Association of DNA methylation of vitamin D metabolic pathway related genes with colorectal cancer risk.

BACKGROUND: Vitamin D might have anti-tumor effect, which is affected by the genes related to vitamin D metabolic pathway. Epigenetic mechanism may affect the expression level of vitamin D metabolic pathway related genes, then plays an important role in the occurrence and development of colorectal cancer. To date, no study has reported on the association between blood-based DNA methylation level of vitamin D metabolic pathway related genes and colorectal cancer risk. METHODS: A case-control study was conducted including 102 colorectal cancer cases and 102 sex- and age-frequency-matched controls in Guangzhou, China. CpG islands in the VDR, CYP24A1, CYP27B1 and CYP2R1 genes were chosen for DNA methylation analysis by MethylTarget sequencing. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of DNA methylation levels for colorectal cancer. Taking the point with the largest Youden index as the boundary value, the cumulative methylation levels of vitamin D metabolic pathway related genes were divided into hypomethylation and hypermethylation. Unconditional multivariable logistical regression model was used to calculate the adjusted odds ratio (aOR) and 95% confidence intervals (95% CIs) after adjusting for potential confounders. RESULTS: Among 153 CpG sites, 8 CpG sites were significantly different between the cases and the controls. The cumulative methylation level of all CpG sites in CYP2R1 was inversely associated with the risk of colorectal cancer (aOR, 0.49; 95% CI, 0.26-0.91). However, no significant association was found between cumulative methylation levels of all CpG sites in VDR, CYP24A1 and CYP27B1 and colorectal cancer risk. Significant inverse association was observed between cumulative methylation level of significant CpG sites in VDR (aOR, 0.28; 95% CI, 0.16-0.51) and CYP24A1 (aOR, 0.19; 95% CI, 0.09-0.40) and colorectal cancer risk. There were no significant associations between cumulative methylation levels of significant CpG sites in CYP2R1 and CYP27B1 and colorectal cancer risk. CONCLUSIONS: This study indicated that the cumulative methylation levels of significant CpG sites in VDR and CYP24A1 and all CpG sites in CYP2R1 were inversely associated with colorectal cancer risk.

Cereal intake and mortality in older Chinese: a 15-year follow-up of a prospective cohort study.

PURPOSE: We examined the association between whole grain and refined grain intake with all-cause, cancer and cardiovascular disease (CVD) mortality using the data from the Guangzhou Biobank Cohort Study. METHODS: 19,597 participants aged 50+ years were recruited from 2003 to 2006 and followed-up until April 2021. Multivariable Cox regression was used to calculate hazard radios (HRs) and 95% confidence intervals (CIs). Substitution analysis was used to replace a serving (50 g/day) of whole grain with a serving of refined grain. RESULTS: During 286,821 person-years of follow-up, 4385 deaths occurred, including 1450 from cancer, 1678 from CVD and 1257 from other causes. Compared with never whole grain intake, the highest intake category of whole grain (> 300 g/week) was associated with lower risk of all-cause (HR 0.90, 95% CI 0.82-0.98) and CVD mortality (HR 0.85, 0.74-0.98). Compared with the low-intake category of refined grain (< 500 g/day), the highest intake category (> 900 g/week) was associated with a lower risk of cancer mortality (HR 0.76, 0.62-0.95), but a higher risk of CVD mortality (HR 1.25, 1.03-1.51). No significant associations were found between whole grain intake and cancer mortality nor refined grain and all-cause mortality. The HRs of all-cause, cancer and CVD mortality substituting a serving of whole grain for refined grain were 0.96 (0.94-0.99), 1.01 (0.99-1.02) and 0.95 (0.90-0.99), respectively. CONCLUSION: We have first shown that in older Chinese, whole grain intake was associated with lower risk of all-cause and CVD mortality. Our results suggest that intake of whole grain of at least 300 g/week and refined grain of ≤ 900 g/day might be suitable for older Asian. Substituting 50 g/day of whole grain for refined grain was associated with a 4-5% lower risk of all-cause and CVD mortality.

Low-Carbohydrate Diets and Mortality in Older Asian People: A 15-Year Follow-Up from a Prospective Cohort Study.

