Dr Michael Lucas
MBBS. MOccHS. Grad Dip OHS. Cert Sports Med.FSDrA. FRACGP


The Framingham Study

During the late 1940s, people living in the United States were dying from heart disease in their 50s and 60s like never before. Most Americans knew very little about cholesterol levels, high blood pressure, and the link between smoking and disease, or the effect of diet on health.

That all began to change in the fall of 1948 when the U.S. Public Health launched an attempt to better understand heart disease. The idea? Convince ordinary people living in a suburban Boston town to agree to regular health exams to determine whether there were links between the way they lived and the health of their hearts.

The idea was a hit. More than 5,200 residents of Framingham Mass. - about a fifth of the town's population - signed up for the program, which became the Framingham Heart Study (FHS). The project, now a collaboration of the National Heart, Lung and Blood Institute - one of the National Institutes of Health - and Boston University, is the longest-running epidemiological experiment of its size. Its impact on medicine is unparalleled.

Broadened epidemiology

Since its start, more than 10,000 Framingham residents have participated in regular physical exams every 2 years. The health checks include a number of cardiovascular health measures, such as electrocardiogram (ECG), blood pressure and blood cholesterol. As echocardiography (images of the heart generated by ultrasound), ambulatory blood pressure monitoring and other tests became available, they were added to the screening tools.

The questions asked by the researchers about lifestyle seemed unusual in 1948, when bacon, eggs, butter, jelly, doughnuts, meat-laden diets and cigarettes were common fare. The information was gathered; the scientists waited for cardiovascular disease to occur. And, over the years, it did.

The study started with more than 5,200 healthy men and women ages 30 to 62. Beginning in 1971, more than 5,100 of their children were enrolled in the offspring study. With time, the residents of Framingham became more of a racial and ethnic mix. In 1996, a third project, called the OMNI study, began. So far, more than 500 members of minority groups living in Framingham have been recruited.

The latest Framingham research is focusing on molecular genetics.

Risk Factor term coined

Until Framingham, people who'd had a heart attack, stroke or heart failure were considered unlucky. Framingham's long-term studies have provided important new information about dangerous lifestyles and other factors that increase a person's likelihood of having heart trouble. Framingham researchers coined an important and now common phrase - risk factor. Many of these risks to heart health could be changed by altering behaviours; stop smoking, lose weight, lower elevated blood pressure, reduce high cholesterol, and control high blood sugar.

The study found that reducing the risks, in many cases, could be achieved by making changes in lifestyle. Developing sensible eating habits and engaging in regular physical activity play a role. So do medications.

In a study published in the Jan 9, 1999, issue of the Lancet, the Framingham scientists demonstrated the lifetime chance of coronary heart disease at age 40 was 1 in 2 for a previously healthy man and 1 in 3 for a woman. At age 70, it is 1 in 3 for a man and 1 in 4 for a woman. The results were based on 7,700 participants who had been tracked for more than 100,000 patient years (the total number of follow-up years on each subject).

Since 1972, Americans have seen a 53 percent reduction in age-adjusted deaths from coronary heart disease and a 60 percent reduction in age-adjusted deaths from stroke. Ref: Mayo Clinic Health Oasis

Cardiovascular risk factors

To make the picture of your cardiovascular health more complete, you must consider your other risk factors for cardiovascular disease. Each factor may influence your lipid levels.

The more risk factors you have, in combination with undesirable lipid levels, the greater your risk of developing cardiovascular disease. If you have several risk factors, their effects don't simply add up, they amplify each other.

For example, if you have high total cholesterol and you smoke, you're at much greater risk than a nonsmoker with the same cholesterol level. (or presumably a smoker with a low cholesterol level Ed.)

However you can counter this amplifying effect. Eating a diet that is low in fat, combined with exercise, can help you lose weight. At the same time, you can reduce your risk of high blood pressure, heart attack and stroke.

Risk factors for cardiovascular disease are divided into those you can change and those you can't.

