osteoporosis

introduction

in Australia, lifetime risk of osteoporosis in those over 50yrs age is 42% for women and 27% for men.
affects 2 million Australians
20,000 hip fractures per year in Australia - increasing by 40% each decade
- about 25% die within 12 months
- 15-25% require long term care

risk factors

factors that allow MBS rebate for DEXA scanning in Australia

age > 70yrs
fractures in last ten years caused by minimal trauma
proven low bone density from previous DEXA or CT scan with a T score of -2.5 or less
prolonged corticosteroids Rx such as doses of oral prednisolone greater than 7.5mg per day for 4 months or more.
conditions with excess corticosteroids secretion
male hypogonadism / low testosterone in males
Turner syndrome
amenorrhoea lasting > 6 months before the age of 45 years
complete hysterectomy before the age of 45 years
primary hyperparathyroidism
chronic liver disease
chronic renal disease
proven fat / vit D malabsorption disorders - inflammatory bowel disease (IBD), coeliac
rheumatoid disorders
conditions associated with thyroxine excess - Graves, Hashimotos

other risk factors

postmenopause
FH / genetic factors
- elderly mice showed both reduced levels of Men1 and increased activity of senescence-related genes in osteoblasts ¹⁾
- mitochondrial aldehyde dehydrogenase ALDH2*2 E487K gene mutation (40% of Japanese) ²⁾
- genetic risk factors for schizophrenia also seem to increase risk of osteoporosis ³⁾
slight body build (BMI < 18)
previous low trauma fracture
smoking
high alcohol intake
lack of weight bearing exercise
inadequate sleep, skipping breakfast, and having late dinners according to a large 2025 Japanese study⁴⁾
other medications that cause bone loss:
- anticonvulsants
- loop diuretics ⇒ calciuresis
- long term heparin
- those that induce menopause such as gonadotrophin releasing hormone agonists (GnRH agonists)
- thyroxine in the elderly - a BMJ study in 2011 showed dose related fracture risk of 2.5-3.5x in those over 70yrs taking > 0.044mg/day thyroxine.
the GIT microbiome
- periodontitis may increase risk of osteoporosis via the GIT microbiome effects - mice receiving salivary microbiota from periodontitis patients developed significantly reduced bone mineral density and deteriorated trabecular architecture compared with controls and that this was mediated through the gut microbiome reduced tryptophan metabolism ⁵⁾

diagnosis

Dual energy Xray Absorptiometry Scan (DEXA scan)

used to confirm Dx of osteoporosis and estimates severity of bone loss
can be used to determine response to Rx
lower radiation dose compared to other methods
results are given a T scores which are statistical scores relating to population standard deviations of 20 yr olds:
- T score > -1.0 SD = normal
- T score between -1.0 and -2.5 SD = osteopaenia
- T score less than or equal to -2.5 SD = osteoporosis
- T score less than or equal to -2.5 SD with 1 or more fragility fractures = severe osteoporosis
Monash Med Centre - DEXA scan patient information sheet (pdf)

investigations of the cause

low calcium intake
vitamin D deficiency
oestrogen deficiency states
hyperthyroidism
5% of Caucasian adults with osteoporosis will have coeliac disease as the cause
in men, test for presence of hypogonadism and if present Rx with testosterone when necessary

treatment and prevention

antiresorptive drugs (AR) include:
- bisphosphonates
- osteoclast inhibitors such as denosumab

calcium intake and supplementation

see calcium

vitamin D supplementation for deficiency states

see vitamin D
apparently no short term (5yr) benefit on reducing fractures by taking vit D supplements in those over 50yrs without risk factors ⁶⁾
a 2026 meta-analysis study including 69 trials involving 153,902 participants suggests no benefit for calcium, vitamin D or combined supplementation reduces fracture rates ⁷⁾

