Prenatal anemia and iron deficiency are associated with adverse birth outcomes, but no previous studies have examined the relation between preconception anemia, iron deficiency, and pregnancy outcome in healthy women. We measured hemoglobin (Hb), ferritin, transferrin receptor (TfR), and vitamins B-6, B-12, and folate concentrations before pregnancy in 405 Chinese women (median time from sample collection to gestation end = 316 d). Both mild (95 = Hb < 120 g/L) and moderate (Hb < 95 g/L) anemia were significantly associated with lower birthweight (139 and 192 g, respectively); iron-deficiency anemia alone (Hb < 120 g, ferritin < 12 microg/L, no B-vitamin deficiency) was associated with a 242-g decrease in birthweight. Both low (<12 microg/L) and high (>/=60 microg/L) ferritin were also significantly associated with lower birthweight (106 and 123 g, respectively). The risks of low birthweight (LBW) and fetal growth restriction (FGR) were significantly greater among women with moderate anemia compared with nonanemic controls [odds ratio (OR): 6.5; 95% CI: 1.6, 26.7; P = 0.009 and OR: 4.6; 95% CI: 1.5, 13.5; P = 0.006, respectively]. TfR and low ferritin were not associated with adverse birth outcome, but elevated ferritin, which could be a marker of inflammation, was associated with increased risk of LBW (OR: 2.2; 95% CI: 0.9, 5.7; P = 0.09) and FGR (OR: 2.7; 95% CI: 1.3, 5.6; P = 0.008). Preconception anemia, particularly iron-deficiency anemia, was associated with reduced infant growth and increased risk of adverse pregnancy outcome in Chinese women.
Elevated homocysteine and suboptimal vitamin B-12 and B-6 status may increase the risk of preterm birth. These results need to be confirmed in larger prospective studies.
Low maternal prepregnancy BMI is associated with adverse birth outcomes, but the BMI at which risk increases is not well defined. We assessed whether the relationship between prepregnancy BMI and birth outcomes is influenced by the extent to which mothers were underweight in a prospective study in Anhui, China. The women (n = 575) were 20-34 y old, married, nulliparous and nonsmokers. All measures of infant growth increased with increasing maternal BMI until a plateau was reached at a BMI of 22-23 kg/m2. Infants born to the 27% of women who were severely underweight before pregnancy (BMI < or = 18.5 kg/m2) were at increased risk for fetal growth deficits associated with infant morbidity. Compared with a normal BMI, being severely underweight was associated with mean (+/- SEM) reductions of 219 +/- 40 g in infant birthweight and 6.7 +/- 1.3% in the birthweight ratio and an 80% increase in risk of intrauterine growth restriction [odds ratio (OR) 1.8; 95% CI: 1.0, 3.3; P = 0.05]. Being severely underweight was also associated with smaller infant head circumference and lower ponderal index. Being moderately underweight (18.5 < BMI < 19.8 kg/m2) was not significantly associated with adverse pregnancy outcomes. Gestational age and risk of preterm birth were not associated with maternal BMI. More than half of the women in this study were underweight before pregnancy. Although being moderately underweight was not associated with increased risk of adverse pregnancy outcomes, being severely underweight was an important risk factor for reduced fetal growth.
We observed a significantly lower risk of PMS in women with high intakes of thiamine and riboflavin from food sources only. Further research is needed to evaluate the effects of B vitamins in the development of premenstrual syndrome.
Tuberculosis is highly prevalent worldwide, accounting for nearly two million deaths annually. Vitamin D influences the immune response to tuberculosis, and vitamin D deficiency has been associated with increased tuberculosis risk in different populations. Genetic variability may influence host susceptibility to developing active tuberculosis and treatment response. Studies examining the association between genetic polymorphisms, particularly the gene coding for the vitamin D receptor (VDR), and TB susceptibility and treatment response are inconclusive. However, sufficient evidence is available to warrant larger epidemiologic studies that should aim to identify possible interactions between VDR polymorphisms and vitamin D status.
In summary, obesity is associated with decreased serum folate, which parallels decreased folate intakes. In contrast, obesity is positively associated with RBC folate. Therefore, RBC folate, in addition to serum folate, should also be considered as a critical biomarker for folate status, especially in the obese population. Future research is needed to understand how obesity differentially alters serum and RBC folate status because they are associated with a variety of medical complications.
Maternal vitamin status contributes to clinical spontaneous abortion, but the role of B-vitamin and homocysteine status in subclinical early pregnancy loss is unknown. Three-hundred sixty-four textile workers from Anqing, China, who conceived at least once during prospective observation (1996-1998), provided daily urine specimens for up to 1 year, and urinary human chorionic gonadotropin was assayed to detect conception and early pregnancy loss. Homocysteine, folate, and vitamins B6 and B12 were measured in preconception plasma. Relative to women in the lowest quartile of vitamin B6, those in the third and fourth quartiles had higher adjusted proportional hazard ratios of conception (hazard ratio (HR)=2.2, 95% confidence interval (CI): 1.3, 3.4; HR=1.6, 95% CI: 1.1, 2.3, respectively), and the adjusted odds ratio for early pregnancy loss in conceptive cycles was lower in the fourth quartile (odds ratio=0.5, 95% CI: 0.3, 1.0). Women with sufficient vitamin B6 had a higher adjusted hazard ratio of conception (HR=1.4, 95% CI: 1.1, 1.9) and a lower adjusted odds ratio of early pregnancy loss in conceptive cycles (odds ratio=0.7, 95% CI: 0.4, 1.1) than did women with vitamin B6 deficiency. Poor vitamin B6 status appears to decrease the probability of conception and to contribute to the risk of early pregnancy loss in this population.
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