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世界博览

浙江省缙云中学　应中革　编译

资料来源：约翰斯. 霍普金斯大学的布卢姆堡公共卫生学校

发表时间：3002－12－22

网站地址：www.sciencedaily.com/

未成年女子早孕可导致骨质疏松症

美国每年有超过100万的十几岁的女孩早孕，其中一半即50万竟然生下孩子。这些怀孕的小女孩面临来自社会和经济上的急待解决的问题，例如亲子关系问题和显著的营养需求。

约翰斯. 霍普金斯的布卢姆堡公共卫生学校的人类营养中心合作的最新研究是首次对十几岁女孩早孕影响钙吸收的调查。本次研究对美国马里兰州巴尔的摩市的一组13－18岁的女孩的调查表明，三分之一的之些小妈妈患骨质病，符合骨质疏松症或可导致骨质疏松的骨膜炎。这项研究成果在2003年12月发表在美国期刊《临床营养》上。

该研究调查主任医学博士Kimberly O'Brien说“青少年发育骨质的渠道狭小，时机难得，怀孕的额外需求意味着妈妈和胎儿在竞争钙质。我们的研究表明，青春期女孩怀孕危及获取最佳骨质生长能力，而且她损失的钙可能比普遍公认的补偿骨质损耗还要高。”这位博士是该校人类营养中心和世界卫生部的副教授。他专门从事日益增长的营养需要的人群的矿物代谢研究。他运用稳定同位数技术对三个月与产前早期怀孕少女钙吸收率进行了比较。钙吸收率是怀孕三个月的两倍。这是成年妇女的数据。然而，与成年妇女不同的是，青春期的小妈妈必须自然增加们自身骨质的40%钙量。

小妇孕期消耗更多钙的事实说明产前骨质损失少，低钙吸收和平均吸收者骨质损失大。该研究组的相关研究表明低钙吸收还限制了少年孕妇腹中的胎儿的骨架生长。调查人员还声称需要进行更多的研究来确定未成年人早孕和喂乳对她们自己达到骨质发育高峰能力的长期影响。

O'Brien博士指出，“通过对怀孕的青少年钙量吸收率和骨质更新测定，本研究迈出了关键的第一步，确保小女子获得适量的钙，防止和减少损失，摆脱长的影响骨质生长的危害。”

原文＞＞＞

Teenage Pregnancy May Put Girls At Risk For Osteoporosis

More than one million teenage girls become pregnant each year in the United States, and one-half million of these pregnancies result in live births. In addition to the socio-economic challenges that often accompany early parenthood, pregnant teens face dramatic nutritional demands.

A recent study by researchers with the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health was the first to examine the impact of early childbearing on calcium absorption in teens. The study, conducted with a group of teenagers ages 13 to 18 in Baltimore, Md., showed that one-third of these young mothers had a bone mass that meets the definitions of osteoporosis or osteopenia (the precursor condition to osteoporosis) shortly after pregnancy. The study results appear in the December 2003, issue of the American Journal of Clinical Nutrition.

"Adolescents have a narrow window of opportunity to build bone mass and the added demands of pregnancy mean that a mother and her fetus have to compete for calcium," explained Kimberly O'Brien, PhD, principal investigator for the study. "Our study showed that adolescent pregnancy may compromise a girl's ability to reach optimal bone growth and that she may need to consume more calcium than is currently recommended to offset bone loss," added Dr. O'Brien, who is an associate professor with the School's Center for Human Nutrition and Department of International Health.

Dr. O'Brien, who specializes in the study of mineral metabolism in populations with increased nutritional needs, used stable isotope technology to compare rates of calcium absorption during the girls' third trimester of pregnancy and the early post-partum period. Calcium absorption more than doubled in the third trimester, which is comparable to the existing data for pregnant adults. Unlike adult women, however, girls must accrue forty percent of their total bone mass during adolescence.

Girls who consumed more calcium during pregnancy showed less bone loss when tested post-partum than those with poor or average calcium intakes. A related study by this research group also found that a low calcium intake limits fetal bone growth in pregnant teens. Investigators say that more studies are needed to determine the long-term impact of early pregnancy and breastfeeding on a girl's ability to reach peak bone mass. "By characterizing the rates of calcium absorption and bone turnover in adolescent pregnancy, this study was a critical first step towards new recommendations to insure that girls get adequate calcium to prevent or minimize losses and avert any detrimental, long-term effects on bone growth," said Dr. O'Brien.