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Background: There is no information on the association between exposure to fine particulate matter with an aerodynamic diameter of 2·5 μm or less (PM2·5) and the date-based secondary attack rate (DBSAR) of COVID-19. Methods: In this retrospective cohort study performed in Guangzhou, China, based on hourly concentration data of PM>sub>2·5, PM10, SO2, NO2, and CO from January 1, 2020 to February 15, 2020 from approximately 1,500 monitoring stations in China and the addresses of the participants, we used the Kriging interpolation method to calculate the moving average (MA) concentrations of the pollutants over the previous 1 to 14 days before symptom onset of secondary cases. After simultaneously adjusting for a series of key covariates, we evaluated the dose-response relationship between PM2·5 and DBSAR using a generalized linear mixed model. Findings: DBSAR fluctuated from 2·12% on January 17 to 6·61% on February 13. The significantly positive relationship between PM2·5 exposure and DBSAR at prior 1 to 14 MA days. For example, the dose-response relationship was as follows, for every 10 μg/m 3 increase in PM2·5, DBSAR increased by 2·77% (95% CI: 1·32% to 4·22%; P < 0·001) at prior 1 MA day and 5·82% (95% CI: 4·00% to 7·65%; P < 0·0001) at prior 14 MA days. The effect of PM2·5 exposure in DBSAR significantly differed by age and exposure time. Interpretation: There was a strong nonlinear dose-response relationship between exposure to PM2·5 and DBSAR at prior 1 to 14 MA days, which provide significant evidence and suggests that transmission by aerosol is possible. Funding Statement: This study was supported by grants from the Health Science and Technology Plan Project of Guangzhou (20191A01158). Declaration of Interests: All authors declare no competing interests. Ethics Approval Statement: This study was approved by the ethics committee of the Guangzhou CDC (Guangzhou, China). Analyses involving personally identifiable data were conducted at the Guangzhou CDC. The analyses were performed with anonymized data.

Elevated levels of postprandial triacylglycerol-rich lipoproteins (ppTRLs) are atherogenic. Patients with type 2 diabetes mellitus (T2DM) have exaggerated postprandial lipemia associated with elevation or prolonged residence of ppTRL remnants. We examined whether dietary fatty acid compositions (DFACs) decrease atherogenic lipid profiles in ppTRL subfractions in T2DM Chinese patients. A single-blind randomized controlled trial was conducted among 28 T2DM patients. Patients consumed 1 of 3 standardized DFAC-specific fat meals: equidominant (1:1:1), polyunsaturated fatty acid (PUFA)-dominant (PUFA-D, 1:1.7:2.3), or monounsaturated fatty acid (MUFA)-dominant (MUFA-D, 1:1.7:1.2) meals. Numbers in parenthesis, respectively, represent the ratio of saturated fatty acids, MUFA, and PUFA to saturated fatty acids. The MUFA-D meal was the control. Triacylglycerol and cholesterol levels were measured in Svedberg flotation rate (S(f)) greater than 400, S(f) 60 to 400, S(f) 20 to 60, and S(f) 12 to 20 ppTRL subfractions at fasting (0 hour) and 2, 4, and 6 hours after the consumption of the fat meals. Effects of DFACs on mean concentrations of triacylglycerols and cholesterol averaged over 0, 2, 4, and 6 hours in ppTRL subfractions were assessed using linear mixed models. Stability and robustness were validated with 1000 bootstrap replicates. Contrasted to the control, equidominant meal reduced 6-hour average triacylglycerol levels in S(f) greater than 400 (P = .002, bootstrap P < .05) and S(f) 20 to 60 (P = .02, bootstrap P < .05) subfractions, and decreased average S(f) 20 to 60 cholesterol (P = .04, bootstrap P < .05); PUFA-D decreased S(f) greater than 400 average triacylglycerol levels (P = .09, bootstrap P < .05). Bootstrap samples suggested that PUFA-D decreased average S(f) 20 to 60 cholesterol levels (bootstrap P < .05). Therefore, modifying DFACs attenuates the atherogenic lipid profile of ppTRLs in T2DM patients; but increasing PUFA ratio may be more feasible.

