Subclinical hypothyroidism is not a risk factor for polycystic ovary syndrome in obese women of reproductive age

Abstract

Obese women are at high risk for polycystic ovary syndrome (PCOS). Subclinical hypothyroidism (SCH) has been associated with weight gain, insulin resistance and impaired fertility, which are also factors involved in PCOS. However, there is limited information regarding the influence of SCH on the presence of PCOS. In order to determine whether SCH increases the prevalence of PCOS, we performed a cross-sectional study in a cohort of reproductive-aged obese women. All subjects underwent anthropometric evaluation, laboratory tests and ultrasound examination. Diagnosis of PCOS was based on the Rotterdam criteria. A total of 534 obese women were included and 108 (20.2%) of them were diagnosed with SCH. Patients with SCH showed similar insulin resistance, comparable androgen levels, and higher triglycerides levels (1.7 vs. 1.5 mmol/L, p = .002) compared to those with normal thyroid status. The frequency of PCOS did not differ between the two groups (56.1% for normal thyroid function vs. 60.2% for subclinical hypothyroidism, p = .514). In logistic regression analysis, SCH was not an independent risk factor for PCOS after adjusting for confounding factors (OR = 0.984, 95% CI 0.581–1.667). For the first time, our results suggest that SCH does not increase the risk of PCOS in obese women of reproductive age.

Chinese abstract

肥胖女性患多囊卵巢综合征（PCOS）的风险增加。亚临床甲状腺功能减退（SCH）与体重增加、胰岛素抵抗和生育能力受损有关, 这些也是与PCOS相关的因素。然而, 关于SCH对PCOS的影响的报道有限。为了确定SCH是否增加PCOS的患病率, 我们在一群生育年龄的肥胖女性中进行了一项横断面研究。所有受试者均接受人体测量、实验室检查和超声检查。PCOS的诊断基于鹿特丹标准。总共纳入534名肥胖妇女, 其中108名（20.2%）被诊断患有SCH。与甲状腺功能正常的患者相比, 患有SCH的患者表现出相似的胰岛素抵抗、类似的雄激素水平和更高的甘油三酯水平(1.7 vs. 1.5mmol/L, p = .002)。PCOS的发生率在这两组之间没有差别(甲状腺功能正常者56.1% vs. 亚临床甲状腺功能减退者60.2%, p = .514)。在logistic回归分析中, 在对混杂因素进行调整后, SCH并不是PCOS的独立危险因素(OR = 0.984, 95% CI 0.581-1.667)。我们的研究结果第一次表明在生育年龄的肥胖女性中, SCH不会增加患PCOS的风险。

Keywords:

• Obese women
• polycystic ovary syndrome
• risk factor
• subclinical hypothyroidism

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by grants from the National Natural Science Foundation of China Grant Awards [81570737, 81370947, 81570736, 81770819, 81500612, 81400832, 81600637, 81600632, and 81703294], the National Key Research and Development Program of China [2016YFC1304804], the Jiangsu Provincial Key Medical Discipline [ZDXKB2016012], the Key Research and Development Program of Jiangsu Province of China [BE2015604 and BE2016606], the Jiangsu Provincial Medical Talent [ZDRCA2016062], the Key Discipline of Medicine of Jiangsu Province of China [no. XK201105], the Key Project of Nanjing Clinical Medical Science, the Nanjing Science and Technology Development Project [201605019].