Effects of Dietary and Exercise Intervention on Progression of Carotid Intima-Media Thickness
The Women’s Healthy Lifestyle clinical trial has reported that a dietary and exercise intervention results in the prevention of weight gain and LDL cholesterol rise over a 54 month follow-up in pre-menopausal women approaching menopause (average age 47 at baseline and 52 at final follow-up). During this trial, serial carotid ultrasound was performed in 234 women with an average of 3.5 years between scans. Intima-Media Thickness (IMT) was the mean of measures taken in the right and left common, bulb and internal carotid arteries. The average change in carotid IMT over time was +0.033 mm. Change in IMT was higher among the control than the intervention group (.039 mm vs. .027 mm, p = .172). Among 109 women who had reached menopause by the end of the study, average IMT progression was .058 mm among controls vs. .017 mm among the intervention group (p=.003, a difference of .041 mm). Among HRT users, IMT progression was .037 mm greater among control vs intervention women (N= 60, p = .040) and this difference was .047 mm among HRT non-users (N= 46, p=.035). Linear regression was used to determine whether the treatment effect was independent of minor differences between treatment groups at baseline and changes in vessel diameter over follow-up. After controlling for age, baseline IMT, baseline adventitial diameter, change in adventitial diameter, hysterectomy status, smoking, baseline waist girth and baseline energy expenditure, the treatment effect remained significant (p=.005). Among these postmenopausal women, the control group had greater increases in weight, waist circumference and LDL, and a lower increase in Kilocalories of energy expenditure over follow-up in comparison to the intervention group (p < .01 for all but LDL). When change in each risk factor was tested in the model above, only change in waist girth modified the treatment effect. Increase in waist girth was positively associated with IMT progression (p=.04) and the p-value associated with the treatment effect was reduced from .005 to .04. We conclude that among women entering menopause, a successful dietary and exercise intervention was associated with measurable slowing of atherosclerosis progression.