Gender differences in effectiveness of the Complete Health Improvement Program (CHIP) lifestyle intervention : an Australasian study

Issue addressed: Complete Health Improvement Program (CHIP) is a lifestyle modification program that promotes healthy diet, physical activity and stress management techniques. Among US CHIP participants, differences in gender responsiveness to improvements in chronic disease risk factors were demonstrated. This study examined gender differences in outcomes to the CHIP intervention in Australasia. Methods: Changes in body weight, blood pressure (BP), blood lipid profile and fasting plasma glucose (FPG) were assessed in 925 participants (34.3% men, mean age=56.0±12.5 years; 65.7% women, mean age=54.4±13.5 years) 30 days after program commencement. Results: Significant reductions (P<0.001) in all biometrics measured were found for men and women but were greater among men for total (TC) and low-density lipoprotein cholesterol (LDL), triglycerides (TG), FPG, body mass index (BMI) and TC/high-density lipoprotein cholesterol (HDL) ratio. Participants with highest baseline classifications of BMI, systolic BP, blood lipids and FPG showed greatest reductions in 30 days. Conclusions CHIP more effectively reduced chronic disease risk factors among men than women. All participants, but particularly men, entering the program with the greatest risk achieved the largest reductions. Possible physiological or behavioural factors include food preferences, making commitments and differential support modes. So what? Developers of lifestyle intervention programs should consider gender differences in physiological and behavioural factors when planning interventions. In particular, developers should manage expectations of people entering lifestyle interventions to increase awareness that men tend to respond better than women. In addition, this is a call for further research to identify the underlying mechanisms responsible for the disproportionate responsiveness of males.