Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B building, Bethesda, MD 20892, USA.
Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B building, Bethesda, MD 20892, USA.
Hum Reprod. 2018 Mar 1;33(3):426-433. doi: 10.1093/humrep/dex379.
Is iodine deficiency associated with decreased fecundability?
Moderate to severe iodine deficiency is associated with a 46% decrease in fecundability.
Iodine deficiency is common in women of childbearing age but its effect on fecundability has not been investigated.
STUDY DESIGN, SIZE, DURATION: The LIFE Study, a population-based prospective cohort study, enrolled 501 women who had discontinued contraception within 2 months to become pregnant between 2005 and 2009.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Women reported on risk factors for infertility by interview then kept daily journals of relevant information. Women used fertility monitors to time intercourse relative to ovulation then used home digital pregnancy tests to identify pregnancies on the day of expected menstruation. Urine samples for iodine analysis were collected on enrollment.
Samples were in the deficiency range in 44.3% of participants. The group whose iodine-creatinine ratios were below 50 μg/g (moderate to severe deficiency) had a 46% reduction in fecundity (P = 0.028) compared with the group whose iodine-creatinine ratios were in the adequate range: adjusted fecundability odds ratio of becoming pregnant per cycle, 0.54 (95% confidence interval 0.31-0.94).
LIMITATIONS, REASONS FOR CAUTION: Iodine concentrations vary within individuals over time, so the data must be interpreted by group as we have done; residual confounding is possible.
Significant delays in becoming pregnant occur at iodine concentrations that are common in women in the USA and parts of Europe. Replicating these findings will be important to determine whether improving iodine status could be beneficial in improving fecundability.
STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA. Contracts N01-HD-3-3355; N01-HD-3-3356; N01-HD-3-3358 and HHSN275201100001l/HHSN27500007. None of the authors has any conflict of interest to declare.
碘缺乏是否与生育能力下降有关？
中度至重度碘缺乏与生育能力下降 46%有关。
育龄妇女中碘缺乏很常见，但尚未研究其对生育能力的影响。
研究设计、大小、持续时间：LIFE 研究是一项基于人群的前瞻性队列研究，共招募了 501 名在 2005 年至 2009 年期间停止避孕后 2 个月内怀孕的女性。
参与者/材料、地点、方法：女性通过访谈报告不孕相关的危险因素，然后每天记录相关信息。女性使用生育监测器来安排与排卵相关的性交时间，然后使用家用数字妊娠试验在预计月经来潮的当天确定怀孕。在入组时收集尿液样本进行碘分析。
44.3%的参与者样本处于缺乏范围。碘肌酐比值低于 50μg/g（中度至重度缺乏）的组生育能力下降 46%（P=0.028），与碘肌酐比值处于充足范围的组相比：每个周期怀孕的调整生育能力优势比为 0.54（95%置信区间为 0.31-0.94）。
局限性、谨慎的原因：碘浓度随时间在个体内变化，因此我们必须按组来解释数据；仍然存在潜在混杂因素。
在美国和欧洲部分地区，女性中常见的碘浓度会导致明显的怀孕延迟。复制这些发现对于确定改善碘状况是否有益于提高生育能力将非常重要。
研究资金/竞争利益：这项研究由美国国立卫生研究院儿童健康与人类发育国家研究所内部研究计划、Eunice Kennedy Shriver 国家儿童健康与人类发育研究所资助。合同号 N01-HD-3-3355；N01-HD-3-3356；N01-HD-3-3358 和 HHSN275201100001l/HHSN27500007。所有作者均无利益冲突声明。