daily tea or coffee intake in moderation

studies suggest that daily drinking coffee or tea reduces risk of osteoporosis by about 17-25% with tea seeming to have the greater benefit however excessive coffee at over 5 cups a day increased osteoporosis risk ⁸⁾
the effect may be due to catechins while caffeine theoretically can interfere with calcium absorption and bone metabolism although this effect appears to be minimal and further reduced by drinking it with milk

bisphosphonates

bisphosphonates can reduce progression of osteoporosis by inhibiting the resorption of bone and has been shown to reduce fractures in the following 10yrs after infrequent dosing in post-menopausal women
regarded as 1st line Rx used in conjunction with calcium and vitamin D supplementation.
C/I include oesophageal diseases and the impairments to bone healing mean dental work should be done prior to dosing
see bisphosphonates

raloxifene

may be useful, particularly in women < 60yrs age (esp. in those concerned of breast cancer risk with hrt) or where bisphosphonates can't be used.
has similar risk of DVT as for HRT but does not relieve symptoms of menopause
only subsidised for post-menopausal women with PH osteoporotic fracture
C/I in men, premenopausal women, pregnancy and those with PH DVT

calcitriol

active form of vitamin D can be used as a 3rd line Rx for osteoporosis although evidence for its efficacy is less robust and it requires adequate calcium intake and risks hypercalcaemia, thus requires monitoring of serum calcium levels.
only subsidised for post-menopausal women with PH osteoporotic fracture

parathyroid hormone analogues

Although parathyroid hormone (PTH) increases the release of calcium from bone, intermittent use stimulates osteoblasts more than osteoclasts. By mimicking this effect of parathyroid hormone, teriparatide, an amino acid sequence similar to parathyroid hormone (PTH) aims to stimulate bone formation in patients with osteoporosis.
- Aust Presc 2004
listed on PBS in 2009 for Rx of severe established osteoporosis (BMD T-score of -3.0 or less) in those at very high risk of fracture, who develop symptomatic fracture(s) despite at least 12 months of continuous antiresorptive Rx. Requires initialisation by a specialist (Auth. req.)
Rx duration limited to 18 months as risk of osteosarcoma, and thus Rx requires informed consent.
daily sc injection

oestrogen replacement therapy (HRT or ERT)

may be considered for postmenopausal women who are considered at low risk for cardiovascular disease or breast cancer

osteoclast inhibitors

denosumab (Prolia)
- humanised monoclonal antibody which binds RANKL blocking the interaction with its receptor on the surface of osteoclasts which then inhibits development and activity of osteoclasts, leading to decreased bone resorption and increased bone density
- studies suggest it reduced vertebral fractures, #NOF by around 50% compared with placebo incidence, but appears to cause more eczema, cellulitis, myalgias, arthralgias, bone pains, urinary issues, alopecia, flatulence and perhaps a risk of immunocompromise with mildly higher rates of infections (URTI, diverticulitis) and malignancies
- may cause hypocalcaemia
- 1 in 1000 develop medication-related osteonecrosis of the jaw (MRONJ) (1 in 200 if > 10yrs Rx) and it can also occur after stopping treatment.
  - incidence of MRONJ was 0.3% in low-dose and 9.0% in high-dose AR recipients in a Finnish population study⁹⁾
    - risk is 5 times higher in both low-dose and high-dose AR recipients compared to bisphosphonates users
    - risk doubles further if are also taking steroids and on high dose AR (steroids increase risk 6x if on low dose AR)
    - risk is higher in males and those with a cancer diagnosis
- may cause lichenoid drug eruptions in the mouth
- some people have developed unusual fractures in their thigh bone
- introduced in Aust in 2010, long acting s/c injection usual dose 60mg once per six months

Bone Densitometry Unit

Level 4 - Western Centre For Health Research and Education Sunshine Hospital
To make a booking please fax your referrals to 03 8395 8258 or call 03 8395 8246/8119.
The unit is open for scanning on Tuesday and Wednesday between 9:00am-5:00pm.