Latent growth modeling with domain-specific outcomes comprised of mixed response types in intervention studies

Effects of a Multi-Component Workplace Intervention Program with Environmental Changes on Physical Activity among Japanese White-Collar Employees: a Cluster-Randomized Controlled Trial

PURPOSE

This study aimed to investigate effects of a flexible multi-component workplace intervention program for improving physical activity among Japanese white-collar employees in a cluster randomized controlled trial design.

METHODS

A total of 208 worksites and nested employees were approached. Any worksite interested in a 3-month physical activity promotion intervention and white-collar workers aged 18 years or older were eligible. The worksites were randomly assigned to an intervention or a control, stratified by worksite size. The intervention worksites were offered an intervention program that allows these worksites to select intervention components from a set of options, including environmental changes. The control worksites were offered feedback and basic occupational health services. Physical activity level was measured using a self-reported questionnaire at baseline and at 3 and 6 months of follow-up.

RESULTS

Three worksites (92 employees) were allocated to the intervention and five worksites (98 employees) to the control worksites. The overall physical activity level in the intervention worksites significantly increased compared with the control worksites (Coeff = 0.45, SE = 0.19, p = 0.018). For subgroup analyses, the intervention effect on the overall physical activity level was significant among medium- and large-sized worksites but not among small-sized worksites.

CONCLUSION

This trial showed a significant and positive effect of the intervention program on physical activity. The program is unique because of its flexibility and feasibility. However, small worksites might receive less benefit from the program, indicating a need for further support and/or new technologies.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (ID=UMIN000024069).

Effects of a multicomponent workplace intervention programme with environmental changes on physical activity among Japanese white collar employees: a protocol for a cluster randomised controlled trial

INTRODUCTION

Physical activity is one of the most important health behaviours as a determinant of physical and mental health. Although intervention strategies for promoting physical activity among workers are needed, evidence for the effectiveness of multilevel workplace interventions with environmental changes on the promotion of physical activity are still limited due to lack of cluster randomised controlled trials (RCTs). The aim of this study is to investigate effects of a 3-month workplace intervention programme with environmental changes on the improvement in physical activity among Japanese white collar employees.

METHODS AND ANALYSIS

This study will be a two-arm and parallel-group cluster (worksite) RCT. Japanese worksites and employees who are employed by the worksites will be recruited through health insurance associations and chambers of commerce. Worksites that meet the inclusion criteria will be randomly allocated to intervention or control groups. The intervention worksites will be offered the original intervention programme that consists of 13 contents with environmental changes. The control worksites will be able to get three times feedback of the assessment of the amount of physical activity and basic occupational health service in each worksite. The primary outcome will be the total amount of physical activity measured by the Global Physical Activity Questionnaire at baseline, 3 months and 6 months. Multilevel latent growth modelling will be conducted to examine the effectiveness of the intervention programme.

ETHICS AND DISSEMINATION

This study was ethically approved by the research ethics committee of the Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Japan (No. 11230). Results will be submitted and published in a scientific peer-reviewed journal.

TRIAL REGISTRATION NUMBER

UMIN000024069; Pre-results.

Investigation of Parameter Estimation Accuracy for Growth Curve Modeling With Categorical Indicators

Abstract. Growth curve modeling (GCM) is an important and commonly used methodology in the social sciences for examining change over time in a variable value. While much of the empirical research examining the performance of various estimators under a variety of conditions has focused on continuous (and typically normally distributed) observed indicators, in practice researchers frequently make use of categorical indicators with anywhere from two to as many as seven categories. Given the popularity of GCMs, along with the frequent use of categorical indicators, and the relative dearth of simulation research focusing on estimation of these models with such variables, the current study focused on the issue of parameter estimation accuracy as related to the number of categorical indicators, and the number of categories per indicator. Results of this research found that for models with only a linear component, parameter estimation was very accurate for as few as four indicators with two categories each and a sample size of 200. On the other hand, when the underlying model included both linear and quadratic terms, parameter estimation accuracy suffered for a small number of dichotomous indicators unless the sample size was 1,000 or more. However, with six or more indicator variables, and/or at least three categories, parameter estimation accuracy remained high.

Topiramate and motivational enhancement therapy for cannabis use among youth: a randomized placebo-controlled pilot study

Cannabis misuse accounts for nearly all of the substance abuse treatment admissions among youth in the United States. Most youth do not experience sustained benefit from existing psychosocial treatments; however, medication development research for treating adolescent cannabis misuse is almost nonexistent. We conducted a double-blind, placebo-controlled, pilot study to test the potential efficacy of topiramate plus motivational enhancement therapy (MET) for treating cannabis use among adolescents. Sixty-six heavy cannabis users, ages 15 to 24 years, were randomized to one of two 6-week treatment conditions: topiramate plus MET or placebo plus MET. Topiramate was titrated over 4 weeks then stabilized at 200 mg/day for 2 weeks. MET was delivered biweekly for a total of three sessions. Only 48 percent of youths randomized to topiramate completed the 6-week trial (n = 19), compared with 77 percent of youths in the placebo condition (n = 20). Adverse medication side effects were the most common reason for withdrawal among participants in the topiramate group. Latent growth models showed that topiramate was superior to placebo for reducing the number of grams smoked per use day, but it did not improve abstinence rates. The same pattern of results was found when values for missing outcomes were imputed. We show that topiramate combined with MET demonstrated efficacy for reducing how much cannabis adolescents smoked when they used but did not affect abstinence rates. The magnitude of this effect was modest, however, and topiramate was poorly tolerated by youths, which calls into question the clinical importance of these findings.