Risk for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to close contacts of infected persons has not been well estimated. To evaluate the risk for transmission of SARS-CoV-2 to close contacts in different settings. Prospective cohort study. Close contacts of persons infected with SARS-CoV-2 in Guangzhou, China. 3410 close contacts of 391 index cases were traced between 13 January and 6 March 2020. Data on the setting of the exposure, reverse transcriptase polymerase chain reaction testing, and clinical characteristics of index and secondary cases were collected. Measurement: Coronavirus disease 2019 (COVID-19) cases were confirmed by guidelines issued by China. Secondary attack rates in different settings were calculated. Among 3410 close contacts, 127 (3.7% [95% CI, 3.1% to 4.4%]) were secondarily infected. Of these 127 persons, 8 (6.3% [CI, 2.1% to 10.5%]) were asymptomatic. Of the 119 symptomatic cases, 20 (16.8%) were defined as mild, 87 (73.1%) as moderate, and 12 (10.1%) as severe or critical. Compared with the household setting (10.3%), the secondary attack rate was lower for exposures in healthcare settings (1.0%; odds ratio [OR], 0.09 [CI, 0.04 to 0.20]) and on public transportation (0.1%; OR, 0.01 [CI, 0.00 to 0.08]). The secondary attack rate increased with the severity of index cases, from 0.3% (CI, 0.0 to 1.0%) for asymptomatic to 3.3% (CI, 1.8% to 4.8%) for mild, 5.6% (CI, 4.4% to 6.8%) for moderate, and 6.2% (CI, 3.2% to 9.1%) for severe or critical cases. Index cases with expectoration were associated with higher risk for secondary infection (13.6% vs. 3.0% for index cases without expectoration; OR, 4.81 [CI, 3.35 to 6.93]). There was potential recall bias regarding symptom onset among patients with COVID-19, and the symptoms and severity of index cases were not assessed at the time of exposure to contacts. Household contact was the main setting for transmission of SARS-CoV-2, and the risk for transmission of SARS-CoV-2 among close contacts increased with the severity of index cases. Guangdong Province Higher Vocational Colleges and Schools Pearl River Scholar Funded Scheme.

Air pollution has been associated with elevated blood pressure in adults. However, epidemiological evidence from children and adolescents is limited. We investigated the associations between long-term exposure to particulate matter (PM) air pollution and blood pressure in a large population of children and adolescents. A cross-sectional analysis was performed in a nationally representative sample consisting of 43,745 children and adolescents aged 7 to 18 years in seven provinces in China. Exposure to ambient fine particles (PM2.5) and thoracic particles (PM10) was estimated using spatiotemporal models based on satellite remote sensing, meteorological data and land use information. Mixed-effects (two-level) linear and logistic regression models were used to investigate the associations between PM exposure and systolic blood pressure (SBP), diastolic blood pressure (DBP) and hypertension. After adjustment for a wide range of covariates, every 10 μg/m3 increment in PM2.5 and PM10 concentration was associated with 1.46 [95% confidence interval (CI): 0.05, 2.88] and 1.36 (95% CI: 0.34, 2.39) mmHg increases in SBP, respectively. PM10 was also associated with higher prevalence of hypertension [odds ratio per 10 μg/m3 increment: 1.45 (95% CI: 1.07, 1.95)]. Long-term exposure to ambient PM air pollution was associated with increased blood pressure and higher prevalence of hypertension in children and adolescents. Our findings support air pollution reduction strategies as a prevention measure of childhood hypertension, a well-recognized risk factor of future cardiovascular health.

We sought to develop and validate a national blood pressure (BP) reference based on age, sex, and height for Chinese children. Data were obtained on 197 430 children aged 7 to 17 who participated in the Chinese National Survey on Students’ Constitution and Health in 2010. BP percentiles were estimated and fitted using the lambda, mu, and sigma method and then compared with a US reference and China existing reference. In an external independent validation sample of 59 653 children aged 7 to 18 from 7 Chinese provinces in 2013, the prevalence of elevated BP was compared applying the 3 references. BP values were similar for boys and girls at the younger ages (7–13 years) and lower height percentiles, whereas higher at the older ages (14–17 years) for boys than girls. At medial height in boys and girls aged 7 to 13, the 50th, 90th, 95th, and 99th percentiles of BP for the new national reference were consistent with US reference and lower than current Chinese reference. In the independent sample, elevated BP prevalence, based on the new national reference, ranged from 7.8% to 18.5% among children aged 7 to 17, which was higher than the US reference values (4.3%–14.5%) and lower than the current Chinese reference (12.9%–25.5%) in each age group. The new national BP reference for Chinese children based on age, sex, and height from large-scale and nationally representative data seems to improve the ability for identifying Chinese hypertensive children and for stratifying them with regard to cardiovascular risk.

