Monthly Archive for: ‘August, 2012’
Job-related activity associated with lower CHD risk
When the Seven Countries Study started in the 1960s, the emphasis in the lifestyle factor of physical activity was on occupation, that is, on job-related physical activity. The men were classified in three categories: sedentary, moderately active and very active. An analysis using data from 12 of the 16 cohorts showed that sedentary men compared to moderately active men had a 21% lower risk of 20-year CHD mortality. A 38% lower CHD mortality was observed comparing those with heavy activity jobs to sedentary men.
More active leisure time related to lower CVD risk
In the US railroad cohort leisure-time activity was measured by detailed questionnaire. Men who spent more than 2000 kcal/week on leisure-time physical activity had a 29% lower 20-year CHD mortality compared men who expended less than 250 kcal/week exercising.
In the elderly men in Zutphen, walking or cycling at least three times per week for 20 minutes (the recommended level of physical activity for the elderly) was associated with a 34% lower 10-year cardiovascular mortality compared to more sedentary men.
- Keys et al. Harvard University Press, ISBN 0-674-80273-3, 1980:196-217
- Menotti et al. Ann Med 1989;21:175-9
- Slattery et al. Circulation 1989;79:304-11
- Bijnen et al. Arch Intern Med 1998;158:1499-58
Large differences in alcohol intake between Italy and The Netherlands
In the rural Italian cohorts and in Zutphen information on alcohol consumption was collected with the cross-check dietary history method among all men. In the 1960s the average alcohol intake in the rural Italian cohorts was more than 80 g/day, while less than 10 g/day in the Zutphen cohort.
Moderate alcohol use associated with low CVD risk
In rural Italian and in Zutphen men a J-shaped relation was observed between alcohol intake at entry and CHD mortality. In Italian men the lowest 15-year CHD risk was observed in the mid-range (third quintile) of alcohol intake. A 30% lower CHD risk among alcohol users compared to non-users was found throughout the range of use up to 80 g per day. Zutphen men using less than 20 g per day, compared to non-users, had 30% lower CVD mortality during 40 years of follow-up. Above 20g/day the CVD risk was greater.
These results are compatible with a protective effect of alcohol for CHD risk in Italy and CVD risk in The Netherlands in the low range of 1-20 g/day intake. The Italian data showed that the possible protective effect of alcohol on CHD keeps until very high levels of alcohol intake. Also other studies in Mediterranean areas reported a higher protective effect of alcohol than countries outside the Mediterranean. This may be due to differences in consumption pattern. Northern European men used mainly beer and spirits outside meals and men in Mediterranean areas consumed mostly wine with meals.
Smoking increases CHD risk
When the Seven Countries Study started in 1958 the prevalence of smokers was very high and ranged from 44% in Belgrade professors in Serbia to 78% in fisherman from Ushibuka in Japan. The 10-year follow-up data showed that smoking was associated with a higher risk of CHD mortality in countries where there were enough events for analysis and the strongest associations were observed in northern Europe where CHD was highest. An analysis using the 25-year CHD mortality data showed similar results.
Smoking a long-term predictor of CVD
The Finnish cohorts showed that the relative risk of CHD mortality among cigarette smokers compared to non-smokers decreased the longer the follow-up, but the excess CHD risk remained significant after 35 years of follow-up.
The 40-year data from the Zutphen Study showed that cigarette smokers at entry had a 59% higher CHD and a 66% higher CVD mortality risk compared to non-smokers. The duration as well as intensity of smoking was also independently predictive of CVD mortality.
- Keys et al. Harvard University Press, ISBN 0-674-80273-3, 1980:136-60
- Jacobs et al. Arch Intern Med 1999;159:733-40
- Qiao et al. Eur Heart J 2000;21:1621-6
- Streppel et al. Tob Control 2007;16:107-13
Eating fish associated with lower risk of fatal CHD and stroke
The Zutphen Study showed in 1985 that eating fish once or twice a week compared to eating no fish was associated with a 50% lower 20-year fatal CHD risk.
In 1994 we also found that fish consumption was inversely associated with a 50% lower incidence of non-fatal and fatal stroke.
Fatty fish compared to lean fish
The Finnish, Dutch and Italian cohorts showed that men eating fatty fish (e.g. mackerel and herring) had a 34% lower 20-year CHD mortality risk compared to those eating no fish. The consumption of lean fish, such as plaice and cod, had no comparable association with lower CHD risk.
Analysis of the dietary data repeatedly collected between 1960 and 2000 in the Zutphen Study also showed that eating fatty fish but not lean fish was inversely associated with long-term risk of sudden coronary death.
- Kromhout et al. N Engl J Med 1985;312:1205-9
- Keli et al. Stroke 1994;25:328-32
- Oomen et al. Am J Epidemiol 2000;151:999-1006
- Streppel et al. Eur Heart J 2008;29:2024-30
High fiber associated with low CHD mortality
Every additional amount of 10 g/d of recently consumed fiber was associated with a significant 17% lower risk of fatal CHD during 40 years of follow-up. A non-significant 13% lower risk was observed for long-term fiber intake.
A dietary fiber intake of more than 36 g/d at entry in 1960 was also associated with a 4 times lower risk of fatal CHD during 10 years of follow-up, when compared to an intake of less than 20 g/d. However, this association became non-significant in multivariable analysis.
Dietary fiber intake in 1960 and 2000
Between 1960 and 2000 seven dietary surveys were carried out in the Zutphen Study. The average dietary fiber intake was 33 g/d in middle-aged men in 1960 and 21 g/d among survivors in 2000. The average energy intake amounted to 3100 kcal/d in 1960 and 2100 kcal/d in 2000.
