Incidence and associated factors for single and recurrent falls among the elderly in an urban community of Beijing.

OBJECTIVE: To investigate the incidence of falls and recurrent falls, and explore associated factors for single and recurrent falls among urban community-dwelling elderly in Beijing. METHODS: A cross-sectional study was conducted in 472 elderly in the Longtan community of Dongcheng district, Beijing in 2009. Data regarding the incidence of fall and recurrent falls in the previous year, as well as associated factors were collected from the elderly through face-to-face interviews. RESULTS: The incidence of falls and recurrent falls was 17.8% and 6.1%, respectively, and it increased with age (χ2for trend=21.06, 19.20, P=0.001, 0.002). Binary logistic stepwise regression analysis showed that age (OR=2.20), living alone (OR=4.67) and gait disturbance (OR=1.27) were risk factors, while housing with elevators (OR=0.35), appropriate width/height of stair steps (OR=0.78), sufficient lighting for stairway (OR=0.45) and regular exercise (OR=0.12) could lower the risk for single fall; factors such as low monthly family income (OR=1.39), poor vision (OR=1.83), low physical ability (OR=4.47), abnormal static balance (OR=2.48), and fear of falls(OR=2.23) were risk factors, while appropriate width/height of stair steps (OR=0.49) and easiness of access to daily supplies (OR=0.41) were protective factors for recurrent falls. CONCLUSION: The incidence of falls in community-dwelling elderly people in Beijing is common, and falls and their related injuries have been associated with both intrinsic and extrinsic factors.

[Effectiveness on the education and food safety programs among senior primary students in 2 counties from west China-a cluster randomized trial].

OBJECTIVE: To evaluate the effectiveness of nutrition and food safety educational programs on primary students from grade 4 to 6 in impoverished areas of Western China, under a school-based cluster-randomized trial. METHODS: Twelve primary schools were selected from 2 impoverished counties in West China and assigned to intervention or control groups, randomly, with 6 schools in each group. Self-rating knowledge, attitude and practice questionnaires were used at both baseline and final stages. Textbooks and supportive materials were designed according to the characteristics of baseline data. All students in the intervention group were treated with targeted nutrition and food safety lectures of 0.5 hour per week for 2 semesters. Generalized linear mixed effects model was applied to fit the random effects on individual and clusters as well as to fit the fixed effect of the programs. RESULTS: Three hundred seventy-eight students from grade 4 to 6 were randomly selected at the baseline study and the differences of scores on knowledge, attitude and practice between the 2 groups were statistically insignificant (P > 0.05). No cluster was lost during the trial. In the final investigation, 478 students were randomly selected at the individual level. Scores on knowledge, attitude and practice among students in the intervention group were significantly higher, when comparing to the control group (P < 0.01). At the cluster level, more schools in the intervention group showed significant changes on knowledge and practice, yet the change in attitude was less obvious. Data from the mixed-effects model demonstrated that the program served as an influential factor on scores related to knowledge after the intervention(P = 0.015)but did not affect the scores on related attitude or practice (P > 0.05). CONCLUSION: Lectures seemed to have improved the cognition of nutrition and food safety among primary students from grade 4 to 6. However, long-term observation and larger sample size were needed to evaluate the changes on attitude and practice among the students.

[Status on knowledge, attitudes, behavior regarding nutrition and food safety among 4-6 grade students from Chinas' two poverty-stricken counties].

OBJECTIVE: To investigating knowledge, attitudes, current behavior among primary school students on nutrition and food safety in two State-level poverty-stricken counties, and to explore the best educational model on nutrition and food safety. METHODS: 478 pupils at 4-6 grades were selected, using the method of stratified cluster sampling and questionnaire. RESULTS: The average score on knowledge was 18.66 ± 3.75, with the qualified rate as 61.09% (the highest was 60.6%). The average score in the section of attitude was 5.82±1.50. More than 97% of the students agreed that it was necessary to receive knowledge on nutrition and food safety. The average score of behavior was 8.52±2.56. CONCLUSION: Rate of awareness on knowledge of nutrition and food safety had greatly improved among the students under study. Their habit tended to be more regular. However, we also noticed the gap between knowledge and behavior on this issue.