The long-term effects of a low-carbohydrate diet (LCD) on mortality, accounting for the quality and source of the carbohydrate, are unclear. Hence, we examined the associations of LCDs with all-cause and cause-specific mortality in a prospective cohort study. A total of 20,206 participants (13.8% diabetes) aged 50+ years were included. Overall, vegetable-based and meat-based LCD scores were calculated based on the percentage of energy as total and subtypes of carbohydrates, fat, and protein. Cox regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). During 294,848 person-years of follow-up, 4624 deaths occurred, including 3661 and 963 deaths in participants without and with diabetes, respectively. In all participants, overall LCD score was not associated with all-cause and cause-specific mortality, after multivariable adjustment. However, for the highest versus the lowest quartiles of vegetable-based LCD, the adjusted HRs (95%CIs) of all-cause and CVD mortality were 1.16 (1.05-1.27) and 1.39 (1.19-1.62), respectively. The corresponding values for highest versus lowest quartiles of meat-based LCD for all-cause and CVD mortality were 0.89 (0.81-0.97) and 0.81 (0.70-0.93), respectively. Similar associations were found in participants without diabetes. In patients with diabetes, the adjusted HR (95%CI) of CVD mortality for the highest versus the lowest quartiles of vegetable-based LCD was 1.54 (1.11-2.14). Although there were no significant associations with overall LCD score, we found that the vegetable-based LCD score was positively, whereas the meat-based LCD score was negatively, associated with all-cause and CVD mortality in older Asian people.

Bullying as a risk for poor sleep quality among high school students in China.

OBJECTIVE: To determine whether involvement in bullying as a bully, victim, or bully-victim was associated with a higher risk of poor sleep quality among high school students in China. METHODS: A cross-sectional study was conducted. A total of 23,877 high school students were surveyed in six cities in Guangdong Province. All students were asked to complete the adolescent health status questionnaire, which included the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) and bullying involvement. Descriptive statistics were used to evaluate sleep quality and the prevalence of school bullying. Multi-level logistic regression analyses were conducted to examine the association between being victimized and bullying others with sleep quality. RESULTS: Among the 23,877 students, 6,127 (25.66%) reported having poor sleep quality, and 10.89% reported being involved in bullying behaviors. Of the respondents, 1,410 (5.91%) were pure victims of bullying, 401 (1.68%) were bullies and 784 (3.28%) were bully-victims. Frequently being involved in bullying behaviors (being bullied or bullying others) was related to increased risks of poor sleep quality compared with adolescents who were not involved in bullying behaviors. After adjusting for age, sex, and other confounding factors, the students who were being bullied (OR=2.05, 95%CI=1.81-2.32), bullied others (OR=2.30, 95%CI=1.85-2.86) or both (OR=2.58, 95%CI=2.20-3.03) were at a higher risk for poor sleep quality. CONCLUSIONS: Poor sleep quality among high school students is highly prevalent, and school bullying is prevalent among adolescents in China. The present results suggested that being involved in school bullying might be a risk factor for poor sleep quality among adolescents.

The association between smoking quantity and hypertension mediated by inflammation in Chinese current smokers.

OBJECTIVES: Previous studies indicated that cigarette smokers were more likely to develop hypertension, and both smoking and hypertension were associated with inflammation. Whether inflammation mediates the relationship of them is unclear. This study aims to examine whether inflammation mediates the association between smoking and hypertension. METHODS: Nine hundred and eighty-four Chinese current smokers from a community-based chronic diseases survey in Guangzhou and Zhuhai were interviewed about sociodemographics, smoking, chronic conditions, and other health-related variables. Hypertension was defined according to 2007 European Society of Hypertension and European Society of Cardiology (ESH-ESC) Practice Guidelines. Inflammatory markers including C-reactive protein (CRP), interleukin (IL)-6, IL-1ß, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and vascular cell adhesion molecule-1 (VCAM-1) were measured by flow cytometry. Logistic regressions were performed to assess the mediation of inflammation on the relationship between smoking quantity and hypertension. RESULTS: We observed a positive association between smoking quantity and hypertension (P<0.05). After controlling for potential confounders, daily cigarette consumption was significantly associated with higher level of CRP and VCAM-1 and lower level of TNF-α among six measured inflammatory markers, and the current smokers with hypertension had significantly higher level of MCP-1 and CRP than those smokers who were normotensive. Furthermore, the association between smoking quantity and hypertension was mediated by CRP, which accounted for 58.59% of the estimated causal effect of smoking on hypertension. CONCLUSION: We have confirmed previous observations that smoking quantity was positively associated with hypertension, and the results of our study suggested that the association between smoking and hypertension was probably mediated by CRP.

Behavioural development of school-aged children who live around a multi-metal sulphide mine in Guangdong province, China: a cross-sectional study.

