RAND Corporation, Arlington, Virginia 22202, USA.
Environ Health Perspect. 2011 Mar;119(3):326-31. doi: 10.1289/ehp.1002256. Epub 2010 Oct 29.
The putative effects of postmenopausal hormone therapy on the association between particulate matter (PM) air pollution and venous thromboembolism (VTE) have not been assessed in a randomized trial of hormone therapy, despite its widespread use among postmenopausal women.
In this study, we examined whether hormone therapy modifies the association of PM with VTE risk.
Postmenopausal women 50-79 years of age (n = 26,450) who did not have a history of VTE and who were not taking anticoagulants were enrolled in the Women's Health Initiative Hormone Therapy trials at 40 geographically diverse U.S. clinical centers. The women were randomized to treatment with estrogen versus placebo (E trial) or to estrogen plus progestin versus placebo (E + P trial). We used age-stratified Cox proportional hazard models to examine the association between time to incident, centrally adjudicated VTE, and daily mean PM concentrations spatially interpolated at geocoded addresses of the participants and averaged over 1, 7, 30, and 365 days.
During the follow-up period (mean, 7.7 years), 508 participants (2.0%) had VTEs at a rate of 2.6 events per 1,000 person-years. Unadjusted and covariate-adjusted VTE risk was not associated with concentrations of PM < 2.5 µm (PM(2.5)) or < 10 µm (PM(10))] in aerodynamic diameter and PM × active treatment interactions were not statistically significant (p > 0.05) regardless of PM averaging period, either before or after combining data from both trials [e.g., combined trial-adjusted hazard ratios (95% confidence intervals) per 10 µg/m(3) increase in annual mean PM(2.5) and PM(10), were 0.93 (0.54-1.60) and 1.05 (0.72-1.53), respectively]. Findings were insensitive to alternative exposure metrics, outcome definitions, time scales, analytic methods, and censoring dates.
In contrast to prior research, our findings provide little evidence of an association between short-term or long-term PM exposure and VTE, or clinically important modification by randomized exposure to exogenous estrogens among postmenopausal women.
尽管绝经后激素疗法在绝经后妇女中广泛应用，但在一项关于激素疗法的随机试验中，尚未评估其对颗粒物（PM）空气污染与静脉血栓栓塞（VTE）之间关联的潜在影响。
本研究旨在探讨激素疗法是否会改变 PM 与 VTE 风险之间的关联。
在这项研究中，我们招募了年龄在 50-79 岁之间、无 VTE 病史且未服用抗凝药物的 26450 名绝经后女性，这些女性参加了美国 40 个地理位置不同的临床试验中心的妇女健康倡议激素治疗试验。这些女性被随机分配接受雌激素治疗或安慰剂治疗（E 试验），或接受雌激素加孕激素治疗或安慰剂治疗（E+P 试验）。我们使用年龄分层 Cox 比例风险模型来检查参与者地理编码地址的每日平均 PM 浓度与中心判定的 VTE 发病时间之间的关联，PM 浓度的空间插值是基于参与者的地理编码地址进行的，并在 1、7、30 和 365 天的时间内进行平均处理。
在随访期间（平均 7.7 年），有 508 名参与者（2.0%）发生了 VTE，发病率为每 1000 人年 2.6 例。未经调整和调整混杂因素后，VTE 风险与空气动力学直径中 PM<2.5 µm（PM2.5）或<10 µm（PM10）的浓度均无关联，且 PM 与活性治疗之间的交互作用无统计学意义（p>0.05），无论 PM 平均时间是在合并两项试验数据之前还是之后（例如，联合试验调整后的危险比（95%置信区间），每年 PM2.5 和 PM10 每增加 10 µg/m3，分别为 0.93（0.54-1.60）和 1.05（0.72-1.53））。研究结果对于替代暴露指标、结局定义、时间尺度、分析方法和删失日期均具有稳健性。
与之前的研究结果相反，本研究结果几乎没有提供证据表明短期或长期 PM 暴露与 VTE 之间存在关联，也没有提供证据表明绝经后女性随机接触外源性雌激素会对 VTE 产生明显影响。
