from Heartwire — a professional news service of WebMD

October 24, 2007 — A new Swedish study looking at the benefit of a combination of several healthy lifestyle behaviors has found that most myocardial infarctions (MIs) in women could be prevented by consuming a healthy diet, being physically active, not smoking, and maintaining a healthy weight [1].

Dr Agneta Akesson (Karolinska Institute, Stockholm, Sweden) and colleagues report their findings in the October 22, 2007 issue of the Archives of Internal Medicine. They say there is little prior information on the benefit achieved with a combination of several healthy lifestyle behaviors. The results indicate that the combined benefit of diet, lifestyle, and healthy body weight "may prevent more than three of four cases of MI," they note.

"Our study shows the great effect you get from each of these and by combining them," Akesson told heartwire . "It's quite a simple health message, and you can do them by yourself."

In healthiest women, 92% decreased risk of MI

The Swedish researchers say coronary heart disease (CHD) risk-factor characterization and prevention in women need improvement, and despite the proven benefits of pharmacologic therapies, "diet and lifestyle largely influence morbidity and mortality in CHD."

One of the novel things the Swedish group did was to assess behavioral dietary patterns among the 24,444 postmenopausal women they studied, who were participating in the population-based prospective Swedish Mammography Cohort and who were free of diagnosed cancer, cardiovascular disease, and diabetes mellitus at baseline (September 15, 1997).

They identified four major dietary patterns: healthy (vegetables, fruits, and legumes); Western/Swedish (red meat, poultry, rice, pasta, eggs, fried potatoes); alcohol; and sweets (sweet baked goods, candy, chocolate). Those who consumed moderate amounts of alcohol (5 g or more a day; equivalent to a glass of wine every other day) were categorized as low risk. No upper limit for alcohol consumption was defined, because few women consumed high amounts of alcohol (less than 0.3% reported drinking more than 45 g/day). Those in the lowest-risk quintile for diet had an almost fourfold higher weekly consumption of vegetables and fruits, a threefold higher consumption of legumes, and a 70% higher consumption of fish compared with the highest-risk quintile.

During a mean of 6.2 years of follow-up, there were 308 incident cases of primary MI, of which 51 were fatal.

The researchers defined a low-risk dietary behavior based on high scores for the healthy dietary pattern (low-risk quintiles 3-5) and, when combined with moderate alcohol intake, this group had a significant 57% reduction in primary MI.

The researchers also defined three low-risk lifestyle factors: nonsmoking, waist/hip ratios less than the 75th percentile (<0.85), and being physically active.

The 5% of the study population who ate healthily, drank alcohol in moderation, and maintained these three low-risk lifestyle behaviors had a 92% decreased risk of MI compared with women without any low-risk diet and lifestyle factors.

Effect of combined low-risk behaviors in relation to risk of MI ^a

Group	Low-risk group, events, n (%)	Rate per 100,000 person-years	RR compared with high-risk group b	RR compared with remainder of study population	Population-attributable risk (%)
2 low-risk factors c: Healthy quintiles 3-5 and alcohol consumption >5 g/day	42 (29)	95	0.45	0.53	40
3 low-risk factors d: Healthy quintiles 3-5, alcohol consumption >5 g/day, and no current smoking	27 (21)	84	0.21	0.47	48
4 low-risk factors e: Healthy quintiles 3-5, alcohol consumption >5 g/day, no current smoking, and physically active	7 (7)	66	0.14	0.35	63
5 low-risk factors: All of above plus waist/hip ratio <0.85	3 (5)	40	0.08	0.22	77

a. All relative risks were adjusted for age, educational achievement, family history of MI (yes/no), presence of high cholesterol level (yes/no), presence of hypertension (yes/no), use of hormone therapy (ever/never), use of aspirin, and total energy intake.

b. The high-risk group included women with low healthy pattern scores (quintiles 1-2) who consumed less than 5 g/day of alcohol, were current smokers, had a waist/hip ratio above the 75th percentile (<0.85), and did not fulfill the criteria of physical activity.

c. The model was also adjusted for smoking (current vs never and former), physical activity (more or less than 40 min/day of walking or bicycling and one hour/week of exercise), and waist/hip ratio (quartiles).

d. The model was also adjusted for physical activity and waist/hip ratio.

e. The model was also adjusted for waist/hip ratio.

The population-attributable risk in the study population, in which only 5% of the women fulfilled the criteria for the comprehensive low-risk behavior, was 77%, "which suggests that more than three of four of the coronary events could potentially be averted if all women would change their behavior to the low-risk profile," the researchers explain.

Akesson told heartwire that other studies have looked at MIs and diet, but many assessed only dietary behavior and did not include alcohol intake or the combination of these with other healthy lifestyle approaches. A similar study in the New England Journal of Medicine looking at the Nurses' Health Study did find a similar reduction in MI, she notes, although this used body-mass index rather than waist/hip ratio as a measure of obesity.

"Our results suggest that important steps can be taken to significantly reduce the risk of primary nonfatal CHD. Randomized trials are clearly preeminent to establish causality between both diet and lifestyle and CHD risk, but because randomized trials are difficult to perform for multiple risk factors, the combined low-risk behavior may never be able to be tested in primary-prevention trials. Therefore, prevention should build on best available information," they conclude.

