The remodeling transient and the calcium economy

Abstract

Summary-The remodeling transient describes a change in bone mass that lasts one remodeling cycle following an intervention that disturbs the calcium economy. We demonstrated the transient in a study of the response of bone density to calcium/vitamin D3 supplementation and show the hazards of misinterpretation if the transient is not considered.

Changes in Bone Mineral Density During and After Lactation in Ugandan Women With HIV on Tenofovir-Based Antiretroviral Therapy

“…This could be that, by chance, such women were recruited who had higher aBMD, or may reflect a bone remodeling transient. ( 31 ) Alternatively, higher aBMD in WWH could be explained by bone recovery following discontinuation of DMPA. DMPA use is independently associated with bone loss, and aBMD recovery after discontinuation.…”

Bone mineral density changes in protease inhibitor-sparing vs. nucleoside reverse transcriptase inhibitor-sparing highly active antiretroviral therapy: data from a randomized trial*

“…Studies of BMD evolution after receipt of antiresorptive agents, vitamin D or calcium supplementation have confirmed that alterations in bone resorption and formation may not occur simultaneously during the first remodelling cycle after an intervention [19], and consequently Aloia et al argue that studies of agents that affect bone remodelling must be carried out for at least two bone remodelling cycles, corresponding to at least 1 year, before long-term affects can be assessed [19].…”

“…Of interest, we found that low baseline CD4 cell count was associated with decreases in both spine BMD and hip BMD and furthermore low BMI was associated with a decline in hip BMD during the first 24 weeks of treatment. Recently Brown et al also reported an association between low baseline CD4 cell count and subsequent BMD loss [18].Studies of BMD evolution after receipt of antiresorptive agents, vitamin D or calcium supplementation have confirmed that alterations in bone resorption and formation may not occur simultaneously during the first remodelling cycle after an intervention [19], and consequently Aloia et al argue that studies of agents that affect bone remodelling must be carried out for at least two bone remodelling cycles, corresponding to at least 1 year, before long-term affects can be assessed [19].A large randomized study (n 5 602) of tenofovir-vs. stavudine-based HAART also found that spine BMD declined for the first 24 weeks and then stabilized, while hip BMD declined for 48 weeks before stabilizing [7]. The hip has more cortical bone than the lumbar spine, which has mainly trabecular bone, and as bone remodelling is more rapid for trabecular than for cortical bone [20], a new balance between formation and resorption may take longer to occur in the hip.…”

Soy Components vs. Whole Soy: Are We Betting Our Bones on a Long Shot?

“…The question of effective dietary adaption arises for individuals unaccustomed to soy ingredients, but not for East Asian participants in epidemiological studies in which no adaption period is required and no interruption to lifelong dietary habits occurs. Furthermore, considering that a full bone remodeling cycle involving subsequent periods of bone cell quiescence, activation, resorption, reversal, and formation activity can take up to 9 mo or more to complete (28), any dietary, supplement, or pharmaceutical intervention that does not persist for at least 1 full cycle can create a remodeling transient by disproportionally affecting a specific stage(s) of the cycle and not others. Shorter term interventions (,1 y), of which there are many in relation to soy component effects on bone (29), likely reflect temporary distortions in the bone remodeling process rather than informative steady-state effects.…”