Dietary exposure to polychlorinated biphenyls is associated with increased risk of stroke in women.

OBJECTIVE: The potentially beneficial effects of fish consumption on stroke may be modified by major food contaminants in fish. Polychlorinated biphenyls (PCBs) in particular are proposed to play a role in the aetiology of stroke. The aim of this study was to assess the association between dietary PCB exposure and stroke risk with the intake of long-chain omega-3 fish fatty acids and fish consumption. DESIGN: The prospective population-based Swedish Mammography Cohort was examined. It was comprised of 34,591 women free of cardiovascular diseases and cancer at baseline in 1997 and followed up for 12 years. Validated estimates of dietary PCB exposure were obtained via a food frequency questionnaire at baseline. Incident cases of stroke were ascertained through register linkage. RESULTS: During 12 years of follow-up (397,309 person-years), there were 2015 incident cases of total stroke (1532 ischaemic strokes, 216 intracerebral haemorrhages, 94 subarachnoid haemorrhages and 173 unspecified strokes). Multivariable-adjusted relative risks (RR), controlled for known stroke risk factors and fish consumption, were 1.67 [95% confidence interval (CI), 1.29-2.17] for total stroke, 1.61 (95% CI, 1.19-2.17) for ischaemic stroke and 2.80 (95% CI, 1.42-5.55) for haemorrhagic stroke for women in the highest quartile of dietary PCB exposure (median 288 ng day(-1) ) compared with women in the lowest quartile (median 101 ng day(-1) ). CONCLUSION: Dietary exposure to PCBs was associated with an increased stroke risk in women, especially haemorrhagic stroke. The results provide important information regarding the risk-benefit analysis of fish consumption, particularly for cerebrovascular disease prevention.

Assessment of early-life lead exposure in rural Bangladesh.

Lead is a well-known neurotoxic metal and one of the most toxic chemicals in a child's environment. The aim of this study was to assess early-life lead exposure in a pristine rural area of Bangladesh. The exposure was expected to be very low because of the absence of vehicle traffic and polluting industries. Lead was measured in erythrocytes, urine, and breast milk of 500 randomly selected pregnant women, participating in a randomized food and micronutrient supplementation trial in Matlab (MINIMat). Lead was also measured in urine of their children at 1.5 and 5 years of age, and in rice, well water, cooking pots, and materials used for walls and roof. All measurements were performed using ICPMS. We found that the women had relatively high median erythrocyte lead levels, which increased considerably from early pregnancy to late lactation (81-136microg/kg), probably due to release from bone. Urinary lead concentrations were unchanged during pregnancy (median approximately 3.5microg/L) and non-linearly associated with maternal blood lead levels. Children, at 1.5 and 5 years of age, had a median urinary lead concentration of 4microg/L, i.e., similar to that in their mothers. Rice, the staple food in Matlab, collected from 63 homes of the study sample, contained 1-89microg/kg (median 13microg/kg) dry weight and seems to be an important source of lead exposure. Other sources of exposure may be cooking pots and metal sheet roof material, which were found to release up to 380 and 4200microg/L, respectively, into acidic solutions. Based on breast milk lead concentrations (median 1.3microg/L) a median daily intake of 1.2microg was estimated for 3 months old infants. However, alternatives to breast-feeding are likely to contain more lead, especially rice-based formula. To conclude, lead exposure in women and their children in a remote unpolluted area was found to be surprisingly high, which may be due to their living conditions.

Factors influencing intestinal cadmium uptake in pregnant Bangladeshi women--a prospective cohort study.

Experimental studies indicate that zinc (Zn) and calcium (Ca) status, in addition to iron (Fe) status, affect gastrointestinal absorption of cadmium (Cd), an environmental pollutant that is toxic to kidneys, bone and endocrine systems. The aim of this study was to evaluate how various nutritional factors influence the uptake of Cd in women, particularly during pregnancy. The study was carried out in a rural area of Bangladesh, where malnutrition is prevalent and exposure to Cd via food appears elevated. The uptake of Cd was evaluated by associations between erythrocyte Cd concentrations (Ery-Cd), a marker of ongoing Cd exposure, and concentrations of nutritional markers. Blood samples, collected in early pregnancy and 6 months postpartum, were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Ery-Cd varied considerably (range: 0.31-5.4microg/kg) with a median of 1.1microg/kg (approximately 0.5microg/L in whole blood) in early pregnancy. Ery-Cd was associated with erythrocyte manganese (Ery-Mn; positively), plasma ferritin (p-Ft; negatively), and erythrocyte Ca (Ery-Ca; negatively) in decreasing order, indicating common transporters for Cd, Fe and Mn. There was no evidence of Cd uptake via Zn transporters, but the association between Ery-Cd and p-Ft seemed to be dependent on adequate Zn status. On average, Ery-Cd increased significantly by 0.2microg/kg from early pregnancy to 6 months postpartum, apparently due to up-regulated divalent metal transporter 1 (DMT1). In conclusion, intestinal uptake of Cd appears to be influenced either directly or indirectly by several micronutrients, in particular Fe, Mn and Zn. The negative association with Ca may suggest that Cd inhibits the transport of Ca to blood.