<s>[INST] Why is osteoporosis related to age? [/INST] It is known that ageing leads to a progressive loss of bone mass. This loss usually begins at around 45–50 years and in the case of women it is more notable during the menopause, a period in which there is a marked decrease in oestrogen levels.  Source: Clinic Barcelona. Link: https://www.clinicbarcelona.org/en/assistance/diseases/osteoporosis/frequently-asked-questions. Field: Rheumatology. Disease: Ostoeporosis </s>