Age at smoking initiation and smoking cessation influence the incidence of stroke in China: a 10-year follow-up study

Our study aimed to explore the correlation between age at smoking initiation and smoking cessation for the risk for stroke in China. We investigated 50,174 participants from one of the urban areas of China Kadoorie Biobank (CKB) Study. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for association between smoking and incidence of stroke were estimated using Cox regression model. During a median of 10.7 years of follow-up, 4370 total stroke cases were documented. Among men, comparing current smokers to never smokers, the HR of total stroke for current smokers was 1.279 (95% CI, 1.134-1.443) for total stroke. The HRs of total stroke were 1.344 (1.151-1.570) for those started smoking at age less than 20 years, 1.254 (1.090-1.443) for those started smoking at age 20-30 years, and 1.205 (1.012-1.435) for those started smoking at age 30 year and above, with a dose-response relation (P for trend, 0.004). Comparing former smokers to current smokers, in the low pack-year group, those stopped smoking at age less than 65 years had a 18.2% decreased risk for total stroke (0.818; 0.673-0.994). The decreased risk was not found in those stopped smoking at age 65 years and above. Similar results were observed in the high pack-year group. In conclusion, we found that current smokers had a higher stroke risk than never smokers, and the risk increased with a younger age at smoking initiation. Smoking cessation can reduce the risk for stroke, especially could benefit from cessation at a younger age.

Residential greenness and dyslipidemia risk: Dose-response relations and mediation through BMI and air pollution

BACKGROUND

Evidence on associations of residential greenness with dyslipidemia is limited, particularly regarding dose-response relations and mediation.

OBJECTIVES

To investigate associations between greenness and dyslipidemia, non-linear dose-response relationships and mediators.

METHODS

This cross-sectional study draws on the 2018 Fujian Behavior and Disease Surveillance (FBDS) cohort that used multi-stage stratified random sampling from the general population of Fujian Province, China. Participants with one or more abnormities in total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), or low-density lipoprotein cholesterol (LDL-C) were classified as having dyslipidemia. Residential greenness was operationalized as 3-year average of the normalized difference vegetation index (NDVI_500m) and enhanced vegetation index (EVI_500m). A doubly robust approach was used for effect quantification. Dose-response relations were studied with natural cubic splines. Mediation via physical activity (PA), body mass index (BMI), PM_2.5, PM₁₀, SO₂, and NO₂ was also examined.

RESULTS

Data from 43,183 participants were analyzed. Increases in NDVI_500m and EVI_500m residential greenness were associated with decreased dyslipidemia risk and improved blood lipids. Non-linear dose response relationships were discovered. Significant reduction of dyslipidemia risk was observed at levels of EVI_500m > 0.48 and NDVI_500m > 0.65. Joint mediation effects of PA, BMI, PM_2.5, PM₁₀, NO₂, and SO₂ on the associations of NDVI_500m and EVI_500m with dyslipidemia risk were 49.74% and 44.64%, respectively.

CONCLUSIONS

Increased residential exposure to greenness was associated with decreased risk of dyslipidemia. A non-linear dose-response relationship between greenness and dyslipidemia suggests that specific thresholds of greenness need to be reached in order to achieve effects. BMI, PM_2.5, and PM₁₀ partially mediated the association.

Associations between school bullying and anxiety in children and adolescents from an ethnic autonomous county in China

School bullying is a widespread public health issue that negatively impacts the mental health of children and adolescents. This study aimed to investigate associations between school bullying involvement and anxiety of children and adolescents. A survey covering all types of pre-college schools (primary, middle, high, and vocational school) was conducted in an ethnic autonomous county in China. 1,943 students participated in this study. Being a victim of verbal (OR=3.08, 95%CI = [2.43,3.91]), physical (OR=3.24, 95%CI = [2.46,4.27]), relational (OR=3.72, 95%CI = [2.90,4.76]), or cyberbullying (OR=3.47, 95%CI = [2.61,4.61]) were associated with increased symptoms of generalized anxiety. Similarly, being a perpetrator of verbal (OR=2.12, 95%CI = [1.45,3.10]), physical (OR=1.85, 95%CI = [1.22,2.79]), relational (OR=1.78, 95%CI = [1.15,2.74]), or cyber-bullying (OR=1.59, 95%CI = [1.08,2.33]) were related to a higher degree of anxiety. Moreover, in both victims and perpetrators higher levels of anxiety were associated with a greater number of types of bullying they were involved in, suggesting a dose-response relation between school bullying involvement and anxiety. Therefore, both bullying victims and perpetrators need mental health support and anti-bullying strategies should address different forms of bullying evenhandedly.

