Vitamins & Colorectal Cancer

There have been a number of factors linked to the development of colorectal cancer, many of which I have discussed in past columns.  A new study in the journal Gastroenterology looks at the relationship between dietary intake of the vitamins folate and B12 and the incidence of colorectal cancer.  The addition or removal of methyl groups (one carbon atom attached to three hydrogen atoms) to or from specific regions of our DNA can result in changes in the expression of the affected genes.  Low levels of folate in the body can result in a reduction of the number of genes that contain attached methyl groups (hypomethylation).

In this study, 35 patients with precancerous polyps of the colon (adenomas), 28 patients with colorectal cancer, and 76 patients without any colorectal disease, were evaluated. At the time of colonoscopy, biopsies of the lining of the colon were obtained on all study patients, and blood samples were colleted and tested for levels of folate, vitamin B12, and the extent of DNA methylation.   Dietary folate intake was estimated using detailed questionnaires.

This study determined that the patients with colorectal cancer had an average blood level of folate that was 26% lower than the average of the control patients without colorectal disease, as well as a 21% lower blood level of vitamin B12.  The degree of DNA hypomethylation in the colon biopsy samples was 26% lower in the adenoma patients, on the average, when compared to the control patients, and 30% lower among the patients with colorectal cancer.  High folate concentrations in the blood were associated with a significantly reduced risk of developing colorectal cancer in this rather small study.

Although this study was modest in size (and should be repeated using larger numbers of patient volunteers), it does suggest that high levels of folate and vitamin B12 in the diet and blood may lead to a reduction in the risk of developing colorectal cancer.  This study joins previous studies that have identified a colorectal cancer risk reduction in people with calcium-rich and red meat-poor diets, and in patients who take certain antiinflammatory medications.  A healthy balanced diet, based upon currently accepted standards, will already cover most of these colon cancer prevention factors.  Regular colonoscopies after age 60-65 (and earlier in patients with a strong family history of colorectal cancer) have also been demonstrated to substantially reduce the risk of dying of colorectal cancer.

Unnecessary Prescribing of Antibiotics in Hospitals

By now, most of us know that many disease-causing bacteria are becoming resistant to many of the antibiotics historically used to treat such infections.  This is a particular problem in hospitals, where such killer bugs tend to lurk.  Seriously ill and immunocompromised hospitalized patients are the most susceptible hosts to such resistant bacteria.  In the current issue of the Archives of Internal Medicine is a study that looked at the antibiotic prescribing habits of doctors caring for non-intensive care hospital patients.  The appropriateness of the selected antibiotics was assessed based upon the patients’ diagnoses and, when performed, the results of bacterial cultures taken from ill patients.  A total of 129 patients were included in this study, with each patient staying an average of 15 hospital days.  The study’s experts calculated that antibiotics were not even indicated 30% of the time, although they were prescribed by attending doctors nonetheless.  The most common reasons for unnecessary antibiotic therapy included: excessively long durations of otherwise appropriately prescribed antibiotic therapy; use of antibiotics in the absence of apparent bacterial infections; and treatment of bacterial cultures that actually represented the patients’ own normal bacteria, or bacteria that were not causing any clinical infections. 

In view of the alarming rate at which life-threatening infection-causing bacteria are becoming resistant to our best antibiotics (as well as the risk of patients becoming infected with normally innocuous bacteria following the elimination of their naturally-occurring indigenous bacterial flora after prolonged exposure to broad spectrum antibiotics), this study should be made required reading for all physicians.

Relationships between Bullying & Violent Behavior among Students

Common sense would seem to dictate that children who bully other children may go on to exhibit violent behaviors against others later in life.  A Health & Human Services Department study, just published in the Archives of Pediatric & Adolescent Medicine takes a more scientific look at this problem.

A cross-sectional sample of 15,686 American students in public and private schools, in grades 6 through 10, participated in the World Health Organization’s Health Behavior in School-aged Children survey in 1998.  The survey asked students to anonymously report on weapon-carrying behaviors, fighting with other students, and being injured in fights with other students.  These threatening or violent behaviors were then correlated with self-reporting on the incidence of engaging in or being the recipient of bullying behaviors. 

Involvement in each of the violence-related behaviors ranged from 13% to 23% of boys, and in 4% to 11% of girls.  Bullying others and being bullied were consistently related to each violence-related behavior for both boys and girls.  Not surprisingly, greater odds of engaging in violence-related behaviors were linked with bullying others rather than with being the recipient of bullying.  Moreover, the likelihood of engaging in violence-related behaviors was greater among children who engaged in bullying outside of school property when compared to schoolyard bullies.  As an example, and based upon statistical analysis, being on the receiving end of weekly bullying at school was associated with a 1.5 times greater likelihood of weapon-carrying, while bullying other kids at school translated into a 2.6-fold increased risk of weapon-carrying.  Being bullied by other kids off of school property was associated with a 4.1 times greater risk of weapon-carrying, while children who bullied other kids away from school had a nearly 6-fold increased likelihood of engaging in weapon-carrying behaviors.  The study concludes what most parents, and probably all kids who have been on the receiving end of intimidating or violent behavior at the hands of their schoolmates, already know: bullying behavior is not a benign rite of passage for school kids.  It is abnormal, unhealthy and inexcusable behavior in virtually every case.  Such behaviors are also clearly linked to a greater propensity towards engaging in patently violent and illegal behaviors towards others.  Sadly, even the recipients of such abuse appear to, subsequently, be at increased risk of displaying the violence-related and sociopathic behaviors displayed by their tormentors. 

