Primary Osteoporosis

Primary Osteoporosis

Primary osteoporosis occurs as a result of normal physiological process of ageing. The two most important categories of primary osteoporosis are post-menopausal and senile. Secondary osteoporosis occurs due to a disease or intake of certain drugs.

Senile ( or old age osteoporosis): Senile osteoporosis is primarily due to age-related decrease in the function of osteoblasts (bone forming cells) together with secondary hyperparathyroidism ( increase in function of parathyroid glands). Parathyroid glands, located in the neck region, secrete a hormone called ‘parathormone’, which is one of the factors responsible for maintaining calcium balance in the body. Calcium deficiency could also be due to decreased absorption of calcium from the intestines. There is substantial evidence that many factors associated with calcium metabolism change during the course of normal ageing. With advancing age, intestines absorb lesser calcium from the diet. As a result more and more calcium is drained from the bones, consequently depleting calcium stores of the bones. The relative importance of these factors may vary from one population to the other, depending on level of sunlight, dietary calcium intake, Vitamin D intake, nutritional fortification of food, exercise, smoking and genetic factors.

The process of reduction in bone mass begins at about 35 years of age and continues well into old age, common to both sexes. These losses are substantial. By 90 years of age, Bone Mineral Density (BMD) of the hip region falls by an estimated 58 per cent in women and 39 per cent in men. As age-related bone loss progresses, an increasing number of elderly men and women will have a bone density below the ‘Fracture threshold’. Those with the lowest BMD values will have the greatest risk of fractures. 
Senile osteoporosis is typically seen in men and women 75 years of age or older, resulting principally in hip and spinal fractures.

Post – menopausal osteoporosis: Osteoporosis affects approximately one-third of women over age of 50 years. It is the classic form of the disease. It typically affects women within 15 to 20 years after menopause. Although all post-menopausal women are estrogen-deficient., osteoporosis develops only in 10 to 20 per cent of them. it is characterized by fractures that occur at spine, wrist and ankles. Bone density decreases by about 2-3 per cent per year in the lumbar spine (lower back) following menopause. The primary change in glandular function that occurs in the menopausal period is loss of secretion of estrogen and progesterone hormones from the ovaries. These changes are gradual, beginning well before the overt cessation of bleeding that we call menopause. Oestrogen facilitates uptake of calcium by the bone loss than bone formation, thus gradually producing a permanent reduction in bone mass that cannot be reversed easily. Post-menopausal loss declines with time, and most of the bone mass is lost during the first 4 to 8 years after menopause.