Insight on genetic features prevalent in five Ipomoea species using comparative codon pattern analysis reveals differences in major codons and reduced GC content at the 5' end of CDS.

Ipomoea plants possess important commercial, medicinal, and ornamental value. Molecular and morphological studies have confirmed that most species of this genus exhibit similar phenotypes but complex phylogenetic relationships. To date, limited information is available on these evolutionary relationships. In this study, systematic analysis of diverse species from Ipomoea was used to elucidate the relationships in this genus. To this end, we employed the concept of codon usage bias (CUB) to analyze the codon usage bias of five Ipomoea species such as effective number of codons (ENC) and GC content at the third synonym codon position (GC3s). Three types of plots including ENC-GC3s, parity rule 2 (PR2) and neutrality plots were employed to discover the factors determining CUB, and the frequency of hydrogen bonds and nucleotide were calculated to dissect changes in GC content at the 5'-end of the coding sequence. Our results showed little distinctness in CUB among the five species, with a reduction of hydrogen bonds content at the 5'-end (with similar changes in cytosines). In addition, optimal codons of Ipomoea aquatica ended with G or C, different from those of the other four species, which ended in A or T. These results may be useful for exploring the evolutionary relationships among this group, and for understanding the reasons for the variation among Ipomoea species.

Indoor exposure to phthalates and its burden of disease in China.

China's profoundly rapid modernization in the past two decades has resulted in dramatic changes in indoor environmental exposures. Among these changes, exposure to phthalates has attracted increasing attention. We aimed to characterize indoor phthalate exposure and to estimate the disease burden attributable to indoor phthalate pollution from 2000 to 2017 in China. We integrated the national exposure level of indoor phthalates from literature through systematic review and Monte Carlo simulation. Dose-response relationships between phthalate exposure and health outcomes were obtained by systematic review and meta-analysis. Based on existing models for assessing probabilities of causation and a comprehensive review of available data, we calculated the disability-adjusted life years (DALYs) among the general Chinese population resulting from exposure to indoor phthalate pollution. We found that DnBP, DiBP, and DEHP were the most abundant phthalates in indoor environments of residences, offices, and schools with medians of national dust phase concentration from 74.5 µg/g to 96.3 µg/g, 39.6 µg/g to 162.5 µg/g, 634.2 µg/g to 1,394.7 µg/g, respectively. The national equivalent exposure for children to phthalates in settled dust was higher than that of adults except for DiBP and DnOP. Dose-response relationships associated with DEP, DiBP, DnBP, BBzP, and DEHP exposures were established. Between 2000 and 2017, indoor phthalate exposure in China has led to 3.32 million DALYs per year, accounting for 0.90% of total DALYs across China. The annual DALY associated with indoor phthalate pollution in China was over 2000 people per million, which is about 2~3 times of the DALY loss due to secondhand smoke (SHS) in six European countries or the sum of the DALY loss caused by indoor radon and formaldehyde in American homes. Our study indicates a considerable socioeconomic impact of indoor phthalate exposure for a modernizing human society. This suggest the need for relevant national standard and actions to reduce indoor phthalate exposure.

Lung cancer as adverse health effect by indoor radon exposure in China from 2000 to 2020: A systematic review and meta-analysis.

Indoor radon exposure is thought to be associated with adverse health effect as lung cancer. Lung cancer incidences in China have been the highest worldwide during the past two decades. It is important to quantitively address indoor radon exposure and its health effect, especially in countries like China. In this paper, we have conducted a meta-analysis based on indoor radon and its health effect studies from a systematic review between 2000 and 2020. A total of 8 studies were included for lung cancer. We found that the relative risk (RR) was 1.01 (95% CI: 1.01-1.02) per 10 Bq/m3 increase of indoor radon for lung cancer in China. The subgroup analysis found no significant difference between the conclusions from the studies from China and other regions. The health effect of indoor radon exposure is relatively consistent for the low-exposure and high-exposure groups in the subgroup analysis. With a better understanding of exposure level of indoor radon, the outcomes and conclusions of this study will provide supports for next phase of researches on estimation of environmental burden of disease by indoor radon exposures in countries like China.

Indoor exposure levels of radon in dwellings, schools, and offices in China from 2000 to 2020: A systematic review.

