Inflammation linked to stroke risk

Two recent studies, whose data was presented at the 25th International Stroke Conference sponsored by the American Stroke Association, found a link between inflammation and stroke. Specifically, the studies found that inflammation in the blood is linked to an increased risk of stroke, suggesting an inflammatory process may lead to stroke.

C-reactive protein is a protein produced in response to inflammation. According to findings from the Framingham Heart Study, stroke risk is increased in individuals with high blood levels of C-reactive protein. The Northern Manhattan Stroke Study shows that a high white cell count, which is characteristic of inflammation, is linked with the thickening of plaques in the carotid artery-a risk for stroke.

The findings were presented by Natalia S. Rost, a medical student at Boston University in Massachusetts. The 591 men and 871 women who took part in the Framingham Heart Study had no evidence of cardiovascular disease when the study began in 1980 to 1982. Rost and colleagues correlated plasma C-reactive protein levels with the incidence of stroke during the following two decades.

Rost reported that women with the highest levels of C-reactive protein have a three-fold risk of stroke compared to those with the lowest levels. For men, those with the highest levels of C-reactive protein have a two-fold risk compared to those with the lowest levels.

Similar findings were observed in the Northern Manhattan Stroke Study, according to Dr. Mitchell S. Elkind of Columbia-Presbyterian Medical Center in New York. Out of the 1,293 subjects in the study, those with the highest white blood cell (WBC) counts had significantly greater thickening of carotid artery plaque thickness compared with the lowest counts. The average age of those who took part in the study was 69 years.

Framingham researchers are looking into whether anti-inflammatory treatment, such as taking aspirin for cardiovascular risk reduction, has an effect on C-reactive protein levels. Manhattan Stroke Study investigator Dr. Ralph L. Sacco of Columbia University noted that the dose of aspirin used to reduce C-reactive protein is lower than what would be used for an anti-inflammatory effect. But added that the findings of both studies "might change our thinking about stroke as an inflammatory condition," as well as the treatment or prevention of stroke.

PSA Testing Gains Ground

Despite the controversy surrounding PSA (prostate specific antigen) testing to screen for prostate cancer in healthy people, a trio of new studies presented at the American Urological Association's (AUA) annual meeting are showing support for the detection method as an effective way to catch cancer growth early.

An Austrian study of 65,000 men in Tyrol, aged 45 to 75, found that free annual PSA testing could be credited with a 42% drop in prostate cancer deaths in 1998. The 5-year screening study led not only to a decrease in the incidence of death but an increase in the rate of finding early stage cancers, and a rise in the number of potentially curable cancers. Similarly, researchers at Washington University suggest that following the AUA's recommendation of combined annual digital rectal exams and PSA testing for men starting at age 50 yielded similar positive findings for them. Their study of over 12,000 men aged 50 to 60 over a decade-long period led to follow-up biopsies for 1571 of the tested men and, subsequently, a diagnosis of localized cancer growth in 165 of them. Luckily, say the authors, the testing provided the opportunity to find potentially harmful cancers at an early stage. Meanwhile, a third study conducted by the National Cancer Institute (NCI) revealed a drop in prostate cancer incidence by 16% in white men and 11% in black men over the 1990s, when they were subjected to annual PSA testing. The authors comment that PSA testing for prostate cancer is no different than early screening for other types of cancer-if you catch it earlier, you have a better chance of curing it.

Both the American Cancer Society (ACS) and the American Urological Association (AUA) recommend annual PSA testing starting at age 50, when prostate diseases become increasingly common. Other organizations such as the American Medical Association (AMA) still think that the testing method isn't accurate enough to warrant being a standard annual screening method in the fight against prostate cancer. PSA is a protein produced by the prostate gland that's present and measurable in men's blood, and has been widely used to detect prostate cancer since the early 90s. Higher levels of PSA-levels over 4.0 ng/mL are deemed borderline, and over 10 ng/mL are considered high-may indicate the presence of prostate cancer. New guidelines suggest that PSA levels as low as 2.6 ng/mL should be further evaluated.

Some of the reasons for opposing PSA testing have included a high rate of false-positives that have led to unnecessary biopsies. High levels of PSA in the blood can actually be due to causes other than cancer, including non-cancerous conditions such as benign prostatic hyperplasia (BPH), prostatitis or simply age. Another cause for skepticism is the suggested lack of specificity and sensitivity in terms of being able to predict what growth stage a tumor is at and how rapidly it is progressing, and PSA levels may be normal in some men even when there is cancer. While those in opposition to PSA testing have pointed to a lack of evidence-based results, the new research still adds to the body of literature that exists to endorse the blood test as an effective, simple screening tool. With the advent of the new blood test that measures the percentage of free PSA present, biopsies of the prostate gland can sometimes be avoided.

Fewer Hip Fractures

Vitamin K has often been depicted as the unsung nutrient found in green, leafy vegetables. Regardless of its low profile, it is recognized as being essential for regulating the blood-clotting process and proper bone formation. Studies to date have already outlined vitamin K's key role in helping to synthesize osteocalcin, a protein that forms the framework for bone mass to build and regulates bone mineralization. In addition, other research has demonstrated that vitamin K may prevent osteoporosis by halting the loss of calcium through the urine, or in working synergistically with vitamin D to reduce bone loss. Now, a newly published study in the American Journal of Clinical Nutrition (2000;71:1201-1208) shows that vitamin K can also boast significant protection against hip fractures related to bone loss.

Vitamin K may prevent osteoporosis by halting the loss of calcium through the urine, or in working synergistically with vitamin D to reduce bone loss

Research conducted at Tufts University, Boston, MA, followed a group of 342 men and 558 women with an average age of 75 for over a 7-year period. Looking at their dietary intake of vitamin K using a written survey, the study found that those subjects who consumed the most vitamin K (254 mcg/day) suffered the least number of hip fractures. Meanwhile, individuals with the lowest consumption (56 mcg/day) had twice as many hip fractures. Study figures revealed, more specifically, that 7.2% of those in the low-intake group had an incidence of hip fractures while only 3.1% of the high-intake group did. In fact, note the authors, there was also a linear trend over the last 30 months of follow-up that showed a steep, steady rise in the number of hip fractures among the two groups with the lowest vitamin K consumption.

The authors suggest that further investigation is required to consider how vitamin K plays a protective role against hip fractures relative to other risk factors and bone mineral density (BMD). They also note that high fruit and vegetable intake in general has been associated with greater BMD and less age related bone loss, so perhaps a higher consumption of vitamin K may simply be indicative of an overall healthy diet that includes lots of vegetables.