Navigator for the muscle-bone-function domain — the substrate of the older-adult health-lever question: what predicts decline (muscle mass, strength, function, sarcopenia), what the modifiable levers are (resistance training, protein, fall prevention), and where bone supplementation does and does not help. The through-line is the metric-vs-lever distinction — most muscle measures predict mortality partly as markers of underlying health, and few are proven treatment targets — and the deficiency-vs- enhancement split on the bone side (Deficiency Repletion vs Enhancement).

Muscle — mass, strength, and function (as predictors)

  • Sarcopenia Definition and Diagnosis — how age-related muscle loss is defined and diagnosed, and what to measure: mass, strength, or function (EWGSOP2 screens strength first)
  • Grip Strength and Mortality — how strongly grip (the cheap proxy for muscle function, distinct from mass) predicts all-cause + cause-specific mortality (Celis-Morales, UK Biobank n=502,293); a cheap risk metric, out-ranking blood pressure and self-reported activity in-model — but a predictor, not a proven lever
  • Low Muscle Mass and Mortality — whether low appendicular muscle mass predicts all-cause mortality independent of strength (de Santana SR-MA: yes, SMD -0.18) — mass and strength are different quantities, and strength tends to out-predict mass
  • Muscle-Strengthening Activity and Mortality — whether strength training reduces mortality and disease independently of aerobic activity, and at what dose — the interventional test of the observational muscle-mortality associations above

Building and keeping muscle (the levers)

Bone, joints, and fracture

  • Knee Osteoarthritis and Modifiable Levers — for knee OA, which modifiable exposures reduce pain and preserve function, and how they rank (weight loss the dominant lever; appraises the risk/function levers, not the clinical management of established disease)
  • Knee Osteoarthritis Incidence and Risk Factors — the DEVELOPING-OA counterpart (Duong gold SR+MA): which exposures raise risk of incident knee OA as route-(a) prognostic associations — obesity dominant (aOR 1.17/BMI-unit, 77% of the attributable fraction), prior injury (aOR 2.67), occupational load (the PA paradox at the knee); observational, richest on radiographic not symptomatic OA
  • Vitamin D and Calcium Supplementation for Fracture Prevention — for whom supplementing vitamin D and/or calcium reduces fracture (Yao: null in the replete community-dwelling, benefit concentrated in the deficient/institutionalized), and the supplemental-calcium cardiovascular-harm signal (Bolland)
  • Dairy and Bone Health — whether more milk/dairy reduces osteoporosis and hip fracture (Malmir: null once weighted by design) — the food route lands where the supplement route does, via Deficiency Repletion vs Enhancement
  • Exercise for Preventing Falls in Older Adults — the falls nucleus: exercise cuts the rate of falls 23% (HIGH certainty, Cochrane 108-RCT SR); the active ingredient is balance/functional training, not volume — the better-evidenced modifiable fracture lever for the replete older adult
  • Exercise Safety in Osteoporosis — the route-(c) contraindication facet (is exercise SAFE for fragile bone, which movements to avoid): serious harm rare/unattributable, excess is minor AEs only; avoid repetitive loaded spinal flexion, favour extension, but do not over-restrict daily bending; the safety verdict is capped by systematic UNDER-reporting of adverse events (streetlight on the harms side)
  • Exercise and Bone Mineral Density — the bone-loading efficacy facet: exercise raises BMD in postmenopausal women (Mohebbi 2023, gold updated SR-MA; SMD ~0.29-0.41, moderate at best, cleanest at total hip), but BMD is a SURROGATE — the moderators (bone/menopausal status, supervision) are all null, and transmission to fewer fractures is not shown here (the falls channel, BMD-independent, carries the larger fracture signal); same-group non-independence caps confidence