BACKGROUND: The deleterious biological effects of low-level, long-term exposure to heavy metals are well known, and children are the most susceptible population. Dabaoshan Mine in the southeast of Guangdong Province is at high risk of discharging multi-metals pollutants into a local river (Hengshihe) and the surrounding area. The present study aimed to estimate relationships between measured multi-metal exposures and the presence of behavioural problems for the school-aged children in the polluted area. METHODS: A cross-sectional study was performed. Children aged 7-16 years living in three villages of the Hengshihe area with different degrees of heavy-metal pollution participated in this study. Local environmental samples (water and crops) and children's hair were collected, and concentrations of heavy metals were determined. The Child Behaviour Check-list (CBCL) was used to assess the presence of behaviour problems. General linear regression was used to analyze the contribution of hair metals to each CBCL subscale with adjustment for socio-demographic confounding factors. RESULTS: Multiple regression analyses revealed significant effects of hair lead, cadmium and zinc levels on CBCL subscales. Log-transformed hair lead, cadmium and zinc levels accounted for an incremental of 8% to 15% variance in anxious/depressed, withdrawn, somatic complaints, social problems, thought problems, attention problems, delinquent behaviour and aggressive behaviour. The concurrent log-transformed hair lead and zinc levels were strongly associated with all subscales while the concurrent log-transformed hair cadmium was only significantly associated with withdrawn, social problems and attention problems. CONCLUSION: This study reveals that heavy metal exposure was associated with increased risk of behavioral problems for school-aged children.

Cardiovascular risk factors in overweight and obese Chinese children: a comparison of weight-for-height index and BMI as the screening criterion.

BACKGROUND: Childhood obesity is a widespread and growing problem in the world. Body mass index (BMI) and weight-for-height criterion have been used to determine childhood obesity. No data was available to evaluate cardiovascular risk factors in overweight and obese Chinese children screened by weight-for-height index and Chinese newly developed BMI criterion. AIM OF THE STUDY: To evaluate cardiovascular risk factors in overweight and obese Chinese children by using Chinese BMI and weight-for-height index as screening criterion. METHODS: A total of 215 children aged 7.5-13 years were recruited from 3 primary schools in Guangzhou, PR China. Measurements included body weight, height, waist and hip circumference, fasting serum glucose, insulin, total triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A (apo A), apolipoprotein B (apo B). Chinese BMI and weight-for- height criterion were used to classify overweight and obesity. RESULTS: According to Chinese BMI criterion, 65 from 108 obese children originally identified by weight-for-height were reclassified as obese and other 41 children were classified as overweight. Compared with non-obese children, obese children screened by Chinese BMI and weight-for-height index had increased levels of TG, LDL-C, apo B, insulin; decreased levels of HDL-C, apo A; and significantly higher prevalence of hypertriglyceridemia and high LDL-C. Children identified as overweight by Chinese BMI criterion had also shown high TG, LDL-C, apo B, insulin levels, low HDL-C, apo A levels, and significantly higher prevalence of hypertriglyceridemia than the normal weight children. CONCLUSIONS: Our study reveals that overweight and/or obesity screened by both Chinese new BMI and weight-for-height criterion are associated with increased levels of cardiovascular risk factors (e.g., elevated serum TG, LDL, apo B, and reduced HDL-C, apo A levels). Using Chinese BMI criterion may underestimate the prevalence of childhood obesity but it could be adopted as a unique tool for screening children's overweight in population-based screening programs.

Energy expenditure and energy intake in 10-12 years obese and non-obese Chinese children in a Guangzhou boarding school.

OBJECTIVE: The objective of this study was to observe the variation of energy intake and energy expenditure in the obese Chinese children. METHODS: Basic metabolic rate was measured by using open-circuit indirect calorimetry in 54 obese children and 60 non-obese children aged 10-12 years in a full- time boarding school in Guangzhou suburb, China. Total energy expenditure was estimated by using a factorial method. Dietary intake was surveyed by the weighed inventory method. Physical activity was determined using a 2-day activity diary. RESULTS: Univariate analysis showed that basic metabolic rate was significantly higher (p<0.05) in obese children than in non-obese ones, but the significant difference disappeared after controlling for fat free mass and fat mass. Energy intake and total energy expenditure were significantly higher (p<0.05) in obese than in non-obese children. Obese children spent more time in sleeping and light physical activity, but less time in moderate physical activity and vigorous physical activity than non-obese children (p<0.05). CONCLUSIONS: Compared to non-obese children, both energy intake and expenditure were higher in obese Chinese children. It appears that an area for preventive strategies may be to encourage increased physical activity expenditure in this age group.

[Study on the impact of related psychological stress and fatigue to different smoking behaviors among undergraduate students].

