<Tr> <Td> Osteoporosis </Td> <Td> T - score ≤ − 2.5 </Td> <Td> 0.6% </Td> </Tr> <Tr> <Td> Severe osteoporosis </Td> <Td> T - score ≤ − 2.5 with fragility fracture </Td> <Td> </Td> </Tr> <P> The International Society for Clinical Densitometry takes the position that a diagnosis of osteoporosis in men under 50 years of age should not be made on the basis of densitometric criteria alone . It also states, for premenopausal women, Z - scores (comparison with age group rather than peak bone mass) rather than T - scores should be used, and the diagnosis of osteoporosis in such women also should not be made on the basis of densitometric criteria alone . </P> <P> Chemical biomarkers are a useful tool in detecting bone degradation . The enzyme cathepsin K breaks down type - I collagen protein, an important constituent in bones . Prepared antibodies can recognize the resulting fragment, called a neoepitope, as a way to diagnose osteoporosis . Increased urinary excretion of C - telopeptides, a type - I collagen breakdown product, also serves as a biomarker for osteoporosis . </P>

Which of the following is a risk factor for developing osteoporosis