HEALTH BRIEFS
Ejaculation Frequency & Prostate Cancer, Television & Attention Deficit Disorder, Aspirin & Pancratic Cancer; Walnut & Heart Health

April 12, 2004

TELEVISION & ATTENTION DEFICIT DISORDER

A new study in the journal Pediatrics has raised a great deal concern among both parents and pediatricians. This University of Washington study evaluated seven-year old children who had previously participated in a national youth study. Based upon data collected in the National Longitudinal Survey of Youth project from 1,278 one-year olds and 1,345 three-year olds, this research study assessed these same children at age seven, noting that 10% of these kids had “attentional problems.” Based upon the survey results, this study’s authors correlated television watching habits at ages one and three with the likelihood of attention deficit problems arising by age seven. This study was performed because a few previous studies have associated frequent television viewing during childhood with short attention spans. What has not been clear, however, is whether the association between high levels of TV viewing and short attention spans is caused by TV viewing, or if kids with short attention spans tend to watch more TV than their peers with longer attention spans. Moreover, it has also not been clear that ALL television viewing is associated with the development of short attention spans, or if certain types of program content are more—or less—likely to impair attention spans.

In this new study, statistical analysis of survey results when the children were one or three years of age revealed a correlation between TV watching at these ages and the probability of attention deficit problems developing by age seven. However, the impact of television viewing habits was actually quite small. Among the children who were surveyed at ages one and three, there was a 9% RELATIVE increase in the risk of attention deficits at age seven among the kids who had watched the most TV, which is a very small incremental increase when compared to the probability of attention deficit problems in the kids who watched very little TV at the same ages. While I certainly don’t endorse the substitution of television for direct interactions with mom, dad, siblings and other caregivers, I am frankly underwhelmed by the results of this study. As with most survey-based studies, there is a great deal of room for subjectivity in the responses of those being surveyed. Also problematic in these studies is the difficulty in “controlling” for other factors that might influence the studies’ findings. Do young children who watch an excessive amount of TV do so because, for whatever reasons, they lack close and frequent interactions with their parents, or is it the other way around? Do they lack adequately enriched environments where they are stimulated to actively interact with their parents, and to participate in active learning rather than passive absorption of whatever is projected from a television screen? Or, are their presumed TV-related attention span problems related to the content (or lack thereof) of the programs that these kids are watching? Once again, I absolutely do not recommend that television replace the critical nurturing interactions and stimulation that infants and toddlers receive from their caregivers, as we know that these stimuli play a profoundly positive role in the normal development of the brains of babies and toddlers. At the same time, based upon this study’s results, limited television viewing (and particularly the viewing of stimulating and educational age-appropriate programs) seems unlikely to be harmful to young children and babies who receive the necessary nurturing and stimulating interactions with their parents. Of course, additional research should be conducted to either validate or invalidate the findings of this study.

ASPIRIN & RISK OF PANCREATIC CANCER

A recent report by the Nurses’ Study suggested a link between regular aspirin intake and an increased risk of pancreatic cancer (an especially lethal form of cancer). This finding was somewhat surprising, as aspirin, like other anti-inflammatory medications, blocks a key enzyme (cyclooxygenase, or COX) that has been found to play a key role in the development of many cancers. Indeed, there are several ongoing research trials looking at the use of COX inhibitors to prevent cancer. Moreover, previous studies of cultured pancreas cancer cells, and pancreas tumors in laboratory animals, further suggested that blockade of the COX enzyme reduces the ability of pancreas cancer cells to divide and grow. Now, a new study in the Journal of the National Cancer Institute revisits this issue.

In this new study, 987,590 adults who were participating in a huge cancer prevention study (the Cancer Prevention Study-II) were carefully evaluated by self-administered surveys, and were followed for at least 18 years during the course of this study. Within this group of nearly one million adults, 4,577 developed pancreas cancer. In this study, the impact of aspirin on the risk of developing and dying from pancreas cancer was assessed. Known risk factors for pancreas cancer, including age, sex, race, body mass index, diabetes, and cigarette smoking history, were all controlled for in this study, as well. This huge study found that even people who consumed aspirin at least 30 times per month, and for 20 or more years, experienced no increased risk of pancreas cancer when compared with those who did not report regular aspirin use. Although this study was based upon survey results reporting aspirin usage (and, hence, suffers from the potential limitations of all such studies), the extremely large number of participants in this study, the careful efforts of the study’s authors to control for other known pancreas cancer risk factors, and the close follow-up of these patients over an extended period of time, all add great power to the findings of this study. Based upon the results of this very large study, it seems very unlikely that even frequent aspirin use significantly increases the risk of pancreas cancer. At the same time, the results of this study strongly suggest that regular aspirin use probably does not protect against pancreas cancer, either.

