RESUMEN
Purpose: The aim of this work was to investigate and compare back and lower extremity joint moments and muscle excitation during stoop and squat postures by incorporating gender-based differences and analyzing lifting phases. Methods: 18 healthy adults (9 males and 9 females; age: 24.44 ± 4.96 years, body mass: 66.00 ± 12.10 kg, height: 170.11 ± 9.20 cm, lean body mass: 48.46 ± 7.66 kg) lifted an object 30% of their lean body mass using squat and stoop postures. Marker-based motion capture, force plate, and surface electromyography were synchronously used to acquire joint moments and muscle excitation. A 3-way mixed model analysis was performed to determine the effect of gender, posture, and phase on internal joint moments and muscle excitation of the lower back and extremities. Results: Significant differences were observed in the interaction of lifting posture and phase on lower extremity moments and excitation of rectus femoris and medial gastrocnemius. Individual effects of posture were significant for peak internal joint moments of the lower extremities only. Anterior lower extremity muscles showed significantly increased excitation during squat, whereas medial gastrocnemius was higher in stoop. Joint moments and muscle excitations were all higher during the lifting than the bending phase. Gender differences were found only in the peak lumbosacral sagittal plane moment and rectus femoris muscle excitation. Conclusions: The study identified significant variations in the joint moments and muscle excitation in lifting, influenced by gender, posture, and phase, highlighting its complex nature. Overall interactions were lacking, however individual effects were evident, necessitating larger future studies.
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Elevación , Extremidad Inferior , Músculo Esquelético , Postura , Humanos , Femenino , Masculino , Postura/fisiología , Extremidad Inferior/fisiología , Estudios Transversales , Adulto Joven , Adulto , Músculo Esquelético/fisiología , Caracteres Sexuales , Dorso/fisiología , Electromiografía , Fenómenos BiomecánicosRESUMEN
OBJECTIVE: To analyze the epidemiological characteristics and changing trend as well as the related affecting factors of hepatitis C in China. METHODS: Data analysis was performed based on the case-reporting data of hepatitis C from 1997 to 2011, using SPSS 19.0. RESULTS: The number of reported cases and incidence of hepatitis C had been increasing annually since 1997, especially in 2004. The hepatitis C reported incidence increased from 3.03 per 100 000 in 2004, to 12.97 per 100 000 in 2011. The 15 to 49 age group accounted for more than 50% of all the reported cases, seen in every year. The number and proportion of hepatitis C reported cases among those over 50 year-olds had an annually increase. From 2005 to 2011, the number of cases in both urban areas and rural areas increased annually, while the urban-rural ratio decreased from 1.47 in 2005 to 0.99 in 2011. There appeared an increasing trend of hepatitis C reported incidence in China, with most of the high reported incidence of hepatitis C fell in the northern parts of China. 74.8% of the HCV/HIV co-infected cases had histories of intravenous drug use, plasma donation, blood transfusion or surgical operation. CONCLUSION: The reported number and incidence of HCV infection had been increasing annually. To develop a more realistic control measures for hepatitis C, it is necessary to strengthen the monitoring program and carrying out specific epidemiological study among target groups and key areas.
