The prevalence and influencing factors of anemia among pre-pregnant women in mainland China: A large population-based, cross-sectional study.

Anemia is a global public health problem affecting women worldwide, and reproductive-age women are at increased risk. We conducted a population-based cross-sectional study analyzing the prevalence of overall anemia and anemia according to severity in Chinese pre-pregnant women to update current knowledge on anemia epidemiology. Based on the National Free Preconception Check-up Projects supported by the Chinese government, 5,679,782 women participating in this project in 2017 were included in this study. The cyanmethemoglobin method was applied to assess hemoglobin concentrations. Univariate and multivariate logistic regressions were applied for associated factors. The prevalence of anemia among Chinese pre-pregnant women was 21.64% (mild anemia: 14.10%, moderate anemia: 7.17%, severe anemia: 0.37%). The prevalence of overall and severe anemia was the highest in Tibet and the lowest in Beijing among 31 provinces. Women's age, region, ethnic origin, educational level, occupation, and pregnancy history were all correlated with anemia. Women with B blood type (aOR=0.89), higher BMIs (overweight: aOR=0.84; obesity: aOR=0.70), and alcohol consumption (aOR=0.69) were less likely to have anemia, while those with rhesus negative blood type (aOR=1.10), history of anemia (aOR=2.60), older age at menarche (aOR=1.19), heavy menstrual blood loss (aOR=1.39), longer menstrual period (aOR=1.09) and shorter menstrual cycle (aOR=1.08) were more likely to suffer from anemia. Meat or egg eaters were not significantly associated with severe anemia. Anemia is of moderate public health significance among Chinese pre-pregnant women. Interventions should be considered to prevent anemia to the greatest extent possible to avoid potential harm in this population.