Guang-Hui Dong

Gender difference of childhood overweight and obesity in predicting the risk of incident asthma: a systematic review and meta-analysis

The aims of our meta‐analysis were (i) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; and (ii) to evaluate the gender difference on this relationship. The selection criteria included prospective cohort paediatric studies which use age‐ and sex‐specific body mass index (BMI) as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1,027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non‐overweight children (relative risk, 1.19; 95% confidence interval [CI], 1.03–1.37). The relationship was further elevated for obesity vs. non‐obesity (relative risk, 2.02; 95% CI, 1.16–3.50). A dose–responsiveness of elevated BMI on asthma incidence was observed (P for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57–3.87; girls: 1.25; 95% CI, 0.51–3.03), with significant dose‐dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity–asthma relationship.

Association between long-term air pollution and increased blood pressure and hypertension in China.

Several studies have investigated the short-term effects of ambient air pollutants in the development of high blood pressure and hypertension. However, little information exists regarding the health effects of long-term exposure. To investigate the association between residential long-term exposure to air pollution and blood pressure and hypertension, we studied 24 845 Chinese adults in 11 districts of 3 northeastern cities from 2009 to 2010. Three-year average concentration of particles with an aerodynamic diameter ⩽10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated from monitoring stations in the 11 districts. We used generalized additive models and 2-level logistic regressions models to examine the health effects. The results showed that the odds ratio for hypertension increased by 1.12 (95% confidence interval [CI], 1.08–1.16) per 19 &mgr;g/m3 increase in PM10, 1.11 (95% CI, 1.04–1.18) per 20 &mgr;g/m3 increase in SO2, and 1.13 (95% CI, 1.06–1.20) per 22 &mgr;g/m3 increase in O3. The estimated increases in mean systolic and diastolic blood pressure were 0.87 mm Hg (95% CI, 0.48–1.27) and 0.32 mm Hg (95% CI, 0.08–0.56) per 19 &mgr;g/m3 interquartile increase in PM10, 0.80 mm Hg (95% CI, 0.46–1.14) and 0.31 mm Hg (95% CI, 0.10–0.51) per 20 &mgr;g/m3 interquartile increase in SO2, and 0.73 mm Hg (95% CI, 0.35–1.11) and 0.37 mm Hg (95% CI, 0.14–0.61) per 22 &mgr;g/m3 interquartile increase in O3. These associations were only statistically significant in men. In conclusion, long-term exposure to PM10, SO2, and O3 was associated with increased arterial blood pressure and hypertension in the study population.

Long-term exposure to ambient air pollution and mortality due to cardiovascular disease and cerebrovascular disease in Shenyang, China.

Background The relationship between ambient air pollution exposure and mortality of cardiovascular and cerebrovascular diseases in human is controversial, and there is little information about how exposures to ambient air pollution contribution to the mortality of cardiovascular and cerebrovascular diseases among Chinese. The aim of the present study was to examine whether exposure to ambient-air pollution increases the risk for cardiovascular and cerebrovascular disease. Methodology/Principal Findings We conducted a retrospective cohort study among humans to examine the association between compound-air pollutants [particulate matter <10 µm in aerodynamic diameter (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2)] and mortality in Shenyang, China, using 12 years of data (1998–2009). Also, stratified analysis by sex, age, education, and income was conducted for cardiovascular and cerebrovascular mortality. The results showed that an increase of 10 µg/m3 in a year average concentration of PM10 corresponds to 55% increase in the risk of a death cardiovascular disease (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.51 to 1.60) and 49% increase in cerebrovascular disease (HR, 1.49; 95% CI, 1.45 to 1.53), respectively. The corresponding figures of adjusted HR (95%CI) for a 10 µg/m3 increase in NO2 was 2.46 (2.31 to 2.63) for cardiovascular mortality and 2.44 (2.27 to 2.62) for cerebrovascular mortality, respectively. The effects of air pollution were more evident in female that in male, and nonsmokers and residents with BMI<18.5 were more vulnerable to outdoor air pollution. Conclusion/Significance Long-term exposure to ambient air pollution is associated with the death of cardiovascular and cerebrovascular diseases among Chinese populations.

