Comparison of 7 methods for sample size determination based on confidence interval estimation for a single proportion / 南方医科大学学报

OBJECTIVE@#To compare different methods for calculating sample size based on confidence interval estimation for a single proportion with different event incidences and precisions.@*METHODS@#We compared 7 methods, namely Wald, AgrestiCoull add z2, Agresti-Coull add 4, Wilson Score, Clopper-Pearson, Mid-p, and Jefferys, for confidence interval estimation for a single proportion. The sample size was calculated using the search method with different parameter settings (proportion of specified events and half width of the confidence interval [ω=0.05, 0.1]). With Monte Carlo simulation, the estimated sample size was used to simulate and compare the width of the confidence interval, the coverage of the confidence interval and the ratio of the noncoverage probability.@*RESULTS@#For a high accuracy requirement (ω =0.05), the Mid-p method and Clopper Pearson method performed better when the incidence of events was low (P < 0.15). In other settings, the performance of the 7 methods did not differ significantly except for a poor symmetry of the Wald method. In the setting of ω=0.1 with a very low p (0.01-0.05), failure of iteration occurred with nearly all the methods except for the Clopper-Pearson method.@*CONCLUSION@#Different sample size determination methods based on confidence interval estimation should be selected for single proportions with different parameter settings.

Sample size estimation in acupuncture and moxibustion clinical trials / 中国针灸

The appropriate sample size estimation is very important in the design of clinical trials. However, insufficient or inappropriate sample size estimation is still a prominent problem in the currently published acupuncture and moxibustion clinical trials. At present, the superiority test, non-inferiority test and equivalence test have been widely used in acupuncture and moxibustion clinical trials. This article focuses on the application, calculation methods and PASS11 software using of these three hypothesis test types. In view of the problems in the estimation of sample size in acupuncture and moxibustion clinical trials, the particularity of sample size estimation in acupuncture and moxibustion is summarized from the aspects of parameter setting, ratio of intervention group and control group, and multi-group comparison, in order to guide acupuncture clinical researchers to correctly estimate sample size when conducting clinical trials.

Size estimation of MSM population in Pudong New Area using new media technology / 公共卫生与预防医学

Objective To explore the use of new media technology to estimate the size of the online MSM population in Pudong New Area, to understand the frequency of new media software use, HIV testing and high-risk behavior, and to provide a basis for AIDS prevention and control. Methods The online MSM registration information in Pudong New Area was collected through a gay dating APP. At five time points on March 28 and April 11, 2019, MSM who logged into the gay dating APP were counted. The MSM were confirmed by comparing the login name and registration information. The capture-recapture (C-R) method was used to calculate the MSM population size. Meanwhile, a questionnaire survey was conducted on the online MSM. Results The MSM population size in Pudong New Area was estimated at 13 174 [95% CI: 9,672~16,676] through the C-R method. The proportion of multiple sexual partners accounted for 72.5%. According to the ordered multi-classification logistics analysis, age, education level, experience of attending a talk on AIDS, and experience of receiving AIDS publicity and education in the VCT clinic were the influencing factors of AIDS awareness. Conclusion New media technology provided new technical means for estimating the size of MSM population. The MSM population’s awareness of AIDS risk and prevention still needs to be strengthened. It is worthy of further studies on the role of new media technology in AIDS prevention and health education in the future.

Estimating The Size Of The Drug Using Population In Three Deep-South Provinces Of Thailand: Results From A Service Multiplier And Respondent Driven Sampling (RDS) Method

Objective: The deep-south provinces of Thailand, the border area where the population is majority Malay ethnic, have faced with armed-conflicts for the decade and are a major route for drug trafficking. Several studies have reported concerns about drug problems among local population but the size of drug using population has not been studied. The objective of this study is to estimate the size of drug using population in the deep-south provinces of Thailand. Methods: A cross-sectional survey, including interviews was conducted in 2016. Males aged 18-40 years who had used any drugs in past six months were recruited. Respondent-driven sampling method was used to reach the target population and multiplier method to estimate the size of drug using population. Results: The estimated number of male using drug population in three deep-south provinces was 13,545, making the prevalence of 50.2 per 1,000 male population of this age group, twice as high as the national prevalence. Most drug users were in Pattani (60.6%), followed by Narathiwas and Yala provinces. Kratom is the illicit drug with the highest number of current users (85.2% of all users). The majority of current users (60.6%) used more than one type of illicit drug, with kratom and methamphetamine being the most common combination (25.6%). Conclusion: This study depicts the situation of drug abuse in deep-south Thailand. Kratom was the most popular substance. The high prevalence of drug users in the area should be of concern by stakeholders and interventions to minimize and control the abuse are needed.

Sample size estimation for survival analysis in single-arm trials / 复旦学报（医学版）

Objective To propose a method to calculate sample size for survival analysis in single-arm trials.Methods Through theoretical formula derivation,we provided sample size estimation method for survival analysis in single-arm trials.Monte-Carlo simulations using STATA software were conducted to obtain the empirical power,so as to verify the accuracy of the estimated sample size.Results Simulation results showed that,when α =0.025 and α =0.01,the power of the sample size calculated by the formula is in accordance with the predetermined power.Conclusions The formula of sample size estimation we proposed could achieve the predetermined power for survival analysis in single-arm trials.Findings of this study provide reliable basis for sample size estimation of early stage antineoplastic drug clinical studies.

