Conteúdo e densidade mineral óssea de adolescentes do sexo feminino. DOI: 10.5007/1980-0037.2011v13n5p354

Abstract

-The aim of the present study was to characterize bone mineral density (BMD) and content (BMC) in Brazilian adolescent girls according to age and pubertal stage. A total of 329 girls ranging in age from 10 to 20 years participated in this study. Body weight, height, body mass index, pubertal stage, race, daily calcium intake, and time spent per week performing moderate-to vigorous-intensity physical activity (MVPA) were evaluated. Lumbar spine and femoral neck BMD and BMC were assessed by dual-energy x-ray absorptiometry. One-way ANOVA with Tukey post-hoc test was used to identify differences in bone mass between ages and pubertal stages (p≤0.05). The daily calcium intake reported by the adolescents was inadequate, corresponding to only 26-47% of the recommended allowance (1,300 mg/day). On the other hand, weekly MVPA was higher than that recommended for adolescents. Significant differences in BMD and BMC were observed for girls aged 10-14 years. In addition, lumbar spine and femoral neck BMD was 58 and 31% higher in postpubertal girls, respectively, when compared to prepubertal adolescents. Key words: Bone mineral density; Bone mineral content; Adolescents; Puberty. Resumo -O presente estudo teve como objetivo caracterizar o conteúdo mineral ósseo (CMO) e a densidade mineral óssea (DMO) de adolescentes do sexo feminino de acordo com a faixa etária e o estágio de maturação sexual. A amostra desse estudo foi composta por 329 meninas com idades entre 10 e 20 anos. Foram avaliados o peso corporal, estatura, índice de massa corporal, estágio de maturação sexual, a raça, o consumo diário de cálcio e o tempo dispendido em atividades físicas de intensidades moderada a vigorosa por semana (AFMV

Factors associated with bone mineral density in adults: a cross-sectional population-based study

“…Bone loss in both genders is a consequence of the deleterious effects of aging, because the balance between bone formation and absorption changes and BMD progressively decreases as age increases. There is a peak in bone mass and accumulation of bone tissue up to 30 years, such that men accumulate 25% more BMD than women (22) , which contributes to delaying the loss of BMD in men. Then there is a gradual decline which intensifies after menopause for women due to a decrease in estrogen, while it occurs for men after 70 years when there is also a decrease in testosterone levels, which delays the consequences of loss of BMD, such as fractures (for example) in relation to women (8) .…”

“…Thus, bone metabolism during adulthood should remain balanced, as this will contribute to good bone health and will lower the risk of bone loss as one ages. Therefore, bone loss is also related to hormonal issues, with sex hormones being one of the main biological agents regulating bone health and responsible for maturation and sexual dimorphism of the skeleton (22) . However, no differences were observed among women who use or do not use hormone replacement therapy in our study, since less than 5% used it because it is a younger population, and it is known that hormone replacement has been used as a prevention for the decline of bone health during menopause in an attempt to delay the deleterious effects of bone health in women during this period (12) .…”

Densidade mineral óssea associada a características físicas e estilo de vida em adolescentes

“…However, only age was an explanation factor for the femoral neck bone BMD. In a previous study 14 , BMD of adolescents was compared concerning age and sexual maturation and significant increase of BMD between 10 and 14 years of age and sexual maturation stages (classified as pre--puberty, puberty and post-puberty) was observed. This fact was also observed in adolescents from other countries 1,2,7 .…”

“…In Brazil, there are still few studies which present relevant data about these factors related to physical traits or lifestyle and BMD of female adolescents [12][13][14] . Moreover, no study which considers phenotype characteristics of race and/or skin color and BMD in the Brazilian population has been found.…”

Osteometabolic profile and bone mass in the transition phase: ethnic differences in Brazilians treated with somatropin during childhood

“… 16 , 17 The originality of ours is to compare the ethnic differences related to osteo metabolic profile and bone mass assessed by DXA in Brazilian adolescents who used rhGH, since, in Brazil, most research were carried out in healthy teenagers through ultra sonometry. 18 , 19 , 20 …”