OSTHEOPOROSIS

Osteoporosis is an age related condition characterized by low bone mass, with microarchitectural deterioration of bone tissue leading to enhanced bone fragility and increased fracture risk affecting people over 50 years, 80% being women.

Bones are made of calcium hydroxyapatite (mineral) and collagen (protein). Bones undergo a continuous physiological process of remodeling where they are dissolved (bone resorption) and remineralised according to the demand of the mineral calcium by the body. This process of remodeling is kept in a balance to maintain bone strength. Osteoporosis occurs when bone resorption outpaces bone formation. The bone cell osteoclast is responsible for bone dissolution whereas osteoblast is for mineral deposition. Decreased or a lack of gonadal (sex) hormones (decreased estrogen in menopause) increase osteoclatic activity, vigor and lifespan of mature osteoclast with resultant increase in bone resorption (dissolution). Also, in aging, there is progressive decrease in the supply of osteoblast in proportion to physiological demand reducing mineral bone mass. Steroids also inhibit osteoblast function and enhance osteoblast apoptosis (death) predisposing to osteoporosis.

Osteomalacia is another bone condition where the bones are soft as a result of reduced mineral composition in relation to organic matter (collagen) content; non calcification of bone from either lack of vitamin D or renal tubular dysfunction; more common in women than in men, osteomalacia often occurs during pregnancy. In osteoporosis, the bones are porous and brittle whereas in osteomalacia, the bones are soft. The mineral-to-collagen ratio in osteoporosis is within the reference range, whereas the proportion of mineral content is reduced relative to collagen content in osteomalacia.

Peak bone mass occurs at 35-40 years of age. Good nutrition and activity (bone use) can increase bone mass and strength preventing osteoporosis. After this peak, there is a gradual bone loss. This loss is associated with declining estrogen levels and low calcium intake.

SIGNS AND SYPTOMS
• No early warning signs; fracture often is first sign (usually hip fracture)
• Gradual height loss due to silent vertebral crush fractures
• Dorsal kyphosis (hunch back)
• Chronic back pain
• Hip fracture and its sequel
• Breathing problems

RISK FACTORS (mnemonic=OSTEOPOROSIS)
lOw calcium intake
Seizure medication/diuretics
Thin built
Ethanol (alcohol) /caffeine intake
hypOgonadism (decreased sex hormones)/premature menopause
Previous fracture
thyrOid excess- increased bone dissolution
Race (common in whites, Asians)
Other relatives with osteoporosis
Steroids
Inactivity
Smoking

Menopausal women are especially at risk of osteoporosis. Have an X-ray taken and your DEXA (Dual Energy X-ray Absorptiometry) checked by your physician. The DEXA score provides the patient’s T-score which is the Bone Mass Density (BMD) value compared with that of control subjects who are at their peak BMD.

PREVENTION
Life style modification - Identifying risk factor and managing it appropriately.
Adopting Hormone Replacement Therapy (HRT). It is believed to be most appropriate to start estrogen at the earliest sign of the menopause, since bone loss probably begins before the cessation of menses. Estrogen therapy must be continued through later life to maintain optimal bone density.