Bone mineral density in children and adolescents. Literature review

Abstract

Osteoporosis is a skeletal disease characterized by low bone mass and is nowadays a serious public health problem worldwide due to the high prevalence and its health costs, such is the case in Colombia where the costs associated with having a hip fracture are estimated at $ 6,500 per person. The risk of fractures is high and increases with age, it is estimated that the probability of a hip fracture in white women over 50 years old is 14% and 6% in black women, being the race an important factor for determining the possibility of fractures. It is essential to know that one in five hip fracture patients die between years after the event. A very good measure to prevent the onset of osteoporosis is physical activity it has a positive osteogenic effect, so it turns to be a protective factor for this disease due to increased peak bone mass and the reduction of falls (one major cause of fractures). There have been numerous investigations and reviews on the subject which directly and positively correlates the effect of exercise in bone mineral density (amount of bone per unit area) at all ages. However, some research suggests that are the high-impact physical activities which generate the mayor gains in bone mass, for example in England 724 adolescents who practiced physical exercise were classified according to the level of impact of the physical activity. Physical activity is ranked in level 1, 2, 3, 4 and 5 after the gravity forces that are generated during its practice, such activities are walking, brisk walking, jogging, jogging faster than 10 K/h and jump respectively and concluded that those physical activities with a level above 3 were positively associated with bone mineral density of the femoral neck. With respect to the age for obtaining higher bone gains it seems that childhood and adolescence are periods very sensitive and important in life to achieve greater gains in bone compared to adulthood and older ages. It seems even more important to practice physical activity according to Tanner stages because it can be a very reliable indicator when it comes to obtain more bone, according to research, exercise during steps 2 and 3 produces the most gains in bone mass. Exercise can be then considered as an effective tool to reduce the chances of osteoporosis in older ages. However, some questions arise: Is any kind of physical activity more effective than the others in generating a positive response in the bone?, ¿Are there evidence of positive effects of exercise for all ages ?, ¿Is there an ideal age for expect greater physical activity benefits ?, ¿How important are the child and adolescent periods to achieve higher bone density gains ?