Prevalence, awareness, treatment, control, and risk factors associated with hypertension in urban adults from 33 communities of China: the Chpsne study

Objective To assess the prevalence, awareness, treatment, and control of hypertension and their associated factors in an urban Chinese population. Methods A cross-sectional study was conducted in three cities in northeast China from 2009 to 2010, using a multistage cluster sampling method to select a representative sample. A total of 25 196 adults, aged 18–74 years, were examined in 33 communities. Hypertension was defined as a mean SBP of at least 140 mmHg, DBP at least 90 mmHg, and/or use of antihypertensive medications. Results Overall, the prevalence of hypertension was 28.7% for urban residents, and 39.1% for middle-aged and elderly residents (aged ≥35 years). Among all the hypertensive patients examined in the study (n = 7237), 42.9% were aware of their condition, 28.2% were receiving treatment, and only 3.7% had their blood pressure adequately controlled. Female hypertensive patients had more effectively controlled blood pressure than their male counterparts. Among the study participants, 37.9% did not think that high blood pressure would endanger their lives. Among hypertensive patients aware of their conditions, the primary reason for not taking antihypertensive medication was a lack of money (34.8%). Age, sex, education, occupation, income, body mass, waist circumference, and family hypertension history significantly correlated with the prevalence of hypertension. Conclusion Hypertension is highly prevalent in the urban population of China, and the effects of being overweight/obesity on hypertension were much larger than any other examined factors. The percentage of hypertensive patients aware of their condition, receiving proper treatment, and keeping their hypertension under control is unacceptably low.

Gender Differences and Effect of Air Pollution on Asthma in Children with and without Allergic Predisposition: Northeast Chinese Children Health Study

Background Males and females exhibit different health responses to air pollution, but little is known about how exposure to air pollution affects juvenile respiratory health after analysis stratified by allergic predisposition. The aim of the present study was to assess the relationship between air pollutants and asthmatic symptoms in Chinese children selected from multiple sites in a heavily industrialized province of China, and investigate whether allergic predisposition modifies this relationship. Methodology/Principal Findings 30139 Chinese children aged 3-to-12 years were selected from 25 districts of seven cities in northeast China in 2009. Information on respiratory health was obtained using a standard questionnaire from the American Thoracic Society. Routine air-pollution monitoring data was used for particles with an aerodynamic diameter ≤10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), ozone (O3) and carbon monoxide (CO). A two-stage regression approach was applied in data analyses. The effect estimates were presented as odds ratios (ORs) per interquartile changes for PM10, SO2, NO2, O3, and CO. The results showed that children with allergic predisposition were more susceptible to air pollutants than children without allergic predisposition. Amongst children without an allergic predisposition, air pollution effects on asthma were stronger in males compared to females; Current asthma prevalence was related to PM10 (ORs = 1.36 per 31 µg/m3; 95% CI, 1.08–1.72), SO2 (ORs = 1.38 per 21 µg/m3; 95%CI, 1.12–1.69) only among males. However, among children with allergic predisposition, more positively associations between air pollutants and respiratory symptoms and diseases were detected in females; An increased prevalence of doctor-diagnosed asthma was significantly associated with SO2 (ORs = 1.48 per 21 µg/m3; 95%CI, 1.21–1.80), NO2 (ORs = 1.26 per 10 µg/m3; 95%CI, 1.01–1.56), and current asthma with O3 (ORs = 1.55 per 23 µg/m3; 95%CI, 1.18–2.04) only among females. Conclusion/Significance Ambient air pollutions were more evident in males without an allergic predisposition and more associations were detected in females with allergic predisposition.

Serum polyfluoroalkyl concentrations, asthma outcomes, and immunological markers in a case-control study of Taiwanese children.

