Long-Term Effectiveness of a Lifestyle Intervention: A Pragmatic Community Trial to Prevent Metabolic Syndrome

Introduction The purpose of this study is to evaluate the long-term effectiveness of a community-based lifestyle education on primary prevention of metabolic syndrome in a middle-income country. Study design This study followed 3,180 individuals free of metabolic syndrome who were under the coverage of three health centers in Tehran from 1999 until 2015. They were undergoing triennial examinations resulting in four re-exams. People in one of three areas received interventions consisting of family-, school-, and community-based educational programs, including a face-to-face educational session at baseline. Data were analyzed considering the incidence of metabolic syndrome at each re-exam and also repeated-measure analysis including all re-exams together. Weighting was considered to correct selection bias because of loss to follow-up. Data were analyzed in 2017. Results After 3 years, 149 of 852 participants in the intervention and 471 of 2,328 people in control area developed metabolic syndrome at first re-exam resulting in a RR of 0.78 (95% CI=0.67, 0.92). The difference between groups remained unchanged up to the 6-year follow-up (RR=0.79, 95% CI=0.66, 0.93, at second re-exam), but disappeared during the third and fourth re-exams (RR=1.04, 95% CI=0.91, 1.18 and RR=1.03, 95% CI=0.91, 1.16, respectively). Marginal models for longitudinal data showed a significant interaction between intervention and time of re-exams. Further analyses showed that the effect of the intervention might have been rooted in improvement of lipid profile and glucose level. Conclusions In a middle-income country, face-to-face educational sessions followed by a long-term maintenance community-level educational program could reduce the risk of metabolic syndrome for up to 6 years. A booster face-to-face session is recommended to retain this preventive effect. Trial registration This study is registered at Iran Registry for Clinical Trials ( http://irct.ir ) IRCT138705301058N1.