Schneider D L, Barrett-Connor E L
University of California, San Diego, La Jolla, USA.
Arch Intern Med. 1997 Jun 9;157(11):1241-5.
The level of urinary, type I collagen, crosslinked N-telopeptides (NTX) is a new marker of bone resorption. To our knowledge, no population-based studies of older adults have determined whether this measure can identify individuals with osteoporosis.
To measure the levels of NTX in a cross-sectional study of ambulatory, older, white adults and to evaluate whether this measure of bone resorption could identify individuals with osteoporosis.
The subjects, aged 50 to 98 years, formed 3 groups: 374 men, 223 women currently using estrogen, and 364 women not currently using estrogen. A standard medical history and validated record of medication use were obtained. Height and weight were measured. Bone mineral density (BMD) was measured at the hip and lumbar spine using dual energy x-ray absorptiometry. The levels of NTX were measured by enzyme-linked immunosorbent assay.
Overall, the levels of NTX increased slightly with age in men and in estrogen users and more dramatically in nonestrogen users. In a model adjusted for all major risk factors for osteoporosis, there was a significant decrease in BMD levels by increasing quintiles of NTX levels at the hip and spine in women with and without estrogen use and at the hip in men. Using sex-specific, peak bone mass criteria and age-adjusted analyses, the levels of NTX discriminated between normal (< or = -1.0 SD), osteopenic (> -1.0 and < -2.5 SD), and osteoporotic (> or = -2.5 SD) BMD levels in all groups except the spine in men.
The levels of NTX uniquely discriminated between older adults with normal, osteopenic, or osteoporotic BMD levels. If confirmed, these data suggest that NTX levels could be used to predict current osteoporosis in older men and women.
尿中 I 型胶原蛋白交联 N-末端肽（NTX）水平是骨吸收的一种新标志物。据我们所知，尚无基于人群的老年人研究确定该指标能否识别骨质疏松个体。
在一项针对能自由活动的老年白人成年人的横断面研究中测量 NTX 水平，并评估这种骨吸收指标能否识别骨质疏松个体。
研究对象年龄在 50 至 98 岁之间，分为 3 组：374 名男性、223 名目前正在使用雌激素的女性以及 364 名目前未使用雌激素的女性。获取了标准病史和经过验证的用药记录。测量了身高和体重。使用双能 X 线吸收法测量髋部和腰椎的骨密度（BMD）。通过酶联免疫吸附测定法测量 NTX 水平。
总体而言，男性和使用雌激素者的 NTX 水平随年龄略有升高，而未使用雌激素者升高更为显著。在针对所有主要骨质疏松风险因素进行校正的模型中，无论是否使用雌激素，女性髋部和脊柱以及男性髋部的 BMD 水平均随着 NTX 水平五分位数的增加而显著降低。采用性别特异性的峰值骨量标准和年龄校正分析，除男性脊柱外，NTX 水平在所有组中均能区分正常（≤ -1.0 SD）、骨量减少（> -1.0 且 < -2.5 SD）和骨质疏松（≥ -2.5 SD）的 BMD 水平。
NTX 水平能够独特地区分 BMD 水平正常、骨量减少或骨质疏松的老年人。如果得到证实，这些数据表明 NTX 水平可用于预测老年男性和女性当前的骨质疏松情况。