Estimations of the lethal and exposure doses for representative methanol symptoms in humans

Background

The aim of this review was to estimate the lethal and exposure doses of a representative symptom (blindness) of methanol exposure in humans by reviewing data from previous articles.

Methods

Available articles published from 1970 to 2016 that investigated the dose-response relationship for methanol exposure (i.e., the exposure concentration and the biological markers/clinical symptoms) were evaluated; the MEDLINE and RISS (Korean search engine) databases were searched. The available data from these articles were carefully selected to estimate the range and median of a lethal human dose. The regression equation and correlation coefficient (between the exposure level and urinary methanol concentration as a biological exposure marker) were assumed from the previous data.

Results

The lethal human dose of pure methanol was estimated at 15.8–474 g/person as a range and as 56.2 g/person as the median. The dose-response relationship between methanol vapor in ambient air and urinary methanol concentrations was thought to be correlated. An oral intake of 3.16–11.85 g/person of pure methanol could cause blindness. The lethal dose from respiratory intake was reported to be 4000–13,000 mg/l. The initial concentration of optic neuritis and blindness were shown to be 228.5 and 1103 mg/l, respectively, for a 12-h exposure.

Conclusion

The concentration of biological exposure indices and clinical symptoms for methanol exposure might have a dose-response relationship according to previous articles. Even a low dose of pure methanol through oral or respiratory exposure might be lethal or result in blindness as a clinical symptom.

Factors of concern in a human 3D cellular airway model exposed to aerosols of nanoparticles

Mucilair 3D bronchial airway models, cultured at an air-liquid interface, were exposed to aerosols of copper oxide (CuO) nanoparticles in Vitrocell air exposure modules. Four cell donors, four exposure modules and four exposure concentrations were varied within four different exposure sessions using a statistical experimental design called a hyper-Graeco-Latin square. Analysis of variance techniques were used to investigate the effects of these factors on release and RNA expression of inflammation markers monocyte chemoattractant protein-1 (MCP-1) interleukines 6 and 8 (IL-6 and IL-8) an cytotoxicity marker lactate dehydrogenase (LDH) determined 24h after exposure. The same techniques were also used to conduct a global analysis on RNA expressions of 10,000 genes. There were no major signs of cytotoxicity. Release of IL-6 and MCP-1 was affected by CuO concentration, and, for MCP-1, by donor variation. IL-8 release was not affected by these factors. However, gene expression of all three inflammation markers was strongly affected by CuO concentration but not by the other factors. Further, among the 10,000 genes involved in the global analysis of RNA expression, 1736 were affected by CuO concentration, 704 by donor variation and 269 by variation among exposure sessions. The statistical design permitted the assessment of the effect of CuO nanoparticles on 3D airway models independently of technical or experimental sources of variation. We recommend using such a design to address all potential sources of variation. This is especially recommended if test materials are expected to be less toxic than CuO, because the variation among the concentration levels could then be close to the variation among donors or exposure sessions.

Cumulative childhood maltreatment and its dose-response relation with adult symptomatology: Findings in a sample of adult survivors of sexual abuse

In the present study, we examined the role of cumulative childhood maltreatment experiences for several health related outcomes in adulthood, including symptoms of psychological distress as well as perceived social support and hardiness. The sample comprised adult survivors of sexual abuse (N=278, 95.3% women, mean age at first abusive incident=6.4 years). One-way ANOVAs revealed a statistically significant dose-response relation between cumulative childhood maltreatment scores and self-reported symptoms of posttraumatic stress (PTSS), anxiety, depression, eating disorders, dissociation, insomnia, nightmare related distress, physical pain, emotional pain, relational problems, self-harm behaviors as well as on a measure of symptom complexity. Cumulative childhood maltreatment was also associated with lower levels of work functioning. An inverse dose-response relation was found for perceived social support and hardiness. Using a Bonferroni corrected alpha level, cumulative childhood maltreatment remained significantly associated with all outcome measures with the exception of eating disorder symptoms after controlling for abuse-related independent variables in hierarchical regression analyses. Results add to previous literature by showing that dose-response relation between cumulative childhood adversities and adult symptom outcomes could also be identified in a sample characterized by high exposure to adversities, and lends support to the notion put forth by previous authors that cumulative childhood adversities seem to be related to the severity of adult health outcomes in a rule-governed way.