WALNUTS & HEART HEALTH

A diet rich in nuts has been shown to be effective in reducing cholesterol levels in the blood. Several prior epidemiological studies have suggested that a nut-rich diet may actually reduce the risk of coronary artery disease as well. Most nuts are rich in monounsaturated fats and antioxidants, which have been assumed to be the sources of their heart-protective effects. However, a new study in the journal Circulation suggests that there may be more to the beneficial effects of nuts than their ability to lower cholesterol levels. The study was designed as a “crossover” study, such that volunteers were switched over to a different treatment at the mid-point of the study, and the impact of this switch was then measured. In the case of this study, 21 adult patients with elevated blood cholesterol levels were initially placed on a cholesterol-lowering Mediterranean diet for 4 weeks. The volunteers were then switched to a non-Mediterranean diet in which walnuts provided approximately 32% of dietary calories in the form of monounsaturated fat. Following each 4-week diet, each participant underwent blood tests and an ultrasound examination of the major artery in their arms. When compared with the Mediterranean diet, the walnut-rich diet was associated with significant improvement in arterial function (measured by ultrasound), as well as significantly reduced levels of total cholesterol and LDL (the “bad cholesterol”). This study, therefore, suggests that walnuts in the diet may directly improve blood vessel function in people with elevated blood cholesterol, and by mechanisms distinct from their cholesterol-lowering effects. Although rich in fat calories, many nuts are also rich in the types of fats that actually reduce cholesterol. In view of this intriguing evidence of additional beneficial health effects from dietary nuts, it would seem prudent to include moderate regular nut consumption in our diets.

EJACULATION FREQUENCY & RISK OF PROSTATE CANCER

A new study in the Journal of the American Medical Association has also provoked a great deal of publicity. (And appears to have raised the hopes of millions of men around the world that science has finally proven that more frequent sex can extend their health, if not their lives!)

As men pass through their early adult years, their blood testosterone levels begin to decline. Libido gradually declines, beginning when men reach their 30s, and sexual activity generally becomes less frequent as men approach mid-life. Prostate cancer, like breast cancer, can occur in young adults, but most commonly arises in older men. Some researchers have attempted to draw a connection between the decreased sexual activity of older men and the higher risk of prostate cancer in this age group. Somewhere between 30 to 40% of male ejaculate is produced by the prostate gland. There is some evidence that the accumulation of unejaculated fluid in the prostate, over time, may cause chronic inflammation in this walnut-sized gland that sits just below the urinary bladder. Although there is no solid scientific evidence that these events lead to an increased risk of prostate cancer, there isn’t much evidence that this process does not contribute to the risk of prostate cancer, either.

This study was a prospective study of 29,342 men, aged 46 to 81 years. Each man completed a sexual history upon entry into this study in 1992, as well as follow-up questionnaires every two years until 2000. The men were asked to report on the average number of their ejaculations per month during ages 20 to 29 years, 40-49 years, and during the previous year (1991). The incidence of prostate cancer among the study volunteers was closely followed and documented during the course of this study. The study, therefore, assessed 222,426 “person-years” of follow-up, during which 1,449 new cases of prostate cancer were diagnosed in the study participants. The study determined that most categories of ejaculation frequency were unrelated (either positively or negatively) to the risk of developing prostate cancer. However, a very high monthly frequency of ejaculation did appear to be significantly associated with a decreased risk of developing prostate cancer. Specifically, among the men reporting 21 or more ejaculations per month during the ages of 20 and 29 years, when compared to men reporting 4 to 7 ejaculations per month, were 11% less likely to develop prostate cancer (relative risk). When these two “ejaculation categories” were compared for men in the 40 to 49 year range, those men reporting 21 or more ejaculations per month experienced a 32% relative risk reduction in the incidence of prostate cancer. Finally, when the same ejaculation categories were compared for the year prior to entering the study, the men with 21 or greater ejaculations per month were 41% less likely to develop prostate cancer when compared to the men reporting 4 to 7 ejaculations per month. When averaged over all periods evaluated in the study, the lifetime risk of developing prostate cancer among the high-frequency ejaculators was 33% lower than for the low-frequency ejaculators. The authors rather conservatively concluded that ejaculation frequency is not associated with an increased risk of developing prostate cancer.

Although this is yet another epidemiological study that depends in part upon self-reporting, and is therefore prone to subjective inaccuracies on the part of the study’s participants, the results of this study do strongly suggest that, at a minimum, the monthly frequency of ejaculations (whether high or low) probably do not increase the risk of prostate cancer.

Undoubtedly, thousands (if not millions) of men around the world have already presented their spouses and significant others with a written summary of this study, and with an urgent request to assist them in reaching their new goal of at least 21 ejaculations per month….