[Effects of weight-loss tools and a group-based weight-loss support program: rationale and study design of a...

Purpose We have focused on providing weight-loss tools and implementing group-based weight-loss support programs and here document the first steps in implementation of a randomized controlled trial for determining the effectiveness of program components for weight change.

The present study covered 6-month weight-loss and 2-year follow-up periods. Participants were randomly assigned to the following 3 intervention groups: control (CON), weak intervention (WI), and strong intervention (SI). The CON group attended a single motivational lecture on weight loss. Participants in the WI group attended this lecture and were also provided with textbooks, notebooks, and a pedometer as weight-loss tools. Participants in the SI group attended the lecture, were given the aforementioned tools, and underwent a 6-month group-based support program for weight loss (8 sessions). The recruitment target was 180 participants--60 in each group. Individuals who were 40-64 years old, had a body mass index (BMI) of 25-40 kg/m2, and satisfied at least one of the following criteria were eligible: (i) waist circumference > or = 85 cm in males and 90 cm in females; (ii) systolic blood pressure > or = 130 mmHg; (iii) diastolic blood pressure > or = 85 mmHg; (iv) triglyceride level > or = 150 mg/dL; (v) high-density lipoprotein (HDL) cholesterol level < 40 mg/dL; and (vi) fasting plasma glucose level > or = 110 mg/dL. The primary outcome measure was body weight, and the secondary outcome measures were parameters associated with the metabolic syndrome, such as waist circumference, systolic blood pressure, diastolic blood pressure, serum levels of triglycerides and HDL cholesterol, and fasting plasma glucose. The protocol was registered with the UMIN Clinical Trials Registry (UMIN000001259).

Participants were recruited through advertisements placed in local newspapers until March 2009 and were screened for eligibility through baseline measurements. In total, 188 adults (145 females, 43 males) were eligible and randomly assigned to the CON (n = 63), WI (n = 62), or SI (n = 63) groups. The weight-loss period was from April to October 2009 (for all 3 groups), and the follow-up duration extends from October 2009 to October 2011 (for the WI and SI groups).

The present study should reveal the short-term (6 months) effectiveness of weight-loss tools and a group-based weight-loss support program as well as the long-term (30 months) effectiveness of the group-based weight-loss support program.