Reduction of risk for lifestyle diseases: group diet and physical activity intervention in the workplace

Abstract

Cardiovascular disease is a major cause of death in most Westernised countries. The prevalence of obesity, type 2 diabetes mellitus and cancers is rapidly increasing. Older people with elevated blood lipids, obesity and DNA damage are at high risk of developing these diseases. There is a plethora of research to support the claim that a healthy diet and increased physical activity can reduce the risk of increased body fatness, diabetes and generally improve health. However, most interventions require intensive one to one advice. The aim of this study was to measure the effect of a group approach to advising on changes in lifestyle with particular attention to foods high in fibre. The study spanned a period of 12 weeks with a follow up session at 52 weeks to ascertain sustainability. The study: This study was a 12 week longitudinal intervention study with a follow up after 52 weeks. Measurements of anthropometry (skin folds, girths, weight and height), blood pressure, body fat by bio impedance and fasting blood (lipids, glucose and insulin) were made at weeks 0, 3, 6, 9,1 2 and 52. The participants were asked to complete a food frequency questionnaire and a physical activity questionnaire at each of the 6 measuring sessions and to provide an indication of what the goals that they had set and if they had accomplished them after 9,12 and 52 weeks. Between measurements at weeks 0 and 3 the volunteers were left to follow their usual food and activity pattern. Then as a group they were given a diet and exercise talk and provided with written material and pedometers to increase motivation. After measurement at week 6 they were randomly divided into two groups. The first group (A) were prescribed and provided with kiwifruit at a dose of 100g/30 kg body weight for three weeks while the second group (B) continued with the changes in diet and physical activity. Following measurement at week 9 group A abstained from kiwifruit while Group B added the kiwifruit to their diet and the measurements repeated. After 52 weeks, with only emails as ongoing communication, they were remeasured. Results For this multicultural, relatively middle aged group of 53 staff (28 women, 25 men) of mean age 46 years, measurable and statistically significant metabolic gains were made in the lipid profile over 12 weeks. Total cholesterol, LDL cholesterol, triglycerides and the ratio of total cholesterol to HDL all decreased and HDL increased significantly. Total cholesterol decreased from 5.6(±1.1) mean (±SD) mmol/L at baseline to 5.3(±1.1) mmol/L at week 12 (p<0.001); LDL cholesterol decreased from 3.5(±0.97) mmol/L at baseline to 3.3(±0.94) mmol/L at week 12 (p<0.001); and total cholesterol to HDL ratio decreased from 4.0(±1.1) to 3.7(±0.9) (p<0.001). In the 36 who were measured at 52- week follow- up these changes persisted. With the other outcome measures glucose showed a statistically but not biologically significant decrease over the 12 week period and body composition, blood pressure and insulin showed no significant change. The kiwifruit crossover had no apparent affect on the measures of any of the measurements reported. The participants reported that they increased fruit and vegetable and oily fish consumption and increased physical activity. These increases took place over the initial 12 week period and were maintained over 52 weeks. Conclusion: This study has shown that changes in diet and physical activity can favourably influence blood biochemistry even without accompanying changes in percentage body fat and weight. Furthermore, small, manageable lifestyle changes can result in biochemical changes persisting over 52 weeks.