After decades of development, the indoor environment in China has changed. A systematic review was conducted from peer-reviewed scientific papers with field test data of indoor radon in China from 2000 to 2020 for three types of buildings. The mean concentrations of indoor radon for dwellings, school buildings, and office buildings are 54.6, 56.1, and 54.9 Bq/m3 . The indoor radon concentration was related to seasons, climate regions, ventilation, decoration, and other factors such as soil and outdoor air. Colder seasons, especially in severe colder areas of China, newer decorated buildings, closed windows, and doors were all associated with higher indoor radon concentrations. Variables like climate region and ventilation showed statistical significance in the correlation analysis. Regarding the increasing trend of indoor radon concentration in China during the last two decades, further study of indoor radon is necessary especially for school buildings and office buildings, and will help access its environmental burden of disease in China more accurately.

Time-trends for eczema prevalences among children and adults from 1985 to 2015 in China: a systematic review.

BACKGROUND: Several studies have reported that childhood prevalence of eczema has been increasing worldwide. However, none study quantitatively evaluated prevalence trends of eczema among children and adults in the last 30 years in China. METHODS AND FINDINGS: Via a systematic review of literature databases in English and Chinese, we summarized all studies reporting eczema prevalences from 1985 to 2015 in China as well as diagramed prevalence and eczematous population trends against year for different age groups. A total of 93 studies and 17 studies (16 for children and one for adults) were selected for qualitative and quantitative synthesis, respectively. Childhood lifetime-ever eczema prevalences ranged from 10.0% to 30.0%. Prevalences among 3-12-year-olds children showed increasing trends in most specific cities, but national lifetime-ever eczema prevalences among 13-14-year-olds children decreased from 10.6% in 2001 to 8.6% in 2009 in mainland China. We estimated that about 1.5 million children aged 13-14-year-olds in 2009 and 15.5 million children aged 3-6-year-olds in 2012 had lifetime-ever eczema in mainland China. Similar studies were too few to ascertain time-trends of eczema prevalence among adults. About 39.4, 20.0, and 11.6 million adults aged 15-86-year-olds in 2010 had contact dermatitis, seborrheic dermatitis, and atopic dermatitis in the mainland China, respectively. CONCLUSIONS: The burden of eczema became heavier in young children, whereas perhaps had been reduced in adolescent in China. More studies for eczema prevalence in adults are warranted.

Association of childhood rhinitis with phthalate acid esters in household dust in Shanghai residences.

OBJECTIVE: Phthalate acid esters (PAEs) have been identified to be associated with children's health. Present study was conducted to assess associations between PAEs in household dust and childhood rhinitis. METHODS: Based on phase II of CCHH study (China, Children, Home, Health) conducted in Shanghai, China, 266 indoor dust samples were collected from participants' families. Concentrations of PAEs in dust samples were measured by chemical treatment and gas chromatograph-mass spectrometer. Information about individuals and residences was surveyed by questionnaires. Logistic regression models were applied to obtain the associations between PAEs and childhood rhinitis. RESULTS: Higher concentrations of benzyl butyl phthalate (BBP) were found in those families with children who had diagnosed rhinitis. Significantly higher concentrations of bis(2-ethylhexyl) phthalate (DEHP) and PAEs with high molecular weight (HMW-PAEs) were found in the positive group of lifetime rhinitis. Using the multiple and ordinal logistic regression models adjusted by covariates, dibutyl phthalate (DBP), DEHP, and HMW-PAEs were found to be significantly associated with diagnosed rhinitis. Boys who exposure to higher concentrations of DBP, DEHP, HMW-PAEs, and total PAEs have significant associations with diagnosed rhinitis compared with girls who exposure to lower concentration of PAEs. CONCLUSIONS: Present observational study indicated that exposure to high concentrations of DBP, DEHP, and HMW-PAEs in house settled dust was a risk factor for rhinitis for children, especially for boys.

Associations between phthalic acid esters in household dust and childhood asthma in Shanghai, China.

Phthalic acid esters (PAEs) have a negative impact on human health and are widely distributed in China. As part of the China, Children, Home, Health (CCHH) study, we investigated the associations between childhood asthmatic symptoms and PAEs in settled house dust in Shanghai, China. We found that di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DiBP) were abundant in the indoor environment. A total of 27 % of children suffered from diagnosed asthma. The Mann-Whitney U test and multiple logistic regression were used to obtain the associations between PAEs and childhood asthmatic symptoms. Stratification analysis was performed to reveal the influence of gender on the associations between PAE exposure and target symptoms. Compared with low concentrations of PAEs, high concentrations of high molecular weight PAEs (HMW-PAEs) were significantly associated with childhood diagnosed asthma (adjusted odds ratios (AORs) > 1, P < 0.05). Moreover, significantly negative associations were found between high concentrations of DiBP and current cough (AORs<1, P < 0.05). All significantly positive associations were observed among girls, and most of the associations of dimethyl phthalate (DMP) and diethyl phthalate (DEP) exposure with the studied symptoms among girls were higher than those among boys. Exposure to PAEs may be a risk factor for asthmatic symptoms in children, especially in girls.

