Exploring the effect of menstrual loss and dietary habits on iron deficiency in teenagers: a cross-sectional study

This cross-sectional study was conducted in two Swedish high schools in 2023. Post-menarchal female students, aged 15 and older, were included (n=394). Data were collected on-site through a patient-reported survey, including the SAMANTA questionnaire for heavy menstrual bleeding, and by blood sampling. Meat-restricted diet was analyzed in relation to iron status. Descriptive analysis and regression analysis were used to assess the prevalence of heavy menstrual bleeding and its relationship with dietary habits and iron deficiency, defined as ferritin <15 µg/L.

The prevalence of heavy menstrual bleeding and iron deficiency in the cohort was 53% (208/394) and 40% (157/394), respectively. In univariate analysis, heavy menstrual bleeding (OR 3.0, 95% CI [2.0, 4.6]) and a meat-restricted diet (OR 3.5, 95% CI [2.2, 5.6]) were both associated with increased odds of iron deficiency. When assessing the joint effect of having heavy menstrual bleeding and a meat-restricted diet, the odds of iron deficiency were 13.5 times higher compared to omnivore individuals with normal menstruation (OR 13.5, 95% CI [6.4, 28.7]).

Overall, the prevalence of iron deficiency in this population of adolescent girls was very high. Heavy menstrual bleeding and a meat-restricted diet were both independently associated with increased odds of iron deficiency. However, odds for iron deficiency were monumentally higher when combining these two variables, thus highlighting the importance of assessing and addressing both excessive output and low intake of iron.

本横断面研究（cross-sectional study）于2023年在瑞典两所高中开展。纳入研究对象为15岁及以上的月经初潮后女学生，共394例。研究通过现场患者自评问卷与血液采样收集数据，其中自评问卷包含用于评估月经过多的SAMANTA问卷（SAMANTA questionnaire）。本研究分析了限肉饮食与铁营养状态的关联，采用描述性分析与回归分析，评估月经过多的患病率及其与饮食习惯、铁缺乏的关联；铁缺乏定义为血清铁蛋白＜15 μg/L。

本队列中，月经过多与铁缺乏的患病率分别为53%（208/394）与40%（157/394）。单因素分析结果显示，月经过多（比值比（odds ratio, OR）=3.0，95%置信区间（confidence interval, CI）：2.0~4.6）与限肉饮食（OR=3.5，95%CI：2.2~5.6）均与铁缺乏风险升高显著相关。在评估月经过多与限肉饮食的联合效应时，与月经正常的杂食者相比，铁缺乏的发生风险升高至13.5倍（OR=13.5，95%CI：6.4~28.7）。

总体而言，本研究纳入的青春期女性群体中铁缺乏患病率极高。月经过多与限肉饮食均为铁缺乏风险升高的独立危险因素。但当两者同时存在时，铁缺乏风险呈显著叠加升高，这凸显了同时评估并干预铁丢失过多与铁摄入不足的重要性。