ObjectiveTo investigate the effect of ambient ozone on mortality risk and its temperal-spatial distribution in the Pearl River Delta cities, and further explore modification factors of the variation in the distribution. MethodsA time-series study design was employed. Cities of Guangzhou, Dongguan, Foshan, Jiangmen, and Zhaoqing were selected as study settings. Daily non-accidental mortality data from 2013 to 2014 in each city were collected from Guangdong Provincial Center for Disease Control and Prevention. The contemporaneous daily ambient ozone concentration and meteorological indictors were obtained from Guangdong Environmental Monitoring Center and Guangdong Meteorological Service, respectively. A generalized additive model was used to estimate the excess risk (ER) of mortality for each 10μg/m3 increment in average ambient ozone concentration during Lag 02 days in the full year, cold season (November to April), and warm season (May to October) in each city. Then a Meta-analysis was used to quantitatively combine the ERs in each city. Finally, a Meta-regression model was used to explore the effects of city specific ambient ozone level, elderly population proportion (>65 years), and average income level on the ER in the cities.ResultsFrom 2013 to 2014, the average daily nonaccidental deaths were 136.2, 29.5, 9.3, 77.2, and 18.9 and the average concentrations of atmospheric ozone were 57.0, 71.9, 53.9, 53.9, and 64.6 μg/m3 in cities of Guangzhou, Dongguan, Foshan, Jiangmen, and Zhaoqing, respectively. In the full year, a 10μg/m3 increment in ambient ozone concentration was associated with an increment in ER by 0.37% (95%CI：0.07% - 0.66%), 0.44% (95%CI：-0.11% -0.99%), -0.05% (95%CI：-1.08% - 0.99%), 0.21% (95%CI：-0.23% - 0.66%), and 0.65% (95%CI: -0.09% - 1.40%) of total mortalities in Guangzhou, Dongguan, Foshan, Jiangmen, and Zhaoqing, respectively. The combined ER in the five cities was 0.35% (95%CI：0.14% -0.56%). The pooled ER in the cold season (ER=0.51%，95%CI：0.20% - 0.83%) was larger than that in the warm season (ER=0.22%，95%CI：-0.07% - 0.51%). Meta regression analysis showed that the city specific ER was positively related to the annual average ozone concentration and elderly population proportion, but negatively related to average income level although without statistical significance.ConclusionThe ambient ozone in the Pearl River Delta region could increase the mortality risk of population with a higher effect in the cold season. The health effects of ozone largely differentiated between cities. The modification effects of ambient ozone level, proportion of the elderly, and income level on the ER are still not clear, which needs further study.

ObjectiveTo investigate HIV/AIDS/STD risk behaviors and influencing factors among men who have sex with men (MSM) in Lianzhou City, Guangdong Province.MethodsRespondent-driven sampling, snowball sampling, and network recruiting were applied to recruit MSM from October 2014 to August 2015. A structured questionnaire survey and the blood collection of participants were carried out simultaneously. The contents of the survey included demographic characteristics, sexual behavior, HIV/AIDS intervention service, and the HIV/AIDS related knowledge and attitude. Logistic regression was used to analyze factors influencing high risk behaviors. ResultsA total of 312 MSM were recruited. Their average age was (30.53±11.52) years. Of the participants, 58.65% had the education level of high school, secondary specialized school, or below; main occupations were student (22.44%), worker (22.44%), and service personal (20.19%); 61.86% were unmarried; 62.18% were homosexual. The awareness rate of HIV/AIDS was 75.32%. In the past one year, the coverage of intervention service was 31.41%. During the past six months，79.81% (249/312) of them had anal sex with male partners, but only 24.10% used condom every time when having anal sex, and the condom using rate for the latest anal sex was 44.18% (110/249); 28.85% of the MSM had sex with females and only 14.44% of them used condom every time. The positive rates of HIV antibodies, HBsAg, and syphilis antibodies were 12.18%, 5.92%, and 2.96%, respectively. No cases were found to be positive for HCV antibody. In the multivariate logistic regression, the subjects who were 20 years old or older when having first sex with males were not more likely to have multiple male sexual partners (OR=0.44), those who had monthly income above 3 000 Yuan were more likely to have multiple male sexual partners (OR=4.66), those who had lower level of education were not more likely to use condoms each time (OR=0.30), and those who did not have related diseases tested voluntarily (OR=3.39) and the male sexual partners were non-fixed or both (OR=1.73) were much easier to have unprotected anal intercourses with male partners.ConclusionHIV infection rate is high, awareness of HIV/AIDS knowledge is low, and high risk behaviors exist generally among MSM in Lianzhou. It is necessary to take targeted publicity and interventions including peer education, network intervention, and school education for HIV prevention.

