sissymaidlola -> RE: ejaculation frequency and prostate cancer (3/16/2005 3:23:41 PM)
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But you missed my point about the accuracy of the article's conclusion. The baseline incidence of prostate cancer for the U.S. population is known. The study compared this rate to the rate of prostate cancer in three sample groups. One group had lower incidence compared to the national population. The other wo groups did not have lower *nor* did they have higher incidence of prostate cancer compared to the U.S. population. No, chris, sissy didn't miss your point at all about the accuracy of the article's conclusion. BTW, two of the three groups suffering from prostate cancer - groups (1) and (2) (see below) - had a lower incidence compared to the national population baseline WRT high ejaculation frequency, and not one of the three as you stated. At least that is how sissy interprets the statement, "Similar associations were observed for organ-confined prostate cancer," as it appears in the study results (see below). The three sample prostate cancer groups identified by the study were: (1) 1449 new cases of total prostate cancer (2) 953 organ-confined cases, and (3) 147 advanced cases of prostate cancer. For all these groups, most categories of ejaculation frequency were unrelated to risk of prostate cancer. The one category that was an exception to all the others is the "high ejaculation frequency" category. For this category, taking each of the three cancer groups in turn, the results were (now sissy is quoting from the results section of the AMA study report, but the formatting and numbering that have been added are his in order to make it a little easier to follow): quote:
(1) However, high ejaculation frequency was related to decreased risk of total prostate cancer. The multivariate relative risks for men reporting 21 or more ejaculations per month compared with men reporting 4 to 7 ejaculations per month at ages 20 to 29 years were 0.89 (95% confidence interval [CI], 0.73-1.10); ages 40 to 49 years, 0.68 (95% CI, 0.53-0.86); previous year, 0.49 (95% CI, 0.27-0.88); and averaged across a lifetime, 0.67 (95% CI, 0.51-0.89). (2) Similar associations were observed for organ-confined prostate cancer. (3) Ejaculation frequency was not statistically significantly associated with risk of advanced prostate cancer. What isn't clear to sissy from the AMA report is how many ejaculation frequency categories were used. Did the researchers take a Goldilocks approach (viz., low, medium, and high) or are there more categories involved ? It is a little hard to understand the full import of the statement, "most categories of ejaculation frequency were unrelated to risk of prostate cancer" without knowing this. Most of how many ? ... three, five, twelve, what ? Exactly how small a fraction of ALL the ejaculation frequency categories does the "high ejaculation frequency category" represent for it to be so easily dismissed as anomalous by the study report's conclusion ? Maybe you can clarify this for sissy, chris, because he was unable to determine that ? Since all of the other ejaculation frequency categories did not show any significant statistical deviation from the mean for the national baseline incidence of prostate cancer for each of the three groups, as you say, no conclusion whatsoever can be made for them as to their correlation to cancer incidence. So if you ask the question: "What will happen to my cancer risk if I change from a low frequency of ejaculation to a medium frequency of ejaculation ?" the answer is a firm, "no idea, cannot say, the results are inconclusive!" The only category of ejaculation frequency category one can make any useful comment about is the "high ejaculation frequency category." It has a demonstrable correlation to some significant statistical deviation from the mean for the national baseline incidence of prostate cancer for the first two of the three cancer groups (total prostate cancer cases and organ-confined cancer cases - see quoted results above). This category would appear to have a discernable lower risk based on these deviations from the national baseline. So if you ask the question: "What will happen to my cancer risk if I change from a high frequency of ejaculation to one of the other frequencies of ejaculation ?" the answer now is that it will be higher, because you have moved from the only ejaculation frequency category with a discernable lower risk to one of the (many?) other categories with no discernable risk either way. sissy Feels that he has more than adequately demonstrated in his prior lengthy post to you that one can indeed make meaningful relative risk assessment statements when comparing this category to any of the others. As an analogy, consider how life insurance works. There are lifestyles that are low risk, some that are medium risk, and some that are high risk. The insurance companies have actuarial tables that covers every major category of risk group which are used to determine your life insurance premiums (the cost of which are merely a reflection of the relative risk you have of dying compared to all the other males in your age group based on the nature of your lifestyle). If you phone the insurance company up and tell them that, although you were an accountant when you took out the policy, you are now a computer programmer, they would probably thank you and simply update your file. But if you told them that you were now a professional NASCAR race driver, a freefall skydiver, or that you had recently taken up smoking and were already up to three packs a day, expect your premiums to soar, or even your life insurance policy to be cancelled! Moving from low to medium ejaculation frequency categories, or vice versa, has no discernable effect on perceived cancer risk, as does moving between safe middle class lifestyles such as accountancy or computer programming. But moving from one of those ejaculation frequency categories to the high ejaculation frequency category, or vice versa, does have a discernable effect on perceived cancer risk, in the same manner as an accountant becoming a skydiver has discernable effect on perceived expected life span risk. When you state: quote:
For this reason it could be concluded that frequency of ejaculation was not related to increased risk of prostate cancer. The incidence of prostate cancer in the samples was *not* higher than that of the U.S. population. it applies ONLY to all the other ejaculation frequency categories. However, if the "high ejaculation frequency category" represents only 3%, say, of the complete population of statistics extracted from the submitted questionnaires analyzed, then it is probably OK to dismiss this group as anomalous and declare the conclusion that the AMA did declare at the end of its report (but sissy feels that such a rationalization should, nevertheless, have been explained in the conclusion). OTOH, if the "high ejaculation frequency category" represents 53%, say, of the complete population of statistics extracted from the submitted questionnaires analyzed, then no way should such a large sample have been dismissed as an insignificant aberration when writing the study report's conclusion. Unless you can enlighten sissy otherwise, chris, he is assuming that only three ejaculation frequency categories were examined in this study - viz. 4-7 ejaculations/month (or low), 8-20 ejaculations/month (or medium), and >20 ejaculations/month (or high). Even if this is the case, it is not clear how the submitted questionnaire statistics analyzed are actually distributed amongst these three categories. Taking a gross approach, if the "high ejaculation frequency category" represents at least 33% of the total submitted questionnaire statistics analyzed (i.e., assuming that the three categories were fairly evenly populated), then IsHO such a large sample should not have been completely dismissed or ignored when writing the study's conclusion ... at least not without any kind of justification. Why bother to publish the measured statistical deviations for this category in the results section of the report only to ignore these results in the conclusion ? That, essentially, is the problem sissy has with the AMA study report. Maybe he is missing something here ... please enlighten sissy if he is. What caused sissy to engage in this conversation, more than anything, chris, was your apparent belief that nothing meaningful can be said about the relative cancer risks of the ejaculation frequency categories referenced by the study, because the study reported that no statistical correlation could be established for "most categories of ejaculation frequency." Whatever the empirical accuracy of the AMA study, or however badly the abstract to the subsequent study report was written (some of which sissy has also documented in his prior posts), hopefully sissy has convinced you with his arguments in both this post, and his previous post, that that is not necessarily the case. Regards, sissy maid lola [image]local://upfiles/21203/7550AAD373274EA8911F0BC3852D002C.jpg[/image]
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