Asignación de etiquetas de talla a terceros en función de las características sociodemográficas del observador / Body size labeling of other people according to the sociodemographic characteristics of the observer

Resumen Se averiguó si el sexo, la edad y el nivel educativo de un observador influyen sobre la etiqueta de talla que asigna a un tercero. Adultos (99 hombres y 176 mujeres; edad media de 40.52 años) asignaron las etiquetas de delgado, normal, con sobrepeso u obeso a ocho siluetas masculinas y ocho femeninas. Entre el 1 y el 82% de los participantes asignó una misma etiqueta a varias siluetas que no se correspondió con la etiqueta conforme al índice de masa corporal de los hombres y mujeres que representaban. Las mujeres, los participantes más jóvenes y los participantes con educación universitaria sobreestimaron la talla de hombres y de mujeres en mayor grado que sus contrapartes. En cambio, los hombres, los participantes adultos y los participantes con educación básica tendieron a subestimarla. Así, la estimación de la talla de otros efectivamente varió en función de las características sociodemográficas del observador. El etiquetamiento de las siluetas femeninas tendió a ser más preciso que el de las masculinas. Las normas culturales de cada subgrupo posiblemente uniformaron dentro de cada subgrupo el etiquetamiento de terceros. Los resultados añaden la asignación de etiquetas de talla a terceros al conocimiento previo sobre la influencia de los preceptos culturales sobre la percepción visual.

Abstract The purpose of the study was to determine if body-size-labeling of other people varies according to the sex, age and educational level of the labeler. Adults (99 men and 176 women; mean age 40.52) assigned body size labels (thin, normal, overweight or obese) to eight masculine and eight feminine silhouettes. Between 1 and 82% of the participants assigned a same label to various silhouettes, that differed from the one that corresponded to the men and women represented by the silhouettes according to their body mass index. Results showed that women, younger participants and those with university studies overestimated the body size of both men and women to a greater degree than their counterparts. By contrast, men, adult participants and those with basic education underestimated the body size of men and women. Thus, body size labeling indeed varied with the sociodemographic characteristics of the observer. Labeling feminine silhouettes tended to be more precise than labeling masculine silhouettes. It was concluded that the cultural norms of each group might have uniformed within each subgroup the labeling of third parties. Results add body-size-labeling of third parties to the previous knowledge on the influence of cultural norms on visual perception.

Body size estimation: Discrimination of subtle differences in male and female body parts / Estimación del tamaño corporal: discriminación de diferencias sutiles en partes corporales de hombres y mujeres

Abstract: The study determined the sensitivity of adults to detect subtle differences in male and female body parts (face, arms, chest, waist, hips, thighs and calves). A total of 202 adults (84 men and 118 women) with a mean age of 34.9 years adjusted the size of each part of a comparison silhouette until it matched that of a sample silhouette. The sensitivity to detect subtle differences was greater for the male than for the female silhouette (mean Weber Fractions, WF = .032, .036, respectively). The greatest sensitivity for both silhouettes was in the waist and hips (WF = .019 in both cases) and the smallest in the arms and face (WF = .048, .049, respectively). Men, young participants and those with high education (WF between .017 and .043) detected subtle differences to a greater degree than their counterparts (WF between .019 and .053). According to the environmental approach of social psychology, the latter suggests that members of those subgroups have been subjected to more social pressures to sharpen their discrimination of small differences in the body shape of their conspecifics. This study adds evidence to previous knowledge about how cultural variables shape visual perception.

Resumen: Se determinó la sensibilidad de adultos para detectar diferencias pequeñas en partes del cuerpo masculino y femenino (cara, brazos, pecho, cintura, cadera, muslos y pantorrillas). Participaron 202 adultos (84 hombres, 118 mujeres) con edad promedio de 34.9 años, quienes ajustaron el tamaño de cada parte de una silueta de comparación, hasta igualarlo con el de una silueta muestra. La sensibilidad para detectar diferencias pequeñas fue mayor para la silueta masculina que para la femenina (fracciones medias de Weber, FW = 0.032, 0.036, respectivamente). La mayor sensibilidad fue para la cintura y la cadera de ambas siluetas (FW = 0.019 en ambos casos) y la menor para los brazos y la cara (FW = 0.048, 0.049, respectivamente). Los hombres, los jóvenes y aquellos con educación universitaria (FW entre 0.017 y 0.043) fueron más sensibles para discriminar diferencias que sus contrapartes (FW entre 0.019 y 0.053). De acuerdo con el enfoque ambientalista de la psicología social, esos subgrupos han estado sujetos a mayores presiones sociales para afinar su discriminación de diferencias en la forma del cuerpo de sus conespecíficos. Este estudio añade evidencia al conocimiento existente sobre cómo las variables culturales moldean la percepción corporal.

