Abstract
ObjectiveTo assess the status of the vitamin B12 and folate of Chinese women living in northwest China.MethodsA population-based cross-sectional study was conducted in 2008 among Chinese women aged 10–49 years living in Shaanxi province of northwest China. A stratified multistage random sampling method was adopted to obtain a sample of 1170 women. The women were interviewed for collection of their background information and their plasma vitamin B12 and folate were measured with the immunoassay method. The status of both vitamins was evaluated and the prevalence of deficiency was estimated.ResultsThe median value of the women was 214.5 pg/mL for vitamin B12 and 4.6 ng/mL for folate. The urban women had a significantly higher vitamin B12 (254.1 vs. 195.9 pg/mL) but lower folate (4.4 vs. 4.7 ng/mL) than rural women. Total prevalence of deficiency was 45.5% (95% CI: 42.6%∼48.4%) for vitamin B12 and 14.7% (95% CI: 12.6%∼16.8%) for folate. About 36% of women presented vitamin B12 deficiency alone, 5.2% belonged to folate deficiency alone and 9.5% was combined deficiency in both vitamins. More than 25% of the women were in marginal vitamin B12 status (200–299 pg/mL) and 60% in marginal status of folate (3–6 ng/mL). About 75.2% of rural women with folate deficiency were deficient in vitamin B12 and 46% for urban women. Quantile regression model found decreasing coefficient of folate status across 73 different quantiles of vitamin B12, which indicated that the women with folate deficiency had lower vitamin B12 significantly compared with those with no deficiency.ConclusionsThe deficiency of vitamin B12 and folate is still prevalent among the Chinese women in northwest China. Vitamin B12 deficiency could be more serious and the improvement of poor vitamin B12 status should be invoked when practicing the supplementation of folate against the neural tube defects in northwest China.
Highlights
There was a widespread low folate status around China, especially in the region of northern China [1,2,3,4]
Most of studies on folate status focused on specific regions and women of childbearing age so it was difficult to estimate the number of folate deficient people in China
This study was conducted in Shaanxi province of China with a stratified multistage random sampling method based on population distribution, so the sample was a representative of the Shaanxi women and the results from the study reflected the status of folate and vitamin B12 of Chinese women to some extent
Summary
There was a widespread low folate status around China, especially in the region of northern China [1,2,3,4]. A previous study showed that the mean plasma folate in the adults of northern China was about 8.4 nmol/L, which was significantly lower than 16.7 nmol/L in southern region controlling for age, gender, season and so on [3]. Most of studies on folate status focused on specific regions and women of childbearing age so it was difficult to estimate the number of folate deficient people in China. In China the policy of supplementation of folic acid played an important role in preventing NTD [8]. Magnitude of reduction in NTD rate much varied with regions of China. Other micronutrient deficiency such as vitamin B12 could be taken into account in addition to lower compliance of the folate supplementation. Vitamin B12 deficiency could impair the folate-mediated one-carbon metabolic pathway to present as folate deficiency or to exacerbate folate deficiency
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