[A study on indicator system for early-warning on hemorrhagic fever with renal syndrome epidemic].

OBJECTIVE: To establish an early-warning indicator system on outbreak of hemorrhagic fever with renal syndrome by Delphi method seeking expert advices. METHODS: Firstly, the literature review and the experts meeting method were used to formulate the initiator frame work and indicators. A two-round consultation was used to filter indicators, discuss the boundary of indicators and determine the weighting coefficient among 25 experts from 14 provinces, municipalities and autonomous regions. The relative weightiless of indicators was determined by the weight coefficients method. RESULTS: The experts' average length of service in prevention and control of hemorrhagic fever with renal syndrome was (23.80 ± 11.70) years. The positivity coefficients of the two-round experts were 100% and 72%. Kendall's coefficients of the two-round consultation were 0.50 (χ(2)(R) = 148.95, P < 0.01) and 0.54 (χ(2)(R) = 212.63, P < 0.01) and opinions among experts became consistent and the consultation had achieved the need of forecast. Four first-class indicators (host animals, risk population, social environment and case-related indicators) and 14 second-class indicators were filtered to develop the indicators system. The weight coefficients of the first-class indicators were 0.28, 0.23, 0.23 and 0.26. CONCLUSION: The early-warning index system of hemorrhagic fever with renal syndrome has been established and it could provide a reference for the forest and warning of HFRS outbreak.

[Study on the relations between smoking and the risk of age-specific lung cancer deaths in urban and rural areas of China].

OBJECTIVE: To study the association between smoking and lung cancer mortality of residents living in the urban and rural areas of China. METHODS: Using the national census data on causes of death and case-control studies, stratified analysis was conducted by parameters as geography and age, to calculate the risk ratios, excess risks, average years lost for life expectancy by smoking in males and females in 103 cities/counties in China. RESULTS: Smoking increased the risks for lung cancer death in all ages older than 35 years of age, in urban and rural areas, through data analysis on 52 193 cases died from lung cancer in 1986 - 1988 and 307 934 matched controls in China. The risk ratio was 3.0 (95%CI: 2.9 - 3.1) with 53.0% excess for lung cancer deaths in the male smokers. The years lost for life expectancy were 18.5 in urban, and 17.7 in rural male smokers aged 35 to 69 years. Similarly, the risk ratio was 3.0 (95%CI: 2.9 - 3.1), with 26.0% excess for lung cancer deaths in female smokers. The life-expectancy lost was 13.0 and 20.4 for female smokers aged 35 to 69 years in urban and rural areas, respectively. CONCLUSION: In both urban and rural areas, risk on lung cancer deaths caused by smoking in all males and females aged at 35 years and older had been significantly increased. Control of smoking prevalence should play a vital role in the prevention of the lung cancer death risks in China.

[Association of Taq I T/C and Fok I C/T polymorphisms of vitamin D receptor gene with outcome of hepatitis B virus infection].

OBJECTIVE: To determine whether Taq I T/C and Fok I C/T polymorphisms of vitamin D Receptor (VDR) gene was associated with the outcomes of hepatitis B virus (HBV) infection. METHODS: A total of 212 HBV self-limited infection individuals, 244 asymptomatic HBsAg carriers and 391 chronic hepatitis B (HB) patients were recruited to conduct a case-control study. VDR-Taq I T/C and VDR-Fok I C/T polymorphisms were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The frequency of VDR-Fok I allele C in the chronic HB patients was 45.8%, significantly higher than 38.2% of the self-limited infection individuals (chi(2) = 6.43, P = 0.01). The frequencies of VDR-Fok I genotypes TT, TC, and CC in HB patients were 30.7%, 47.1%, and 22.2% respectively, and 41.0% (TT), 41.5% (TC), and 17.5% (CC) in the self-limited infection individuals. There was a statistically significant difference between HB patients and self-limited infection individuals (chi(2) = 6.76, P = 0.03). The results of univariate analysis showed that the subjects carrying VDR-Fok I CC/TC genotype had 1.57-fold elevated risk for developing chronic HB when they were infected HBV (OR = 1.57, P = 0.01). A multiple logistic regression analysis revealed that VDR-Fok I CC/CT was independently associated with chronic HB after adjusting both potential confounding effects of gender (OR = 1.70, P = 0.021). The statistically significant association between TaqI T/C polymorphism and outcome of HBV infection was not demonstrated in the study. The frequency of haplotype TC of VDR-TaqI and Fok I in HB patients was 2.3080%, significantly higher than 0.5391% of the self-limited infection individuals (chi(2) = 6.08, P = 0.01). However, the frequency of haplotype TT in the HB patients was 1.5283%, significantly lower than 3.7061% of the self-limited infection individuals (chi(2) = 5.65, P = 0.02) and 3.4820% of the HBV carriers (chi(2) = 5.12, P = 0.02). CONCLUSION: VDR gene polymorphism is probably an influence factor on the genetic susceptibility of HBV infection.

