivity disorder (ADHD) and its symptom domain in children.

METHODS

This case-control study was based on the results of a community survey using the ADHD rating scale conducted in 49 elementary schools. Both cases and control subjects were confirmed by a child psychiatrist. Each case was matched with one control subject according to gender, school, and grade in school. Using a multivariate conditional logistic regression model, we analyzed 214 case-control pairs of children who ranged in age from 6 to 10 years. Urine and blood levels of cotinine and of lead were determined, and information pertaining to SHS exposure was obtained by means of a questionnaire.

RESULTS

Exposure to low levels of lead (geometric mean = 1.65 µg/dL) was related to ADHD, particularly inattention (odds ratio [OR] = 1.67, 95% confidence interval [CI] = 1.07-2.59), whereas SHS exposure was associated mainly with hyperactivity/impulsivity (OR = 3.85, 95% CI = 1.55-9.56). In the pathway from blood lead to hyperactivity/impulsivity, children's SHS exposure mediated and indirectly accounted for about 73% of this relationship. The combined exposure to lead and SHS synergistically increased the risk of ADHD, evident as both inattention and hyperactivity/impulsivity.

CONCLUSION

SHS, which is associated with hyperactivity/impulsivity in particular, combined with exposure to low blood levels of lead synergistically increased the risk of ADHD. Therefore, the exposure of children to both SHS and lead needs to be reduced.

IMPLICATIONS

Although exposure to low levels of lead has been shown to be associated with ADHD, there is little evidence of symptom domain specificity. In our study, low blood lead levels were related to inattention. In addition, prenatal or postnatal exposure to SHS increased the risk of ADHD, particularly hyperactivity/impulsivity. Combined exposure to lead and SHS synergistically increased the risk for both these ADHD symptom domains. To protect children from environmental risk factors related to ADHD, it is necessary to further reduce children's exposure to SHS and lead, even in those with low blood lead levels.

Affecting Factors of Secondhand Smoke Exposure in Korea: Focused on Different Exposure Locations

Exposure to secondhand smoke (SHS) not only can cause serious illness, but is also an economic and social burden. Contextual and individual factors of non-smoker exposure to SHS depend on location. However, studies focusing on this subject are lacking. In this study, we described and compared the factors related to SHS exposure according to location in Korea. Regarding individual factors related to SHS exposure, a common individual variable model and location-specific variable model was used to evaluate SHS exposure at home/work/public locations based on sex. In common individual variables, such as age, and smoking status showed different relationships with SHS exposure in different locations. Among home-related variables, housing type and family with a single father and unmarried children showed the strongest positive relationships with SHS exposure in both males and females. In the workplace, service and sales workers, blue-collar workers, and manual laborers showed the strongest positive association with SHS exposure in males and females. For multilevel analysis in public places, only SHS exposure in females was positively related with cancer screening rate. Exposure to SHS in public places showed a positive relationship with drinking rate and single-parent family in males and females. The problem of SHS embodies social policies and interactions between individuals and social contextual factors. Policy makers should consider the contextual factors of specific locations and regional and individual context, along with differences between males and females, to develop effective strategies for reducing SHS exposure.

Exposure to Hookah and Cigarette Smoke in Children and Adolescents According to Their Socio-Economic Status: The CASPIAN-IV Study

Background

Exposure to smoking or passive smoking is one of serious health problems especially in the pediatric age group.

Objectives

To compare the prevalence and determinants of passive smoking in a nationally representative sample of Iranian children and adolescents according to their socioeconomic status (SES).

Materials and Methods

This nationwide study was conducted in 2011 - 2012 among 14880 students aged 6 - 18 years, living in 30 provinces in Iran. Exposure to the smoke of hookah or cigarette was documented by using validated questionnaires. Possible influencing factors were determined and the frequency of passive smoking was compared according to the regional and familial SES.

Results

Participants consisted of 13,486 children and adolescents including 49.2% girls and 75.6% urban inhabitants (90.6% participation rate). The mean age of participants was 12.47 ± 3.36 years. Overall, 43.87% of them (44.07% of boys and 43.66% of girls) were exposed to second hand smoke at home. Exposures to hookah or cigarette smoke at home were respectively reported in 21.46% and 34.49% of participants. The prevalence of passive smoking was lower in children of families with higher SES level, but higher in high SES regions of the country than in low SES ones, and ranged from 39.2% in the region with lowest SES to 49.05% in the highest SES region. Higher education levels of fathers and mothers were significantly associated with lower frequency of passive smoking.