[A prospective study on recurrent falls and related factors in elderly from the urban communities in Beijing].

OBJECTIVE: To investigate the incidence and risk factors for recurrent falls in community-dwelling elderly in Beijing. METHODS: A cross-sectional study was conducted in 472 elderly in the Longtan community of Dongcheng district,Beijing in 2009. Data on recurrent falls within the past 12 months were collected through face-to-face interview, with both single factor analysis and logistic regression analysis used to explore the related factors on recurrent falls in the elderly. RESULTS: The incidence of recurrent falls among 472 older adults was 6.1% (29) within the past 12 months. Results from logistic regression analysis showed that factors as higher family monthly income(OR = 1.39, 95% CI:0.67-2.16), afraid of being fallen(OR = 2.23, 95% CI:1.47-3.85)and abnormal static balance(OR = 2.48, 95% CI:1.84-4.05)were risk factors, while bench height in the surrounding environment(OR = 0.49, 95% CI:0.21-1.12)and easiness of access to daily supplies (OR = 0.41, 95%CI:0.14-1.16)were protective factors for recurrent falls. CONCLUSION: The incidence of recurrent falls among the elderly from the communities in Beijing was high. Since falls could be caused by various factors, intervention should be targeting on risk factors in a multi-dimensional way.

Epidemiological survey of the prevalence of non-fatal injury among children aged 5-14 years in China.

OBJECTIVE: To determine the prevalence of non-fatal injuries among children aged 5-14 years in China. METHODS: Data of 21 973 children aged 5-14 years were extracted from the Fourth National Health Service Survey of China carried out between June 15 and July 10, 2008. Injury-related indicators included: history of ever having had an injury, and injury frequency, cause, location and severity. RESULTS: The overall prevalence of non-fatal injuries among the children in the previous 12 months was 17.0 per 1000 subjects. The leading causes of non-fatal injuries were falls, animal bites, traffic accidents, falling objects and burns. The majority of children sustained only one injury. The main place of injury was at home in 40% and 54% of urban boys and girls, respectively, at school in 48% of rural boys, and at home and at school each in 33% of rural girls. Medical treatment for one day was the main option for 80% of urban boys and girls, 84% of rural boys, and 72% of rural girls. CONCLUSION: Nonfatal injuries among children aged 5-14 years are a serious public health concern in China.

[A survey on condom-use and associated factors among men who have sex with men in Shenzhen, Guangdong].

OBJECTIVE: To learn the condom-use and it's associated factors among men who have sex with men (MSM) in Shenzhen, so as to provide scientific basis for the development of prevention and control program. METHODS: Cross-sectional survey was conducted with standardized questionnaire used on individual case. Associated factors with behavior of not persistent condom use were analyzed, using logistic regression method as dependent variable and associated factors with behaviors as independent variables. RESULTS: Most of the MSM were young, with average age as 27.9, coming from 26 provinces of China. Only 20.5 percent of the participants were persistently using condoms every time with their sex partners in the past year. The main reasons of not constantly using condom with their male sex partners were having fixed partners, being young, healthy and being faithful. CONCLUSION: High risk sexual behaviors and the low rate of condom-use among MSM might serve as potential risks for HIV epidemics. Data on the rate of condom use and the influencing factors among MSM varied for different sexual partners, suggested that targeted prevention measures should be conducted.

[Spatial and temporal patterns of primary and secondary syphilis in Shenzhen, China].