OBJECTIVE: To explore the relationship between psychological stress, fatigue and different smoking behaviors among undergraduate students. METHODS: 8138 undergraduate students in grade 1 to 3 were sampled with cluster sampling method from a comprehensive university in Guangzhou, and were studied on their psychological stress, peer and self smoking behaviors, as well as socio-demographic factors with a self-administered questionnaire. Physical and mental fatigue was measured by Chalder fatigue scale. A multinomial logistic regression analysis was performed to explore the association between psychological stress, fatigue and different smoking behaviors with 'non-smokers' defined as control group while 'triers' and 'current smokers' as case group, respectively. RESULTS: There were students trying to smoke or becoming current smokers on university campus. After adjusting the effect of relevant socio-demographic factors and peer smoking behavior, physical fatigue (OR = 1.044, 95% CI: 1.013-1.075) and 'worry about current academic and future work' (OR = 1.020, 95% CI: 1.001-1.040) were the risk factors of trying to smoke among male students, while 'study stress (OR = 1.063,95% CI: 1.012-1.117) was the risk factor for female students when start smoking. 'Personnel relationship and environment stress' (OR = 1.152, 95% CI: 1.012-1.312) were the risk factors for female students' current smoking behavior. CONCLUSION: Psychological stress and fatigue were moderately associated with smoking behavior among undergraduate students and the impact was different on different gender and smoking behaviors that suggesting that some specific psychological measures should be taken so as to control different smoking behaviors among undergraduate students.

[Analysis on factors influencing the smoking behaviors among male secondary school students under the structural equation model].

OBJECTIVE: To analyze the direct and indirect outcomes of influencing factors on smoking behaviors among adolescents. METHODS: Self-administered questionnaires were used to collect smoking-related information from 2021 respondents. Measurement models were built by confirmatory factor analysis and parameters were estimated by ERLS method. The final structural equation model was determined by comprehensive evaluation and necessary modification. RESULTS: Three latent variables were extracted from 10 manifest variables of environment, while only one latent variable was identified from 9 manifest variables of attitudes. The goodness of fit for the structural equation model was satisfactory that all indices had met corresponding requirements. The final model could explain 38.8% of the variance of smoking behaviors. Four factors (smoking environment, smoking restriction from parents and teachers, determination of cigarette refusal and attitudes toward smoking) were directly affecting the smoking behaviors, while another three factors (grade, health knowledge and school environment) had indirect impacts. According to the percentages of their contribution, the risk factors were ranked as follows: smoking environment (45.76%), attitudes toward smoking (19.88%) and grade at school (0.44%). Similarly, the top protective factor were: determination of cigarette refusal (16.61%), followed by smoking restriction from parents and teachers (10.51%), health knowledge (3.89%) and school environment (2.92%). CONCLUSIONS: Heath knowledge had minor effect on smoking in adolescents but could indirectly affect their smoking behaviors through changing their belief. Grade at school had a doubled influence on smoking, but mainly served as a risk factor. Tobacco control measures for adolescents should not only be limited to health education but environment factors as well.

[Study on the related factors of smoking behavior transition at different stages among undergraduate students].

OBJECTIVE: To explore the influencing factors of smoking behavior transition at different stage of smoking among undergraduate students. METHODS: 8138 undergraduate students from grade 1 to 3 were selected using cluster sampling method from an university in Guangzhou with their smoking behaviors and relevant factors studied through a self-administered questionnaire. Beginners, un-regular smokers and regular smokers were defined as "case group", while non-smokers, beginners and un-regular smokers were defined as "control group" accordingly. Three multivariable logistic regressions were separately conducted to explore the influencing factors of behavioral transition at different stage of smoking. RESULTS: Of the 8138 students investigated, the prevalence rates of beginners, un-regular smokers and regular smokers were 19.6%, 2.0% and 1.1%, respectively; while all of the above said three rates increased with grades of the students. Some students might still try to smoke or become regular smoker in the university. In male undergraduate students, determinants for the transition from non-smokers to s mokers were: source of students, father' s educational level, smoking-related knowledge and belief, and smoking habit of the roommates. Risks that influencing the transition from beginners to un-regular smokers were: being non-medical students,smoking-related belief, roommates and classmates who were smokers and transition from un-regular smokers to regular smokers would include father' s educational level and average income of family. In female undergraduate students,influencing factors from non-smokers to beginners were mother's educational level, smoking-related belief, and roommates smokers, while father's educational level, roommates and classmates' smoking habits were significant associated with beginners' change to un-regular smokers. CONCLUSION: The influencing factors related to the transition of different stage on smoking would be different in undergraduate students,and some specific measures should be taken based on the different stage of smoking.