To evaluate the association of early-life exposure to the Chinese Great Famine (1959–1961) with DNA methylation in IGF2 and its subsequent influence on blood lipid levels in late adulthood among participants of the Genomic Research of the Chinese Famine (GRECF) study. The GRECF study recruited 790 participants born between 1956 and 1964 from 2 neighbor provinces, Anhui and Jiangxi, in China through a multistage, clustered, random sampling. The current study included a random sample of 188 GRECF participants. IGF2 differential methylation region (DMR) is an intragenic DMR located upstream of the imprinted promoters of IGF2 exon 3. DNA methylation were quantified at 8 cytosine-phosphate-guanine dinucleotides (CpG) sites at the IGF2 DMR (chr11p15.5) using the Sequenom EpiTYPER method and the MassARRAY system. Multivariate linear regressions were used to evaluate pairwise associations among famine severity, DNA methylation in the IGF2 gene, and lipid levels. We controlled for age and sex in the base model and additionally controlled for education, smoking, and drinking status in the fully adjusted model. Mediation analysis was applied to assess the mediation effect of DNA methylation at the IGF2 gene on the association between early-life exposure to severe famine and adult lipid levels. Exposure to severe famine was associated with elevated methylation at CpG1 (chr11: 2126041, build 36) of the IGF2 DMR (β = 0.07; P = 0.0008) and total cholesterol (β = 0.72; P = 1.09 × 10−7). After adjustment for age and sex, each unit increase in methylation of the CpG1 site was associated with 1.09-unit increase in total cholesterol (P = 0.03). After further adjustment for all covariates, these associations were still significant (Pfamine-CpG1 = 0.002, Pfamine-total cholesterol = 1.28 × 10−6, and PCpG1-total cholesterol = 0.05). Increased methylation level in the IGF2 gene was associated with early-life exposure to severe famine, and this change was also positively associated with total cholesterol in late adulthood.

There was growing interest in endocrine disrupting chemicals that might have effect on the obesity epidemic, but few studies on the association of phthalates (PAEs) with childhood overweight and obesity in China based on longitudinal cohort study were available, which was the purpose of the present study. A nested case-control study was conducted in a prospective cohort of 2298 children aged 7-13 years from October 2017 to October 2020 with five waves visits in Xiamen city, China. A total of 829 children remained in the first wave of follow up with collection of urine for measuring seven PAEs metabolites, including mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MBP), mono-iso-butyl phthalate (MiBP), mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) and mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), utilizing ultra high performance liquid chromatography-triple quadrupole mass spectrometry. Overweight and obesity, defined by WHO classifications, were allocated to the cases group, and those of all normal weight and matched cases with normal weight in each wave of follow-up as two control groups. Logistic regression models after adjusting for confounders were utilized to analyze the effect of PAEs on overweight and obesity in children with divided four groups based on the quartile distribution of each and total PAEs concentration. The detection rates of children for each PAEs metabolite were 99.4% for MMP, 99.4% for MEP, 99.8% for MBP, 54.5% for MEHP, 84.4% for MEOHP, 99.9% for MEHHP, and 97.2% for MiBP. The geometric mean of concentrations of PAEs, MMP, MEP, MBP, MEHP, MEHHP, and MiBP were 310.085, 34.658, 9.127, 166.347, 7.043, 3.400, 18.571, and 24.093 (ng/ml), respectively. The total PAEs and seven metabolites concentrations were positively associated with childhood BMI Z-Scores with statistically significant slope rates and correlation coefficients, and were higher in the cases group than those in two controls groups in each wave of follow-up. The PAEs concentrations in the cases group was 5.90 (95 %CI: 5.79, 6.01) ng/ml in the first wave of survey, which was higher than those normal controls group (5.68 (95 %CI: 5.61, 5.75) ng/ml, P < 0.001) and matched controls group (5.72 (95 %CI: 5.61, 5.84) ng/ml, P = 0.018). The prevalence and ORs of overweight and obesity increased with quartile group of each and total PAEs concentrations accompanying a dose-response relationship. Compared with the quartile1 reference group with lowest total PAEs concentrations, the ORs of overweight and obesity in quartile2, quartile3 and quartile4 group increased gradually and reached at 1.20 (0.74-1.95), 1.49 (0.93-2.38) and 2.22 (1.41-3.48), respectively (P_trend < 0.001). The strength of the associations between PAEs and overweight and obesity was sex-specific in children. Children in China were extensively exposed to PAEs, and the exposure to PAEs during childhood could significantly increase the risk of overweight and obesity with a dose-response relationship, particularly in girls. While limiting the exposure of PAEs products, the determination of exposure limit of plasticizer should be further strengthened.