OBJECTIVE: To learn the spatial and temporal patterns of primary syphilis and secondary syphilis in Shenzhen and to provide evidence for carrying out further research on syphilis. METHODS: Primary syphilis and secondary syphilis cases among residents in Shenzhen between 2005 and 2009 (n = 11 303) were geocoded at street office level (n = 55) based on residence at the time of diagnosis. Both spatial and space-time scan statistics were used to identify clusters of street office by using SaTScan software. RESULTS: In the purely spatial analyses, clusters were seen in the junction of the Baoan district and Nanshan district (Xinan, Xixiang, Nanshan and Nantou street office) and in the region near Hong Kong (Dongmen, Shekou, and Futian street office), as well as in the other streets where entertainment industry was relatively developed (Longhua, Huafu, Huangbei and Cuizu street office). The clusters had not changed much in the first four years, but nine clusters appeared in 2009. Annually, the most likely clusters were located in Longhua (2005, P ≤ 0.001, RR = 3.34), Bamboo (2006, P ≤ 0.001, RR = 9.59), Huafu (2007, 2008 years, P ≤ 0.001, RR values were 4.18 and 4.75) and Cuizu (2009, P ≤ 0.001, RR = 8.02). In the space-time scan analysis, we found 16 significant clusters, which were similar to the pure spatial analyses. However, regional difference were also found, with the most likely cluster was the Guiyuan street office in 2006. CONCLUSION: Spatial and space-time scan statistics seemed to be effective ways in describing the circular disease clusters. We have had a better understanding on spatial and temporal patterns of primary syphilis and secondary syphilis in Shenzhen through spatial and space-time scan statistics of syphilis surveillance data in the recent years. The changes of spatial and temporal patterns of primary syphilis and secondary syphilis were also described by SaTScan software, which also provided useful reference for the preventive strategies on sexually transmitted diseases as well as on HIV. Useful information was also provided for financial investment and cost-effective studies.

[Diagnostic and therapeutic status of benign prostatic hyperplasia outpatients at department of geriatrics in China].

OBJECTIVE: To assess the diagnostic and therapeutic modality preferences of physician implementation of the Chinese Clinical Practice Guidelines for Benign Prostatic Hyperplasia (BPH) for geriatric BPH patients. METHODS: This cross-sectional survey was conducted at 33 medical centers located in 11 different cities in China (4 in north; 7 in south). A total of 190 physicians were requested to record their preferences in diagnostic tests and treatment options for elderly BPH cases. RESULTS: The physician response rate was 97.4%. Respondents generally selected those practices consistent with the guidelines, but their preferences for recommended tests varied. The use of medical history, ultrasonography and urinalysis was higher (> 90.0%) and that of uroflowmetry was lower (31.2%). In addition, the rate of use of recommended tests was higher among physicians in the north than those in the south. Drug therapy was the preferred treatment option. The proportion of drug treatment increased with the severity of symptoms in elder patients. In the south, the proportion of drug treatment in severe cases increased to 82.6% versus 61.9% in mild cases. In the north, the proportion of rug treatment in severe cases increased to 83.5% versus 54.6% in mild cases. CONCLUSION: This study provides insights into the physician preferences of diagnosis and treatment. The physicians generally comply with the BPH clinical practice guidelines. It may also serve as a practical reference for updating and improving the Chinese Clinical Practice Guidelines for BPH.

Relationships between serum adiponectin, leptin concentrations and bone mineral density, and bone biochemical markers in Chinese women.

BACKGROUND: Adiponectin and leptin, as the main circulating peptides secreted by adipose tissue, are potential contributors to bone metabolism. However, their association with bone mineral density (BMD) is unknown. We investigated whether these serum adipocytokines concentrations are associated with BMD and bone turnover markers. METHODS: Serum adiponectin, leptin concentrations, bone turnover biochemical markers, and BMD were determined in 265 premenopausal and 336 postmenopausal Chinese women. RESULTS: In postmenopausal Chinese women, the multiple linear stepwise regression analysis showed that year since menopause, lean mass, estradiol, and adiponectin, but not fat mass, leptin, were independent predictors of BMD in postmenopausal Chinese women. However, in premenopausal Chinese women, adiponectin was not the predictor of BMD. The significant positive correlations between adiponectin and bone-specific alkaline phosphatase (BAP), bone cross-linked N-telopeptides of type I collagen (NTX) were found only in postmenopausal women. Serum BAP, and NTX, but not adiponectin, decreased in response to alendronate therapy. CONCLUSIONS: Adiponectin was an independent predictor of BMD, and positively correlated with bone turnover biochemical markers in postmenopausal Chinese women, but not premenopausal women. It suggested that adiponectin may exert a negative effect on bone mass by promoting excessive bone resorption associated with bone loss. However, these effects may be mediated by menopausal status.