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Hepatitis C/epidemiología , Adulto , China/epidemiología , Femenino , Hepacivirus , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
OBJECTIVE: To effectively monitor the time trend of HIV prevalence and epidemic among injecting drug users (IDUs), female sex workers (FSWs), sexually transmitted disease (STD) clinic attendants, men who have sex with men (MSM) and pregnant women etc., to provide information for evaluation on strategies regarding comprehensive HIV prevention and effectiveness of intervention, in China. METHODS: Cross-sectional studies had been repeatedly conducted on sentinel surveillance program with uniformed questionnaire and collection of venous blood specimen among IDUs, FSWs, STD clinic attendants, MSM and pregnant women, from 1995 to 2009. RESULTS: HIV prevalence (median) among IDUs had been increasing rapidly since 1996, reaching the plateau (19.2%) in 1999-2000, then gradually decreasing in 2001-2003, and leveling off since 2004 in those relatively hard-hit epidemic provinces. HIV prevalence among drug users had increased a bit since 2001, achieving high level (2.9%) in 2004 before leveling off, showing a slight downward trend in the past two years among the medially-hit epidemic provinces, while it maintained at a low level in those low epidemic provinces. HIV prevalence (median) among FSWs had been slightly increasing, reaching a high level (1.5%) in 1999, then decreased and maintained at a low level in relatively hard-hit provinces. HIV prevalence among FSWs maintained at a low level in medially-hit and low epidemic provinces. HIV prevalence (median) among STD clinic attendants had been maintained at a lower level, lower than 0.7%. HIV prevalence among MSM had been consistently greater than 1%, and was increasing year by year, becoming one of the most important drivers of the HIV/AIDS epidemic over the past years. HIV prevalence (median) among pregnant women had slightly been increasing since 1997, then leveling off over the past years in those relatively hard-hit provinces (0.3%). HIV prevalence among pregnant women had maintained at a low level in the medial and low epidemic provinces. CONCLUSION: Data from sentinel surveillance programs showed a leveling-off situation on HIV prevalence rates among IDUs, FSWs, sexually transmitted infections clinic patients and pregnant women. However, HIV prevalence among MSM had increased significantly since 2005, indicating the high speed of transmission among this population. Epidemic among IDUs had still been concentrated in those relatively hard-hit epidemic provinces. As for FSWs and STD patients, the overall epidemic remained at low level, but the areas of epidemic kept expanding.
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Seroprevalencia de VIH , Vigilancia de Guardia , China/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , EmbarazoRESUMEN
OBJECTIVE: To analyze the HIV/AIDS epidemic situation and related behavioral components among young students in the last years and to provide information for integrated control and prevention programs. METHODS: Data on young students (15 - 24 years) through case reporting system was collected from 2006 to 2009 and continuous sentinel surveillance data regarding 6 national sentinel sites carried out from 2006 to 2009 was also collected. The sentinel sites would include universities, junior college and secondary vocational colleges registered students, using cluster sampling phases method. Self-administered questionnaire survey and blood (HIV antibody testing and syphilis antibody testing) tests were carried out, with the sample size was about 800 cases per site per year. RESULTS: The number of case report on HIV/AIDS among the young students of 15 - 24 years age group had been rising. Similar trend was also observed on the number of reported cases over the years, accounting for the proportions of the total number of reported cases, as 0.39%, 0.50%, 0.83% and 1.02% respectively from 2006 to 2009. Sexual contacts continued to be the major route of transmission, with the increasing proportion of homosexual transmission. In the 6 national sentinel sites of young students which continuous surveillance was conducted during the period from 2006 to 2009, data showed the following facts as: proportion (median) of objects who admitted to have had sex, were: 4.3%, 4.5% and 6.1%, proportions (median) of commercial sex occurred in the past year were: 0.3%, 0.2% and 0.3%; proportions (median) of MSM occurred in the past year were: 0.7%, 0.2% and 0.2%; median of HIV antibody positive rate and syphilis antibody positive rate were 0%; median of awareness rate on HIV/AIDS were: 49.0%, 75.0% and 80.5%; proportion (median) of monitor objects who received intervention services in the past year were: 44.2%, 54.3% and 50.2% respectively. CONCLUSION: In recent years, the HIV/AIDS number through case reporting system on the young students under 15 - 24 years age group, was increasing, but the HIV prevalence among young students was still relatively low, in general. The main transmission was sexual. Some young students had been engaged in commercial sex and MSM activities. Health education should be strengthened to increase the awareness of young students on AIDS/STD prevention. It is necessary to take more effective intervention measures to decrease new infection and control HIV/AIDS epidemic among young students.