Conclusions

Exposure to second hand smoke is a major problem among Iranian children and adolescents. Low family SES and low parental education increased the frequency of passive smoking. Appropriate public health education and legislation for smoke free home as well as family-centered counseling should be strengthened.

Social disparities in parental smoking and young children's exposure to secondhand smoke at home: a time-trend analysis of repeated cross-sectional data from the German KiGGS study between 2003-2006 and 2009-2012

Background

Children who are exposed to secondhand smoke (SHS) have an increased risk of a wide range of health problems and illnesses. Smoke-free legislation aims to improve indoor air quality and in this way protect the health of people who do not smoke. This paper examines trends in SHS exposure at home among children in Germany since the introduction of smoking bans in public places. Special focus is placed on the importance of the family of origin’s socioeconomic status (SES) and on parental smoking behaviour.

Methods

The analyses are based on two waves of the “German Health Interview and Examination Survey for Children and Adolescents” (KiGGS)—one of which was conducted immediately before the introduction of central smoke-free legislation in the 2003-2006 period, the other approximately 6 years later from 2009 to 2012. A comparison is made between the answers given by the parents of children aged between 0 to 6 (KiGGS baseline study, n = 6680; KiGGS Wave 1, n = 4455). Domestic SHS exposure is covered in the parent interviews by asking whether anyone is allowed to smoke at home in the presence of their child. Parental smoking behaviour is determined separately for mothers and fathers. SES is determined on the basis of the parents’ education, occupational status and income.

Results

The percentage of 0- to 6-year-old children exposed to SHS in the parental home fell from 23.9 to 6.6 % in the period from 2003-2006 to 2009-2012. At the same time, the percentage of children with at least one parent who smokes decreased from 49.8 to 41.8 %. While relative social inequalities in parental smoking behaviour have tended to increase over time, inequalities in domestic SHS exposure have persisted. Children whose parents smoke and children from low-SES families are still most likely to be exposed to tobacco smoke. In both study periods and after statistical adjustment for parental smoking behaviour, children with a low SES had a 6.6-fold higher risk for SHS exposure in the parental home than children from high-SES households.

Conclusions

The results of the KiGGS study show that the proportion of children in Germany who are exposed to SHS at home has declined significantly over the last few years. There is much to suggest that the smoke-free legislation that has been introduced in Germany has led to a heightened awareness of the health risks of SHS both in public and in the private sphere, as well as to a denormalization of smoking. Children whose parents smoke, and among them particularly children from socially disadvantaged families, should be recognised as key target groups when implementing future tobacco-control measures.

Regional Deprivation Index and Socioeconomic Inequalities Related to Infant Deaths in Korea

Deprivation indices have been widely used to evaluate neighborhood socioeconomic status and therefore examine individuals within their regional context. Although some studies on the development of deprivation indices were conducted in Korea, additional research is needed to construct a more valid and reliable deprivation index. Therefore, a new deprivation index, named the K index, was constructed using principal component analysis. This index was compared with the Carstairs, Townsend and Choi indices. A possible association between infant death and deprivation was explored using the K index. The K index had a higher correlation with the infant mortality rate than did the other three indices. The regional deprivation quintiles were unequally distributed throughout the country. Despite the overall trend of gradually decreasing infant mortality rates, inequalities in infant deaths according to the deprivation quintiles persisted and widened. Despite its significance, the regional deprivation variable had a smaller effect on infant deaths than did individual variables. The K index functions as a deprivation index, and we may use this index to estimate the regional socioeconomic status in Korea. We found that inequalities in infant deaths according to the time trend persisted. To reduce the health inequalities among infants in Korea, regional deprivation should be considered.