I urge each and every parent to take bullying seriously, whether their child is on the “giving” end or the receiving end, and to adopt a zero-tolerance attitude towards such behaviors.  Children who have been victimized by such behaviors should understand that, quite apart from the humiliation and risk of emotional and physical harm that they may suffer, they too are at increased risk of recapitulating the bullies’ behaviors.  Such children should seek help from their parents, and from trusted school officials.  In those cases where school officials are properly notified that bullying behaviors are known or suspected, it is absolutely incumbent upon those authorities to take aggressive and preemptive action to stop such behaviors.  The failure to do so, by all parties concerned, can have especially tragic consequences, as many of us who follow the news carefully are already aware.

Pneumococcal Vaccine Update

The bacterium Streptococcus pneumoniae, or “pneumococcus,” is a common cause of ear infections, sore throats and respiratory infections in children, and in adults as well.  This disease-causing bug has also started to show a worrisome trend towards becoming resistant to the traditional first line antibiotics long used to treat pneumococcal infections.  In 2000, a new vaccine against pneumococcus was approved for use in children in the United States.  Two new studies in the current issue of the New England Journal of Medicine look at the impact of this new vaccine on the incidence of pneumococcal infections in the US.

The first study looked at Centers for Disease Control data on pneumococcal infections among a database encompassing 16 million people between 1998 and 2001.  The data shows that the rate of invasive pneumococcal disease dropped from an average of 24.3 cases per 100,000 persons in 1998 and 1999 to 17.3 cases per 1000,000 in 2001.  The largest decline was seen among children less than 2 years of age.  In this age group, the rate of disease was 69% lower in 2001 than in the pre-vaccine years studied.  Pneumococcal disease rates also fell among adults following the introduction of the vaccine to children in 2000.  Following vaccine introduction in 2000, the rate of pneumococcal disease for adults 20 to 39 years of age dropped 32%, while for 40 to 64 year-old adults, the disease rate dropped 8%.  In the 65 years and above age group, the rate of pneumococcal disease fell 18%.  The authors of this study conclude that the pneumococcal vaccine appears to be having a significant impact on pneumococcal disease, and not only among the vaccinated children, but among adults in the population as well. This vaccine “bystander” effect is a common observation for children’s vaccines against communicable diseases, and points out the population-wide benefits of having all children immunized against serious diseases.

The second study looked at the impact of administering the pneumococcal vaccine to elderly adults.  Pneumococcus is a major cause of severe bacterial pneumonia in adults, and among the elderly in particular (Muppet creator Jim Henson died from pneumococcal pneumonia in 1990 at the age of 53).  In this retrospective study, the association between pneumococcal vaccine administration and the incidence of pneumococcal disease was studied among 47,365 volunteers 65 years of age and older, over a three year period. 

Prior receipt of the pneumococcus vaccine cut the risk of pneumococcal blood infections nearly in half among these elderly volunteers.  However, the overall incidence of pneumonia did not appear to be affected by patient vaccine status.  The study concluded that the pneumococcal vaccine protected elderly patients against developing infections with pneumococcus in the blood, but did not appear to have any significant impact on the risk of developing bacterial pneumonia, which is the most common disease caused by this bug in older adults.  This suggests that other strategies for preventing bacterial pneumonia in the elderly must be found.

Long Chain Fatty Acids in Infant Formula & Blood Pressure:

Breast milk is rich in a form of fat known as long chain fatty acids (LCFA).  However, most commercial formulas do not contain a sizable portion of their fat content in the form of LCFA.  There is some scientific evidence that babies fed with breast milk tend to have a lower incidence of high blood pressure in later childhood.  In adults, dietary supplementation with omega-3 fatty acids has also been shown to reduce elevated blood pressure in patients with established hypertension. 

A new European study, just published in the British Medical Journal, looked at the effects of supplementing commercial infant formula with LCFA.  A total of 111 newborns were fed with LCFA-supplemented formula, while 126 newborns were fed with unsupplemented formula.  The babies were then followed until age 6.  The study determined that the children who had received the LCFA-supplemented formula as infants had significantly lower average blood pressures when compared to the children who had been fed standard infant formula.  The study’s authors noted that blood pressure trends during childhood tend to continue into adulthood, and postulate that early exposure to dietary LCFA may reduce the incidence of high blood pressure during adulthood.  A study of much longer duration will, obviously, be required to prove the authors’ hypothesis.

Physical Activity & the Risk of Breast Cancer in Asian-American Women

Over a thousand Asian-American women, including 501 with breast cancer, were included in this interesting study, which has just been published in the journal Cancer.  A survey looking at levels of recreational physical activity was administered to all study participants, and the results were statistically analyzed.

The study found that increasing levels of recreational physical activity were significantly associated with a decreased risk of breast cancer.  Asian-American women reporting the highest levels of recreational physical activity experienced just under half the risk of developing breast cancer when compared to women with little or no recreational physical activity.  Intermediate levels of physical activity were, in turn, associated with a 9% to 47% decrease in breast cancer risk that was proportional to the amount of regular weekly recreational physical activity.  Thus, this study strongly suggests that physical exercise confers a significant protective effect against breast cancer.  Of course, there may be other factors in play here.  The women with the greatest investment in regular exercise may also be engaging in other health-positive behaviors that might be additive to the cancer-reducing effects of regular exercise.  Still, we know that physically fit people have a smaller risk of developing cancer, cardiovascular disease, stroke, high blood pressure and diabetes when compared to people who are not physically fit.

Dr. Robert A. Wascher