[Study on the time of retention and related influencing factors of patients receiving methadone maintenance treatment in Hunan province].

OBJECTIVE: to explore the current situation and related influencing factors on the retention time of patients receiving methadone maintenance treatment (MMT). METHODS: Information on basic situation and daily treatment of the patients were collected from the 7 MMT clinics opened in the pro-two batch in Hunan province. Retention rate and influencing factors were analyzed. RESULTS: (1) The retention rates after 6 and 12 months of MMT became 72.06% and 49.65% respectively. (2) The retention rates of high-dosage group and low-dosage group were 85.03% and 68.03% after 6 months on MMT program while became 60.48% and 46.28% after 12 months of MMT respectively. (3) The mean retention time of HIV+ patients and HIV patients were 9.46 months and 8.62 months respectively during the 12 months follow-up observation, showing a significant difference. (4) Patients who took large dose methadone, did not share needles, at older age or HIV+, were prone to keep MMT at a long period. CONCLUSION: The retention rates for 6 months and 12 months in the MMT program in Hunan province were similar to the national data. Dose, type of drug abuse, age and HIV status were related to the period of retention.

Prevalence and related factors of falls among the elderly in an urban community of Beijing.

OBJECTIVE: To understand the prevalence, consequences and risk factors of falls among urban community-dwelling elderly in Beijing. METHODS: A cross-sectional study was conducted in Longtan Community, Beijing. A total of 1512 individuals aged 60 years or over were selected by stratified cluster sampling. Data regarding the frequency of falls in the previous year, as well as circumstances, consequence and related factors of falls were collected from the elderly through face-to-face interviews with questionnaires in their home. RESULTS: The prevalence of falls was 18.0% on the average among 1512 participants, higher in women (20.1%) than in men (14.9%) (P = 0.006), and increased with age (chi2(for trend) = 10.37, P = 0.001). The total rate of falls-induced injuries among the fallers was 37.7%. Falls usually resulted in soft-tissues bruises (58.7%), fear of repeated episodes of falls (58.8%), loss of independence and confidence in movement (35.7%) and even in hip fracture. In addition to the burden of medical care, falls also generated a big economic burden. Occurrence of falls was significantly associated with both intrinsic and extrinsic factors. The related factors of falls in the elderly included age > or = 60-70 years, femininity, less physical activities, fear of future falls, living alone, severely impaired vision, health problem-impacted activities of daily living, chronic diseases (diabetes, hypertension, postural hypotension, stroke sequela, cataract, arthritis, dementia and depression), medications (psychoactive, anti-diabetic), gait imbalance, high bed and faintly-lighted stairway. CONCLUSION: The prevalence of falls among urban community-dwelling elderly in Beijing is closely associated with significant associated with intrinsic and extrinsic factors. Efforts to prevent falls in the elderly should be made at community level.

[Using multivariate multilevel model in studying the influential factors of violence among rural high school students in Changsha].

OBJECTIVE: To provide evidence for setting up violence intervention programs in rural middle schools, through studying the influential factors. METHODS: Taking variables including emotional, physical and sexual violence in the past year as the multi-dependent variables before multivariate multilevel model logistic regression model was adopted to analyze the correlations among the three kinds of violence and the influential factors. RESULTS: Among 3620 respondents, the incidence rates of emotional, physical and sexual violence weres 21.5%, 24.3% and 2.0% respectively. The correlation coefficients between emotional violence vs. physical violence, emotional violence vs. sexual violence, physical violence vs. sexual violence were 0.337, 0.133, 0.131 respectively when the random effect of class difference was separated by multivariate multilevel model. There was an internal aggregation of the incidence rate on physical violence in different grades (chi2=4.286, P = 0.038) and an internal relevant between emotional violence vs. sexual violence (chi2 = 4.239, P = 0.039), physical violence vs. sexual violence (chi2 = 4.482, P = 0.034). The influential factors on the incidence rates of violence would include: sex, smoking status, family without harmony, tendency of bullying others and the level on self-esteem etc. CONCLUSION: When the random effect of class difference was separated by multivariate multilevel model, the estimated results would be more precise. Other than paying more attention to both individual and family influential factors when taking measures to reduce the incidence rate of violence in high school students, the effect of environment in the class should not be ignored.

