Osteoporosis is a disease related to bones and joints that, over time, causes bones to weaken and makes them susceptible to sudden and unexpected fractures.Osteoporosis is a disease related to bones and joints that, over time, causes bones to weaken and makes them susceptible to sudden and unexpected fractures.Osteoporosis is a disease related to bones and joints that, over time, causes bones to weaken and makes them susceptible to sudden and unexpected fractures.