Globally, cardiovascular disease (CVD) is the number one cause of death and is projected to remain so in the future. An estimated 17.5 million people died from CVD in 2005 alone, representing 30% of all global deaths. Around 80% of these deaths occurred in low and middle-income countries [¹]. In countries of the Eastern Mediterranean Region (including Iran), increasing economic wealth along with rapid population growth have led to an increasing mortality rate from CVD [²]. In the Iranian Ministry of Health and Medical Education (MOH & ME) Death Registration System, data on causes of death are collected from various sources and have been assessed. According to this latest data (2004), the main cause of death in Iran was CVD which accounted for almost half (40%) of total deaths [³].

Menopause is a risk factor for CVD because estrogen withdrawal has a detrimental effect on cardiovascular function and metabolism [⁴]. Men and women are similar in some coronary heart disease (CHD) risk factors such as age, dyslipidemia, hypertension, smoking, diabetes, obesity and physical inactivity. Besides that, women have additional risk factors, such as the use of contraceptives and the reduction of ovarian function after menopause [⁵]. Menopause, obesity, and sedentary lifestyle are independent risk factors for cardiovascular disease (CVD) [⁶,⁷]. Several research investigations have suggested that as women enter menopause, there is a marked increase in the prevalence of atherosclerosis and clinical CVD, including a greater likelihood of myocardial infarction (MI) and all-causes of mortality [^8-10]. In the Healthy Women Study in which enrolled 541 middle-aged women when they were premenopausal and followed them through menopause, reported that weight gain in transition from pre-menopause to menopause was significantly associated with increases in blood pressure, total cholesterol, low-density lipoprotein (LDL), triglycerides and fasting insulin [¹⁰]. Increasing weight in postmenopausal women was related to increases in CHD risk factors (i.e., a significant decrease in high-density lipoprotein [HDL] and an increase in LDL). Weight gain during and after menopause can contribute more to CVD than weight gain prior to menopause and that weight loss and increased physical activity could mitigate some of the CVD risk factors (i.e., high cholesterol, insulin resistance). Not surprisingly, a panel of experts convened through the National Cholesterol Education Program (NCEP) concluded that therapeutic lifestyle change, emphasizing increased physical activity, reduced intake of fat and cholesterol, and moderate weight loss, is "the foundation of clinical primary prevention" of CVD [¹¹]. These conclusions regarding lifestyle change can be significant in the light of recent research suggesting that lifestyle changes can be considered as a primary prevention and treatment of CVD in postmenopausal women.

Healthy lifestyle is an important strategy for the whole community, and it revolves around a balanced diet, avoiding saturated fats, taking regular exercise, reducing weight and not smoking.

The present study examined the effect of an educational program on healthy diet interventions at reducing cardiovascular risk defined in this study as weight loss, body composition, diet, blood pressure (BP) and blood lipids.

After six months 12 subjects dropped out (three in the diet group and nine in the control group) (did not attend in the classes, or did not provide any reason). A total of 64 women completed six months trial, 35 in the diet and 29 in the control group. There were no statistically significant differences between the diet and control groups on the demographic, anthropometric, blood lipid and glucose and dietary intake at baseline (Table 1).

The primary aim of this research was to determine whether a 6-month educational intervention on diet would significantly improve CVD risk factors in postmenopausal Iranian women. The women in the intervention group exhibited some significant improvement in weight loss, BMI, total cholesterol, TG, LDL, FBS, daily intake of dietary fiber and sodium intake.

Participants in the diet group significantly lowered their weight, BMI, total cholesterol (-12 mg/dl), TG (-18.9 mg/dl) and FBS (-4.5). Considerable weight loss and BMI reduction demonstrated in other investigation (9.7 kg and 6.2 kg over 26 weeks of treatment) [¹⁶,¹⁷]. These disparate findings are due to than in our study, women in the diet group did not encourage to do physical activity and they trained to decrease their dietary fat to less than 30%. However greater changes happened with dietary restriction of energy from fat to less than 25% and even 15% [¹⁸]. The blood lipid changes in the present study are similar to other investigations [¹⁷]. The HDL increase in the diet group was negligible (0.40 mg/dl) confirming that diet restriction without exercise cannot increase the HDL level [¹⁹].

In the present study, the percentages of energy from total fat and saturated fat in the diet group did not changed; however they could increase their dietary fiber intake. Fiber can decrease blood cholesterol levels. Fiber works by attaching itself to the cholesterol so that it can be eliminated from the body. This process prevents cholesterol from recirculation and being reabsorbed into the bloodstream and can decrease the blood cholesterol [²⁰]. In a cross-sectional study, the researchers found that highest total dietary fiber intake were associated with a significantly (P < 0.05) lower risk of overweight and elevated WHR, blood pressure, blood cholesterol, TG and homocysteine [²¹].

The educational intervention in the present study has been successful in reducing some dietary risk factors of CVD including increasing the consumption of fruit, vegetables and fiber and decreasing consumption of salt. A study in Iran-Tehran with 840 adult participants showed that increasing in consumption of fruit and vegetable were inversely associated with CVD risk factors e.g. LDL and total cholesterol [²²]. The findings of the present study is similar with the study in Tehran, as LDL and FBS of participants in the diet group reduced significantly. Participants in study did not reduce the percentages of energy from fat, or dietary cholesterol. Other investigation with combining of diet and exercise education could reduce the daily calorie from fat and saturated fat [¹⁷]. These disparate findings are likely secondary to the participants in other research underwent the exercise and dietary intake change at the same time, but in the present study participants in the intervention group got healthy diet educational intervention solely. Furthermore the diet which recommended to participants in this study was intake of fat < 30% of total energy. Other investigations could reduce the percentages of energy from total fat with intake of fat < 25% and even < 15%.

Although the findings in this investigation suggest an association between diet intervention and reduced cardiovascular risks, these conclusions should be viewed tentatively, and replication is warranted for several reasons. The participants in the study were not well educated, and only 2.9% of diet and 6.95 of the control group had college degree. Secondly the participants in the diet group did not train according to their educational level. Thirdly all dietary intakes gathered through interview and self-report. Therefore, the self-reported levels and changes in dietary intake should be viewed with caution. Research suggests that when 3-4-day food records are evaluated against doubly labeled water, under-reporting can range from 10% to 32% [²¹].

The findings in this investigation are encouraging for a number of reasons. Obesity peaks after menopause, and being postmenopausal, obese, and sedentary are independent risk factors for CVD [^6-8]. The main strength of this study is that this was a randomized study and intensive intervention trial. In addition this was the first time in Iran that postmenopausal women were chosen randomly for changing lifestyle with emphasizing on healthy diet and followed up for six months. The lifestyle change intervention in this investigation, through its encouragement of gradual weight loss, and a progressive decrease in energy and fat intake through self-selected, permanent, lifestyle changes, may be a cost-effective treatment for reducing CVD risk in postmenopausal women. Lifestyle change intervention with emphasizing on healthy diet can be an effective means of reducing cardiovascular risk in obese postmenopausal women.

Thanks to the Universiti Putra Malaysia and its lecturers for the supervision, constructive suggestion and immense amount of guidance throughout this Ph.D thesis. Appreciation is also extended to the Medical University of Jondishapor in Ahvaz-Iran for their cooperation during the data collection.