To clarify the necessity of applying appropriate statistical methods to calculate sampling error from data of cluster sample survey, we take a two-stage cluster sample survey developed from a population aged 15 and over as example. We use statistical methods based on the assumption of simple random samples and methods considering complex sample design to analyze our data, respectively. Through comparison, we hope to show the potential effects of using improper statistical methods to estimate sampling error on parameter estimation and hypothesis testing. Using standard error algorithms based on the assumption of simple random samples,the standard errors calculated often underestimate sampling error and the hypothesis testing even gets wrong conclusion. When the statistical methods and statistics package for complex survey data are already available, it is necessary for us to use appropriate methods to analyze and report the sampling errors of data from cluster sample survey.
Cluster Analysis ; Data Interpretation, Statistical ; Epidemiologic Studies ; Sampling Studies

OBJECTIVETo estimate the number of death from malignant tumor and to assess the completeness of cancer registry data using the capture-recapture method.

METHODSData about death form malignant tumor were collected during the period of 2004 and 2005 from cancer registry, civil administration and police registries in Linzhou. Cases in every source were matched on the address, name, sex, ID card, date of death, cause of death. A 3-source log-liner poisson model was used to estimate the real number of death from malignant tumor during the period of 2004 and 2005 in Linzhou.

RESULTSThe real number of death from malignant tumor that estimated by capture-recapture method was 3140 (95% CI: 3124 - 3161) during 2004-2005 year in Linzhou. Underreported number by source linkage was 71. Log-liner model demonstrated positive dependence between the 3 sources, implying that 2-source model would underestimate missing cases. Using the mortality number estimated by the capture-recapture as the denominator, under-reporting rate of cancer registry was 6.6%.

CONCLUSIONIt is feasible to estimate the real number of death from malignant tumor and to correct data bias by applying the capture-recapture method.

China ; epidemiology ; Humans ; Neoplasms ; mortality ; Registries ; Sampling Studies

OBJECTIVETo analyze the difference and correlation of food intakes assessed by Food Weighted Record, 24 Hours Recall and Food Frequency Questionnaire (FFQ) methods.

SUBJECTSThe data of 2002 China National Nutrition and Health Survey were used. All 23,198 subjects (male 11,107, female 12,091) finished all three dietary survey methods. Food Weighted Record method weighted all food items consumed at home by all family members in last 3 days; 24 Hours Recall recorded all food items the subjects consumed at and out home in last 3 days; FFQ recorded the main 33 categories food items that the subjects consumed at and out home in last year.

RESULTSCompared to Food Weighted Record method, food intakes assessed by 24 hours recall were similar, and the relative differences were less than 10% of most food items. The proportion of over-report and under-report (+/- 25%) by 24 Hours Recall were less than 40%. The correlation coefficients of food intakes between Food Weighted Record and 24 Hours Recall methods ranged from 0.58 to 0.88. The results from Food Weighted Record and FFQ were similar among the high frequently consumed food items. The relative differences of the food intakes investigated between Food Weighted Record and FFQ were less than 15% and the proportion of over-report and under-report (+/- 25%) by FFQ were more than 50%. The correlation coefficients of food intakes between Food Weighted Record and FFQ ranged from 0.08 to 0.76.

CONCLUSIONFood intakes might be assessed accurately by the Food Weighted Record revised 24 Hours Recall method, and FFQ method be also used to assess the food intakes, especially for the frequently consumed food items, as to studying the relationship between food consumption and health.

Data Collection ; Diet Surveys ; Eating ; Female ; Humans ; Male ; Sampling Studies

No abstract available.
Statistics as Topic ; Models, Statistical ; Data Interpretation, Statistical ; Sampling Studies ; Biometry

OBJECTIVETo investigate level and its influential factors of occupational stressors and strains in workers of a steel plant and explore the feasibility of occupational stress and mental health as indicators of effect evaluation of health promotion at workplace.

METHODS1039 workers were investigated by using cross-sectional method. The questionnaires included job stressors, skill discretion, job control latitude, mental health and sleep disorders.

RESULTS54.5% of respondents reported "job doesn't allow mistakes" as stressor, while 47.6% of respondents reported "too job responsibility" as stressor. The scores of job stressors were significantly higher than female workers (P<0.01). Workers with high education level scored more skill discretion, job control latitude and lower mental health than ones with low educational level (P<0.05 or P<0.01). Elder workers had more skill discretion and job control latitude scores than younger. There were significant differences in scores of skill discretion among different length of service groups (P<0.05). There were also significant differences in scores of skill discretion among different job title groups (P<0.01). Occupational stressors were correlated significantly positively with sleep disorder (r=0.37, P<0.01), but job control latitude negatively to mental health (r=-0.19, P<0.01).

CONCLUSIONThe workers in the steel plant report occupational stressors, which is related to poor self-reported health symptoms. The occupational stressors and mental health should be considered as one of effect evaluation indicators of health promotion at workplace.

Adult ; Burnout, Professional ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; Sampling Studies ; Steel ; Surveys and Questionnaires

OBJECTIVETo study the application of decision tree in the research of anemia among rural children.

METHODSIn the Enterprise Miner module of software SAS 8.2, 3000 observations were sampled from database and the decision tree model was built. The model using decision tree of CART bases on Gini impurity index.

