Instituto Nacional de Salud Pública (INSP), Av. Universidad 655, Col. Sta. María Ahuacatitlán, 62100, Cuernavaca, Morelos, México.
Hospital General de México, Dr. Balmis 148, Col. Doctores, Deleg. Cuauhtémoc, 06726, México, Ciudad de México, Mexico.
BMC Cancer. 2018 Feb 7;18(1):160. doi: 10.1186/s12885-018-4065-7.
Inconsistent associations between smoking status and prostate cancer (PC) could be due to exposure assessment error. Reconstructing smoking behaviors over the life course could reduce exposure assessment error.
As part of a case-control study, we identified 402 incident and histologically confirmed PC cases that were matched by age (±5 years) to 805 population controls. Through direct interview, we obtained information about: age at smoking onset, intensity and frequency of cigarette smoking at different life stages, and smoking cessation age. Smoking status at interview and average smoking index over the lifetime (packs/year) were estimated. Life course smoking patterns were obtained applying the k-means+ method for longitudinal data to the smoking index (pack/year) for each life stage.
Two life-course smoking patterns were identified among ever smokers: "pattern A" characterized by males who reported low and constant smoking intensity (87.8%), and "pattern B" (12.2%) males with an initial period of low intensity, followed by an increase during the second period. Compared to never smokers, pattern B was associated with higher poorly differentiated PC, (OR 2.30; 95% CI 1.21-4.38). No association was observed with average smoking index.
Life course smoking patterns seem to capture the smoking variability during life course and reduce the likelihood of reverse causation. Using this assessment strategy our findings support the potential role of tobacco smoking in PC, particularly poorly differentiated PC. Prospective studies with comprehensive smoking history during the lifetime are needed to confirm these findings.
吸烟状况与前列腺癌（PC）之间的关联不一致，可能是由于暴露评估错误所致。重建整个生命过程中的吸烟行为可以减少暴露评估错误。
作为一项病例对照研究的一部分，我们确定了 402 例新发且组织学证实的 PC 病例，并按年龄（±5 岁）与 805 名人群对照相匹配。通过直接访谈，我们获得了有关信息：吸烟开始年龄、不同生命阶段吸烟的强度和频率，以及戒烟年龄。根据访谈时的吸烟状况和一生中的平均吸烟指数（包/年）来估计吸烟状况。应用 k-means+方法对每个生命阶段的吸烟指数（包/年）进行纵向数据分析，得出生命过程中的吸烟模式。
在曾经吸烟者中发现了两种生命过程中的吸烟模式：“模式 A”，其特征是男性报告吸烟强度低且稳定（87.8%），以及“模式 B”（12.2%），男性在初始阶段吸烟强度较低，随后第二阶段增加。与从不吸烟者相比，模式 B 与分化不良程度较高的 PC 相关（OR 2.30；95%CI 1.21-4.38）。与平均吸烟指数无关。
生命过程中的吸烟模式似乎可以捕捉到整个生命过程中的吸烟变化，并降低反向因果关系的可能性。使用这种评估策略，我们的研究结果支持烟草吸烟在 PC 中的潜在作用，特别是分化不良的 PC。需要进行前瞻性研究，在一生中进行全面的吸烟史评估，以证实这些发现。