Gestational exposures to outdoor air pollutants in relation to low birth weight: A retrospective observational study.

Findings for impacts of outdoor air pollutants on birth outcomes were controversial. We performed a retrospective observational study in 2527 preschoolers of Shanghai, China and investigated associations of duration-averaged concentrations of outdoor sulphur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with an aerodynamic diameter ≤ 10 µm (PM10) in different months and trimesters of gestation, with preterm birth (PB), low birth weight (LBW), term low birth weight (T-LBW), and small for gestational age (SGA). Daily concentrations of outdoor air pollutants were collected in each residence-located district. Parents reported health information. In the multivariate logistic regression analyses, exposures to outdoor NO2 were consistently associated with the higher odds of LBW and T-LBW. These associations were generally stronger for early months than for later months of the gestation. Adjusted odds ratios generally were larger in multi-pollutant model than in single-pollutant model. Exposure to NO2 in the first month of the gestation was significantly associated with T-LBW (adjusted OR, 95%CI: 1.91, 1.02-3.58 for increment of interquartile range (18.5 µg/m3); p-value = 0.044) in multi-pollutant model. This association was stronger in girls, renters, and children whose mothers ≥30 years-old, with household dampness-related exposures, and with parental smoking during pregnancy. Our results indicate that exposure to NO2 during gestation perhaps is a risk factor for LBW and T-LBW, and effects of NO2 exposures could be greater during early periods than during later periods of gestation.

Indoor exposure levels of ammonia in residences, schools, and offices in China from 1980 to 2019: A systematic review.

Indoor ammonia (NH3 ) pollution has been paid more and more attention in view of its health risk. However, few studies have investigated the exposure level in the non-occupational environment in China. This study systematically reviewed the indoor ammonia exposure level in different regions, the equivalent exposure concentration of different populations, and the factors that influence indoor air ammonia in residences, offices, and schools in China. The literature published in 1980-2019 from main databases was searched and detailed screened, and finally, 56 related studies were selected. The results illustrated that the median concentration of indoor air ammonia in residences, offices, and school buildings was 0.21 mg/m3 , 0.26 mg/m3 , and 0.15 mg/m3 . There were 46.4%, 71.4%, and 40% of these samples exceeding the NH3  standard, respectively. The national concentrations and the equivalent exposure levels of adults and children were calculated and found to be higher than 0.20 mg/m3 . The concentration of ammonia varied greatly in different climate zones and economic development regions. Higher concentrations were found in the severe cold zone and the regions with higher economic level. This review reveals a high exposure risk of indoor air ammonia and the crucial impact of human emission, indoor air temperature, new concrete, and economic level, suggesting further investigation on indoor air ammonia evaluation and health effects.

Associations between household renovation and rhinitis among preschool children in China: A cross-sectional study.

During 2010-2012, we surveyed 40,010 3- to 6-year-old children in seven Chinese cities (Beijing, Taiyuan, Urumqi, Shanghai, Nanjing, Changsha, and Chongqing). Their parents reported information on household renovation, including the timing of renovation and the choice of materials for walls and floors in the child's room, and the incidence of their child's rhinitis. Multivariate and two-level (city-child) logistic regression analyses yielding adjusted odds ratios (AOR) with 95% confidence intervals were performed. Sensitivity analyses stratifying data for location and economic level were also performed. About 48.0% of the children had ever had allergic rhinitis, 41.2% had current allergic rhinitis, and 9.0% had had doctor-diagnosed rhinitis. Exposure to household renovation during early lifetime (birth to 1-year-old) had an AOR of 1.43 (1.04-1.9) for allergic rhinitis. The incidence of allergic rhinitis was significantly different in children exposed to different floor and wall covering materials. Floor or wall covering material composed of organic materials significantly increased the risk of childhood allergic rhinitis compared with tile flooring or lime wall covering. Oil paint had an AOR of 1.66 (1.28-2.14) for diagnosed rhinitis compared with lime wall covering. Adding new furniture the year before pregnancy was associated with an AOR of 1.18 (1.10-1.27) and 1.18 (1.11-1.25) for lifetime and current rhinitis. Solid wood or tiles/ceramic as floor materials, and using wallpaper, oil paint, or emulsion panels as wall materials were risk factors for doctor-diagnosed rhinitis. Sensitivity analyses showed that children living in southern or higher economic level China cities were more likely to have allergic rhinitis with household renovation.

