Observations on the incidence, aetiology, and pathology of senile osteoporosis

Abstract

SYNOPSIS Using previously described methods, lumbar vertebral body slabs were investigated radiologically and histologically from 300 unselected cases coming to necropsy. Calcium estimations were also made on the bones of the first 150 cases. High calcium values were mostly encountered in young adults and the calcium values tended to diminish with age, but a wide range of calcium values was still encountered in older subjects. Radiographic density of bone and calcium content tended to be higher in male than in female bone at all ages. The study showed that in subjects aged 50 years or more bone was osteoporotic in 22 5 % of males and in 23-1 % of females. This is a higher incidence than has been previously reported, and is the first accurate study to show equality of incidence in the two sexes. Although in the relationship between radiographic density and age there was a highly significant overall regression effect, no significant difference was demonstrated between the separate sexes. There was, however, an accelerated falling away in the bone density readings in the fifth and sixth decades which was more pronounced in females. This drop is considered to be connected more with oestrogen deficiency than with deficiency of dietary calcium. Vertebral biconcavity was measured in all cases but was found to be an unreliable sign of osteoporosis.Osteoporosis, which may be defined as a reduction of calcified bone mass per unit volume of anatomical bone, the remaining bone apparently being normally calcified, occurs in a number of different forms. The commonest variety, called senile osteoporosis, affects women over 45 and men over 55 years of age (Ball, 1960) in the absence of obvious aetiological factors such as Cushing's syndrome or hyperthyroidism.It seems to be generally agreed that in this type of osteoporosis the spine is affected earliest and most severely, followed by the pelvis, then the peripheral limb bones, and occasionally even the skull bones. Assessment during life is difficult, and is usually made by clinical radiography of the spine which has inherent inaccuracies, not the least of which is, that before diagnosis is possible the vertebral bodies must already have lost about 50% of their bone mass (Fusi, 1953). Although a useful assessment may be made during life by histological examination of bone biopsy material (Beck and Nordin, 1960), only a limited field can be studied, and this is a disadvantage, because as will be shown, osteoporosis does not lPresent address: Department of Pathology, Princess Alexandra Hospital, Brisbane, Queensland, Australia. Received for publication 27 April 1962. always occur uniformly even within the same bone.Authorities agree that senile osteoporosis is a more common condition than is generally suspected, but fairly wide differences of incidence and sex distribution continue to be described. Cooke (1955) reviewed over 800 reported cases and found that females predominated over males in the ratio of 6: 1. Lawrence (quoted by Ball, 1960) from a clinical radiographic su...

Age-related changes in trabecular bone microstructures: global and local morphometry

“…Where earlier, osteoporosis was defined as an absolute decrease in the amount of bone [1][2][3] to a level below that required for mechanical support [4], later definitions added the importance of microarchitecture [5,6] and bone quality [7], a term referring to architecture, turnover, damage accumulation, and mineralization. With the changed definition of osteoporosis, the focus of investigation also changed over the years.…”

“…With the changed definition of osteoporosis, the focus of investigation also changed over the years. Most early studies in age-related bone changes concentrated in the description of the amount of bone volume [1][2][3][8][9][10][11][12][13][14][15][16][17], and only few investigated structural parameters such as bone surface density (BS/TV) [11,14,15], trabecular number (Tb.N) [14,18], trabecular thickness (Tb.Th) [12,14], or trabecular spacing (Tb.Sp) [12]. This was based on the intuitive idea that the mechanical properties of trabecular bone depend strongly on its apparent density or bone volume [19,20], and it became an indisputable fact that bone is lost in aging people.…”

Effect of sex hormones on bone in primary osteoporosis

“…Some authors have suggested that the association of osteoporosis with the menopause is largely fortuitous because autopsy studies have conclusively demonstrated that maximal bone mass is attained between ages 20 and 40 yr in both sexes, and then there is a progressive bone atrophy which begins premenopausally in women and correlates linearly with age (18)(19)(20). Clinical and in vivo densitometric studies have given conflicting results, some showing (21,22) and others failing to show (23)(24)(25) an effect of the menopause independent of age.…”

Osteomalacia and osteoporosis

“…All these studies show a loss of bone with age which starts earlier and is more rapid in women than men (Meema, 1962;Garn, Rhohman & Nolan, 1964;Nordin, McGregor & Smith, 1966;Smith & Rizek, 1966;Morgan et al, 1967b (Caldwell, 1962;Virtama, Gastrin & Telkka, 1962). Attempts to detect lesser degrees of biconcavity have failed or have been abandoned because of lack of precision (Smith & Rizek, 1966).…”