Socioeconomic disparities in household secondhand smoke exposure among non-smoking adolescents in the Republic of Korea

This nationally representative study examined (a) gender and age differences in household secondhand smoke exposure (HSHSE) and (b) associations between socioeconomic status (SES) and HSHSE among non-smoking Korean adolescents. Two subsamples were analysed: males (n = 25,648) and females (n = 30,240). The HSHSE measures were incidence of HSHSE (yes/no) and number of days of HSHSE (1-7 days); the SES measures were parental education, perceived economic status, and family wealth. For the first aim, chi-square test, t-test, and bivariate negative binomial regression analysis were performed; For the second aim, multivariate logistic regression and negative binomial regression analyses were performed. The incidence and number of days of HSHSE were significantly higher among females (32.35% and 3.48 days) than males (26.83% and 3.08 days). The HSHSE incidence was significantly higher among younger adolescents (23.32% to 31.08% of males and 26.58% to 37.03% of females). Lower SES was associated with (a) greater odds of HSHSE (odds ratio: 1.12-1.58 among males and 1.19-1.85 among females) and (b) greater incidence rates of HSHSE (incidence rate ratio: 1.05-1.17 among males and 1.10-1.14 among females). Efforts should be made to decrease HSHSE among adolescents, particularly low-SES youth.

Disparities in Children's Blood Lead and Mercury Levels According to Community and Individual Socioeconomic Positions

We aimed to examine the associations between blood lead and mercury levels and individual and community level socioeconomic positions (SEPs) in school-aged children. A longitudinal cohort study was performed in 33 elementary schools in 10 cities in Korea. Among a total of 6094 children included at baseline, the final study population, 2281 children followed-up biennially, were analyzed. The geometric mean (GM) levels of blood lead were 1.73 μg/dL (range 0.02–9.26) and 1.56 μg/dL (range 0.02–6.83) for male and female children, respectively. The blood lead levels were significantly higher in males, children living in rural areas, and those with lower individual SEP. The GM levels of blood mercury were 2.07 μg/L (range 0.09–12.67) and 2.06 μg/L (range 0.03–11.74) for males and females, respectively. Increased blood mercury levels were significantly associated with urban areas, higher individual SEP, and more deprived communities. The risk of high blood lead level was significantly higher for the lower individual SEP (odds ratio (OR) 2.18, 95% confidence interval (CI) 1.36–3.50 in the lowest educational attainment of the father), with a significant dose-response relationship observed after adjusting for the community SEP. The association between high blood lead levels and lower individual SEP was much stronger in the more deprived communities (OR 2.88, 95% CI 1.27–6.53) than in the less deprived communities (OR 1.40, 95% CI 0.76–2.59), and showed a significant decreasing trend during the follow-up only in the less deprived communities. The risk of high blood mercury levels was higher in higher individual SEP (OR 0.64, 95% CI 0.40–1.03 in the lowest educational attainment of the father), with a significant dose-response relationship noted. Significant decreasing trends were observed during the follow-up both in the less and more deprived communities. From a public health point-of-view, community level intervention with different approaches for different metals is warranted to protect children from environmental exposure.

Predictors of children's secondhand smoke exposure at home: a systematic review and narrative synthesis of the evidence

BACKGROUND

Children's exposure to secondhand smoke (SHS) has been causally linked to a number of childhood morbidities and mortalities. Over 50% of UK children whose parents are smokers are regularly exposed to SHS at home. No previous review has identified the factors associated with children's SHS exposure in the home.

AIM

To identify by systematic review, the factors which are associated with children's SHS exposure in the home, determined by parent or child reports and/or biochemically validated measures including cotinine, carbon monoxide or home air particulate matter.

METHODS

Electronic searches of MEDLINE, EMBASE, PsychINFO, CINAHL and Web of Knowledge to July 2014, and hand searches of reference lists from publications included in the review were conducted.

FINDINGS

Forty one studies were included in the review. Parental smoking, low socioeconomic status and being less educated were all frequently and consistently found to be independently associated with children's SHS exposure in the home. Children whose parents held more negative attitudes towards SHS were less likely to be exposed. Associations were strongest for parental cigarette smoking status; compared to children of non-smokers, those whose mothers or both parents smoked were between two and 13 times more likely to be exposed to SHS.

CONCLUSION

Multiple factors are associated with child SHS exposure in the home; the best way to reduce child SHS exposure in the home is for smoking parents to quit. If parents are unable or unwilling to stop smoking, they should instigate smoke-free homes. Interventions targeted towards the socially disadvantaged parents aiming to change attitudes to smoking in the presence of children and providing practical support to help parents smoke outside the home may be beneficial.