[Study on the prevalence of urinary incontinence and its related factors among elderly in rural areas, Jixian county, Tianjin].

OBJECTIVE: To understand the prevalence of urinary incontinence (UI) and its related factors so as to develop a three-tier program for prevention of the disease. METHODS: A cross-sectional study was carried out in two townships of Jixian county, Tianjin, during July to November 2007. A total of 743 people aged 60 years and over were selected under cluster sampling, and all information were collected with a standardized structured questionnaire by face-to-face interview. All the data were analyzed with multivariate logistic regression method to explore the related factors for UI in the elderly. RESULTS: The overall prevalence of UI was 33.38 percent among people aged 60 years and over in two townships. Risk factors for UI in men would include older age (OR = 1.39), occupation (OR = 5.00), awareness of UI (OR = 1.91), having in chronic respiratory diseases (OR = 2.23), prostate (OR = 11.47), neurological (OR = 11.76), or motor systems (OR = 2.48), while protective factors would include high educational level (taking primary school or below as control group), OR for the junior middle school group appeared to be 0.35, for senior middle school group it was 0.77, and of undergraduate group it was 0.53. Risk factors for UI in women would include older age (OR = 1.31), constipation (OR = 1.46), awareness of UI (OR = 1.94), increased body mass index (when normal weight group served as control group, OR in the overweight group was 1.03 and in the obesity group OR was 1.54), suffering from chronic respiratory diseases (OR = 4.84), diabetes mellitus (OR = 2.36), or motor system diseases (OR = 1.37), more gravidity (OR = 1.03), more parity (OR = 1.02), suffering from perinea laceration (OR = 1.72) and wound infection during delivery (OR = 1.65), while protective factors would include physical exercises (OR = 0.64). CONCLUSION: Prevalence of UI was higher among the elderly people in rural areas of Jixian county, Tianjin. UI in the elderly might have been influenced by various factors which suggesting the intervention strategy should be targeted at those related factors as well as focusing on primary prevention.

[Study on the relationship between chronic diseases and falls in the elderly].

OBJECTIVE: To explore the risk factors on chronic diseases related to falls in the urban-community elderly and to provide evidence for developing a three-tier program for prevention. METHODS: A cross-sectional study was conducted in one community of Beijing. People aged 60 years and over were selected, using a stratified cluster sampling method, and data on falls within the past 12 months and falls-related chronic diseases were collected through face-to-face interview. RESULTS: The incidence of falls was 18.0% within one year among the 1512 interviewees. Seven factors showed statistical significances through univariate analysis including diabetes mellitus (OR = 1.62), postural hypotension (OR = 1.84), hypertension (OR = 1.48), cerebral infarction (OR = 1.98), cataract (OR = 1.56), osteoarthritis (OR = 1.50), dementia (OR = 5.34) and depression (OR = 4.61). Data from multivariate logistic regression analysis showed that the risk factors for falls would include dementia (OR = 4.82), depression (OR = 4.27), postural hypotension (OR = 1.92) and suffering from several kinds of chronic diseases etc. CONCLUSION: The incidence of falls in an urban elderly community of Beijing was considered to be high. The risk of falls was higher among persons suffering from dementia and depression and having more than two kinds of chronic disease. The chances of falls would parallel the increase of several kinds of chronic diseases among the elderly, suggesting that measures should be actively taken to prevent from falls.

