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[@PeterAttiaMD] Not All DEXA Scans Are Equal—Here’s What to Look For | Peter Attia AMA 37

· 5 min read
[@PeterAttiaMD] Summarizer
[@PeterAttiaMD] Summarizer
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@PeterAttiaMD - "Not All DEXA Scans Are Equal—Here’s What to Look For | Peter Attia AMA 37"

Link: https://youtu.be/ONyd2tQPRgQ

Short Summary​

Here's the breakdown:

Number One Action Item/Takeaway:

If you are interested in screening your bone mineral density via DEXA Scan, confirm that the entity performing the DEXA is providing a segmental bone analysis for left hip, right hip, and lumbar spine.

Executive Summary:

DEXA scans are a low-radiation method to assess bone mineral density (BMD) and body composition. To accurately screen for BMD, especially for left hip, right hip, and lumbar spine, ensure the DEXA scan provides segmental analysis; whole-body BMD scores may not be sufficient. While standard recommendations suggest starting screening later in life (65 for women, 70 for men), starting in your 30s, if you are already getting a DEXA scan, is not unreasonable.

Key Quotes​

Okay, here are 4 direct quotes from the provided transcript that represent valuable insights or strong opinions:

  1. "If you want to know your bone health, make sure before you go and get the DEXA scan. You confirm with the entity doing this that they are giving you segmental bone analysis for left hip, right hip, lumbar, spine. A lot of DEXA places can only give you whole body BMD."

  2. "Never in the history of civilization has a 90-year-old person ever been heard uttering, 'I wish I was less strong. I wish I had less muscle. I wish my bone density wasn't so high.'" (Peter Attia's "glib stupid joke")

  3. "So when we, you know, when we're looking at a 35-year-old patient and their zcore is already minus1, I mean, that's just as concerning to me as if their O GTT shows, you know, very elevated postprandial glucose and insulin levels. Um, and I'm really happy that I'm seeing that at the age of 35 and not 65."

  4. " I've never, to be honest with you, factored this into my risk assessment except for the male female one. Um, so in other words, if I look at a patient who's black versus white versus versus Hispanic, I kind of have never assumed one is at more or less risk. I've just said, let's do the kitchen sink on everybody."

Detailed Summary​

Here's a detailed summary of the YouTube video transcript in bullet points, excluding sponsor announcements and advertisements:

  • DEXA Scan for Bone Mineral Density (BMD):

    • DEXA scans are a low-radiation method for assessing bone health.
    • The scan takes about 10 minutes and uses two low-dose X-rays to differentiate between adipose tissue, bone, and lean tissue.

  • Importance of Segmental Bone Analysis:

    • Not all DEXA scanners provide a comprehensive segmental bone analysis.
    • For screening BMD, it's crucial to ensure the DEXA scan provides segmental analysis for the left hip, right hip, and lumbar spine.
    • Some DEXA places only provide whole body BMD, which may not be sufficient for screening purposes.

  • Accessibility and Cost of DEXA Scans:

    • DEXA scans are relatively easy to obtain without a doctor's referral.
    • Cost varies by location, ranging from around $100-$150 for a basic scan (body composition and visceral fat) to up to $400 for a full BMD analysis.

  • Key Metrics to Request:

    • Full segmental lean tissue analysis is important to calculate appendicular lean mass index, fat-free mass index and fat mass index.

  • Understanding Z-scores and T-scores:

    • BMD is reported using T-scores and Z-scores to statistically rank an individual's bone density.
    • Scores are not reported in grams per centimeter cubed.
    • Z-score: Compares an individual's BMD to others of the same age. A score of zero means the individual is in the middle of the distribution, higher than 50% and lower than 50% of that age group. A score of plus one is one standard deviation above the mean, higher than 82.5% of the age group, and so on.
    • T-score: Compares an individual's BMD to that of a young, healthy adult (typically 30 years old).

  • Factors Influencing BMD and Interpretation of Scores:

    • Natural variability exists in bone density between individuals.
    • Factors like family history, smoking, lifestyle (activity and weight-bearing exercise), and sex influence BMD.
    • A low Z-score in a premenopausal woman is a significant concern due to the impact of estrogen withdrawal during menopause.
    • Aim to be at the high end of the bone density spectrum (analogous to aiming for elite V2 max levels).

  • Graph on BMD Across Sex and Race:

    • BMD significantly increases from age 8 to around 20.
    • Women tend to experience a precipitous decline in BMD in midlife due to menopause.
    • Non-Hispanic Black individuals tend to have higher BMD than non-Hispanic White, who have higher BMD than Mexican-American individuals.
    • DEXA scans use planer measurement to report the bone density in grams per centimeter squared, which is the area of the bone and imputing the density by what electron beam doesn't go through it.

  • Recommendations for Initial BMD Screening:

    • Standard guidelines (American Association of Family Physicians, etc.) recommend screening women at 65 and men at 70, with follow-up scans no more than every 2 years.
    • For those at serious risk of osteoporosis, screening can be adjusted to occur earlier, but over the age of 50.
    • The WHO recommends screening women by age 40.
    • The speaker prefers to assess BMD in women in their 30s who are undergoing DEXA scans for other reasons.
    • A Z-score of -1 in a 35-year-old is a cause for concern.