Which type is most common osteoporosis in postmenopausal women?

• A. Type II
• B. Tertiary
• C. Type I/Primary
• D. Secondary

Answer: (C)

Primary osteoporosis, occurring after menopause, is the form most commonly seen in postmenopausal women. The key driver is estrogen deficiency, which removes a brake on osteoclasts and accelerates bone resorption, especially in trabecular bone like the vertebrae and the distal forearm. This leads to rapid bone loss and common vertebral fractures even with minimal trauma.

In contrast, senile (age-related) osteoporosis—the other major category—occurs later in life and affects both cortical and trabecular bone, often in both men and women, not specifically tied to menopause. Secondary osteoporosis results from other medical conditions or medications and is not the typical pattern linked to postmenopausal bone loss.