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Lecture 8

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Health Studies
HLTH 230
Jeffery Lalonde

Lecture 8 - Guest Lecturer OSTEOPOROSIS osteoporosis: metabolic (living tissue!) bone disease characterized by low bone mass and micro-architectural deterioration of bone tissue with a resulting increase in fragility fractures fragility fracture: one that results from minimal trauma -ex. fall from a standing height or less, or no identifiable trauma at all -ex. cough/sneeze causing a fractured hip -healthy bone has more cross-bridges (more support) this leads to increased bone fragility and risk of fracture, particularly of the hip, spine, and • wrist • osteoporosis -> often know as the “silent thief” bc bone loss occurs without symptoms -on-going in body but you are not aware of it • can be regarded as a pediatric disease with geriatric consequences -deal with it at the beginning (pediatric) • peak bone mass reached in adolescence -> there fore children and youth need to build bone mass • issue: past and present generations did not build sufficient bone mass future generations? TBD • Osteoporosis - A lesson for Health Care Reform • unique example of nutritional health issue that manifests itself many years later • early prevention and intervention is essential example of a model of health care that is not economically feasible • • lifetime of nutritional and lifestyle habits that have resulted in a health cost tsunami • your generation will pay for the price of past and present generations of health issues Irony! solutions to this health care tsunami were very simple • • osteoporosis is a normal aging process that has been complicated by poor nutritional choices, lifestyle habits, understanding and education • crisis due to medical advances which have allowed baby boomers to live longer in a skeletal framework that is compromised Canadian Prevalence • 2 million Canadians suffer from osteoporosis • 1/4 women that are 50+ has osteoporosis (1/3 will suffer a fracture) • 1/8 men that are 50+ has osteoporosis (1/5 will suffer a fracture) • however, disease can strike at any age Lecture 8 - Guest Lecturer more common in white and asian women • • black women have better calcium absorption *same is true for men white women have a higher fracture risk because of the Q-angle -straighter Q-angle => better support -asian women have a smaller Q-angle *same is true for men Cost of Osteoporosis • 1993 - $1.3 billion • 2010 - $2.3 billion • costs include acute care, outpatient care, prescription drugs, indirect costs • costs rise to $3.9 billion if a proportion of Canadians were assumed to be living in long-term care facilities because of osteoporosis without effective action, estimated $32.5 billion in 2018 • What are the costs from? • diagnosis - blood work, xrays, DEXA imaging • monitoring - regular testing - DEXA, blood work treatment - office visits, specialists, medications • • fractures!!!! Scary Facts • fractures from osteoporosis are more common than heart attack, stroke and breast cancer combined • 1 fracture every 3 seconds in Canada Lecture 8 - Guest Lecturer • populated aged 50+ has increased by 50% from 1993 to 2008 • this % population will continue to increase Fracture Stats • 50 yr old woman has 40% chance of developing hip/vertebral/wrist fractures during lifetime • lifetime risk of hip fracture is greater (1/6) than 1/9 lifetime risk of breast cancer • patients are at highest risk for subsequent fracture in the first few months following vertebral fracture 1/4 women who have a new vertebral fracture will fracture again within 1 year • • both vertebral and hip fractures associated with in increased risk of death Hip Fracture Costs • over 80% of fractures in people 50+ are caused by OP • OP causes 70-90% of 30,000 hip fractures annually • *******28% of women, and 37% of men who suffer a hip fracture will die within the following year******* -results of a hip fracture (healthcare cascade) -immobility, recovery, surgery AFTER fracture each hip fracture costs $21,285 (1st yr after hospitalization) and $44,156 if patient is • institutionalized -take up more hospital beds than stroke, diabetes, heart attack • before hip fracture vs. after • 65% at home vs. 38% at home (huge cost of rehab for these people) Kingston Hip Fractures Sept. 2009 - Sept. 2012 • -610 hip fractures -avg. age: 79.5 yrs Lecture 8 - Guest Lecturer -70% female, 30% male • Model of Care - orthopedic ward with internal medicine/geriatric consultation • standardized admission orders significant care gap “a fracture is to osteoporosis what a heart attack is to cardiovascular disease” • need people to be assessed quickly • people leave hospital without proper info about how to treat for osteoporosis Human Costs • reduced quality of life for those with osteoporosis is enormous • Osteoporosis can result in: -disfigurement -lowered self-esteem -reduction of loss/mobility -decreased independence Symptoms of Osteoporosis • pain • reduced height -> up to 6 inches! 