High prevalence of eczema among preschool children related to home renovation in China: A multi-city-based cross-sectional study.

We surveyed 40 010 three- to six-year-old children in seven Chinese cities (Beijing, Taiyuan, Urumqi, Shanghai, Nanjing, Changsha, and Chongqing) during 2010-2012 so as to investigate possible links between home renovation and childhood eczema. Their parents responded to questions on home renovation and childhood eczema. Multivariate and two-level (city-child) logistic regression analyses yielding odds ratios with 95% confidence intervals were performed. Sensitivity analyses stratifying data for region, climate, and income level were also performed. The prevalences of childhood eczema in children with different floor and wall covering materials were significantly different and were significantly higher with home renovation during early lifetime. Exposure to synthetic materials significantly increased the risk of childhood eczema by 20%-25%. The risks (AOR, 95% CI) of current eczema among children in families with solid wood flooring and oil paint wall covering were 1.25 (1.04-1.49) and 1.35 (1.14-1.60), respectively. Home renovation during pregnancy was related to children's lifetime and current eczema.

Optical waveguide and room temperature high-quality nanolasers from tin-catalyzed CdSSe nanostructures.

A simple two-step CVD method is developed to realize the growth of high-quality tin-catalyzed CdSSe alloy nanowires. Microstructural characterizations demonstrate that these wires are high-quality crystalline nanostructures. Local photoluminescence investigation of these nanostructures shows a typical band edge emission at 656 nm with a full-width at half-maximum of 22.3 nm. Optical waveguide measurement along an individual nanowire indicates that the output signal of the guided light has a rapid linear decrease accompanied with maximum red-shift about 109 meV after the transmission of 102 µm. This obvious red-shift is caused by the intensive band-tail absorption during the optical transmission process. Moreover, optically pumped nanolasers are successfully realized at room temperature based on these unique wires, further demonstrating the achievement of stimulated emission from spontaneous emission, promoted by the pump power intensity. This work may find a simple route to the manufacture of superior nanowires for applications in waveguide and integrated photonic devices.

Breastfeeding and timing of first dietary introduction in relation to childhood asthma, allergies, and airway diseases: A cross-sectional study.

OBJECTIVES: We investigated associations of breastfeeding (BF) durations and patterns and of timing of other dietary introductions with prevalence of asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema among preschool children. METHODS: During April 2011-April 2012, we conducted a cross-sectional study in 72 kindergartens from five districts of Shanghai, China and obtained 13,335 questionnaires of children 4-6-years-old. We used multiple logistic regression models to evaluate the target associations. RESULTS: Compared to children who were never BF, children who were exclusively breastfed 3-6 months had the lowest risk of asthma (adjusted odds ratio and 95% confidence interval: 0.81, 0.72-0.91) and wheeze (0.93, 0.87-0.99); and exclusive BF >6 months was significantly associated with a reduced risk of hay fever (0.93, 0.89-0.97), rhinitis (0.97, 0.94-0.99), pneumonia (0.97, 0.94-0.99), and eczema (0.96, 0.93-0.99). No significant associations were found between time when fruits or vegetables were introduced and the studied diseases. Associations were independent of the child's sex and parent's ownership of the current residence. Longer duration BF was only significantly protective when there was no family history of atopy. CONCLUSIONS: This study suggests that heredity, but not sex and socioeconomic status, may negatively impact the effect of BF on childhood airway and allergic diseases. Our findings support China's national recommendation that mothers provide exclusive BF for the first four months, and continue partial BF for more than 6 months.

Multimorbidities of asthma, allergies, and airway illnesses in childhood: Chance or not chance?