High flavonol intake and low CHD risk
In 1993 the Zutphen Elderly Study showed that a high intake of flavonols was associated with a low risk of CHD. Elderly men in Zutphen with an average intake of 42 mg/d, compared to those with 12 mg/d, had a 68% lower risk of fatal CHD after 5 years of follow-up, confirmed in the 10-year data.
High flavonol intake also related to low stroke incidence
In 1996, we published the results of a study using the average flavonol intake of the Zutphen men in the period 1960-1970 and the 15-year incidence of stroke. Men with an average flavonol intake of 33 mg/d, compared to 14 mg/d, had a 73% lower risk of stroke.
What are flavonols?
The most common flavonol estimated in the diet was quercetin. Flavonols are a subclass of the flavonoids, an extended class of chemically related compounds ubiquitously present in plant foods. In a range of experimental models, these compounds have demonstrated biological effects, which may partially explain the beneficial health effects of a diet high in vegetables and fruits. They are particularly present in tea, apples, onions and red wine.
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- Hertog et al. 1997;349:699
- Keli et al. Arch Intern Med 1996;156:637-42
Silent ECG findings related to CHD mortality
Silent ECG findings meeting specified criteria of the Minnesota Code were found at entry in half of the elderly men from Finland, the Netherlands and Italy. Major Q-waves, ST-T patterns, and arrhythmias were associated with a 3 times greater 10-year CHD mortality rate compared to those with absent or marginal findings. Lesser Q-waves, ST-T patterns, and frequent premature beats were associated with almost twice greater risk. Of the individual codable items, significant associations were observed for major Q-waves, major ST-T patterns, and arrhythmias. A Cardiac Infarction Injury Score designed to discriminate between the presence or absence of a heart attack, along with ST-T patterns were significantly related to risk of fatal CHD in middle-aged and elderly men in Zutphen.
The prevalence of specified ECG findings was high. Major ECG findings were strongly related to fatal CHD. Strength of the associations was similar across cultures despite large differences in absolute risk.
- Blackburn et al. Circulation 1960;21:1160-75
- Menotti et al. Acta Cardiol 2001;56:27-36
- Dekker et al. J Clin Epidemiol 1995;48:833-40
- Dekker et al. J Am Coll Cardiol 1995;25:1321-6
BMI not related to CHD mortality
Body mass index (BMI=Weight/height2) is the most frequently used indicator of body fatness. In middle-aged men of the SCS, BMI was inconsistently related to 10- and 25-year CHD mortality.
Weight fluctuation linked to increased CHD risk
Changes in body weight during the first 10 years of follow-up were related to CHD mortality during the following 15 year. Middle-aged men who gained more than 2 kg, put on an average weight of 7 kg. They had a 20% greater CHD mortality risk (not statistically significant) compared to those whose weight remained stable. A similar result was obtained in men who decreased more than 2 kg weight and lost on average 5 kg. Men were defined as “fluctuating” when their weight at the second examination differed more than 2 kg with their weight at examination 1 or 3. These men lost on average 1 kg and had a significant 50% higher CHD mortality risk compared to those who kept their weight constant. These results indicated that fluctuating weight, the so-called yo-yo effect, rather than BMI per se, was associated with greater CHD risk.
Calculate your own BMI!
- Keys et al. Harvard University Press ISBN 0-674-80273-3, 1980:161-195
- Peters et al. Int J Obesity 1995;19:862-8
- Menotti et al. J Cardiovasc Risk 1996;3:69-75
Glucose intolerance and diabetes associated with the risk of fatal CHD
Dutch men aged 50-69 with glucose intolerance at entry, followed for 15 years, had a 2-fold greater risk of fatal CHD compared to men with a normal glucose tolerance. A similar result was obtained for men who entered the study with clinical diabetes.
In 1970 in the Zutphen Study a glucose tolerance test was carried out with an oral load of 50 g glucose. Blood samples were taken after 30, 60, 120 and 150 minutes. The area under the curve of glucose values was calculated and ‘glucose intolerance’ was based on values above the median.
Blood pressure a strong predictor of CVD mortality
Systolic blood pressure in middle-aged men was an important predictor of 10-, 25-, 35- and 40-year CHD mortality in all cohorts. The 35-year follow-up data showed that past blood pressure levels are more important than recent values. Systolic blood pressure was also strongly associated with 25-, 35- and 40-year stroke mortality. Both recent and past blood pressure level were strongly predictive of stroke. The Zutphen Study found that the strength of the relation between blood pressure and 15-year stroke incidence doubled when 11 repeated casual pressures were measured. Blood pressure was also strongly related to 40-year total CVD mortality in the US railroad cohort.
Population differences in absolute CHD risk
The results after 10 and 25 years of follow-up showed that the relative risks from blood pressure level are similar across cohorts, while at the same level of blood pressure the absolute risks of CHD mortality are different. High absolute risk was present in Northern Europe and the United States and low risk in Mediterranean Southern Europe and Japan.
Relative risk of CHD associated with blood pressure is similar but absolute risk differs among the cohorts. This implies that elevated blood pressure levels need to be treated more intensely in high risk cultures to achieve target levels and potential prevention.
- Keys et al. Harvard University Press. ISBN 0-674-802733, 1980:103-20
- Keli et al. Stroke 1992;23:347-51
- Menotti et al. J Cardiovasc Risk 1996;3:69-75
- Menotti et al. Stroke 1996;27:381-7
- Van den Hoogen et al. N Engl J Med 2000;342:1-8
- Menotti et al. J Hypertension 2004;22:1683-90
- Menotti et al. Eur J Epidemiol 2004;19:417-24
- Boshuizen et al. Am J Epidemiol 2007;165:398-409