under recognized怎么理解？

Use of corticosteroids has been associated with multiple complications including obesity, insulin resistance, diabetes, and osteoporosis [44]. While the effects from systemic use are known to most physicians, the degree of these effects following epidural injections has been somewhat controversial. The relative low dose and infrequent occurrence of injections have been anecdotally cited as a reason for less concern. Improved awareness and increased surveillance have led to a conclusion that the systemic effects of injections have been under recognized [45].One study followed glucose and cortisol levels after epidural or shoulder intra-articular injections over a 3-week period and concluded that at 21 days following injection, diabetic patients continued to have a significant drop in cortisol levels following an epidural steroid injection [46].Another study has found transient increases in systolic blood pressure following epidural steroid injections [47]. A relationship between decreased bone mineral density and frequent epidural steroid injections in postmenopausal women has been described following a retrospective analysis [48]. Ultimately, a therapy and its frequency should be tailored to patient based on clinical necessity and underlying comorbidities.

使用糖皮质激素与多种并发症相关，包括肥胖、胰岛素抵抗、糖尿病及骨质疏松[44]。虽然大多数医师都知道激素对人体的影响，但硬膜外注射激素效应程度一直存在争议。相对低剂量和低频率注射传闻是不太担心硬膜外激素注射会导致并发症的原因。临床上，提高认识和加强监测得出的结论是，注射后全身性影响已得到公认[45]。一项研究对硬膜外或肩关节内激素注射治疗后的葡萄糖和皮质醇水平进行了3周多的跟踪，得出结论：在注射后21天，在硬膜外注射类固醇后糖尿病患者的皮质醇水平显著下降[46]。另一项研究发现，硬膜外类固醇注射后，收缩压会短暂升高[47]。在一项回顾性分析中描述了绝经后妇女骨密度下降与频繁硬膜外类固醇注射间的关系[48]。因此，应根据患者个人的临床需要和基础的伴发症来选择治疗入路和治疗频率。

under recognized怎么理解？是“已得到公认”还是“认识不足”

over a 3-week period 是 3周“多”还是“经过”3周，如果是“ 3周“多””为啥是21天做检查？