Archive for June, 2008

Risk Factors, Diet, and Blood Lipids

Thursday, June 26th, 2008

“Part of the secret of success in life is to eat what you like and let the food fight it out inside.”

Mark Twain

There are over 260 “risk factors”, i.e. conditions, habits, stress, or being just alive, all associated with the risk of developing coronary disease, heart attacks, or sudden death. Unlike bacteria causing specific infections, however, these risk factors are not proven causes of coronary disease. Proving true causality in medicine, in fact, is often a game of endless pirouettes, stretches and rule changes.

For example, these risk factors may be strong and therefore impressive, or weak and debatable. Strong associations with coronary disease, besides age and gender, include heredity, smoking, high blood pressure, diabetes, obesity, probably in that order-and for true believers, the worst culprits are serum fats or lipid levels which include total triglycerides, total cholesterol and its sidekicks, LDL and HDL cholesterol, among other fatty compounds.

Dietary fat has been blamed over the decades for affecting, if not controlling, the blood level of serum lipids. The link, however, between diet, especially the consumption of cholesterol and different types of fats- solid or semi-solid fats (“saturated”) vs. oils or liquid fats, and the level of various lipids or fats in the blood continues in many quarters to be highly questionable.

Moreover, the secondary link between blood levels of fat, including cholesterol-related lipids and the development of coronary disease is a variable, and often confusing one. While individuals with certain metabolic diseases, especially diabetes, have abnormal levels of blood lipids and a high incidence of coronary disease, many normal people with high lipids never develop significant heart disease. Further, almost half of all coronary patients and patients admitted for heart attacks have normal blood lipids. For years, the dietary research community has been reluctant to admit that the scare over dietary fats has long been over-hyped. Diet fat hysteria received its final coffin nail last year when a major study concluded that low-fat diets provide no demonstrable health benefits over high-fat diets.

For decades the diet police told us animal fats like butter were dangerous, and more recently announced that fettucini Alfredo was “a coronary on a plate.” They urged us to substitute margarine for animal fats, and to stay away from red meat. Of course in those rosy times, no one talked or wrote about “trans fats,” abundantly produced when vegetable oils were turned into solid fats like Crisco and margarine. Now, the diet police have done an about-face all the while failing to admit that their butter scare was bogus from the outset, but margarine, containing high trans fats was bad. It turns out that now butter, palm oil, lard, containing natural trans fats, and (new) Crisco, if not tops on the list of desirable fats, are at least considered OK by the diet dogs.

Stay tuned for more on diet and trans fats.

Fractures, Falls, and Osteoporosis

Monday, June 9th, 2008

Falls increase with age and are a stronger predictor of fractures than bone mineral density (BMD) measured by osteoporosis screening, according to the JAMA (Mar.26, 2008). Also, a person after age 45 with a history of fracture resulting from mechanical forces that would not ordinarily cause fracture in a healthy adult (fragility fracture) has a higher risk of bone fracture than an individual without such a history, all other factors, including age and T- score being equal.

More falls with increasing age, are a major cause of death in the elderly, and result from the normal loss of coordination, balance, quick reflexes, and strong muscles. Thus, the ability to avoid injury is a major determinant of fracture, more important than bone strength per se. BMD, bone mineral density which is measured in only two or three pre-defined locations varies greatly from one area of bone to another, and is only one measure of bone strength, the others being the size and thickness of the bone itself, bone microstructure, amount and type of bone protein cross links, porosity, accumulated damage (microcracks), etc.

Bis- or diphosphonates, such as Alendronate (Fosamax ©), Ibandronate (Boniva ©-Thanks, Sally Field), calcium, vitamin D, and estrogens have all been shown to increase bone mineral density and decrease fractures and mortality. “However, in two well-designed studies in which elderly individuals were enrolled on the basis of being at increased risk of hip fracture because of factors other than low BMD, treatment with bisphosponates did not decrease risk of hip fractures.”

Common sense suggests that training exercises for all patients, not just the elderly, to improve muscle strength, balance, techniques to avoid falls, even tai chi, -should be as good an investment as putting everyone on diphosphonates. The World Health Organization (WHO) and other organizations have recommended using an individual’s 10 year-fracture risk as a guide to treatment decisions, not just the BMD.

Far too many patients, especially younger women may be taking diphosphonates solely on the basis of abnormal bone mineral density tests. After all, it’s a $6 billion market, beginning to shrink until the latest and more risky long-acting compounds, such as Zolendronate started appearing. Read what Gillian Sanson has to say in her outstanding book, The Myth of Osteoporosis MCD Century Publications, 2003.