Long-Term Effectiveness of the Community-Based Complete Health Improvement Program (CHIP) Lifestyle Intervention: A Cohort Study

Abstract

Objective: To examine the long-term (three or more years) effectiveness of the volunteer-delivered CHIP intervention. Design: Cohort study Setting: Hawera, New Zealand Participants: Of the total cohort of 284 individuals who self-selected to complete the CHIP lifestyle intervention between 2007 and 2009, 106 (37% of the original cohort, mean age = 64.9±7.4 years, range 42-87 years; 35% males, 65% female) returned in 2012 for a complimentary follow-up health assessment (mean follow-up duration = 49.2+10.4 months). Intervention: 30-day lifestyle modification program (diet, physical activity, substance use and stress management) delivered by volunteers in a community setting. Main outcome measures: Changes in body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), fasting plasma glucose (FPG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides (TG). Results: After approximately 4 years, participants with elevated biometrics at program entry maintained significantly lowered BMI (-3.2%; 34.8±5.4 versus 33.7±5.3 kg/m2, p=0.02), DBP (-9.4%; 89.1±4.1 versus 80.8±12.6 mmHg, p=0.005), TC (-5.5%; 6.1±0.7 versus 5.8±1.0 mmol/L, p=0.04) and TG (-27.5%; 2.4±0.8 versus 1.7±0.7 mmol/L, p=0.002). SBP, HDL, LDL and FPG were not significantly different from baseline. Participants with elevated baseline biometrics who reported being compliant to the lifestyle principles promoted in the intervention (N=71, 67% of follow-up participants) recorded further reductions in BMI (-4.2%; 34.8±4.5 versus 33.4±4.8 kg/m2, p=0.02), DBP (-13.3%; 88.3±3.2 versus 77.1±12.1 mmHg, p=0.005) and FPG (-10.4%; 7.0±1.5 versus 6.3±1.3 mmol/L, p=0.02). Conclusions: Individuals who returned for follow-up assessment and entered the CHIP lifestyle intervention with elevated risk factors were able to maintain improvements in most biometrics for more than three years. The results suggest that the community-based CHIP lifestyle intervention can be effective in the longer-term, even when delivered by volunteers.