Association of dietary and supplemental iron and colorectal cancer in a population-based study.

We evaluated the role of dietary iron, heme iron, and supplemental iron on colorectal cancer (CRC) risk in a population-based case-control study in Pennsylvania, including 1005 incident cases and 1062 controls. Diet was assessed through a modified food frequency questionnaire that included supplement use and a meat-specific module. Cases reported intakes for the year before diagnosis, whereas controls reported intakes for the year before interview. Heme iron intake was calculated using a new heme database developed by the US National Cancer Institute. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. After multivariate adjustment, there were no significant associations between heme iron or total iron intake and CRC incidence. Dietary iron intake was inversely associated with CRC among women (OR Q5 vs. Q1=0.45; 95% CI=0.22-0.92), but not among men. Supplemental iron intake of more than 18 mg/day versus none was positively associated with CRC incidence (OR=2.31; 95% CI=1.48-3.59; P-trend<0.001), an effect that was observed in both men (OR=2.56; 95% CI=1.30-5.05) and women (OR=2.46; 95% CI=1.34-4.52). These findings suggest that consumption of more than 18 mg/day of supplemental iron may increase risk for CRC.

Reduced risk for placental malaria in iron deficient women.

BACKGROUND: Nutritional iron deficiency may limit iron availability to the malaria parasite reducing infection risk, and/or impair host immunity thereby increasing this risk. In pregnant women, there is evidence of an adverse effect with iron supplementation, but the few reported studies are strongly confounded. METHODS: A case control study in pregnant Malawian women was undertaken in Chikhwawa southern Malawi in order to describe iron status in relation to placental malaria controlling for several confounding factors. Pregnancy characteristics were obtained and a blood sample at delivery. A full blood count was performed and serum ferritin and transferrin receptor quantified by enzyme-linked immunoassay. DNA analysis was used to identify genetic polymorphisms for ABO phenotype, hemoglobin HbS, and glucose -6 phosphate dehydrogenase deficiency. Placental tissue was obtained and malaria histology classified as active, past or no malaria infection. RESULTS: 112 cases with placental malaria were identified and 110 women with no evidence of placental infection. Iron deficiency was less frequent in women with placental Plasmodium falciparum infection. In those with acute, chronic or past placental infections the odds ratio for iron deficiency was 0.4, 95% CI 0.2-0.8, p = 0.01; for acute and chronic infections 0.4, 0.2-0.8, p = 0.006; for acute infection 0.3, 0.1-0.7, p = 0.001. The association was greater in multigravidae. CONCLUSION: Women with either acute, or acute and chronic placental malaria were less likely to have iron deficiency than women without placental malaria infection There is a priority to establish if reversing iron deficiency through iron supplementation programs either prior to or during pregnancy enhances malaria risk.

Serum and breast-milk vitamin A in women during lactation in rural Chiang Mai, Thailand.

Vitamin A deficiency can occur during lactation and breast-milk vitamin A has been recommended for monitoring the vitamin A status of lactating women and their infants. This study aimed to investigate the vitamin A status of lactating women in relation to race, age, parity, duration of lactation and anthropometric status. A cross-sectional study was conducted among 262 lactating women in rural Chiang Mai, Thailand. Blood and breast-milk samples were collected. Serum retinol, carotene and breast-milk retinol concentrations were analysed by high-performance liquid chromatography. The results show that mean serum retinol and breast-milk retinol in hill tribes were significantly lower than in Thais, 1.91 (0.59) and 0.79 (0.52) compared with 2.10 (0.51) and 1.04 (0.58) mumol/L, respectively. Mean serum retinol and breast-milk retinol were highest during the 1st 3 months of lactation. Maternal age, parity and anthropometric status (BMI) were not associated with serum or breast-milk retinol concentrations. There was a significant relationship between serum and breast-milk retinol values in women who breastfed for 6 months or longer (regression co-efficients 0.30; 95% CI 0.16, 0.43). Breast-milk retinol levels declined significantly from 4 to 12 months after delivery, which could increase the risk of vitamin A deficiency in children who were exclusively breastfed or receiving inappropriate complementary foods during this period. Weaning foods which commence at 6 months and have an adequate vitamin A content should ensure that the vitamin A status of the young child is maintained.