RESULTSThe misclassification rate of decision tree model was, training set 21.2%, validation set 21.9%. The Root ASE of decision tree model was, training set 0.399, validation set 0.404. The area under the ROC curve was larger than the reference line. The diagnostic chart showed that the corresponding percentage was higher than the other. The decision tree model selected 9 important factors and ranked them by their power, among which mother of anemia (1.00) was the most important factor. Others were children's age (0.75), time of ablactation (0.53), mother's age (0.32), the time of egg supplementation (0.26), category of the project county (0.26), the time of milk supplementation (0.16), number of people in the family (0.13), the education status of the mother (0.12). Decision tree produced simple and easy rules that might be used to classify and predict in the same research.

CONCLUSIONDecision tree could screen out the important factors of anemia and identify the cutting-points for factors. With the wide application of decision tree, it would exhibit important application values in the research of the rural children health care.

Anemia ; prevention & control ; Child, Preschool ; Decision Trees ; Evaluation Studies as Topic ; Humans ; Rural Population ; Sampling Studies

A Nationwide health care utilization survey was conducted from March 11 to September 19, 1985 to assess the level of illness and the magnitude of medical care utilization. A probability sample of 15,427 persons was taken from 180 Enumerated Districts designated by the Economic Planning Board. Of those 4,500 housewives were proxy respondents. A interview was conducted with pre-tested questionnaire schedule which was recorded by well trained interviewers. Age and sex compositions of the study population were similar to those of general population structure in 1985. The major findings of this survey are as follows: 1) A total of 64.5% of the study population lived in city area and 35.5% lived in county area. 2) While no difference was observed in interview rate between city and county area, it showed statistically significant difference in the medical security program coverage rate between the two areas(44.7% and 37.1%, respectively). 3) Morbidity rate was 79 per 1,000 persons during the two week periods. There was difference in age and sex adjusted morbidity rates between city and county area. Furthermore morbidity rates by the status of the program were significantly difference between the two areas. 4) Average ambulatory care utilization rate was 7.2 visits per person per year and average admission rate was 1.8 per 100 persons per year. There was significant difference in average ambulatory care utilization rate by the program. but no significant difference in medical utilization rate between city and county area. 5) The major symptoms of the perceived illness was the respiratory system(44.1%). 6) A total of 50.4% of the perceived illness among the covered group by the program were treated at the hospital and clinics, but those who are not covered used primarily drug stores(61.3%).
Ambulatory Care ; Appointments and Schedules ; Surveys and Questionnaires ; Delivery of Health Care* ; Humans ; Korea* ; Proxy ; Surveys and Questionnaires ; Sampling Studies

OBJECTIVEThere are scant data about normal reference values of blood glucose (BG) in children. This study was conducted to learn the BG profile of children and adolescents in Beijing area.

METHODThe population for survey was selected as a stratified cluster sample from 8 urban and 10 rural areas in Beijing. Fasting capillary blood glucose (FCBG) was determined in 19,593 children and adolescents aged 6 to 18 years in 4 urban and 3 rural areas using haemosaccharometer model II [Roche Diagnostic, (Shanghai) Ltd].

RESULTSThere were 1 9112 (97.5%) individuals with complete records, the mean age was 12.1 +/- 3.3 years (ranged from 6 to 18.9 years); 9514 (49.8%) were boys, 9598 (50.2%) were girls, 9792 were (51.2%) from urban areas and 9320 (48.8%) from rural areas. The average level of FCBG in boys was higher than that in girls (4.7 +/- 0.5 vs. 4.5 +/- 0.5, u = 28.0, P < 0.01). Among urban children, the trend of variation of FCBG was similar between boys and girls, the levels of FCBG increased with age, the peak of FCBG was reached at 12-13 years in urban girls, and from the age of 15 years, the level of FCBG declined. In boys, the FCBG level increased slowly from 13 years of age, there was no significant variation until 17 years old, and declined at the age of 18. Among suburban children, the trend of variation of FCBG was similar between boys and girls, both of them had two peaks, from 6 to 11 years old, FCBG of both boys and girls increased with age, and both reached the first peak at the age of 11 years. While at 13 years of age, there was an obvious drop in FCBG level. From 14 years of age on, there was a rise of FCBG in both boys and girls, and the second peak of FCBG was reached at 15 and 16 years of age in girls and boys respectively. The FCBG level of urban children was higher than that of rural children (4.7 +/- 0.5 vs. 4.6 +/- 0.5, u = 13.8, P < 0.01). The level of FCBG in overweight and obese children was higher than that of normal children. More boys, more obese and more urban children had abnormal FCBG.

CONCLUSIONSThe blood glucose level of children was associated with age, gender, obesity and district.

Adolescent ; Anthropometry ; Blood Glucose ; Child ; China ; epidemiology ; Female ; Humans ; Male ; Sampling Studies

Asthenopia ; epidemiology ; etiology ; Fatigue ; epidemiology ; etiology ; Humans ; Occupational Diseases ; epidemiology ; Railroads ; Sampling Studies

Career Mobility ; China ; Humans ; Occupational Health Services ; statistics & numerical data ; Sampling Studies