OBJECTIVES: We investigated patterns of multimorbidities among asthma, allergies, and respiratory illnesses in preschool children. We investigated multimorbidities of lifetime asthma, allergic rhinitis, eczema, food allergy, pneumonia, and ear infections; and multimorbidities of current (in the last year before the survey) wheeze, dry cough, rhinitis, eczema, and common cold during childhood. We further analyzed whether prevalences of these multimorbidities were due to chance. METHODS: A cross-sectional study was conducted in 72 kindergartens of Shanghai, China. Parents of preschool children were surveyed with a modified ISAAC questionnaire. Observed prevalences (OPs), expected prevalences (EPs), absolute excess comorbidities (AECs), and relative excess comorbidities (RECs) of various combinations of illnesses were calculated to indicate whether the combined illnesses were related. RESULTS: We analyzed questionnaires for children aged 4-6 years, whose 13,335 questionnaires were the majority of the total 15,266 returned questionnaires (response rate: 85.3%). The studied illnesses were common. For children who had more than three lifetime or current illnesses, OPs tended to be higher than EPs. Most OPs and EPs were higher in boys than in girls, and were higher in children with a family history of atopy (FHA) than in children without FHA. AECs and RECs between boys and girls as well as between children with and without FHA were substantially different. CONCLUSIONS: Our findings suggest that multimorbidities among childhood asthma, allergies, and respiratory illnesses are likely not random, but rather share etiology. Specific patterns of childhood asthma multimorbidities perhaps differ between boys and girls and between children with and without FHA.

Household environment, lifestyle behaviors, and dietary habits in relation to childhood atopic eczema in Shanghai, China.

PURPOSES: We aim to investigate associations of the child's individual characteristics, building characteristics, home environmental exposures, family lifestyle behaviors, and dietary habits on childhood eczema during lifetime-ever and in the last year before the survey. METHODS: During April 2011-April 2012, we conducted a cross-sectional study and collected 13,335 parents-reported questionnaires of 4-6-year-old children from 72 kindergartens in Shanghai, China. Logistic regression model was used to investigate associations. RESULTS: After adjusted for sex, age, family history of atopy, and questionnaire reporter, the factors which were strongly associated (increased odds >30% and p value <0.05) with lifetime-ever eczema included mother employed during pregnancy (adjusted OR 1.33), residence renovated during pregnancy (1.49) and in the child's first year of life (1.31), using laminate (1.58) and solid (1.42) wood as material of floor covering (compared to using cement), residence located in urban district (1.38), and dampness-related exposures in the early residence (mold spots/stains: 1.41; mold odor: 1.41) and in the current residence (water damage: 1.33; damp stains: 1.34; mold spots: 1.32; and windows pane condensation: 1.31). Parental smoking, pet-keeping, and incense-burning had no significant associations with childhood eczema. Similar associations were found for eczema in the last year before the survey. Families with sick children likely changed lifestyle behaviors and dietary habits. CONCLUSIONS: Childhood eczema could be influenced by many household environmental and non-environmental factors. Exposures during early lifetime likely have greater impact on childhood eczema than current exposures. Associations of lifestyle behaviors and dietary habits with childhood eczema could be modified by family avoidance behaviors.

Home dampness-related exposures increase the risk of common colds among preschool children in Shanghai, China: Modified by household ventilation.

Few studies have estimated the effects of dampness-related exposures and its interaction effects with poor household ventilation on common colds of preschool children. During April 2011-April 2012, we conducted a cross-sectional survey on home environment and childhood health and collected 13,335 parents-reported questionnaires of 4-6 year-old children in Shanghai, China. In this paper, we investigated associations between the incidence and duration of common colds among these children during the past 12 months before the survey and frequency of opening windows, as well as household dampness-related exposures (indicated by six dampness indicators). Significantly higher incidence (≥3 times) and longer duration (≥2 weeks) of common cold were found among children with than without these dampness exposures (p-value <0.01 for mold spots and p-value <0.001 for all other indicators). The number of dampness-related indicators had a positive and strong dose-response relationship with common colds (p-trend <0.01). Low frequency of ventilation was also a risk factor for children common colds. After adjusted for the potential confounders in the multiple logistic regression analyses, all dampness-related indicators were significantly associated with the increased odds of common colds and the highest odds ratios was 1.21 (95% CI: 1.16-1.27). We also found that dampness-related exposures and household ventilation habits (p-value for interaction <0.001) had a strong interaction effect on the incidence and duration of common cold. The stratified analysis of ventilation condition displays that the influence of dampness-related exposures has been modified by ventilation. Therefore, good household ventilation habits may have an effect of modification for dampness-related exposures.

Eu-doped Si-SiO2 core-shell nanowires for Si-compatible red emission.

