指代谁？

To gain a true understanding of any topic within the healthcare field, it is important to examine its past, present trends, and future directions. As a whole, an estimated 100 million American adults live with chronic pain [4]. This figure is likely an underestimate, as it does not include acute or pediatric pain. However, even at this underestimated rate, chronic pain is more common than the total estimated number of adults suffering from diabetes, coronary heart disease, and cancer combined [4–8]. Because the scope of chronic pain is so boundless, multiple studies have been conducted in attempt to narrow the focus to the most prominent conditions within this category. The National Institutes of Health conducted a study in which adults, 18 years old and over, were interviewed and asked a series of questions regarding pain during the 3 months prior to their interview. Their attention was directed to four different types of pain, and they were instructed to report any pain that lasted 24 h or more, excluding minor aches. Low back pain was the most commonly reported type of pain in each age group, involving 27% of respondents [9]. This was followed by severe headache or migraine (15%), neck pain (15%), and facial pain (4%).Similarly, the Institute of Medicine reports that low back pain is the most common type of pain reported in US adults at a rate of 28.1% of respondents, followed by migraine (16.1%) and neck pain (15.1%) [4]. Correspondingly, data published from the 2002 National Health Interview Survey (NHIS) demonstrated that low back pain was reported by 26.4% of adults and neck pain by 13.8% [10]. These surveys each demonstrate complementary data supporting the notion that spine pain plays a major role in the vast field of chronic pain and, therefore, our field of healthcare as well.

要真正理解医疗保健领域的任何问题，必须审视它的过去、当前趋势和未来方向。总体而言，约有1亿美国成人有慢性疼痛^[4]，该数值可能被低估，因为其不包括急性或儿科疼痛。然而，即使这个低估的数值，慢性疼痛也比成人糖尿病、冠心病和癌症患者加起来的估计总人数更高^[4-8]。由于慢性疼痛的范围太广，许多研究试图将重点缩小到这一类中最突出的疾病。美国国立卫生研究院进行了一项研究，采访了≥18岁的成年人。并在采访前3个月询问了一系列关于疼痛的问题。他们的注意力被引导向四种不同类型的疼痛上，并指示他们报告任何持续≥24小时的疼痛，但不包括轻微疼痛。腰痛是每个年龄组中最常见的疼痛类型，涉及27%的受访者^[9]。其次是严重头痛或偏头痛（15%）、颈部疼痛（15%）和面部疼痛（4%）。同样，美国国家医学研究所报告称，在美国成年人中，腰痛比例28.1%，是最常见的疼痛类型，其次是偏头痛（16.1%）和颈部疼痛（15.1%）^[4]。相应地，2002年美国国民健康访谈调查（National Health Interview Survey，NHIS）公布的数据显示，26.4%的成年人有腰痛，13.8%有颈部疼痛^[10]。这些调查数据互相证实脊柱疼痛在慢性疼痛也在我们的医疗保健领域中扮演着主要角色。

Their 我认为指代美国国立卫生研究院，they指代采访的≥18岁的成年人，不知道对不对？谢谢