B6.052 Prework 5: Mechanisms of Osteoporosis Flashcards
bone mass changes with age
osteoblasts have reduced proliferative and biosynthetic potential
reduced physical activity leads to decreased mechanical forces that stimulate normal bone remodeling
most effective exercises for increasing bone mass
resistance exercises
heritability of bone mass
50-70%
single gene defects are rare but have large effects
polymorphisms in other genes contribute to variation in peak bone density
nutritional influences on osteoporosis
calcium nutritional state contributes to peak bone mass
calcium def in adolescence/ adulthood restricts peak bone mass ultimately achieved
vit d absorption and metabolism decline with age
postmenopausal osteoporosis
characterized by acceleration of bone loss
decade after menopause: yearly reduction in bone mass up to 2% of cortical bone, 9% of cancellous bone
women may lose up to 35% of cortical and 50% of cancellous bone 30+ years after menopause
effect of decreased estrogen on bone turnover
decreased estrogen increases both bone resorption and formation, but formation does not keep up with resorption
high turnover osteoporosis
cytokines associated with decreased estrogen
increased RANKL lowered OPG decreased osteoblast proliferation reduced osteoclast proliferation increased IL-6, TNF-a, IL-1
effect of inflammation on bone remodeling
PRIMARILY promotes osteoclast maturation/activity
T cells secrete RANKL and TNFa
TNFa, IL-6, and IL-1 inhibit osteoblasts
therapy for steroid induced bone loss
treat underlying disease
reduce doses of glucocorticoids to lowest possible
how does osteoporosis affect spine curvature
loss of trabecular bone in vertebral bodies, anterior wedging, or overt fracture
kyphosis
buffalo hump
lordosis
lower spine curved anteriorly