Surveillance of social and geographic inequalities in housing-related issues: the case of the Eastern Townships, Quebec (Canada)

Even though health inequalities are conditioned by many aspects of the environment, much of the existing research focuses on the social environment. This emphasis has the effect to neglect other environmental aspects such as its physical dimension. The physical environment, which is linked to housing conditions, may contribute to the uneven distribution of health. In this study, we examined 19 housing-related issues among a representative sample of 2,000 adults residing in a Quebec (Canada) health region characterized by a mix of rural, semi-rural, and urban areas. The distribution of these issues was examined according to socioeconomic and geographic indicators of social position. Summary measures of inequalities were assessed. Our results showed that the prevalence of nearly all housing-related issues was higher among low-income households compared to more affluent ones. Highly educated individuals showed better housing conditions, whereas different issues tended to cluster in deprived or densely populated areas. To conclude, we observed steep gradients between social class and poor housing conditions. This may explain a substantial part of health inequality on the regional scale. The surveillance of housing-related issues is therefore essential to properly inform and mobilize local stakeholders and to develop interventions that target vulnerable groups on this level.

Association between wheeze and selected air pollution sources in an air pollution priority area in South Africa: a cross-sectional study

BACKGROUND

An association between wheeze (a symptom of asthma) and environmental tobacco smoke (ETS), types of fuel used for residential heating or cooking and the frequency of trucks passing near homes, has been reported mainly in developed countries. Little is known about the strength of such associations in developing countries. This study was conducted in residential areas situated in Ekurhuleni Metropolitan Municipality, namely Tembisa and Kempton Park, which form part of the Highveld region, a priority area in terms of air pollution in South Africa.

METHODS

From 3764 eligible school children, aged between 13 and 14 years, from 16 selected high schools in the study area, 3468 completed a modified questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC). Data were analysed using multiple logistic regression models.

RESULTS

The results are based on data from 3424 children. In the adjusted models, exposure to ETS at school was associated with wheeze ever (OR 1.22 95% CI: 1.03 - 1.45) and current wheeze (OR 1.33 95% CI: 1.08 - 1.64). When gas was most frequently used for residential heating the likelihood of wheeze ever increased by 47% (OR 1.47 95% CI: 1.15 - 1.88). Trucks passing near homes for almost the whole day during weekdays, increased the likelihood of wheeze ever (OR 1.32 95% CI: 1.01 - 1.73), current wheeze (OR 1.61 95% CI: 1.15 - 2.24) and current severe wheeze (OR 2.22 95% CI: 1.28 - 3.77). When data were stratified according to residential area, for children living in Tembisa, ETS exposure at home was associated with current wheeze (OR 1.36 95% CI: 1.06 - 1.77); gas most frequently used for residential heating was associated with wheeze ever (OR 1.68 95% CI: 1.23 - 2.28) and current wheeze (OR 1.61 95% CI: 1.08 - 2.39); paraffin most frequently used for residential heating was associated with current severe wheeze (OR 1.85 95% CI: 1.04 - 3.28).

CONCLUSION

It was concluded that children living in one of the air pollution priority areas of South Africa, have an increased risk of wheezing due to exposure to both indoor and outdoor air pollution sources.

Korean Environmental Health Survey in Children and Adolescents (KorEHS-C): survey design and pilot study results on selected exposure biomarkers

For the first nationwide representative survey on the environmental health of children and adolescents in Korea, we designed the Korean Environmental Health Survey in Children and Adolescents (KorEHS-C) as a two-phase survey and planned a sampling strategy that would represent the whole population of Korean children and adolescents, based on the school unit for the 6-19 years age group and the household unit for the 5 years or less age group. A pilot study for 351 children and adolescents aged 6 to 19 years in elementary, middle, and high school of two cities was performed to validate several measurement methods and tools, as well as to test their feasibility, and to elaborate the protocols used throughout the survey process. Selected exposure biomarkers, i.e., lead, mercury, cadmium in blood, and bisphenol A, metabolites of diethylhexyl phthalate and di-n-butyl phthalate and cotinine in urine were analyzed. We found that the levels of blood mercury (Median: 1.7 ug/L) and cadmium (Median: 0.30 ug/L) were much higher than those of subjects in Germany and the US, while metabolites of phthalates and bisphenol A showed similar levels and tendencies by age; the highest levels of phthalate metabolites and bisphenol A occurred in the youngest group of children. Specific investigations to elucidate the exposure pathways of major environmental exposure need to be conducted, and the KorEHS-C should cover as many potential environmental hazards as possible.