Protection of capsaicin against hypoxia-reoxygenation-induced apoptosis of rat hippocampal neurons.

The aim of this study was to investigate the effect of capsaicin on hypoxia-reoxygenation (H/R)-induced apoptosis in primary rat hippocampal neurons. Three hours of hypoxia (1% O2) and subsequent reoxygenation for 24 h significantly increased the apoptotic death of hippocampal neurons, as evidenced by increases in both TUNEL-positive cell number and caspase-3 activity. Pretreatment with capsaicin (3-30 micromol/L) or the caspase-3-specific inhibitor acetyl-DEVD-CHO (100 micromol/L) markedly attenuated H/R-induced apoptosis in hippocampal neurons. Capsaicin also markedly induced the phosphorylation of Akt. The phosphoinositide 3-kinase (PI3K) inhibitor LY294002 (10 micromol/L) prevented any capsaicin-induced survival effect in hippocampal neurons. Intracellular levels of reactive oxygen species (ROS), which were greatly increased after H/R, were significantly inhibited by capsaicin, pyrrolidine dithiocarbamate (PDTC) (50 micromol/L), and LY294002. Taken together, these data suggest that capsaicin protects against H/R-induced apoptosis of hippocampal neurons via the PI3K/Akt-mediated signaling pathway, which is related to the inhibition of oxidative stress and caspase-3 activation.

[Assessment of capacity for logisty, public education, and training in public health emergency management in China].

OBJECTIVE: To assess the capacity for logistics, public education, and training in managing public health emergency in China at present. METHODS: Four provinces were selected using stratified sampling. All the municipalities of these 4 provinces were assessed using the 9th and 10th subscales (logistics, public education and training) of Preparedness and response capacity questionnaire for public health emergencies for provincial or municipal governments developed by the Center for Health Statistics and Information, Ministry of Health of China. RESULTS: Sixty of the 66 questionnaires (90.91%) were collected. Among the 60 investigated municipalities, 80% established a specific agency to take charge of emergency material storage, management and allocation, 65% developed standard for material storage, 35% developed standard of places for material storage, 25% built regulation for testing, maintaining, and updating the emergency materials regularly, 45% arranged budget for routine payment, 27% established standard of emergency fund, and 28% set up the procedure to initiate emergency fund. The average of standard score of subscale 9 was 43.33 (95% confidence interval, 35.65~51.01). 25% of the 60 municipalities conducted assessment for training in the past 2 years, 53% developed plan for emergency personnel training, 20% developed effectiveness assessment regulation of emergency personnel training, 80% assigned a specific agency to be responsible for public education, and 23% established regulation for public education. The average of standard score of subscale 10 was 47.43 (95% confidence interval, 40.69~54.17). CONCLUSION: Serious problems are found in logistics, public education, and training for public health emergency management in China. Measures should be taken immediately by the central and local government to improve these capacities.

[Quality of life for drug abusers accepting methadone maintenance treatment].

OBJECTIVE: To explore the change and influence factors of quality of life QOL for drug abusers who accepted methadone maintenance treatment (MMT). METHODS: The questionnaire of QOL-BRIEF was used to measure the level of QQL when patients just entered the study and 6 months after the treatment respectively. The effect of therapy and characteristic of patients on change of QOL was analyzed. RESULTS: The scores in physiological domain, psychological domain, and the total score obviously increased after the treatment. There was no significant difference in the change of QOL between the patients of different dose groups. The QOLs of males and patients with long-time drug use improved significantly after the treatment. CONCLUSION: MMT can raise the QOL of drug abusers. Gender and time of drug use may be the risk factors of QOL improvement.

[Brief self-administered risk questionnaire for common nutrition-related diseases in middle school students].