Risk factors you can change:
  • Blood cholesterol - High levels may result from genetic makeup or lifestyle choices, or both. Your genes can give you cells that don't remove LDL cholesterol from your blood efficiently, or a liver that produces too much cholesterol as VLDL particles, or too few HDL particles. Lifestyle choices such as smoking, diet and inactivity can also cause or contribute to high cholesterol levels, leaving you at risk from atherosclerosis.
  • Smoking - Smoking cigarettes damages the walls of your blood vessels, making them prone to accumulate fatty deposits. Smoking may also lower your HDL by as much as 15 percent. If you stop smoking, your HDL may return to its higher level.
  • High blood pressure - By damaging the walls of your arteries, high blood pressure can accelerate the development of atherosclerosis. Some medications for high blood pressure increase LDL and triglyceride levels and decrease HDL levels. Other medications don't.
  • Inactivity - Lack of physical exercise is associated with a decrease in HDL. Aerobic exercise is one way to increase your HDL. Aerobic activity is any exercise that requires continuous movement of your arms and legs and increases your breathing. Even 30 to 45 minutes of brisk walking every other day helps protect your cardiovascular system.
  • Obesity - Excess weight increases your triglycerides. It also lowers your HDL and increases your VLDL cholesterol. Losing just 5 or 10 pounds can improve your triglyceride and cholesterol levels.
  • Diabetes - Diabetes can increase triglycerides and decrease HDL in many people. Diabetes accelerates the development of atherosclerosis, which, in turn, increases the risk for heart attack, stroke and reduced circulation to your feet.

If you have diabetes, have your total cholesterol, triglycerides and HDL tested at least annually. Keep your weight and blood sugar under control. Still, complications may develop. Diabetes is not a risk factor you can always change.

Risk factors you can't change
  • Age - As you age,your level of LDL cholesterol usually increases. Researchers aren't sure why. The increase could be caused by aging or by an increase in your body fat.
  • Gender - Until the age of 45, men generally have higher total cholesterol levels than women. Also, up to about this age, women tend to have higher HDL levels. However, after menopause, women's total cholesterol rises and the protective HDL drops unless they take hormone replacement therapy.
  • Hormone replacement therapy - Customize, don't compromise.

Caution: Don't think of cardiovascular disease as mainly a man's disease. Cardiovascular disease is also the No. 1 killer of women, claiming almost 500,000 women each year. Cancer kills fewer than 220,000 women. Women get cardiovascular disease as often as men: it just happens later in life.

  • Family history - If members of your family have undesirable lipid levels and cardiovascular problems, your risks for these problems are increased. Children in families in which adults have high cholesterol are more likely to have high cholesterol themselves. The early signs of atherosclerosis appear in childhood. It is important that children in "at risk" families have their cholesterol checked. Children with high cholesterol should receive a doctor's advice about proper intervention, such as diet modification.
NHF Lipid Management Guidelines

Risk Category
Initiate Drug
Therapy if: target Level
1. Highest Risk
  • Existing CHD
  • Existing extracoronary vascular disease
TC > 5.0
or LDL-C > 3.0
or TG > 2.0
TC < 4.5
and LDL-C < 2.5
and TG < 2.0
2. High Risk
  • Diabetes
  • Positive family history of CHD
  • Familial hypercholesterolaemia
  • Hypertension
  • Smoking
TC > 6.0
or LDL-C > 4.0
or TG > 4.0
or TG > 2.0 if HDL < 1.0
TC < 5.0
and LDL-C < 3.0
and TG < 2.0
3. Lower Risk
  • Others
TC > 7.0
or LDL-C > 5.0
or TG > 8.0
TC < 6.0
and LDL-C < 4.0
and TG < 4.0


BMJ: Beer drinking protects against heart disease

Controversy continues over whether the protective effect of moderate alcohol consumption in coronary heart disease is confined to specific types of drinks, particularly wine, or relates to ethanol itself. Bobak et al used a case-control study among Czech men aged 25-64 who had had an infarction (and controls from the same population) to analyse the data from men who never drank or drank only beer (p 1378). The lowest risk of infarction was found among daily drinkers and those who drank 4-9 litres of beer a week. The authors conclude that it is ethanol that is protective.

Final Footnote - BMJ 7 June 2000 Donald McLintock

Its a helluva life being a CHD implementer.
I am sitting here at home doing some personal analysis on a bottle of Czech Premium Lager. Apparently it is made from the finest Saaz Aroma Hops, carefully selected Moravian Malt and
...soft water from wells 300 metres deep.
I can feel my arterioles expanding as my research progresses.
Surely we can help our patients to have enjoyable and lengthy lives. I shall have to try harder myself to be a foremost exemplar so to the backyard to split some logs before I start my research tomorrow evening.

Mike Lucas

Page created on March 3rd 2001 and updated on January 24th. 2014.    You are visitor number  number of hits articles   home    sign guestbook