Background: Perfluorinated compounds (PFCs) are ubiquitous pollutants. Experimental data suggest that they may be associated with adverse health outcomes, including asthma. However, there is little supporting epidemiological evidence. Methods: A total of 231 asthmatic children and 225 nonasthmatic controls, all from northern Taiwan, were recruited in the Genetic and Biomarkers study for Childhood Asthma. Structure questionnaires were administered by face-to-face interview. Serum concentrations of 11 PFCs and levels of immunological markers were also measured. Associations of PFC quartiles with concentrations of immunological markers and asthma outcomes were estimated using multivariable regression models. Results: Nine PFCs were detectable in most children (≥ 84.4%), of which perfluorooctane sulfonate (PFOS) was the most abundant (median serum concentrations of 33.9 ng/mL in asthmatics and 28.9 ng/mL in controls). Adjusted odds ratios for asthma among those with the highest versus lowest quartile of PFC exposure ranged from 1.81 (95% CI: 1.02, 3.23) for the perfluorododecanoic acid (PFDoA) to 4.05 (95% CI: 2.21, 7.42) for perfluorooctanic acid (PFOA). PFOS, PFOA, and subsets of the other PFCs were positively associated with serum IgE concentrations, absolute eosinophil counts (AEC), eosinophilic cationic protein (ECP) concentrations, and asthma severity scores among asthmatics. Conclusions: This study suggests an association between PFC exposure and juvenile asthma. Because of widespread exposure to these chemicals, these findings may be of potential public health concern.

Long-Term Exposure to Ambient Air Pollution and Respiratory Disease Mortality in Shenyang, China: A 12-Year Population-Based Retrospective Cohort Study

Background: In China, both the levels and patterns of outdoor air pollution have altered dramatically with the rapid economic development and urbanization over the past two decades. However, few studies have investigated the association of outdoor air pollution with respiratory mortality, especially in the high pollution range. Objective: We conducted a retrospective cohort study of 9,941 residents aged ≥35 years old in Shenyang, China, to examine the association between outdoor air pollutants [particulate matter <10 µm in aerodynamic diameter (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2)] and mortality using 12 years of data. Methods: We applied extended Cox proportional hazards modeling with time-dependent covariates to respiratory mortality. Analyses were also stratified by age, sex, educational level, smoking status, personal income, occupational exposure and body mass index (BMI) to examine the association of air pollution with mortality. Results: We found significant associations between PM10 and NO2 levels and respiratory disease mortality. Our analysis found a relative risk of 1.67 [95% confidence interval (CI) 1.60–1.74] and 2.97 (95% CI 2.69–3.27) for respiratory mortality per 10 µg/m3 increase in PM10 and NO2, respectively. The effects of air pollution were more apparent in women than in men. Age, sex, educational level, smoking status, personal income, occupational exposure, BMI and exercise frequency influenced the relationship between outdoor PM10 and NO2 and mortality. For SO2, only smoking, little regular exercise and BMI above 18.5 influenced the relationship with mortality. Conclusion: These data contribute to the scientific literature on the long-term effects of air pollution for the high-exposure settings typical in developing countries.

Epidemiology of general obesity, abdominal obesity and related risk factors in urban adults from 33 communities of northeast china: the CHPSNE study

BackgroundObesity increases the risk of many diseases. However, there has been little literature about the epidemiology of obesity classified by body mass index (BMI) or waist (abdominal obesity) among urban Chinese adults. This study is to fill the gap by assessing the prevalence of obesity and associated risk factors among urban Chinese adults.MethodsA representative sample of 25,196 urban adults aged 18 to 74 years in Northeast China was selected and measurements of height, weight and waist circumference (WC) were taken from 2009–2010. Definitions of overweight and obesity by the World Health Organization (WHO) were used.ResultsThe overall prevalence rates of general obesity and overweight classified by BMI were 15.0% (15.7% for men and 14.3% for women, p<0.01) and 19.2% (20.8% for men and 17.7% for women, p<0.01), respectively, and the overall prevalence rate of abdominal obesity was 37.6% (31.1% for men and women 43.9% for women, p<0.01). Multivariable logistic regression showed that the elderly and those who had a history of parental obesity, alcohol drinking, or former cigarette smoking were at high risk of obesity classified by BMI or WC, whereas those with a higher level of education, higher family income, or a healthy and balanced diet were at low risk of obesity. Analysis stratified by gender showed that men with a higher level education level, a white-collar job, a cadre job, or higher family income were the high risk group, and women with a higher level of education or higher family income were the low risk group.ConclusionsObesity and overweight have become epidemic in urban populations in China; associations of risk factors with obesity differ between men and women.