[Study on association between vitamin D receptor gene polymorphisms and the outcomes of HBV infection].

OBJECTIVE: To explore whether the vitamin D receptor gene (VDR) polymorphisms are associated with the outcomes of hepatitis B virus (HBV) infection in Chinese Han population. METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the polymorphisms of Fok I locus in exon 2 and Taq I locus in exon 9 of VDR gene. One hundred and eighty-four chronic hepatitis B patients and 205 asymptomatic HBV carriers were recruited to make the comparison of frequencies of genotype and haplotype of the VDR gene between the patients and the carriers. RESULTS: The univariate analysis showed a significant difference in Fok I polymorphism between chronic hepatitis B patients group and asymptomatic HBV carriers group. The FF genotype frequency in chronic hepatitis B patients group was 44.6%,higher than 31.7% in asymptomatic HBV carriers group (P<0.05). After adjusting the confounders by multiple logistic regression analysis, the result still showed a significant difference in Fok I site polymorphism between chronic hepatitis B patients group and asymptomatic HBV carriers group (OR=1.95, P<0.05). The FT haplotype frequency in chronic hepatitis B patients group was higher than that in asymptomatic HBV carriers group (OR=1.45, P<0.05). The fT haplotype frequency in chronic hepatitis B patients group was lower than that in asymptomatic HBV carriers group (OR=0.72, P<0.05). CONCLUSION: VDR gene polymorphism may be an influence factor of genetic susceptibility to HBV infection.

[Relationship between smoking and risk of esophageal cancer in 103 areas in China: a large-scale case-control study incorporated into a nationwide survey of mortality].

OBJECTIVE: To examine the relationship between smoking and risk of esophageal cancer (EC), and present a theoretical framework of control selection in population-based case-control study which was incorporated into a nationwide retrospective survey of mortality in China. METHODS: A large-scale population-based case-control study was incorporated into the nationwide retrospective survey of mortality conducted 1989 - 1991 in 24 urban cities selected by non-random sampling and 79 rural counties selected from 3000 counties included in the 1973 - 1975 cancer distribution survey by random sampling during. A questionnaire survey was conducted by home visit to investigate the death causes and smoking history of 19 734 deceased male adults who died of esophageal cancer during 1986 - 1988 at the age >or= 35. Two control groups were set up to undergo questionnaire survey by home visit to investigate the smoking history of the deceased persons and the informants. Control group I included the surviving spouses or other informants of 31 989 male adults who died of non-malignant digestive diseases during 1986 - 1988 at the age >or= 35, and control group II included 104 846 male spouses of the deceased female adults who died of different causes during 1986 - 1989 at the age >or= 35. The relative risks and population smoking attributable risks for EC were calculated using non-conditional logistic model, and the results were compared for consistency between the analyses using two different control groups. RESULTS: The EC absolute death rates were higher in the smokers than in the non-smokers in all urban and rural area groups. The total EC absolute death rate per 1000 among the non-smokers vs. smokers was 0.37:0.65 in the urban areas, 0.99:1.29 in the inland rural areas, and 1.09:1.62 in the coastal rural areas in the control group I, and there was a similar trend in the control group II. There was a significant dose-response relation between the period of smoking and the death risk of EC and between the daily cigarette consumption and the death risk of EC. The risk ratios, for example, for cigarette per day < 10, 10-, and 20- in the urban men were 1.42, 1.82, 2.22 in the control group I (trend test P < 0.01), and 1.57, 1.95, and 3.18 in the control group II (trend test P < 0.01). CONCLUSION: Smoking is an important risk factor for mortality from EC in China. Investigating the surviving spouses of the deceased patients is a creative, effective, and feasible trial, with the prerequisite of whole population-based survey, in study of the main types of death and the relevant risk factors.

Smoking and mortality from esophageal cancer in China: a large case-control study of 19,734 male esophageal cancer deaths and 104,846 living spouse controls.

An innovative population-based case-control study was conducted in a national mortality survey to assess the hazards of tobacco use on esophageal cancer among Chinese men. Cases were 19,734 males aged 35 years or older, who died of esophageal cancer during 1986-1988. Controls were 104,846 male living spouses of the same age when their wife died (of any cause) during the same period in the same county or city. The absolute esophageal cancer death rates were higher in smokers than those in nonsmokers in all geographical groups. The relative risks for esophageal cancer were 1.88 (95% CI: 1.73-2.05) and 1.39 (95% CI: 1.28-1.50) in urban and rural men, respectively, after adjustment for other relevant covariates including age group (5 years) and locality. When the calculation was restricted to men aged 35-69, the risk ratios for current cigarette smokers increased significantly with increasing number of cigarettes smoked daily and duration of smoking. Tobacco use, in any form, is an important risk factor for esophageal cancer in Chinese men. Selecting living spouses as controls is a unique and useful approach in the design of case-control studies of cigarette smoking.

