不知从何时开始，生活中就流传着一种年轻就是资本的歪风邪念，许多年轻人为了努力拼搏，生活习惯越来越差，抽烟喝酒，熬夜念书，饮食结构不合理，以太忙碌为由不爱运动，超重肥胖、三高的同志们越来越多。

然而，不要以为年纪轻轻，看起来身体健康就可以毫不戒指的生活。在近期发表在美国心脏协会官方杂志Circulation的一项研究中，来自德克萨斯州立大学西南医学中心的研究人员对超过3.6万名身体健康且心血管疾病风险低的青年志愿者们进行了长达27年的追踪随访。研究结果表明， 如果在年轻时，低密度脂蛋白胆固醇水平高于正常范围，那在未来十年心血管疾病的死亡风险会增加30%-90%不等，其中冠心病的死亡风险更是有可能翻番。

(Related biology knoweldge)

Low-density lipoprotein (LDL) is one off the five major groups of lipoproteins which transport all fat molecules (cholesterol, phospholipids and triglycerides mainly)around the body in the extracellular water. Those fat molecules can drive the progression of atherosclerosis if they become oxidized within the walls of arteries

Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. Coronary artery disease (CAD) also known as ischemic heart disease, is the most common of CVD. Risk factors include high blood pressure, smoking, diabetes lack of exercise, obesitu, high blood cholesterol, poor diet, depression and excessive alcohol.

Coronary arteries are the arteries of the coronary circulation, which transports blood into and out of the cardiac muscle.

低密度脂蛋白胆固醇(LDL-C)也是心血管疾病文章中的常客了，是导致动脉粥样硬化的坏胆固醇。 在这项研究中，研究人员将LDL-C<100mg/dL视为正常范围，作为分析中的对照组，另外四组分别为100-129mg/dL、130-159mg/dL、160-189mg/dL和190mg/dL， 运用单变量分析模型对志愿者们CVD死亡风险进行了分析， 在不同范围LDL-C组中， 志愿者心血管疾病死亡风险分别上升了40%， 30%，90%和70%。

Control group: in the design of experiments, treatments are applied to experimental units in the treatment group(s), in comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.

Chi-square: the chi-square distribution is used in the common chi-squared tests for goodness of fit of an observed distribution to a theoretical one, the independence of two criteria of classification of qualitative data and in confidence interval estimation for a population standard deviation of a normal distribution form a sample standard deviation.

P-value: in statistical hypothesis testing, the p-value or asymptotic significance is the probability for a give statistical model that, when the null hypothesis is true, the statistical summary (such as the sample mean difference between two compared groups) would be greater than or equal to the actual observed results.

The smaller the p-value, the higher the significance because it tells the investigator that the hypothesis under consideration may not adequately explain the observation, normally, the null hypothesis would be rejected if p<0.05 (p<0.001 for medical research with higher requirement of accurate result)

从研究结果中我们可以看出，这些表面健康的低风险年轻人可以说是既不健康又不低风险，随着年龄的增长，这些年轻时候的不健康生活习惯，都会增加日后的心血管疾病死亡风险。

同时，研究人员也建议，即使是低风险的人也应该采取生活方式干预，将LDL-C水平控制在100mg/dL以下，限制饱和脂肪的摄入、保持健康体重、不吸烟以及增加有氧运动，这些适用于每个年龄段的每一个人。

Abdullah S M, Defina L F, Leonard D, et al. Long-Term Association of Low-Density Lipoprotein Cholesterol With Cardiovascular Mortality in Individuals at Low 10-Year Risk of Atherosclerotic Cardiovascular Disease: Results From the Cooper Center Longitudinal Study[J]. Circulation, 2018: CIRCULATIONAHA. 118.034273.