[Heritability of body mass index based on twin studies: a Meta-analysis].

Objective: To use Meta analysis to understand the prevalence of the heritability of body mass index (BMI) in twins. Methods: All studies on the heritability of the twins' BMI published before December 31, 2020 were retrieved through the China National Knowledge Network, Wanfang, VIP, PubMed and Web of Science databases. The literature quality was evaluated by using Joanna Briggs Institute Critical Appraisal tools. Stata 16.0 was used to perform subgroup analysis on the outcome indicators (heritability, 95%CI) to explore the source of heterogeneity. The local weighted regression method was used to fit the trend of heritability with age. The publication bias test and the sensitivity analysis of included literatures were also performed by using Stata 16.0. Results: A total of 10 articles meeting the inclusion and exclusion criteria were included with 79 twins' independent estimates of heritability for BMI. Meta-analysis showed that the combined value of BMI heritability was 0.69 (95%CI: 0.65-0.71), the combined value of BMI (0.68, 95%CI: 0.65-0.70) in males was lower than that (0.70, 95%CI: 0.68-0.72) in females. The heritability of BMI (0.72, 95%CI: 0.68-0.76) in childhood and adolescence was higher than that (0.68, 95%CI: 0.66-0.70) in adulthood. The gender specific difference in BMI heritability in twins ≤18 years old was even greater, which was lower in males (0.68, 95%CI: 0.61-0.76) than in females (0.75, 95%CI: 0.69-0.81). The heritability increased with age in childhood, reached peak at about 18 years old, and then slowly decreased with age. Conclusions: The heritability of BMI varied with population characteristics, especially age and gender. In view of the high estimated value of BMI heritability in female children and adolescents, more attention should be paid to the start time of health intervention.

[Trends of a burden on atherosclerotic cardiovascular disease and its related risk factors in China, 1990 to 2019].

Objective: To quantitatively analyze the effects of population aging and other risk factors on the burden of atherosclerosis cardiovascular disease (ASCVD) in China from 1990 to 2019. Methods: Disability adjusted life years (DALY) and age-standardized rates obtained from the Global Burden of Disease Study 2019 (GBD2019) were used to describe the temporal trend of a burden on ASCVD. And a decomposition method established by Gupta was applied to quantify the burden related to population growth, aging, age-specific prevalence, and the severity of the disease. Results: In 2019, 61.00% of the burden of cardiovascular disease in China was caused by ASCVD. The DALY of ischemic heart disease increased by 133.66% compared with that in 1990, with 29.57% of the increase attributed to population growth, 108.74% due to population aging, and 8.87% due to the rise of age-specific prevalence and -13.53% benefited from changes in disease severity. The DALY of ischemic stroke increased by 138.64% compared with 1990, and the proportions attributable to the above four parts were 30.95%, 123.38%, 55.80%, and -71.49%, respectively. Hypertension remained the leading risk factor for ASCVD in 2019, followed by high LDL cholesterol. The age-standardized DALY rate attributable to drinking had the most significant increase (486.01%) from 1990, with an average annual growth of 10.93%. Conclusions: Aging population seems responsible for the main reason for the considerable increase in the burden of ASCVD in China. Still, the adverse trends of other avoidable risk factors, especially metabolic risk factors, can not be ignored.

[The association between myopic refraction and near work among children and adolescents based on genetic risk score].