Long-term effectiveness of infancy low-dose hepatitis B vaccine immunization in Zhuang minority area in China.

AIM:To observe the long-term effectiveness of low-dose immunization strategy and risk factors of HBsAg carriers in immunized children of Zhuang minorities of Longan County in the 9th year after infancy immunization.METHODS:Two epidemiologic methods,a cross-sectional follow-up study and a case-control study,were used for the evaluation of the serological effect and the determination of the risk factors. Hepatitis B virus markers were detected with radioimmunoassay.RESULTS:The protective anti-HBs-positive rate was 43.8% in 1183 children aged 1-9 years,who were immunized with three doses of 10&mgr;g hepatitis B vaccine in infancy according to 0, 1 and 6 months schedul.It declined from 87.9% in the first year to 37.1% in the 9th year after vaccination.The HbsAg-positive rate was 1.6%, not increasing with age during 9 years after the infant immunization program. Compared with 14.0% of HbsAg-positive rate of the baseline survey in 1985, the effectiveness of hepatitis B vaccine immunization was 88.6%. Of 36 immunized children with positive HBsAg, 89.1% were likely attributable to HBsAg positivity of their mothers.CONCLUSION:The long-term effectiveness of infancy low-dose hepatitis B vaccine immunization is high,and the booster is not needed 9 years after the vaccination in the Zhuang minority area where hepatitis B is highly endemic.A high-dose immunization strategy should be recommended in order to further decrease the current HbsAg-positive rate.

Survey of coverage, strategy and cost of hepatitis B vaccination in rural and urban areas of China.

AIM:In order to understand the coverage, immunization strategy and cost of hepatitis B (HB) vaccination of China in recent years.METHODS:A two-stage household random sampling method was used in the survey.RESULTS:The survey carried out at 112 Disease Surveillance Points (DSPs) of 25 provinces, autonomous regions and municipalities of China in 1996, showed that the coverage rates of HB vaccination among neonates were 96.9% in the urban DSPs and 50.8% in the rural DSPs in 1993-1994,while in students aged 7-9 years, they were 85.8% and 31.5% in 1994, respective-ly. Up to 1994, 97.5% of the urban DSPs and 73.9% of the rural DSPs on a neonate vaccination against HB program were included in EPI. About 93% of the urban DSPs and 44% of the rural DSPs did HBsAg and HBeAg screening for all or part of pregnant women. The neonates received the regimen of high-dose HB vaccine in combination with hepatitis B immune globin (HBIG) if their mothers were HBsAg and/or HBeAg positive in pregnancy,otherwise they received the low-dose vaccine (10&mgr;gX3). Part of DSPs had a lower neonate coverage due to unreasonable allocation of the vaccines (used for adults not at risk) or higher cost or insufficient supply of the vaccines. It is necessary to evaluate the quality of serological lab test to HBVMs in the maternal prescreening.CONCLUSION:Remarkable achievements have been made according to the national planning and policy of HB immunization in China.

Persistence of hepatitis B vaccine immune protection and response to hepatitis B booster immunization.

AIM:To identify the persistence of immune protection of China-made, plasma derived hepatitis B vaccine after infancy immunization and the time table of booster immunization.METHODS:A cross-sectional follow-up study and an experimental study on booster were used for the evaluation of the serological effect 7 years after vaccination and the antibody anamnestic response. Radioimmunoassay was used for the detection of hepatitis B virus markers. RESULTS:The protective anti-HBs positive rates of 1018 children, who were vaccinated according to the regimen of three doses of 10 &mgr;g hepatitis B vaccine in their infancy, declined from 75.0% during the first two years to 48.2% in the 7th year after the first dosage, however, the positive rates for HBsAg and anti-HBc always fluctuated at a low frequency. A total of 144 subjects aged 6 or 7 years, who were negative for both HBsAg and anti-HBc before booster, were selected from 1018 children of the follow-up study, and boosted with 1&mgr;g intradermally or 2&mgr;g hypodermically hepatitis B vaccines. Their anti-HBs GMT and anti-HBs positive rates were 190.6mIU/ml and 89.6% in the first month after booster,significantly higher than 14.7mIU/ml and 54.9% before booster (P < 0.01), and declined back to 25.3mIU/ml and 75.5% in the 12th month; among 65 children with the anti-HBs negative before booster, 40 had a level of anti-HBS< = 100mIU/ml one month after booster, suggesting retention of immune memory in most of them.CONCLUSION:No need for revaccination against hepatitis B in the 7th year after the initial immunization due to better persistence of immune protection of the vaccine and retention of immune memory to hepatitis B virus in the vast majority of the vaccinees.