Body mass index compared with abdominal obesity indicators in relation to prehypertension and hypertension in adults: the CHPSNE study.

BACKGROUND Debate ensues regarding the stronger indicator of obesity, body mass index (BMI), or waist circumference (WC), in association with hypertension. Furthermore, little research has been done to compare BMI and WC in their associations with prehypertension. METHODS A cross-sectional survey was undertaken in 33 communities randomly selected from 3 cities in Northeastern China during 2009-2010, using a total of 25,196 adults aged 18-74 years with an overall response rate of 87.4%. Diagnoses of prehypertension and hypertension were based on the criteria set by the Seventh Report of the Joint National Committee. Generalized overweight and obesity were defined as BMI 25-29.9 and ≥30 kg/m(2), respectively. Abdominal overweight and obesity were defined as WC 94-102 and >102 cm in men and WC 80-88 and >88 cm in women, respectively. RESULTS Both BMI and WC were positively related to the prevalence rate of elevated blood pressure. Among younger individuals, aged 18-44 years, WC seemed to be associated with a higher odds ratio (OR) than BMI for hypertension (e.g., for men, 17.18 (BMI) vs. 23.28 (WC) for obesity), in contrast, BMI seemed to be associated with a higher OR than WC for prehypertension (e.g., for men, 5.99 (BMI) vs. 1.51 (WC) for obesity). Among older individuals, aged ≥45 years, the adjusted OR for hypertension was modestly higher for WC than for BMI in men. In women, the adjusted OR was modestly higher for BMI than for WC. CONCLUSIONS In this Chinese population, the association of body fat and abdominal fat with hypertension and prehypertension depends on age and sex.

Housing characteristics, home environmental factors and respiratory health in 3945 pre-school children in China

The objective of the study was to assess the effects of housing characteristics and home environmental factors on respiratory symptoms of Chinese children. A cross-sectional study of 3945 children aged 1–6-years-old was conducted at 24 randomly selected kindergartens in Liaoning province, northeast China during April 2007. Information on respiratory symptoms (persistent cough, persistent phlegm, doctor-diagnosed asthma, current asthma, current wheeze and allergic rhinitis) and exposures to home environmental factors was obtained by a standard questionnaire from the American Thoracic Society. We used Chi-square tests, multivariate logistic regression models and adjusted odds ratios (ORs) with 95% confidence intervals (95% CI) for estimates of the risk of respiratory symptoms. Results suggested that the prevalence of asthma-related symptoms was higher for those who lived along the main stem of traffic, and houses near a pollution source. Lower prevalence rates of respiratory morbidity were associated with households with a larger area of residence and more rooms. Pet keeping was associated with doctor-diagnosed asthma (OR = 1.45; 95% CI, 1.03–2.06). Among boys, home decorations significantly increased the risk of doctor-diagnosed asthma (OR = 1.71; 95% CI, 1.21–2.41), current asthma (OR = 1.80; 95% CI, 1.10–2.94) and current wheeze (OR = 1.81; 95% CI, 1.31–2.50). Environmental tobacco smoke, pests and visible mold on walls were associated with the occurrence of asthma symptoms, especially in boys. Based upon the findings of this study, it is concluded that home environmental factors are particularly important for the development of respiratory morbidity among children. Boys may be more susceptible to home environmental factors than girls.