Egger M, Smith G D, Pfluger D, Altpeter E, Elwood P C
Department of Social Medicine, University of Bristol, UK.
Atherosclerosis. 1999 Apr;143(2):275-84. doi: 10.1016/s0021-9150(98)00300-1.
To assess the influence of differential precision in the measurement of the correlated variables total cholesterol and high density lipoprotein (HDL) cholesterol on the estimates of the risk of ischaemic heart disease (IHD) associated with plasma triglyceride levels.
DESIGN, SETTING AND PARTICIPANTS: The Caerphilly Heart Disease Study (CHDS), a prospective cohort study of 2512 middle-aged men living in the town of Caerphilly, south Wales, UK. The results from two sub-studies were used to estimate the degree of measurement imprecision (laboratory error and within-person variation) in triglycerides, total cholesterol and HDL cholesterol.
Multivariable risk estimates for major IHD calculated from logistic regression analysis, adjusted and not adjusted for measurement imprecision. Major IHD events were defined as death from IHD, clinical non-fatal myocardial infarction or electrocardiographic myocardial infarction.
There were 261 men with major IHD events during follow-up. In age-adjusted analyses, taking measurement imprecision into account strengthened associations with IHD for all lipid factors. The odds ratio (OR) for one S.D. increase in triglycerides, ignoring measurement imprecision, was 1.36 (95% confidence interval [95% CI] 1.20-1.55) but 1.57 (95% CI 1.30-1.89) when taking imprecision into account. The standardised odds ratio for triglycerides adjusted for measurement imprecision and the two other lipid factors was 1.35 (95% CI 1.09-1.69). In this model, the triglyceride level showed a stronger association than total cholesterol (OR 1.28; 95% CI 1.05-1.56) and HDL cholesterol (OR for one S.D. decrease 1.20; 95% CI 0.97-1.49). When adding fasting blood glucose and diastolic blood pressure, however, the effect of triglycerides was reduced and ceased to be statistically significant (OR 1.19; 95% CI 0.95-1.49). This was further attenuated upon inclusion of body mass index, smoking status and history of pre-existing IHD. Total cholesterol remained a statistically significant (P < 0.05) risk factor in all models.
In contrast to other cohort studies, triglyceride concentration in the CHDS shows an association with the risk of IHD which is independent of total and HDL cholesterol. This effect was pronounced after adjustment for measurement imprecision. It was reduced, however, when adjusted for other factors. While hypertriglyceridaemia may exert an influence independent of other lipid factors, insulin resistance is probably the underlying metabolic disturbance.
评估相关变量总胆固醇和高密度脂蛋白（HDL）胆固醇测量中的差异精度对与血浆甘油三酯水平相关的缺血性心脏病（IHD）风险估计的影响。
设计、设置和参与者：卡菲利心脏病研究（CHDS），一项对居住在英国威尔士南部卡菲利镇的2512名中年男性进行的前瞻性队列研究。两项子研究的结果用于估计甘油三酯、总胆固醇和HDL胆固醇的测量不精确程度（实验室误差和个体内变异）。
通过逻辑回归分析计算的主要IHD的多变量风险估计值，针对测量不精确进行了调整和未调整。主要IHD事件定义为IHD死亡、临床非致命性心肌梗死或心电图心肌梗死。
随访期间有261名男性发生主要IHD事件。在年龄调整分析中，考虑测量不精确性会加强所有脂质因素与IHD的关联。甘油三酯每增加一个标准差，忽略测量不精确性时的优势比（OR）为1.36（95%置信区间[95%CI]1.20 - 1.55），但考虑不精确性时为1.57（95%CI 1.30 - 1.89）。针对测量不精确性以及其他两个脂质因素调整后的甘油三酯标准化优势比为1.35（95%CI 1.09 - 1.69）。在该模型中，甘油三酯水平显示出比总胆固醇（OR 1.28；95%CI 1.05 - 1.56）和HDL胆固醇（HDL胆固醇每降低一个标准差的OR为1.20；95%CI 0.97 - 1.49）更强的关联。然而，当加入空腹血糖和舒张压时，甘油三酯的影响减弱且不再具有统计学显著性（OR 1.19；95%CI 0.95 - 1.49）。纳入体重指数、吸烟状况和既往IHD病史后，这种影响进一步减弱。总胆固醇在所有模型中仍然是具有统计学显著性（P < 0.05）的风险因素。
与其他队列研究不同，CHDS中的甘油三酯浓度显示出与IHD风险的关联，该关联独立于总胆固醇和HDL胆固醇。在调整测量不精确性后，这种影响较为明显。然而，在调整其他因素后，这种影响减弱。虽然高甘油三酯血症可能独立于其他脂质因素发挥作用，但胰岛素抵抗可能是潜在的代谢紊乱。