The indirect bandgap of single-crystalline silicon has so far precluded the full integration of silicon microelectronics with photonics-which is expected to allow the realization of low-cost, high-speed optical information processing and communication in the future. Here we report the growth of europium (Eu)-doped Si-SiO2 core-shell nanowires by an oxide-assisted chemical vapor deposition method. The Eu concentration in these nanowires is effectively improved by intentionally increasing the thickness of SiO2 shells. As a result, a strong Si-compatible red emission from Eu(3+) ions was observed under laser illumination. The effect of Eu(3+) concentration on the emission efficiency was comprehensively studied, with the highest efficiency at Eu content about 0.8 at%. The relaxation mechanism of this concentration dependent luminescence was further explored through lifetime measurements. In light of the strong characteristic red emission and nanoscale footprint, these nanowires are promising Si-compatible light emission materials for future integrated nanophotonics.

Associations between home dampness-related exposures and childhood eczema among 13,335 preschool children in Shanghai, China: A cross-sectional study.

From April 2011 to April 2012, we conducted a cross-sectional study in Shanghai, China. A total of 13,335 modified ISAAC questionnaires (response rate: 85.3%) were returned by parents or guardians for 4-6 year-old children. Six dampness-related indicators (visible mold spots, visible damp stains, damp bed clothing, water damage, window pane condensation, and moldy odor) were used to evaluate home dampness-related exposures. In the present study, we applied logistic regression model to reveal associations, dose-response relationships, and statistical interaction effects of these dampness-related exposures, with childhood eczema, during lifetime since birth (ever) and in the last 12 months before the questionnaire. The dampness-related indicators were frequently reported in the perinatal and current residences. Prevalences of eczema ever and in the last 12 months were 22.9% and 13.2%, respectively. The dampness-related indicators were robustly associated and dose-response related with increased risk of eczema ever and in the last 12 months in the logistic regression analyses, with adjusted for potential confounders. Specifically, in the perinatal residence, visible mold spots or damp stains could increase 46% (OR, 95% CI: 1.46, 1.29-1.66) odds of childhood eczema (ever); in the current residence, visible mold spots and visible damp stains could increase 34% (1.34, 1.14-1.58) and 38% (1.38, 1.22-1.56) odds of childhood eczema (ever), respectively. Associations were not appreciably different between boys and girls, nor were they different between children with and without parental history of atopy. In conclusion, perinatal and current dampness-related exposures in the residence perhaps are risk factors for childhood eczema.

Household indoor air quality and its associations with childhood asthma in Shanghai, China: On-site inspected methods and preliminary results.

Few studies were conducted for associations of home environment with childhood health by on-site inspection in China. During 2013-2014, we conducted a case-control study with home inspection among 454 children (186 asthma children and 268 non-asthma children) in Shanghai, China. In this paper, we detailedly described the inspected methods and analyzed the preliminarily collected data. Except in winter, most residences meet the national standard for indoor temperature and relative humidity. Most living rooms had ≤1000ppm CO2, whereas over half of the child's bedrooms had slightly >1000ppm CO2 during night. Most residences had notably lower than 2500cfu/m3 airborne culturable fungi and ≤100µg/m3 formaldehyde. More than 70% of the child's bedrooms had ≤75µg/m3 PM2.5 and ≤150µg/m3 PM10. Indoor and outdoor concentrations of particulate matters had strong linear correlations (r=0.891-0.922; p-value <0.001). Most differences between cases and controls were not significant with respect to CO2, culturable fungi, formaldehyde, and particulate matters. Before and after adjusted for potential confounders, indoor averaged concentration of CO2 and particulate matters generally had negative associations with childhood history of doctor-diagnosed asthma in spring, summer, and autumn. Only in winter, indoor CO2 concentration was significantly associated with the increased odds of childhood asthma. Our results indicated that air quality among most residences in Shanghai could meet the national standard for indoor air quality in warm seasons; but household air quality and ventilation status in winter should be greatly improved. We suspected that those "unexpected" negative associations could exist due to changes in lifestyle behaviors regarding indoor air quality after the child being diagnosed asthma by a doctor.

The burden of disease attributable to indoor air pollutants in China from 2000 to 2017.

BACKGROUND: High-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017. METHODS: We first did a systematic review and meta-analysis of 117 articles from 37 231 articles identified in major databases, and obtained exposure-response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52 351 articles. After the systematic review, ten IAPs with significant and robust exposure-response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach. FINDINGS: From 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070-5040) to 3700 (3210-4090) per 100 000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3-15·6) of total DALYs and 3·45% (3·01-3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins. INTERPRETATION: DALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China. FUNDING: The National Key Research and Development Program of China and the National Natural Science Foundation of China.