2 inches is significant • marked curvature of spine (kyphosis) Major Risk Factors • Age > 65 years • vertebral compression fracture • fragility fracture after age 40 • family history of OP fracture (especially maternal hip fracture *** greatest predictor) • systemic glucocorticoid therapy of >3 months duration • Malabsorption syndrome - Celiac/Crohn’s Disease • Primary hyperparathyroidism • Tendency to fall • Osteopenia apparent on x-ray film • hypogonadism • early menopause (before 45 yrs) Systemic Glucocorticoid Use - Puffer • includes prednisone and cortisone for more than 3 months • disease that are often treated with glucocorticoid medications include: -rheumatoid arthritis -Asthma -Crohn’s disease -colitis -COPD Lecture 8 - Guest Lecturer Minor Risk Factors • rheumatoid arthritis • past history of clinical hyperthyroidism • chronic anticonvulsant therapy (epilepsy) low dietary calcium intake • • smoker • excessive alcohol (>2 cups/day) or caffeine (>4cups/day) intake • weight <57 kg (125 lbs) • weight loss >10% of weight at age 25 • chronic heraparin therapy Modifiable Risk Factors - things they can control! :) • low bone mineral density low body weight • • high alcohol use • smoking • excess caffeine diet - low calcium intake • • low vitamin D exposure • sedentary lifestyle Non-Modifiable Risk Factors previous fracture • • history of fragility fracture in a 1st degree relative • poor health/frailty • advanced age female sex • • white/asian race • secondary causes How is Osteoporosis measured? used to do X-rays (a lot of variability, needed a better way) • • plain radiographs - traditional method for many years • not gold standard anymore! • DEXA has replaced plain radiographs Osteopenia vs. osteoporosis more clearly identified • • measure bone mineral density Bone Mineral Density Lecture 8 - Guest Lecturer • if you take a sample of bone and wash out liquid bone marrow, the remaining bone is about 50% mineral and 50% protein • bone mineral density: weight of mineral/volume of bone -strength of bone largely determined by bone mineral density • determined by 2 things 1) how many mineral atoms are deposited within bone matrix 2) how porous the matrix is DEXA bone density measured using Dual Energy X-ray Absorptiometry (DEXA) • • large studies have shown that bone mineral density of hip as measured by DEXA helps to predict whether a person will have a hip fracture • risk of fracture will double if DEXA decreases approx. by 12% Gold Standard! • • Normal vs. osteopenia/osteoporosis • compared to young healthy bone (25 yrs) - not to age-comparable bone • x-ray machine sends out 2 rays with different energies • as rays pass through patient, some are stopped by bone mineral/other tissues (ex. fat, water, protein) • x-ray detector above patient can tell how much energy got through -> this info is sent to a computer, which analyzes and forms and image T-Score and Z-Score • WHO definition of T-Score: # of standard deviations from the mean (average) value of a 25 year old woman (unit of measurement) • normal bone: T-score better than -1 • Osteopenia: T-score better than -1 to -2.5 -some bone loss, not as significant • Osteoporosis: T-score better than -2.5 • Z-score: # of standard deviations below age matched average (unit of measurement) Lecture 8 - Guest Lecturer *the better your bone shape is when you are younger, the less risk -women lose estrogen => higher risk factor Quality of Bone may have quantity, but not quality • • important for assessing fracture risk! • important consideration for surgical outcomes • now using combination of BMD and fracture risk to assess and treat patients modified and adapted risk measurement guidelines due to new info/data - ongoing • process! Bone Remodeling • bone is living tissue, constantly renewing itself (subject to wear and tear) • remodeling happens every 3-4 months in a healthy young adult • osteoCLasts: excavate any areas of crumbling/weakened bone -Clean things up • osteoBLasts: fill in crevices with material that calcifies to form new bone -Build Calcium and Childhood • necessary to grow a healthy skeleton to support a growing body • age 20 in men, 16 in women, bones stop growing in length and almost at peak bone mass • density of bones depends on calcium intake as children and teenagers • children who are active have 5-15% increase in bone growth • ages 20-30 consolidation with some increase • age 30 reach peak bone mass • more mass you have at peak - less likely to have at fracture Lecture 8 - Guest Lecturer • average of calcium consumption is a lot lower than where it should be *calcium in body needs to be steady and regulated within a fine line *if there isn’t enough Calcium, body will take it from bone!! Bone Mass Loss • after age 35, men and women begin to lose bone mass at about 0.5% to 1% per year • women: first 5-10 yrs after menopause, lose 2%-5% of their bone mass every year - as much as 45% over lifetime • men: typically experience accelerated bone loss after age of 65 and lose about 2/3 that of women Maintaining Bone Mass • need to maintain bone mass for healthy bones • Physical Activity, combined with adequate calcium and Vitamin D, plays important role Age related factors that cause Osteoporosis • inefficient bone remodeling -osteoclasts remove old bone faster than osteoblasts can rebuild • reduced Ca++ intake impaired Ca++ absorption • • poor Vitamin D status - decreased exposure, skin changes, decreased ability of kidneys to activate • hormonal changes - parathyroid, calcitonin and estrogen Lecture 8 - Guest Lecturer • many factors come together to affect bone mass! Vitamin D • 2 sources of Vitamin D -natural sunlight -fortification of dietary foods, particularly dairy products and some cereals • radiation that converts vitamin D in the skin is the same wavelength that causes sunburn; sunscreen can inhibit vitamin D production • after age of 70, skin does not convert vitamin D effectively • it is hydroxylated at liver to 25-hydroxyvitamin D, and in the kidney to 1,25-dihydroxyvitamin D (active form) • when you apply sunscreen to protect from skin cancer, you stop skin from absorbing vitamin D • Osteoporosis Canada Healthy limit = 75 nmol/L IOM = 50nmol/L • Lecture 8 - Guest Lecturer UV Radiation Exposure and Vitamin D Synthesis • affected by season, time of day, length of day, cloud cover, smog, skin melanin content and sunscreen • geographic latitude does not predict average serum 25(OH)D levels in a population • ample opportunities exist to form vitamin D and store it in the liver and fat from sunlight during the spring, summer, and fall even in the far north latitudes UV Radiation • complete cloud cover reduces UV energy by 50% shade (including pollution) reduces it by 60% • • UVB does not penetrate glass • sunscreens with SPF of 8 or more block vitamin D producing UV rays • however, skin likely synthesizes some vitamin D due to poor application and maintenance Sun Exposure • 5-30 minutes of sun exposure between 10am and 3pm at least twice a day to the face, arms, legs, or back without sunscreen usually leads to sufficient vitamin D synthesis • prudent to limit exposure to sunlight due to carcinogenic effect • 1.5 million skin cancers and 8,000 deaths to metastatic melanoma (US)/year Lecture 8 - Guest Lecturer • hazard ratio • enough vitamin D = risk goes down • 60 nmol/L = significantly lowers fractures -women with vitamin D supplementation during non-sunshine months reduce risk of fall Vitamin D: Optimal Levels • to most consistently improve clinical outcomes (ex. fracture risk), an optimal serum level of 25-hydroxyvitamin D is probably >75 nmol/L • for most Canadians, supplementation is needed to achieve this level 2010 Osteoporosis Canada Recommendations for Vitamin D • low-risk and younger adults: 10-25 μg (400-1000 IU) daily • high-risk and older adults: 20-50 μg (800-2000 IU) daily *for ind. being treated for OP, vitamin D status should be assessed by serum measurement of 25-hydroxyvitamin D after 3 months of vitamin D supplementation TO ENSURE LEVELS ARE AT/ABOVE 75nmol/L How to reach these recommendations? • 3 sources of vitamin D -diet -sun exposure -supplementation Foods with Vitamin D • salmon • sardines in oil • meat Lecture 8 - Guest Lecturer • eggs • liver milk • • butter/margarine *unlike calcium, few foods contain vitamin D in significant amounts -difficult to reach DRI intake via diet alone *steady state of
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