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Síndrome de Inmunodeficiencia Adquirida/epidemiología , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Estudiantes , Adolescente , Adulto , China/epidemiología , Femenino , Infecciones por VIH/epidemiología , Humanos , Masculino , Vigilancia de Guardia , Conducta Sexual , Sífilis/epidemiología , Sífilis/prevención & control , Adulto JovenRESUMEN
OBJECTIVE: To understand the characteristics and trends of HIV and syphilis infections among drug users. METHODS: Information was collected regarding HIV and syphilis epidemics, as well as on high risk behaviors from the HIV/AIDS surveillance system. Source of information was from HIV/AIDS case-reporting, sentinel surveillance and trend estimation, related to the changes of distribution among HIV positive drug users prevalence rates on HIV and syphilis together with their high risk behaviors. RESULTS: Scale number on drug users remained stable in the past six year (from 2003 - 2009), while the proportion of drug users decreased from 44.2% in 2005 to 25.8% in 2009. Based on the information from HIV/AIDS case reporting system, HIV sentinel surveillance data showed that the HIV prevalence of drug users was quite different from those of Southwestern to Northeastern parts of China. The HIV prevalence in Southwestern China was much higher than that of the Northeastern areas. Sentinel surveillance data showed that the average positive rates were 6.2% and 3.7% on HIV and syphilis, among the drug users. As for injecting drug users (IDU), the average rates on HIV antibody syphilis and HCV were 9.2% and 4.0% respectively. Series surveillance data indicated that the HIV epidemic expanded quickly among drug users from 1995 - 1999 but became plateaued after 2000 among the IDUs. HIV antibody positive rate remained at 9.0% - 10.0% in the past three years while syphilis fluctuated between 3.5% - 4.5% in the past three years. CONCLUSION: Drug users and IDUs still remained an important driven factor for HIV/AIDS epidemic in China, suggesting more specific strategies and methods should be developed, based on the characteristics and trends of HIV epidemic, to optimize the allocation HIV prevention and control resources.
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Síndrome de Inmunodeficiencia Adquirida/epidemiología , Consumidores de Drogas , Sífilis/epidemiología , China/epidemiología , Femenino , Infecciones por VIH/epidemiología , Humanos , MasculinoRESUMEN
OBJECTIVE: To monitor the time trend of behaviors change related to HIV/AIDS epidemic and HIV prevalence, and to provide information and basis for comprehensive HIV prevention responses and evaluation of intervention effectiveness among female sex workers in China. METHODS: During the year of 2004 to 2008, a series of cross-sectional surveys were conducted among female sex workers in community recruited in both entertainment places and in street, during the defined timeframe, a face-to-face interview was conducted with uniformed questionnaire; while, the venous blood specimen was collected. The sample size was 400 per site per survey. RESULTS: In 15 continuous national HIV comprehensive surveillance sites among female sex workers from 2004 to 2008, the median of HIV prevalence was 0.0%; Prevalence (median) of syphilis respectively: 0.5%, 1.8%, 1.6%, 1.8% and 1.0%. The median of target subjects who used condom in the last commercial sex was: 81.8%, 80.5%, 84.6%, 87.0% and 88.9% respectively; the median of always used condom in commercial sex during the last month: 65.8%, 59.6%, 60.3%, 59.8% and 73.7%. The median of awareness rate on HIV/AIDS transmission of female sex workers was: 74.3%, 84.1%, 65.2%, 66.0% and 74.3%. The median of target subjects who attended HIV VCT services were: 12.4%, 20.4%, 25.8%, 25.3% and 31.7%. The median of the proportion of female sex workers who reached intervention in last year respectively: 46.4%, 76.1%, 72.1%, 95.0% and 90.8%. CONCLUSION: Condom use and HIV awareness rate need to enhance further among female sex workers. The proportion of female sex workers who attended VCT and knew their HIV testing result and the proportion of female sex workers who reached intervention in last year both increase. HIV prevalence rate among female sex workers is generally low, but high risk behaviors are still alarming. It is necessary to take more comprehensive and effective prevention measures and intervention.