Whole grains cut heart failure

US doctors writing in the same issue report that a high intake of whole-grain breakfast cereals is associated with a lower risk of heart failure (HF) in 21,376 men participating in the Physician's Health Study I [2]. Dr Luc Djoussé (Harvard Medical School, Boston, MA) and colleagues say, "To our knowledge, this is the first study to prospectively examine the relation between breakfast-cereal consumption and the risk of HF in a large cohort."

They found that during an average follow-up of 19.6 years, 1018 incident cases of HF occurred. For average weekly cereal consumption of zero servings, one or fewer, two to six, and seven or more, hazard ratios for HF were 1 (reference), 0.92, 0.79, and 0.71 (p<0.001 for trend) after adjustment for multiple variables. The association was limited to the intake of whole-grain cereals but not refined cereals.

Djousse told heartwire that "doctors should be advocating the consumption of whole-grain rather than refined cereals, and these findings are consistent with the previous message that whole grain is good." He believes the beneficial effects of whole grains on reducing heart failure are mediated via their effects on blood pressure and lowering the risk of diabetes and coronary heart disease, "all of which are major risk factors for HF."

He cautioned, however, that these effects might have been exaggerated in this study, performed in "a highly educated group of mainly white men, with knowledge about the disease." The results need to be replicated in women and ethnic minorities and in the general population per se, without knowledge of heart disease, he said. In the meantime, he thought that there was no harm in eating products such as [whole-grain] pasta and bread and buying whole-grain products in general.

The Center for Health Care Sciences, the Karolinska Institutet; Swedish Research Council/Medicine and Longitudinal Studies; and the Swedish Council for Working Life and Social Research funded the study by Akesson and colleagues. The authors of this study have disclosed no relevant financial relationships.

Dr. Djousse has disclosed receiving a grant from the National Heart, Lung, and Blood Institute. Dr. Gaziano has disclosed receiving research grants from BASF, DSM Pharmaceuticals, Wyeth Pharmaceuticals, McNeil Consumer Products, and Pliva as well as honoraria from Bayer and Pfizer. He is a consultant for Bayer, McNeil Consumer Products, Wyeth Pharmaceuticals, Merck, Nutraquest, and GlaxoSmithKline. The National Cancer Institute and National Heart, Lung, and Blood Institute supported the Physicians' Health Study.

Sources

1. Akesson A, Weismayer C, Newby PK, et al. Combined effect of low-risk dietary and lifestyle behaviors in primary prevention of myocardial infarction in women. Arch Intern Med. 2007;167:2122-2127.
2. Djousse L and Gaziano M. Breakfast cereals and risk of heart failure in the Physicians' Health Study I. Arch Intern Med. 2007;167:2080-2085.

The complete contents of Heartwire , a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.

Clinical Context

Study Highlights

• Akeeson and colleagues
  • Study subjects were drawn from the Swedish Mammography Cohort, which followed up 24,444 postmenopausal women who were free of previous ischemic heart disease, cardiovascular disease, and cancer.
  • A Food Frequency Questionnaire was used to assess dietary habits, and baseline cardiovascular risk factors such as family history and the presence of chronic disease was determined by the self-report of study participants.
  • Participants' data regarding level of physical activity, smoking status, and abdominal obesity were also recorded.
  • The primary outcome of the study was the incidence of fatal and nonfatal MI as it related to health dietary and lifestyle behaviors. Data on MIs were collected from a national registry.
  • During a mean of 6.2 years of follow-up, there were 308 cases of MI.
  • Each of the following factors was independently associated with a reduced risk for MI: healthy diet focused on vegetables, fruits, and legumes; alcohol consumption of at least 5 g/day, exercise consisting of at least 40 minutes per day of walking or cycling plus 1 hour per week devoted to exercise, and a waist-to-hip ratio of less than 0.85.
  • The combination of no smoking, high levels of physical activity, and low abdominal adiposity reduced the risk for MI by 79% vs subjects with the highest levels of risk factors.
  • The combination of all 5 variables at levels of low risk was present in 5% of participants. Compared with the high-risk group, these women had a 92% reduction in the risk for MI.
  • Overall, more than 3 of 4 coronary events reported during the study could have been prevented if all women had changed their behavior to the low-risk profile.
• Djousse and Gaziano
  • The study population was drawn from the Physicians' Health Study I, a study of male health professionals begun in 1981. The current analysis focused on 21,376 men.
  • Cereal consumption was assessed with a semiquantitative food-frequency questionnaire. Cereals were defined as being whole grain or refined grain.
  • The main outcome of the study was the relationship between cereal consumption and the incidence of HF, which was assessed by patient self-report. This outcome was adjusted for cardiovascular risk factors.
  • The average follow-up period was 19.6 years, and 1018 cases of HF were diagnosed during this interval. The mean age of the subjects was 53.7 years.
  • In comparing average weekly cereal consumption of 0 servings, 1 or fewer, 2 to 6, and 7 or more servings, the adjusted hazard ratios for HF were 1 (reference), 0.92, 0.79, and 0.71 ( P < .01 for trend).
  • The trend toward the reduced incidence of HF was significant for whole-grain cereals but not for refined cereals.

 

Pearls for Practice

• The study by Akeeson and colleagues finds that a low-risk lifestyle and diet can reduce the risk for MI by more than 90% in postmenopausal women vs a high-risk profile.
• The study by Djousse and Gaziano demonstrates that higher intake of whole-grain, but not refined, cereals among middle-aged male physicians reduced the risk for HF.

CME Test