The effect of dietary and smoking cessation advice on changes in risk factors for cardiovascular disease among women and men aged 18-39 years with a familial risk of coronary heart disease: a randomised trial

Background: Coronary heart disease (CHD) is a major cause of death both in Norway and in the world. Current Norwegian guidelines advocate that health care resources target individuals with an increased risk of said disease such as primary relatives of subjects with premature CHD (men before the age of 55 years and women before the age of 65 years). There is limited data on interventions that target young adults with an increased risk of CHD aged below 40 years of age. Aim: To assess the effects of one time dietary advice and intensive smoking cessation aid in young individuals with increased risk of premature CHD after 16 weeks. The primary aim was to detect a difference in change overtime in pre-selected cardiovascular risk factors(total-, LDL- and HDL-cholesterol, triglycerides, blood pressure, weight and waist-to-hip ratio) between randomised groups. The secondary aims were to assess the within group changes in these cardiovascular risk factors and to assess the association between group allocation and smoking cessation. Method: The study was a randomised trial designed to test a simple intervention given once at baseline with no follow-up visit in between randomisation and the final visit. The intervention group received personalised dietary counseling based on a food frequency questionnaire at baseline from a registered dietitian. Subjects in the control group answered the food frequency questionnaire but did not receive any dietary advice during the trial. The smoking cessation intervention was administered by a physician. Smokers in the intervention group received intense smoking cessation aid including the use of pharmacotherapy and recurrent telephone contact. The control group received only routine smoking cessation advice. Smoking status was self-reported and smoking cessation confirmed by measured exhaled carbon monoxide (CO) levels. Results: A total of 161 men and women with a mean age of 31 (SD: 6) years were included in the study out of which 149 subjects completed the trial. The mean duration for participation in the trial was 20 weeks. No difference in change overtime in any of the cardiovascular risk factors was seen between the intervention- and the control group. In the intervention group, there was a reduction in systolic blood pressure (SBP) by -4.50 mmHg (95% CI: -6.36; -2.63) and diastolic blood pressure by -2.50 mmHg (95% CI: -4.38; -0.69). There was also a reduction in SBP in the control group by -2.5 (95% CI: -4.38; -0.69) and an increase in HDL-cholesterol by 0.05 mmol/l (95% CI: 0.01; 0.08). At baseline the prevalence of smoking was 16% and 30% in the intervention and the control group, respectively (P=0.88). At the end of the trial six subjects in the intervention group and six subjects in the control group reported having quit smoking, which was confirmed by CO measurements. Group allocation was not associated with smoking cessation (P=0.86). Conclusion: The results of the trial indicate that dietary advice given once and intense smoking cessation aid was insufficient to significantly improve cardiovascular risk factors in young adults with increased risk of premature CHD after 20 weeks compared to controls.