Objective. To identify modifiable family and school environmental factors associated with Chinese adolescent smoking behaviors including never-smoking, experimental smoking, regular smoking, and attempting to quit. Methods. A cross-sectional survey using self-reported questionnaires was conducted in Huangpu, Guangzhou in December of 2004. A total of 3957 pupils agreed to complete the questionnaires. The prevalence odds ratio (risk) of experimental smoking was compared to never-smoking, adjusting for gender and age in unconditional logistic regression analysis. The risk of regular smoking was compared to experimental smoking, and the risk of attempting quitting was analyzed in regular smokers. Results. The cigarette smoking of peers, mothers, fathers, brothers, and supervising teachers, passive smoking, and seeing someone smoking on campus increased the risk of experimental smoking vs. nonsmoking, while no-smoking signs, perceived anti-tobacco atmosphere in school, and being taught smoking-related health knowledge decreased the risk. The factors associated with regular smoking compared to experimental smoking included the smoking of peers, brothers, fathers and supervising teachers, teacher's tolerance, and passive smoking. Being taught smoking-related knowledge, perceived anti-tobacco atmosphere and no-smoking signs in school were positively associated with regular smoker's attempt to quit, while supervising teacher's smoking, parents' and teachers' tolerance could delay it. Conclusions. These modifiable family and school environmental factors as well as their interaction with gender and age should be highly considered in adolescent smoking prevention in China.

Apolipoprotein (apo)E-deficient mice were used to study the antiatherogenic effect of black rice pigment fraction (BRF) and the possible mechanisms by which it inhibits atherogenesis. The apoE-deficient mice (n = 45) were randomly divided into three groups and received AIN-93G diet (positive group), AIN-93G with 5 g of black rice pigment fraction/100 g (BRF group) and AIN-93G with 5 g of white rice outer layer fraction/100 g (WRF group) for 16 wk. C57BL/6J mice (n = 15) received AIN-93G and were used as a control group. Blood samples were collected for measurement of lipid concentration, antioxidized LDL antibody and nitric oxide concentration. Livers were extracted for determination of cholesterol concentrations, and aortas were used to determine cholesterol concentrations and inducible nitric oxide synthase protein and mRNA expression. Hearts were used to assess atherosclerotic plaque formation. The apoE-deficient mice fed the black rice pigment fraction diet had 48% (P < 0.01) less atherosclerotic lesion area compared with apoE-deficient mice fed only the AIN-93G diet and 46% (P < 0.01) less lesion area compared with mice fed the white rice outer layer fraction diet. This observation corresponded with significantly (P < 0.05) lower total serum cholesterol, lower liver and aorta cholesterol (P < 0.01) and higher HDL cholesterol (P < 0.05) concentrations and lower (P < 0.05) antioxidized LDL antibody titer in apoE-deficient mice fed the black rice pigment fraction diet compared with positive and WRF groups. Notwithstanding this, mice fed the black rice pigment fraction diet also had lower CD4(+) T lymphocyte expression (P < 0.05) and weaker inducible nitric oxide synthase expression (P < 0.05) compared with mice fed the AIN-93G diet and the white rice outer layer fraction diet, respectively. We concluded that the inhibition of atherosclerotic lesions of the black rice pigment fraction is attributed to the improvement in cholesterol accumulation and reduction in oxidative stress and inflammation.