ObjectiveTo understand pathogenic characteristics and variation trend of hand, foot, and mouth disease（HFMD）during 2010-2013 in Guangdong Province.MethodsEight children’s hospitals (maternal and children health hospitals or departments of paediatrics in general hospitals) were selected as sentinel hospitals from 8 cities in Guangdong Province from March 2010 to December 2013. Specimens of mild cases of HFMD were collected for detection of enterovirus (EV). ResultsA total of 6 816 specimens of mild cases of HFMD were collected and 5 403 was positive for EV. The total EV positive rate was 79.27%, of which the positive rates of EV 71, coxsackievirus A16 (Cox A16), and other EV were 25.57%, 17.31%, and 36.38%, respectively. The positive rate of EV 71 was highest in 2010 (37.73%); the positive rate of other EVs was highest in 2011(30.83%) and in 2013 (60.60%); the positive rate of EV 71was almost as high as other EVs in 2012 (29.53% and 29.34%)．During 2010-2012, the predominant pathogens of HFMD switched in April-May and September-October, and the conversion time of predominant pathogens was consistent with the two peaks in the incidence of HFMD (spring-summer and autumn). In 2013 the predominant pathogens were other EVs from January to October, with a unique peak in the incidence of HFMD. ConclusionHFMD epidemic in Guangdong Province was characterized by frequent conversions of predominant EVs (including EV 71, Cox A16 and other EVs ). It is very important to understand the variation of the EVs for early warning and control of HFMD.

ObjectiveTo establish a risk assessment index system for outbreak of infectious diseases after natural hazard.MethodsTwo rounds of Delphi consultation were held among 30 experts on infectious disease prevention and control to determine the first-level and second-level indexes, and the index weights.ResultsThe active coefficients of specialist authority were 96.67% (29/30) and 100.00%(30/30) in the two round consultations, respectively. The authority coefficients of experts ranged from 0.65 to 0.95 and the mean value was 0.83. The mean values of the 7 first-level indexes and 71 second-level indexes were 4.12-4.88 and 3.14-4.76, respectively. The coefficients of variation were < 0.18 for the first-level indexes and < 0.30 for the second-level indexes. Kendall's coefficients of concordance were 0.334 for the first round of consultation and 0.478 for the second round.ConclusionRisk assessment index system for outbreak of infectious diseases after natural hazards established in the study is reasonable and comprehensive, covering the main factors influencing the occurrence of infectious diseases after natural hazard.

ObjectiveTo investigate the status of cadmium contamination in edible aquatic products in Guangdong Province and assess the dietary exposure level of cadmium.MethodsBy using simple random sampling method, 60 various edible aquatic products were collected from each 21 prefectural cities and Shunde District, Foshan City of Guangdong Province. Based on the survey data of aquatic products consumed by residents in Guangdong Province, the method of point assessment was applied to evaluate the level of exposure to cadmium in edible aquatic products. The results were compared and evaluated with the provisional tolerable monthly intake for cadmium recommended by Joint FAO/WHO Expert Committee on Food Additives.ResultsA total of 1 325 samples were analyzed and the total exceeding standard rate was 5.4% (71/1 325). The average ranges of cadmium content in different edible aquatic products were 0.003 6 - 0.587 2 mg/kg and the differences were statistically significant (P<0.01). The average and P＜97.5 intake levels of edible aquatic products were 51.6 and 185.6 g/d separately consumed by Guangdong residents, then the average and P＜97.5 exposure doses of cadmium from edible aquatic products were 0.99 and 7.75 μg/d, respectively. The daily average exposure contribution rate of shellfish was 40.4%, the highest among the edible aquatic products. The monthly assessed intake amounts of cadmium associated with edible aquatic products calculated from daily average and P＜97.5 exposure doses accounted for 2.0% and 15.5% of provisional tolerable monthly intake for cadmium, respectively.ConclusionThe content of cadmium in edible aquatic products exceeded the standard in Guangdong Province, but the dietary exposure levels of residents were far below the value of health-based guidance. The dietary level of exposure to cadmium in edible aquatic products may not pose a health risk according to the assessment.

ObjectiveTo understand health literacy level and analyze influencing factors among medical staffs in Chongwen District, Beijing. MethodsBy using random cluster sampling method, 2 Level-1 hospitals, 1 Level-2 hospital, and 1 Level-3 hospital were selected to conduct a questionnaire survey among medical staffs aged 18 to 59 years. The survey contents included basic information, basic knowledge and concepts, healthy lifestyles and behavior, and health basic skills. Chi-square test and multivariate unconditional logistic regression were used to analyze health literacy status and influencing factors. ResultsA total of 350 questionnaires were distributed and 348 were valid, with an effective response rate of 99.4%. The average age of respondents was (36.29 ± 9.81) years. Of them, 81.6% (284/348) were females, 36.5% (127/348) had college education level, and 56.6% (197/348) had annual household income of 100 000 to 190 000 Yuan. The health literacy level was 66.1%. The levels of basic knowledge and concept, healthy lifestyle and behavior, and health related skills were 75.3%, 32.2%, and 67.8%, respectively. Multivariate logistic regression showed that those having higher educational level (OR=1.554) or chronic diseases（OR=2.472）would have higher level of health literacy. ConclusionThe health literacy level among medical staffs in Chongwen District was low. It should be improved by targeted health education and health promotion activities.