Division of Family Medicine and Primary Care, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.
Division of Family Medicine and Primary Care, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden; Academic Primary Health Care Centre, Stockholm Region, Stockholm, Sweden.
Cancer Epidemiol. 2020 Jun;66:101707. doi: 10.1016/j.canep.2020.101707. Epub 2020 Mar 26.
High thyroid hormone values have been associated with an increased risk of incident cancers, especially breast cancer but also lung cancer and any solid cancers. We explored whether there is an increased risk of overall and cause-specific cancers in those receiving levothyroxine treatment. We included all individuals ≥ 18 years in Sweden (N = 8,573,313) on January 1 2009, and identified patients with two or more dispensed prescriptions of levothyroxine 2005-2006 (n = 253,193, 3.0 %). A cancer diagnosis in the Swedish Cancer Register 2009-2015 was used as outcome. We excluded patients with a cancer diagnosis before 2005. Cox regression was used (hazard ratios, HRs, and 95 % confidence intervals, CI) with adjustments for age, socioeconomic/neighborhood factors and co-morbidities. Totally 399,751 cases of incident cancer were identified, with a slight increased overall risk associated with levothyroxine treatment for both men, adjusted HR 1.06 (95 % CI 1.03-1.10), and women, adjusted HR 1.08 (95 % CI 1.07-1.10). For men, increased risks were found for cancers of the thyroid gland and other endocrine glands. For women, increased risks were found for cancers of the breast, endometrium, other female genitals (ovaries not included), stomach, colon, liver, pancreas, urinary bladder, skin, leukemia, and unspecified primary tumor. Unlike men, for women, no increased risk was found for cancer of the thyroid gland. In conclusions, levothyroxine treatment was associated with an excess cancer risk, including many different types of cancer, especially among women. Our results need confirmation by other studies, but levothyroxine is recommended to be prescribed only on approved indications.
高甲状腺激素值与癌症发病风险增加有关，尤其是乳腺癌，但也与肺癌和所有实体癌有关。我们探讨了接受左甲状腺素治疗的患者是否有整体和特定原因癌症的风险增加。我们纳入了 2009 年 1 月 1 日瑞典所有≥18 岁的个体（N=8573313），并确定了 2005-2006 年有两个或更多左甲状腺素处方的患者（n=253193，3.0%）。瑞典癌症登记处 2009-2015 年的癌症诊断作为结局。我们排除了 2005 年前有癌症诊断的患者。使用 Cox 回归（风险比，HRs 和 95%置信区间，CI）进行分析，并调整了年龄、社会经济/邻里因素和合并症。总共确定了 399751 例新发癌症病例，与左甲状腺素治疗相关的总体风险略有增加，男性调整后的 HR 为 1.06（95%CI 1.03-1.10），女性调整后的 HR 为 1.08（95%CI 1.07-1.10）。对于男性，发现甲状腺和其他内分泌腺的癌症风险增加。对于女性，发现乳腺癌、子宫内膜癌、其他女性生殖器官（不包括卵巢）、胃癌、结肠癌、肝癌、胰腺癌、膀胱癌、皮肤癌、白血病和未指明的原发性肿瘤的风险增加。与男性不同，女性甲状腺癌的风险没有增加。总之，左甲状腺素治疗与癌症风险增加有关，包括许多不同类型的癌症，尤其是女性。我们的结果需要其他研究的证实，但建议仅在批准的适应症下开具左甲状腺素。
