Interval Estimation of Diagnostic Odds Ratio in Meta-analysis by Means of Profile Likelihoods

AbstractThe objectives of this paper are to (1) derive the profile maximum likelihood estimator (PMLE) for a true diagnostic odds ratio over across k studies in meta-analysis, (2) build the confidence intervals by replacing PMLE into the variance of logarithm of each diagnostic odds ratio, leading to two profile likelihood intervals (WPLF, WPLR), (3) create bootstrapping confidence interval (BOOT) from PMLE distribution by using the percentile, (4) compare the interval performance between all profile intervals with the conventional intervals, such as Mantel-Haenszel method (MH) and Weighted least squares method (WLS) in terms of the coverage probability and the width of interval. The results under a simulation plan indicated that for moderated study size (k = 8, 16) and small sample size , there were only three proposed interval estimates (WPLF, WPLR, and BOOT) that could be calibrated the coverage probability at 95% and the interval widths of WPLF and WPLR are narrower than the BOOT. Hence, we recommend to use WPLF and WPLR rather than the conventional intervals in such situations

RISK FACTORS FOR MALARIA INFECTION AMONG RUBBER TAPPERS LIVING IN A MALARIA CONTROL PROGRAM AREA IN SOUTHERN THAILAND

Abstract. Rubber tappers work begins at midnight during the feeding time of Anopheles maculatus and An. minimus, two common malaria vectors in southern Thailand. We studied the association between rubber tapper behavior and malaria infections as reported to the Notified Disease Surveillance System during 2010 in Prachuab Khiri Khan Province, Thailand. In that province insecticide treated bednets are distributed free to the population and insecticide residual spraying is performed annually. A random sample of 394 rubber tapper households was interviewed from October 2010 to May 2011. Twenty-six households (6.6%) had at least one family member who contracted malaria during 2010. Poisson regression was used to identify potential characteristics associated with malaria. Multilevel Poisson regression was used to test for simultaneous effects of tapper behavior and household risk for malaria infection. The estimated incidence rate ratio (IRR) for contracting malaria among those owning a farming hut was 2.9 (95% CI 1.1-7.3, p<0.05) after controlling for other variables. Even in areas where control programs are in place, malaria infection among rubber tappers is common. Given the Thai Government's plan to expand the rubber plantation areas to other regions of the country without specific prevention for this at-risk population, the malaria burden in Thailand may increase

Effectiveness of 85% graphic health warning on cigarette packs on smoking behaviours of Thai teenagers

Background Thailand´s policy on increasing graphic health warning areas on cigarette packs, from 50% to 55% to 85% has the objective of increasing knowledge and perception of harmful health effects of cigarette smoking. The objective of this field experiment study is to find out the effectiveness of the 85% graphic health warning label. Methods Factorial design was implemented after the policy regulation was implemented in 2014. Recruitment of 724 students in 4 high schools and 5 colleges in Bangkok metropolitan area were chosen. Perceptions on intention to quit smoking were tested after introducing the students to 8 mock-up cigarette packs. The study was conducted in June of 2015 and 80 students per school were chosen. Results Results indicated that 85% graphic health warning cigarette pack significantly increased fear arousal, and intention not to smoke, among non-smoking students. Among smoking students, particular type of picture and increasing size of graphic health warning interact significantly to increasing fear arousal and intention to quit. Conclusions The impact of increasing size of graphic health warning on cigarette pack has significant influences on intention to quit among smoking- as well as non-smoking youths. This implied that plain packaging would be an ultimate strategy to increase awareness and perception of harmful health effects of cigarette smoking