The influence of BMI and psychological variables in the body size estimation among adult women / A influência do IMC e variáveis psicológicas na estimação da imagem corporal em mulheres adultas / La influencia de IMC y variables psicológicas en la estimación del tamaño corporal entre las mujeres adultas

This study aimed to quantify the body size estimation to evaluate the variables that influence it - Body Mass Index (BMI), body image dissatisfaction and depressive symptoms in normal (N = 40) and overweight women (N = 40). The body image and depressive symptoms assessment were conducted by the Brazilian Figure Rating Scale (FRS) and the Beck Depression Inventory (BDI) in its Brazilian versions, respectively. In the Normal weight group, the dissatisfaction and BDI scores explained 55% and 12% of the estimation variance, respectively. In the Overweight group, the body image dissatisfaction accounted for 14% of the variance of body size estimation while the BMI individually made in only 9%. When evaluated together, this percentage increased to 42%, indicating that together - BMI and dissatisfaction - aggregate greater explanatory value to this variation. The dissatisfaction was considered the most salient variable, which has influenced large percentages in the estimation values obtained, particularly among normal weight women.

O objetivo desse estudo foi quantificar a estimação da imagem corporal para avaliar as variáveis que a influenciam - Índice de Massa Corporal (IMC), insatisfação com a imagem corporal e sintomas depressivos em mulheres eutróficas (n = 40) e com excesso de peso (n = 40). A avaliação da imagem corporal e dos sintomas depressivos foi conduzida por meio da Escala de Figuras de Silhuetas (EFS) e pelo Inventário de Depressão de Beck (BDI), em suas versões brasileiras, respectivamente. No grupo eutrófico, a insatisfação e a pontuação do BDI explicaram 55% e 12% da variação da estimação, respectivamente. No grupo com excesso de peso, a insatisfação com a imagem corporal foi responsável por 14% da variação da estimação da imagem corporal, enquanto o IMC, individualmente, por somente 9%. Quando avaliados em conjunto, esse percentual aumenta para 42%, indicando que juntos - IMC e insatisfação - agregam maior valor explicativo para essa variável. A insatisfação foi considerada a variável mais saliente, influenciando em maiores proporções os valores de estimação obtidos, particularmente entre as mulheres eutróficas.

El objetivo de este estudio fue cuantificar la estimación del tamaño corporal para evaluar las variables que influyen - Índice de Masa Corporal (IMC), la insatisfacción de la imagen corporal y los síntomas depresivos en mujeres com peso normal (n = 40) y con sobrepeso (n = 40). La evaluación de la imagen corporal y los síntomas depresivos fueron realizados por la Escala de las figuras de silhuetes (EFS) y el Inventario de Depresión de Beck (BDI) en sus versiones brasileñas, respectivamente. En el grupo de peso normal, la insatisfacción y las puntuaciones del BDI explican 55% y 12% de la varianza de estimación, respectivamente. En el grupo con sobrepeso, la insatisfacción con la imagen corporal representó el 14% de la varianza de la estimación del tamaño del cuerpo, mientras que el IMC hecha individualmente en sólo el 9%. Cuando se evaluó en conjunto, este porcentaje aumenta a 42%, lo que indica que, en conjunto - IMC y la insatisfacción - agregan mayor valor explicativo a esta variación. La insatisfacción se consideró la variable más relevante, influido en los valores de estimación en proporciones mayores, sobre todo entre las mujeres de peso normal.

Application on size estimation through the network scale-up method on men who have sex with men in Chongqing municipality / 中华流行病学杂志

Objective To estimate the size of men who have sex with men (MSM) in Chongqing municipality.Methods A community based investigation was conducted in Chongqing to estimate the number of personal social network (c value) in the general population through the network scale-up method (NSUM).All the participants were selected by multistage sampling randomly.Factors as c value,the number of acquaintance of MSM and its respective coefficient were used to estimate and adjust the size of MSM in Chongqing.Results The average size of personal social network for Chongqing residents was 330,with differences among place(P＜0.001),sex (P＜0.0001),age (P＜0.0001),education level (P＜0.0001).The size of social network changed into 310 after the adjustment on demography,back estimation and elimination of the outliers.The estimated population size for MSM was 16 767 after the adjustment according to the respective levels,with 95％CI from 14 602 to 18 932,which accounted for 0.21％ of the total number of males,aged from 15 to 49 in Chongqing municipality.Conclusion NSUM was a new method for estimation of population size,which seemed worthy in promoting the practice of NSUM for its efficiency.

Study on Methods for Population Size Estimation of HIV High Risk Groups and its Application in HIV/AIDS Situation Analysis in China / 医学研究杂志

Objective To investigate HIV high risk population size estimation method,analyze the epidemic situation in China and offer scientific evidence for policy making. Methods Appropriate methods to estimate different type high risk populations were ascertained by experimental study. Results Size estimation methods and procedures for different type high risk population were formed.Epidemic estimation and parameters fit for China were ascertained.HIV epidemic situation and characteristics were stated. Conclusion Methods formed in the study are the key points for the understanding of number of PLWHA,for the exact judgment of HIV epidemic,for the improvement of inspection system and examination work,for the formation of "Four Free and One Care".