Objective: To explore the relationship between myopic refraction and near work in children and adolescents with different genetic risks. Methods: From September to December 2016, Nankai District and Hongqiao District of Tianjin were taken as the study sites. Using the method of stratified cluster random sampling, 533 children and adolescents aged 6-14 years from one primary school and one junior middle school in each of the two districts were included as the study subjects. Refraction measurements by an auto-kerato-refractor and questionnaire survey about near work were conducted. 11 single nucleotide polymorphisms in the selected myopia susceptibility genes were detected, and the genetic risk of each individual was scored. After grouping by genetic risk score, the relationship between myopia and near work was analyzed by the multivariate logistic regression, and the relationship between near work and refraction was analyzed by the multivariate linear regression. Results: The age of 553 subjects was (9.8±2.5) years, including 295 boys (53.3%). The overall detection rate of myopia was 62.0%. The spherical equivalent refraction (SER) was (-1.30±1.85) D. The results of the multivariate logistic regression showed that in the low risk group of GRS, compared with those with continuous near work time less than half an hour, those with continuous near work time no less than half an hour had a higher risk of myopia [OR (95%CI) = 2.64 (1.07, 6.52)]. In the moderate risk group of GRS, the risk of myopia increased with the increase of daily computer use [OR (95%CI) = 2.14 (1.03, 4.77)]. In the high risk group of GRS, the risk of myopia increased with the increase of the total daily reading and writing time [OR (95%CI) = 1.27 (1.01, 1.59)]. The results of the multivariate linear regression showed that in the low risk group of GRS, with increase of 1 hour in the total daily reading and writing time and mobile phone time, the SER decreased by 0.18 D (95%CI:-0.30, -0.07) and 0.95 D (95%CI:-1.51, -0.39), respectively. In the moderate risk group of GRS, with increase of 1 hour in the total daily reading and writing time and computer use time, the SER decreased by 0.25 D (95%CI:-0.31, -0.18) and 0.57 D (95%CI:-0.97, -0.18), respectively. In the high risk group of GRS, with increase of 1 hour in the daily total reading and writing time, the SER decreased by 0.33 D (95%CI:-0.43, -0.22). Conclusion: Continuous near work time no less than half an hour, daily computer use time, the total daily reading and writing time, and daily mobile phone use time were associated with myopic refraction in children and adolescents.

[Sub-health status of middle school teachers and its correlation analysis with occupational stress].

Objective: To study the distribution of sub-health and occupational stress as well as their correlation among middle school teachers in Tianjin, then provide evidences for prevention and control of the status of sub-health. Methods: A total of 3 522 middle school teachers from six districts of Tianjin were recruited with stratified cluster sampling strategy for the investigation of Sub-Health Measurement Scale version 1.0 (SHMS V1.0) and Occupational Stress Inventory-Revised Edition (OSI-R) . Results: Detection rate of sub-health status among Tianjin middle school teachers was 58.55%. Men had significantly lower sub-health detection rate (55.19%) than women (59.71%) . Sub-health detection rate increased with age (P<0.05) , the sub-health detection rate among middle school teachers more than 50 years old was the highest (66.84%) . The mean score of OSI-R was 403.18±41.80 with the scores of 176.00±21.05, 103.17±17.53, and 124.02±20.28 for ORQ, PSQ, PRQ, respectively, which showed significantly difference compared with the occupational stress norm of China (P<0.001) . The mean scores of OSI-R, ORQ, PSQ, PRQ in different health status were significantly different (P<0.001) . The partial correlation analysis between the scores of sub-health and occupational stress of middle school teachers showed that the scores of occupational role and personal strain were negatively correlated with the scores of sub-health state (P< 0.001) , while, there was significantly positive correlation between the scores of personal resource and the scores of sub-health state (P<0.001) . Conclusion: Sub-health detection rate of middle school teachers in Tianjin is higher. Effective measures should be taken to appropriately mitigate the occupational stress level of middle school teachers, increase personal resources, and scientific and effective health guidance and education should be strengthened.

Reassessment of the systematics of the suborder Pseudonocardineae: transfer of the genera within the family Actinosynnemataceae Labeda and Kroppenstedt 2000 emend. Zhi et al. 2009 into an emended family Pseudonocardiaceae Embley et al. 1989 emend. Zhi et al. 2009.

The taxonomic status of the families Actinosynnemataceae and Pseudonocardiaceae was assessed based on 16S rRNA gene sequence data available for the 151 taxa with validly published names, as well as chemotaxonomic and morphological properties available from the literature. 16S rRNA gene sequences for the type strains of all taxa within the suborder Pseudonocardineae were subjected to phylogenetic analyses using different algorithms in arb and phylip. The description of many new genera and species within the suborder Pseudonocardineae since the family Actinosynnemataceae was proposed in 2000 has resulted in a markedly different distribution of chemotaxonomic markers within the suborder from that observed at that time. For instance, it is noted that species of the genera Actinokineospora and Allokutzneria contain arabinose in whole-cell hydrolysates, which is not observed in the other genera within the Actinosynnemataceae, and that there are many genera within the family Pseudonocardiaceae as currently described that do not contain arabinose. Phylogenetic analyses of 16S rRNA gene sequences for all taxa within the suborder do not provide any statistical support for the family Actinosynnemataceae, nor are signature nucleotides found that support its continued differentiation from the family Pseudonocardiaceae. The description of the family Pseudonocardiaceae is therefore emended to include the genera previously classified within the family Actinosynnemataceae and the description of the suborder Pseudonocardineae is also emended to reflect this reclassification.