《内科医学档案》：久坐使人“老”上10年

梅进

此研究将在衰老研究领域激起更多争论，引发更多研究

图片说明：经常不运动会加速老化。

（图片来源：GETTY）

生物谷报道：英国科学家近日研究发现，从生物学意义上来说，经常久坐的人要比常常运动的人“老”上10年。相关论文发表在1月28日的《内科医学档案》（Archives of Internal Medicine）上。

领导此次研究的是伦敦圣·托马斯医院双胞胎研究小组的Tim Spector。研究人员查访了2401个双胞胎的运动水平，并评估了他们端粒的长度。端粒长度随人寿命的增高而缩短，可作为老化的标记。研究人员发现，平均来说，最活跃组（一周锻炼超过3小时20分钟）的端粒要比最不活跃组（一周锻炼少于16分钟）的端粒长出200个核苷。研究人员认为，“这种差别意味着从生物学来说，不活跃的人要比活跃的人老上10年。”

研究小组目前对于活动水平能否直接影响端粒长度并不确定。不过，研究人员认为这是最可能的一种解释，同时他们还考虑了吸烟、肥胖、社会地位及其它可能的混淆因素的影响，修正了统计结果。

研究人员同时也考虑了不活跃影响端粒长度的几种方式。比如，已知细胞更新越快，端粒缩短速度越快，所以不活跃的人可能具有较高的细胞更新速度；另一种可能的解释来自氧化应激（oxidative stress），它会产生更多的氧原子和氧分子来压迫细胞。Spector说，“很可能我们需要锻炼以降低氧化应激。”

在同一期的《内科医学档案》中，美国国立衰老研究所流行病学和人口统计学部主任Jack Guralnick就此次研究发表的社论认为，还需要更多的工作以确定运动和端粒长度之间是否存在因果联系。

他说：“这是一个引人关注的发现，统计学显示的结果相当清楚。但是其它一些疾病因素并没有考虑进修正结果，它们有可能导致了这种联系。而在这类研究中要证明因果联系几乎是不可能的。”

Spector承认，他的这项研究将会在衰老研究领域激起更多的争论。不过有科学家表示，不论此次的结果将来能否得到证明，都会在该领域引发更多的研究。（科学网梅进/编译）

（《内科医学档案》（Archives of Internal Medicine），2008;168(2):154-158，Lynn F. Cherkas，Tim D. Spector）

生物谷推荐原始出处：

Archives of Internal Medicine, Vol. 168 No. 2, January 28, 2008

The Association Between Physical Activity in Leisure Time and Leukocyte Telomere Length

Lynn F. Cherkas, PhD; Janice L. Hunkin, BSc; Bernet S. Kato, PhD; J. Brent Richards, MD; Jeffrey P. Gardner, PhD; Gabriela L. Surdulescu, MSc; Masayuki Kimura, MD, PhD; Xiaobin Lu, MD; Tim D. Spector, MD, FRCP; Abraham Aviv, MD

Arch Intern Med. 2008;168(2):154-158.

Background Physical inactivity is an important risk factor for many aging-related diseases. Leukocyte telomere dynamics (telomere length and age-dependent attrition rate) are ostensibly a biological indicator of human aging. We therefore tested the hypothesis that physical activity level in leisure time (over the past 12 months) is associated with leukocyte telomere length (LTL) in normal healthy volunteers.

Methods We studied 2401 white twin volunteers, comprising 2152 women and 249 men, with questionnaires on physical activity level, smoking status, and socioeconomic status. Leukocyte telomere length was derived from the mean terminal restriction fragment length and adjusted for age and other potential confounders.

Results Leukocyte telomere length was positively associated with increasing physical activity level in leisure time (P < .001); this association remained significant after adjustment for age, sex, body mass index, smoking, socioeconomic status, and physical activity at work. The LTLs of the most active subjects were 200 nucleotides longer than those of the least active subjects (7.1 and 6.9 kilobases, respectively; P = .006). This finding was confirmed in a small group of twin pairs discordant for physical activity level (on average, the LTL of more active twins was 88 nucleotides longer than that of less active twins; P = .03).

Conclusions A sedentary lifestyle (in addition to smoking, high body mass index, and low socioeconomic status) has an effect on LTL and may accelerate the aging process. This provides a powerful message that could be used by clinicians to promote the potentially antiaging effect of regular exercise.

Author Affiliations: Twin Research and Genetic Epidemiology Unit, King's College London, St Thomas' Hospital Campus, London, England (Drs Cherkas, Kato, Richards, and Spector and Mss Hunkin and Surdulescu); and The Center of Human Development and Aging, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark (Drs Gardner, Kimura, Lu, and Aviv).

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