Simulation of Subgroup Analysis Methods with Longitudinal Data Containing Measurement Errors and Missingness / 中国卫生统计

Objective To develop a subgroup analysis method that can simultaneously deal with longitudinal data containing measurement errors and dropouts.Methods Subgroup analysis was carried out based on a threshold regression model.A new generalized unbiased estimation equation is constructed by using the independence between repeated measurements to deal with measurement errors and introducing an inverse probability weighting matrix to deal with missing response.Results The computer stochastic simulation shows that the proposed estimation method is effective in dealing with measurement errors and dropouts,and has smaller bias and mean square error than the generalized estimation equation method without correcting measurement errors or dropouts.Conclusion In subgroup analysis,when there are measurement errors in covariables and missing values in response variables,it is usually necessary to deal with the measurement errors and missing values in order to obtain reliable parameter estimation.

Birth weight and subsequent risk of type 2 diabetes across two generations in Chinese females / 中华流行病学杂志

Objective To evaluate the association between birth weight and subsequent risk of type 2 diabetes (T2DM) across two generations in Chinese females.Methods A cross-sectional survey was conducted among 10 324 blood-related females in Shanghai from November 2012 to January 2013.A structured questionnaire was used to collect data about demographic information,birth weight,lifestyle factors and diagnosis of T2DM.Path analysis was performed to estimate the matemal effect of birth weight and diabetes status on their offspring,and mediation analysis was conducted to test whether birth weight mediates the association between maternal and daughters' diabetes status.Results A positive association was observed between maternal and daughters' birth weight.One kg increase in maternal birth weight was associated with an average of 0.335 (95％CI:0.307-0.363) kg elevated birth weight in female offspring.Maternal diabetes status was also related with an average of 0.066 (95％ CI:0.025-0.107) kg increase in birth weight and tripled risk of subsequent T2DM (OR=3.173,95％CI:1.946-5.174) in female offspring.In all subjects aged ≥20 years,no significant relationship was observed between birth weight and risk of T2DM subsequently after adjusting for age.Offspring' s birth weight,as a mediator of maternal and daughters' diabetes status,explained 2.8％ of their association.Conclusion Maternal birth weight and diabetes status may influence their female offspring' s birth weight and subsequent risk of T2DM.