The influence of white, red and black rice consumption on atherosclerotic plaque formation induced by hypercholesterolemia was investigated in rabbits. Male rabbits (n = 36) were divided into five groups. They were fed a normal laboratory purified diet (normal group, n = 6), a high cholesterol (0.5 g/100 g) diet (HC group, n = 6), a high cholesterol diet with 30 g/100 g white rice (WR group, n = 8), 30 g/100 g red rice (RR group, n = 8), or 30 g/100 g black rice (BR group, n = 8) for 10 wk. Blood samples were collected for lipid measurements and aorta were removed for assessment of atherosclerotic plaques at the end of the protocol. The oxidant and antioxidant status of blood, erythrocytes, liver and aorta was evaluated. The area of atherosclerotic plaque was 50% lower in rabbits fed the red or black rice diets than in those fed the white rice diet. Compared with the HC and WR groups, serum HDL cholesterol and apolipoprotein (apo) A-I concentration were greater (P < 0.05) in the RR and BR groups. Liver reactive oxygen species (ROS) and aortic malondialdehyde (MDA) were significantly lower, and the liver total antioxidative capacity (TAC) and erythrocyte superoxide dismutase (SOD) activity were significantly higher in the RR and BR groups compared with the HC and WR groups. Red or black rice consumption reduced or retarded the progression of atherosclerotic plaque development induced by dietary cholesterol. The enhanced serum HDL cholesterol and apo A-I concentrations, and the increased antioxidant and decreased oxidative status may be mechanisms of the antiatherogenic effect of red or black rice.

Dietary components play an important role in the cause and pathogenesis of colorectal cancer by complicated interaction between diet components and gut microflora. Diet components not only alter bacterial metabolism, but also are chemically modified by microflora in gut into various carcinogens. Dietary fat, fibre, starch, total energy intake, calcium and dairy lactobacilli are currently under the study.

The effects of yogurt containing viable Lactobacillus strain GG (L. GG) and/or fiber supplements on fecal enzyme activities (beta-glucuronidase, nitroreductase, beta-glucosidase, glycocholic acid hydrolase, urease) and on bacterial metabolites in urine (phenol, p-cresol) were studied in 64 females, 20-41 y old. The subjects were randomly divided into three groups: the first group received L. GG yogurt (2 x 150 mL/d, containing 10(11) colony-forming units (cfu)/L of L. GG), the second group received L. GG yogurt and a rye fiber product (30 g/d, equivalent to 9 g fiber/d), and the third group received placebo yogurt (pasteurized) and fiber. The supplementation period lasted 4 wk, with a preceding 2-wk baseline period and a 2-wk follow-up period. The mean fecal count of L. GG was approximately 10(6) cfu/g feces during the supplementation, and L. GG persisted in the fecal samples of 28% of the subjects for 2 wk after supplementation. L. GG yogurt alone or with fiber significantly decreased fecal beta-glucuronidase, nitroreductase and glycocholic acid hydrolase activities. These enzyme activities returned to baseline levels during the follow-up period. beta-Glucosidase and urease activities were not altered significantly during the study. The addition of fiber to L. GG and placebo yogurt had no effect on the enzymic activities. Urinary excretion of p-cresol decreased significantly in groups receiving L. GG. These data demonstrate that L. GG can modify the colonic environment with possible health effects.

The effect of adopting an uncooked extreme vegan diet lacking in cholesterol and readopting conventional diet on serum lipids and apolipoprotein was studied. Eighteen subjects were randomly divided into test and control groups. In the test group, subjects adopted the uncooked extreme vegan diet for one month and then resumed a conventional diet for a second month. Controls consumed conventional diet throughout the study. Total serum cholesterol, triglyceride, LDL, HDL cholesterol and apolipoprotein AI as well as B decreased significantly within two weeks of beginning the new diet. The alleviated levels remained throughout the period of consuming vegan diet. The lipid and apolipoprotein concentrations returned to normal level within one month of resuming the conventional diet. The HDL-cholesterol: LDL-cholesterol ratio was elevated in the test group after one month of consuming the new diet. Serum apolipoprotein AI level was less decreased by the vegan diet compared to that of apolipoprotein B. In the control group, no changes were observed during the study. The results suggest that the uncooked extreme vegan diet causes a significant decrease of the atherosclerosis risk factor.