Navigating bone health: early life influences & strategies for improvement & injury prevention

KEYPOINTS

• 01

  Falls become a leading cause of death after 75, and hip fractures are especially deadly

  Peter's team plotted CDC data from 2019. Before about 60, overdoses dominate accidental deaths. After 65, falls do. Per 100,000 people, fall deaths at 75+ trail only heart disease, cancer and Alzheimer's. This 2022 AMA, rebroadcast in full, argues you can't wait until you're in that age group to act, just as you wouldn't wait for a heart attack to fix apoB.

• 02

  A hip fracture carries a higher one-year death risk than smoking

  In one data set more than 40% of men over 90 die within a year of a hip fracture, and roughly a third of people over 80 do. A ~200-person study found 25% six-month mortality after 65. A Finnish series of ~400 patients found about 27% one-year mortality. A pooled cohort of ~122,000 people aged 60+ found a one-year hazard ratio of 2.78, above end-stage kidney disease (~2.76) and smoking (just under 2).

• 03

  Bone is living tissue that's constantly rebuilt

  Osteoblasts build bone; osteoclasts break it down. Bone is 50–70% mineral (mostly calcium), 20–40% organic matrix, and the rest water and fat. The whole skeleton turns over in about 10 years, and bone holds nearly all the body's calcium. Low blood calcium raises parathyroid hormone, which pulls calcium from bone and activates vitamin D, which helps the gut absorb calcium. Bone marrow also houses the memory B and T cells behind lasting immunity.

• 04

  Osteopenia and osteoporosis are points on a continuum

  Osteopenia is about a 10% drop in bone mineral density versus a young healthy adult; osteoporosis is about 25%. Diagnosis uses both hips and the lumbar spine (L1–L5), where the deadly fractures happen. A T-score compares you with a healthy young adult; a Z-score compares you with people your age. A Z-score of −2 means lower density than 97.5% of peers.

• 05

  Ask for a DEXA scan that reports each hip and the spine separately

  DEXA is quick and very low-radiation. Many centers report only whole-body BMD, so confirm they'll report left hip, right hip and lumbar spine. Peter estimates basic body-composition scans at about $100–150 and full analyses at up to ~$400. Guidelines screen women at 65 and men at 70 (earlier if high risk). The WHO suggests women by 40. Peter looks at BMD in patients in their 30s and finds a Z-score of −1 at 35 as concerning as a bad glucose tolerance test.

• 06

  Peak bone mass is built from about 8 to 20

  BMD roughly doubles between 8 and 20, peaks in the early 20s and stays flat until 40–50. Around menopause women lose about 3–7% a year for 7–10 years, slowing to 0.5–2% after 65. Men over 65 lose 1–2% a year from a higher starting point. Women lose mainly spongy (trabecular) bone. A woman who misses her genetic peak by 20 starts lower for life, though work before menopause can narrow the gap.

• 07

  Estrogen controls how bone responds to load

  Bone cells sense the strain muscles put on them through tendons and add bone in response. Estrogen regulates that signal, so the sudden withdrawal at menopause is devastating without replacement. Men make estrogen from testosterone and lose it gradually as testosterone falls. Extra body fat may add load and estrogen.

• 08

  Peter thinks bone health should be part of the HRT decision

  The consensus still says HRT isn't standard care for postmenopausal bone loss. Peter notes the Women's Health Initiative clearly showed fewer fractures. He calls its breast-cancer increase (about 0.1% absolute) virtually non-existent and says the cardiovascular concern came from oral estrogen. Topical estradiol avoids that, and he believes HRT lowers cardiovascular risk.

• 09

  Resistance training and high-force sports build the most bone

  Resistance training beat running, swimming, cycling and even plain jumping for preserving BMD. Powerlifting beat regular strength training in postmenopausal women. Football and MMA had the highest BMD, but come with head and joint injuries. Peter suspects running underperforms because elite runners are very lean. Walking, gardening and golf (and his own racing and archery) don't load bones enough.

• 10

  How you lose weight affects bone

  Weight loss by diet alone tends to reduce BMD. In a small study, people who lost weight with substantial exercise slightly gained BMD, although they lost a bit less weight. Changes in leptin, adiponectin and estrogen may explain some of the loss, and loading the bones may offset it.