Long-term effectiveness of the community-based Complete Health Improvement Program (CHIP) lifestyle intervention: a cohort study

OBJECTIVE: To examine the long-term (three or more years) effectiveness of the volunteer-delivered Complete Health Improvement Program (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 programme (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 blood pressure (SBP) and diastolic blood pressure (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 programme entry maintained significantly lowered BMI (−3.2%; 34.8±5.4 vs 33.7±5.3 kg/m(2), p=0.02), DBP (−9.4%; 89.1±4.1 vs 80.8±12.6 mm Hg, p=0.005), TC (−5.5%; 6.1±0.7 vs 5.8±1.0 mmol/L, p=0.04) and TG (−27.5%; 2.4±0.8 vs 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 vs 33.4±4.8 kg/m(2), p=0.02), DBP (−13.3%; 88.3±3.2 vs 77.1±12.1 mm Hg, p=0.005) and FPG (−10.4%; 7.0±1.5 vs 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 3 years. The results suggest that the community-based CHIP lifestyle intervention can be effective in the longer term, even when delivered by volunteers.