芝加哥 – 据7月17日发表在《美国医学会杂志》上的一则研究披露，一则对过去30年来在美国招募并被随访的成年人的研究中，这些成年人从成年就开始出现的整体及腹部的肥胖其持续时间的增加与较高的冠状动脉钙化率——这是冠心病的一个亚临床预测因子——相关。
根据文章的背景资料：“亚临床动脉粥样硬化——这可通过存在冠状动脉钙化（CAC）而确认——会随着时间的推移而进展，且它可以预测冠心病事件的发生。”整体及腹部肥胖的程度——分别反映为身体质量指数（BMI）及腰围的增加——是CAC存在及进展的重要的风险因子。
马里兰州贝塞斯达国立心、肺及血液研究所的Jared P. Reis, Ph.D.及其同事开展了一项研究，旨在对整体及腹部肥胖的持续时间是否与CAC的存在及10年性进展有关进行调查。这项研究包括了3275名白人和黑人成年参与者，在1985-1986年研究最开始的时期内他们的年龄为18-30岁；这些人最初没有整体肥胖（BMI ≥30）或腹部肥胖（男性：腰围[WC]>40.2英寸；女性：>34.6英寸）；这些人所参加的是涉及多中心的、基于社区的年轻成年人发生冠状动脉风险(CARDIA)的研究。参与者在随访的第15年、20年或25年的检查时完成了计算机断层扫描检查以确认是否存在CAC。通过分别对BMI和WC的反复测量对整体及腹部肥胖的持续时间进行了计算，其计算的时间是在研究开始后的第2、5、7、10、15、20及25年。
在3275名合格的参与者中，45.7%为黑人，50.6%为女性。在随访期间，有40.4%及41.0%的人分别发生了整体及腹部肥胖；对那些发生整体及腹部肥胖的人来说，其平均的肥胖持续时间分别为13.3年和12.2年。
文章的作者写道：“… 在这一研究中，从成年期开始后在较长持续时间内存在着整体及腹部肥胖与经过中年时的独立于肥胖程度的CAC及其10年性进展有关。这些发现提示，由于肥胖的流行及其较早的发病时间所致的、在较长的时期内持续地出于过度肥胖状态将对美国未来的冠状动脉粥样硬化负担及可能的临床心血管疾病发生率具有重要的意义。”（生物谷Bioon.com）
生物谷推荐英文摘要：
Jama doi:10.1001/jama.2013.7833.
Association Between Duration of Overall and Abdominal Obesity Beginning in Young Adulthood and Coronary Artery Calcification in Middle Age
Jared P. Reis, PhD; Catherine M. Loria, PhD; Cora E. Lewis, MD, MSPH; Tiffany M. Powell-Wiley, MD, MPH; Gina S. Wei, MD, MPH; J. Jeffrey Carr, MD, MS; James G. Terry, MS; Kiang Liu, PhD
Importance Younger individuals are experiencing a greater cumulative exposure to excess adiposity over their lifetime. However, few studies have determined the consequences of long-term obesity.
Objective To examine whether the duration of overall and abdominal obesity was associated with the presence and 10-year progression of coronary artery calcification (CAC), a subclinical predictor of coronary heart disease.
Design, Setting, and Participants Prospective study of 3275 white and black adults aged 18 to 30 years at baseline in 1985-1986 who did not initially have overall obesity (body mass index [BMI] ≥30) or abdominal obesity (men: waist circumference [WC] >102 cm; women: >88 cm) in the multicenter, community-based Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants completed computed tomography scanning for the presence of CAC during the 15-, 20-, or 25-year follow-up examinations. Duration of overall and abdominal obesity was calculated using repeat measurements of BMI and WC, respectively, performed 2, 5, 7, 10, 15, 20, and 25 years after baseline.
Main Outcomes and Measures Presence of CAC was measured by computed tomography at the year 15 (2000-2001), year 20 (2005-2006), or year 25 (2010-2011) follow-up examinations. Ten-year progression of CAC (2000-2001 to 2010-2011) was defined as incident CAC in 2010-2011 or an increase in CAC score of 20 Agatston units or greater.
Results During follow-up, 40.4% and 41.0% developed overall and abdominal obesity, respectively. Rates of CAC per 1000 person-years were higher for those who experienced more than 20 years vs 0 years of overall obesity (16.0 vs 11.0, respectively) and abdominal obesity (16.7 vs 11.0). Approximately 25.2% and 27.7% of those with more than 20 years of overall and abdominal obesity, respectively, experienced progression of CAC vs 20.2% and 19.5% of those with 0 years. After adjustment for BMI or WC and potential confounders, the hazard ratios for CAC for each additional year of overall or abdominal obesity were 1.02 (95% CI, 1.01-1.03) and 1.03 (95% CI, 1.02-1.05), respectively. The adjusted odds ratios for CAC progression were 1.04 (95% CI, 1.01-1.06) and 1.04 (95% CI, 1.01-1.07), respectively. Associations were attenuated but largely persisted following additional adjustment for potential intermediate metabolic factors during follow-up.
Conclusions and Relevance Longer duration of overall and abdominal obesity was associated with subclinical coronary heart disease and its progression through midlife independent of the degree of adiposity. Preventing or at least delaying the onset of obesity in young adulthood may lower the risk of developing atherosclerosis through middle age.