OBJECTIVE: To develop a self-administered risk questionnaire for common nutrition-related diseases in middle school students. METHODS: Two phases were conducted to develop the questionnaire: scale development and validation. Phase 1 included 7 steps: (1) determining the objective, theoretical framework, principles and format for indicator generation; (2) setting up the preliminary indicator pool; (3) selecting indicators and forming pilot questionnaire through focus groups; (4) testing the pilot questionnaire; (5) further correcting the questionnaire using expert consultation; (6) choosing indicators again using good-poor analysis; and (7) shaping the final questionnaire. Phase 2 consisted of: (1) using the Pearson correlation coefficient to assess test-retest reliability; (2) using the Cronbach's alpha coefficient to assess the internal consistency reliability; (3) using the feedback from field investigation to assess face validity; and (4) using explanatory factor analysis to assess construct validity. Students from 96 classes were selected at random in Hunan Province as the field test samples using stratified sampling and cluster sampling. And the students from 4 out of the 96 classes were chosen again to serve as the test-retest samples. We used Epidata 3.0 to build the database and SPSS 11.0 to analyze the data. RESULTS: A brief self-administered risk questionnaire for common nutrition-related diseases in middle school students with 12 items being formed after Phase 1. Good-poor analysis showed results from t tests for each item were statistically significant (P<0.05). The Pearson correlation coefficient was 0.76 (P<0.05) and the Cronbach's alpha coefficient was 0.56. The questionnaire was accepted by the students participating in the field test. Four common factors were extracted using explanatory factor analysis, accounting for 50.18% of the total variation. CONCLUSION: The brief self-administered risk questionnaire for common nutrition-related diseases in middle school students is reliable and valid.

Association between serum soluble membrane type matrix metalloproteinase-1 (MT1-MMP) levels and bone mineral density, and biochemical markers in postmenopausal women.

BACKGROUND: Recently, membrane type matrix metalloproteinase-1 (MT1-MMP) was found to participate in bone metabolism. We investigated the relationship between serum MT1-MMP and bone mineral density (BMD) as well as bone metabolic markers in 206 Chinese postmenopausal women aged 43-80 years. METHODS: Western analysis and ELISA were performed to detect serum soluble MT1-MMP levels. BMD was measured by dual energy X-ray absorptiometry (DXA). Serum alkaline phosphatase (BAP) and N-telopeptides of type I collagen (NTX) were assayed using ELISA. RESULTS: We found that soluble MT1-MMP abundantly existed in human serum as protein lack of transmembrane domain. Serum MT1-MMP levels were detectable in all participants and the range of value was 221.2-863.0 ng/ml (435.6+/-98.2 ng/ml). We found a significant negative weaker correlation between MT1-MMP and BMD at lumbar spine, total hip (Thip), and femoral neck (FN) (all P<0.05). After adjustment for age and BMI, the correlation with BMD at FN and Thip disappeared (all P>0.05). Multiple linear stepwise regression analysis showed that MT1-MMP was not a determinant factor for BMD. The significant positive correlations between MT1-MMP and BAP, NTX were found, and remained significant after adjustment for age and BMI (all P<0.05). Moreover, serum MT1-MMP, BAP, and NTX decreased in response to alendronate therapy. CONCLUSION: Circulating MT1-MMP and bone turnover markers are correlated, and serum MT1-MMP levels may rise with increase in bone turnover.

An entropy-based measure for QTL mapping using extreme samples of population.

Quantitative trait locus (QTL) mapping can be accomplished through the method of selective genotyping, which is based on the differences of frequencies between an upper sample and a lower sample in population. However, amplifying the differences in marker allele frequencies in extreme samples may increase the probability for QTL mapping. Shannon entropy, which is a nonlinear function of allele frequencies, can be used to amplify the differences in marker allele frequencies. In this paper, we present a novel measure for linkage disequilibrium (LD) between a marker and single QTL, that is based on the comparison of the entropy and conditional entropy in a marker in extreme samples of population. This measure of LD between the marker and the trait locus can be used when the marker allele frequencies are known in the extreme samples of a population. We investigate the mapping performance in both analytic and simulation scenarios of a single QTL linked to a single marker. Our results show that the measure has very reasonable performance. In addition, a simulation study is performed on the basis of the haplotype frequencies of 10 SNPs of angiotensin-I converting enzyme (ACE) genes.