Epidemiological studies have suggested a link between low-level radiation exposure and an increased risk of cardiovascular disease, but the possibility of bias or confounding must be considered. We analyzed data from a matched case-control study nested in a cohort of British male industrial (i.e., blue-collar) nuclear fuel cycle workers using paired conditional logistic regression. The cases were comprised of workers from two nuclear sites who had died from ischemic heart disease (IHD) and were matched to controls on nuclear site, date of birth and first year of employment (1,220 pairs). Radiation doses from external sources and to the liver from internally deposited plutonium and uranium were obtained. Models were adjusted for age at start of employment at either site, decade of start, age at exit from study (death or censoring), process/other worker and socio-economic status. Included potential confounding factors of interest were occupational noise, shift work, pre-employment blood pressure, body mass index and tobacco smoking. Cumulative external doses ranged from 0–1,656 mSv and cumulative internal doses for those monitored for radioactive intakes ranged from 0.004–5,732 mSv. In a categorical analysis, additionally adjusted for whether or not a worker was monitored for internal exposure, IHD mortality risk was associated with cumulative external unlagged dose with a 42% excess risk (95% CI: 4%, 95%) at >103 mSv (highest quartile relative to lowest quartile), and 35% (95% CI: –1%, 84%) at >109 mSv 15-year lagged dose. The log-linear increase in risk per 100 mSv was 2% (95% CI: –4%, 8%) for unlagged external dose and 5% (95% CI: –2%, 11%) for 15-year lagged dose. Associations with external dose for workers monitored only for exposure to external radiation reflected those previously reported for the cohort from which the cases and controls were drawn. There was little evidence of excess risk associated with cumulative doses from internal sources, which had not been assessed in the cohort study. The impact of the included potential confounding variables was minimal, with the possible exception of occupational noise exposure. Subgroup analyses indicated evidence of heterogeneity between sites, occupational groups and employment duration, and an important factor was whether workers were monitored for the potential presence of internal emitters, which was not explained by other factors included in the study. In summary, we found evidence for an increased IHD mortality risk associated with external radiation dose, but little evidence of an association with internal dose. External dose associations were minimally affected by important confounders. However, the considerable heterogeneity in the associations with external doses observed between subgroups of workers is difficult to explain and requires further work.

流行病学研究表明，低剂量辐射暴露与心血管疾病风险增加之间存在联系，但必须考虑偏倚或混淆的可能性。我们使用配对条件对数回归分析了来自一组匹配的病例对照研究的数据，该研究嵌套在一组英国男性工业（即蓝领）核燃料循环工人队列中。这些病例由来自两个核站点的工人死于缺血性心脏病（IHD），并与核站点，出生日期和就职第一年的对照（1,220对）相匹配。获得了来自外部来源以及内部沉积的p和铀对肝脏的辐射剂量。针对以下两个方面对模型进行了调整：在任一地点开始工作的年龄，开始工作的十年，退出研究的年龄（死亡或审查），流程/其他工人和社会经济地位。感兴趣的潜在混杂因素包括职业噪声，轮班工作，就业前血压，体重指数和吸烟。累积的外部剂量范围为0–1,656 mSv，对于放射性摄入监测的累积内部剂量范围为0.004–5,732 mSv。在分类分析中，进一步调整了是否对工人的内部暴露进行了监测，IHD死亡风险与累积外部未滞后剂量相关，在> 103 mSv时有42％的额外风险（95％CI：4％，95％）。 （最高四分位数相对于最低四分位数），以及> 109 mSv 15年滞后剂量时为35％（95％CI：–1％，84％）。对于非滞后外部剂量，每100 mSv风险的对数线性增加为2％（95％CI：–4％，8％），而对于15年滞后剂量，则为5％（95％CI：–2％，11％） 。仅监测外部辐射的工人与外部剂量的关联反映了先前报道的病例和对照人群的相关数据。几乎没有证据表明与内部来源的累积剂量相关的额外风险，该队列研究尚未评估。所包括的潜在混杂变量的影响极小，但可能存在的职业噪声暴露除外。亚组分析表明，地点，职业群体和就业时间之间存在异质性的证据，一个重要因素是是否对工人的内部排放物的潜在存在进行了监测，该研究中未包括其他因素。综上所述，我们发现有证据表明与外部辐射剂量相关的IHD死亡风险增加，但与内部剂量相关的证据很少。重要的混杂因素对外部剂量的影响最小。然而，在工人亚组之间观察到的外部剂量与关联的显着异质性很难解释，需要进一步的工作。