Exceptional Longevity in Men; Testosterone & Risk of Prostate Cancer; Smoking & Pre-malignant Colorectal Polyps
Lifespans, for both women and men, continue to rise as the management of chronic diseases and the prevention of communicable diseases have become more effective.
According to the 2007 CIA World Factbook, American men can currently expect to live to an average age of 75, while women should expect to live to age 81. (However, despite spending more than virtually any other country in the world on healthcare, on a per capita basis, the average overall lifespan of 78 in the United States ranks at #29, just above Cyprus.)
As the average age in our society continues to rise, placing enormous funding burdens on an already grossly under-funded healthcare system, a great deal of research is underway to learn more about how we might better preserve good health late in life. A new study, just published in the Archives of Internal Medicine, takes a look at modifiable lifestyle and health factors associated with exceptional longevity in men, a seldom studied group.
A large ongoing study of male physicians, the Physicians’ Health Study, provided the data for this newly published research trial that evaluated 2,357 men, with an average age of 72 upon entering the trial in 1981. After an average of 16 years of follow-up, 970 of these men, or 40 percent, had survived to at least age 90. When this group of exceptionally long-lived men was compared with those who did not survive to age 90, multiple significant factors were found to predict for a lifespan of 90 or more years.
Not surprisingly, smoking doubled the likelihood of not reaching age 90. Men with diabetes were 86 percent less likely to live to age 90, obese men were 44 percent less likely to make it to age 90, and men with hypertension were 28 percent less likely to survive to age 90. However, men who exercised regularly were 30 percent more likely to reach age 90.
Those men who did not smoke, did not live a sedentary lifestyle, and who also did not have diabetes, obesity, or hypertension, by age 70, were observed to have a 54 percent likelihood of living to see their 90th birthday. When 2 of these adverse lifestyle and health factors were present at age 70, the probability of surviving to age 90 plummeted, to somewhere between 22 and 36 percent (depending upon which 2 adverse factors were present). When all 5 adverse lifestyle and health factors were present at age 70, there was only a 4 percent chance of surviving to age 90.
When directly comparing those men who lived to at least age 90 with those who did not, the longer-lived men had healthier lifestyles, fewer adverse lifestyle and health factors, and had a significantly lower incidence of chronic diseases. The group of men living to at least age 90 also enjoyed significantly better late-life physical function and mental well-being than the men who did not live as long. More than 68 percent of the longer-lived men rated their late-life health as excellent or very good, while only 45 percent of the less long-lived men gave the same ratings. Similarly, fewer than 8 percent of the nonagerians rated their health as fair or poor, while 22 percent of the less long-lived men rated their health as fair or poor.
This excellent study should serve as an important guide to men who, in almost every society on the planet, tend to live 5 to 10 years less than our female counterparts. Many reasons for this longevity disparity between men and women have been proposed, and most of them seem to revolve around the generally less healthy and less safe lifestyles that males tend to live when compared to females. While extreme longevity appears to run in some families, suggesting that genetic factors may play a role in longevity in some individuals, this important study concerned itself with non-genetic and mostly modifiable lifestyle and health factors, and their association with longevity.
While it is not wise to over-simplify the findings of this (or any) research study, nonetheless, it provides important evidence that men who reach the age of 70 without smoking, diabetes, obesity, hypertension or sedentary lifestyle have a better than even chance of seeing their 90th birthday, and a much greater chance of being in reasonably good physical and mental condition during the latter years of their lives, when compared with men who have one or more of these adverse factors by age 70.
TESTOSTERONE LEVELS & RISK OF PROSTATE CANCER
In many ways, prostate cancer is analogous to breast cancer in women.
In the majority of cases for both cancers, sex hormones appear to fuel the growth of these two hormone-sensitive cancers. Previous studies have linked high levels of estrogen in the blood with an increased risk of developing breast cancer in women, and scientists have speculated that, similarly, high levels of testosterone and other naturally occurring sec hormones in men may also predispose such men to prostate cancer.
A newly published study in the Journal of the national Cancer Institute reviewed the results from 18 prospective prostate cancer studies involving almost 4,000 men, and compared the levels of male sex hormones in the blood of these men with prostate cancer with the levels found in more than 6,400 men without prostate cancer.
When the researchers looked at the levels of testosterone and other male sex hormones in the blood, as well as the levels of estrogen (which occurs at low levels in healthy men), among these two groups of men, they found that no significant differences were seen between the men diagnosed with prostate cancer and the men without known prostate cancer. Based upon the results of this rater large study, it would appear that, unlike breast cancer, the risk of developing prostate cancer does not appear to vary according to the levels of sex hormones in the blood (both male and female sex hormones). In this aspect, prostate cancer appears to differ, biologically, with its analogous cancer in women.
SMOKING & PRE-MALIGNANT COLORECTAL POLYPS
Several cancers are known to be significantly more common among smokers, including cancers of the oral cavity, larynx, lung, esophagus, stomach, pancreas, uterus, cervix, kidney and bladder. Many, but not all, studies have linked smoking to an increased risk of colon and rectal cancer as well. Other studies have also shown that smoking is associated with a greater risk of developing the pre-malignant polyps, or adenomas, that are thought to be the precursors of most colorectal cancers.
A new study in the journal Gastroenterology analyzed 42 previous colorectal adenoma studies that assessed smoking as a risk factor for pre-malignant colon and rectal polyps. Smoking-associated risk factors were broken down into several different categories, including current smokers, former smokers, and people who had never smoked. When compared to the patients who had never smoked before, current smokers were found to have more than twice the risk of developing pre-malignant colorectal polyps, while former smokers had 1.5 times the risk. Even more worrisome was the finding that current or prior smoking was associated with an increased likelihood of having high-risk adenomas of the colon and rectum, when compared to those polyps found in patients who had never smoked. As if there already were not enough reasons not to smoke, or to quit if you already smoke, this study adds yet another straw to the camel’s back when it comes to the adverse health effects of smoking.
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