Proctor S P, Rotnitzky A, Sparrow D, Weiss S T, Hu H
Occupational Health Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
Int J Epidemiol. 1996 Jun;25(3):528-36. doi: 10.1093/ije/25.3.528.
Previous studies have demonstrated a positive relationship between elevated blood lead (BPb) and blood pressure (BP), but few have additionally examined the role of dietary calcium.
The cross-sectional relationship between BPb and BP and the possible protective influence of increased dietary calcium on that relationship was examined among 798 male participants in the Normative Aging Study (NAS), a cohort of older men with relatively low BPb levels.
The age range of these subjects was 43-93 years (mean = 66.1, SD = 7.4 years) and blood lead concentrations ranged form 0.5 to 35 mcg/dl (median = 5.6 mcg/dl). For the cohort overall, neither ln blood lead nor dietary calcium were significantly correlated with BP. In multivariate linear regression analyses that adjusted for age, body mass index, dietary calcium intake (adjusted for total calorie intake), alcohol intake, sitting heart rate, kilocalories/week expended in exercise, haematocrit, and smoking status, a unit increase in ln BPb predicted an increase on 1.2 mmHg diastolic blood pressure (DBP) (95% CI : 0.11, 2.2; P = 0.03). Adjusted calcium intake of 800 mg/day predicted a decrease of 3.2 mmHg systolic blood pressure (SBP) (95% CI : -5.6, -0.24, P = 0.03). There was no evidence of an interaction between dietary calcium intake and blood lead on BP. When the analyses were restricted to those men <=74 years old, a unit increase in ln BPb predicted an increase of 1.6 mmHg DBP (n = 681; 95% CI : 0.42, 2.7; P = 0.007). However, when men on antihypertensive medication (AHM) were excluded from the analyses, ln BPb was not significantly associated with increased DBP nor was adjusted calcium significantly associated with SBP.
The study did support the hypothesis that increased BPb was associated with increased DBP in a cohort of older men with low blood lead, but there was no evidence of interaction between BPb and dietary calcium on BP. However, the relationship between increased BPb and DBP did not hold when those on anti-hypertensive medications were excluded.
以往研究表明血铅（BPb）升高与血压（BP）之间存在正相关关系，但很少有研究进一步探讨膳食钙的作用。
在规范性衰老研究（NAS）的798名男性参与者中，研究了BPb与BP之间的横断面关系以及膳食钙增加对该关系可能产生的保护作用。NAS是一组血铅水平相对较低的老年男性队列。
这些受试者的年龄范围为43 - 93岁（平均 = 66.1岁，标准差 = 7.4岁），血铅浓度范围为0.5至35微克/分升（中位数 = 5.6微克/分升）。对于整个队列而言，血铅的自然对数（ln血铅）和膳食钙与血压均无显著相关性。在多变量线性回归分析中，对年龄、体重指数、膳食钙摄入量（根据总热量摄入进行调整）、酒精摄入量、静息心率、每周运动消耗的千卡数、血细胞比容和吸烟状况进行了调整，ln BPb每增加一个单位，预测舒张压（DBP）升高1.2 mmHg（95%置信区间：0.11，2.2；P = 0.03）。调整后的钙摄入量为800毫克/天，预测收缩压（SBP）降低3.2 mmHg（95%置信区间：-5.6，-0.24；P = 0.03）。没有证据表明膳食钙摄入量与血铅之间对血压存在相互作用。当分析仅限于年龄≤74岁的男性时，ln BPb每增加一个单位，预测DBP升高1.6 mmHg（n = 681；95%置信区间：0.42，2.7；P = 0.007）。然而，当将服用抗高血压药物（AHM）的男性排除在分析之外时，ln BPb与DBP升高无显著相关性，调整后的钙与SBP也无显著相关性。
该研究确实支持了在血铅水平较低的老年男性队列中，BPb升高与DBP升高相关的假设，但没有证据表明BPb与膳食钙对血压存在相互作用。然而，当排除服用抗高血压药物的人群后，BPb升高与DBP之间的关系并不成立。
