DEAR DR. ROACH: Are vibrating machines safe? Only after buying a used one did I go online to find out more about them. I read they can cause brain damage and neurological damage, possibly permanent. My machine now sits in the garage while I learn what its fate should be. If it is dangerous, it should be destroyed, not passed on to another unwitting buyer. — T.H.

ANSWER: The theory of whole-body vibration machines makes some sense — your body attempts to stabilize you against the vibration, making muscles stronger with less perceived effort. Understanding the science on them, however, takes some judgment.

There are studies that show increased strength among users (compared with before using) and improved weight loss (in conjunction with dietary changes). In the studies I read, I did not find reports of significant adverse effects. The follow-up duration in these studies is short enough that there may indeed by adverse effects that could become apparent only after prolonged use.

Some of these devices do exceed recommended levels for occupational exposure, even after one minute. I found expert opinion that there may be neurological damage from whole-body vibration, but no hard evidence to back this up.

Based on the large body of evidence on the beneficial effects of traditional exercise and the relatively short duration of examining the effects of a whole-body vibration device, I would still recommend regular exercise over the device. However, I did not find much evidence of harm from these devices.

DEAR DR. ROACH: I am 68 and have prostate cancer. I had PSAs, an MRI and a biopsy. My Gleason score was a high 7. No genetic testing as I can recall. My urologist said I had “upper moderate” cancer and that I could remove my prostate or do radiation therapy. I underwent three months of radiation treatment from September to November 2020. I’ve done three PSA tests since the radiation. All have been very low and, per my doc, good.

I don’t specifically recall my doctor making any reference to my having a rather slow cancer or more aggressive cancer. How can I determine this for my situation? — T.P.

ANSWER: There are factors that can help predict whether a prostate cancer will be aggressive. The most useful of these are the size of the tumor (and whether any lymph nodes are involved); the PSA level and Gleason score; and the molecular characteristics of the tumor. The last comes from DNA testing of the tumor. Since I don’t know the size and you didn’t have any molecular tests, the best information I can give is that you have a Gleason score of 7 and apparently no positive lymph nodes or distant disease. This would put you, as your urologist said, into an intermediate risk group.

Without having the details from the pathology report, I can only give a rough estimate, but the best guess is that between 65% and 83% of men like you would continue to be free from prostate cancer five years after diagnosis.

However, there are some additional good findings since your treatment, especially that your PSA levels are staying low. Only after years can we know for sure about the aggressiveness of your cancer, but from what you are telling me, your prognosis is pretty good. Your urologist has all the information to give you the best estimate, and should give you more information if you tell them you want it.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.

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