ABSTRACT
Objective To explore the relationship between maternal passive smoking during early pregnancy and the risk of neural tube defects (NTDs). Methods Data was derived from a populationbased case-control study on birth defects in Shanxi province. The study subjects included 515 NTDs defects cases (236 cases of anencephaly, 237 spina bifida and 42 encephalocele) ascertained during January 2003 and June 2007 in the study areas and 682 normal controls randomly selected in the same residence during the same period as cases. Results The risk of NTDs in their offspring was 1.84 (95 % CI : 1.39-2.44) for mothers with passive smoking history during peri-conceptional period. There was a marked dose-response relation between maternal passive smoking and the risk of NTDs in offspring. Compared to the women without passive smoking, the NTDs risk in offspring was 1.51 for women with occasional passive smoking and 2.44 for women with passive smoking for almost everyday during the peri-conceptional period.Conclusion Maternal passive smoking during peri-conceptional period increased the risk of NTDs in offspring.
ABSTRACT
<p><b>OBJECTIVE</b>Dietary factors that could potentially be related to the risk of birth defects are still unknown in Shanxi province, a region with high prevalence of neural tube defects(NTDs) in China. The main aim of this study was to evaluate the association between NTDs and local dietary factors.</p><p><b>METHODS</b>A population-based case-control study was conducted during 2003-2005 in four selected counties of Shanxi province with 363 NTDs cases ascertained and 523 control babies without any external birth defects.</p><p><b>RESULTS</b>By multivariate logistic regression analysis, we found the NTDs risk was significantly associated with low consumption of meat and legume, high consumption of pickled vegetables, noncentralized supply of drinking water and drinking tea after adjusting for maternal education level and birth defects history. A significant dose response trend was found between the NTDs risk and the lower frequencies of meat and legume consumption and higher frequency of pickled vegetable consumption, with population attributable risks (PAR) of 69.4%, 22.0% and 18.5%, respectively. Mothers who got their drinking water from river or pond during periconceptional period were more likely to have a NTD-affected pregnancy [OR = 3.42, 95% CI: 1.44-8.09, population attributable risk (PAR) = 4.7%] compared with those who utilized tap or well water. Those who drank tea everyday had an elevated risk of having a NTD-affected pregnancy compared with those who didn't (OR = 4.65, 95% CI: 1.41-15.36, PAR = 2.6%).</p><p><b>CONCLUSION</b>Higher intake of meat and legume protects a woman from having a NTD-affected pregnancy, and consumption of pickled vegetables, drinking water from river or pond and drinking tea everyday increase the risk of having such a pregnancy in the study population.</p>
Subject(s)
Female , Humans , Pregnancy , Case-Control Studies , China , Epidemiology , Diet , Meat , Neural Tube Defects , Epidemiology , Risk Factors , Vegetables , Water SupplyABSTRACT
<p><b>OBJECTIVE</b>To study the prevalence rates of birth defects in high and low risk areas in China.</p><p><b>METHODS</b>A population-based surveillance system on birth defects was used to obtain the prevalence rates of 24 kinds of major external birth defects from > or = 20 weeks of gestation to 7 days of life in selected areas in Shanxi and Jiangsu provinces.</p><p><b>RESULTS</b>The birth prevalence of birth defects (232.4 per 10,000 births) and neural tube defects (NTDs) (138.7 per 10,000 births) in four counties of Shanxi province were significantly higher than that in Taiyuan city (75.3 and 28.2 per 10,000 births, respectively). There was no significant difference for all selected birth defects between Wuxi city and Xishan counties in low risk areas. There was a 6.1-fold of higher prevalence for NTDs in Taiyuan city compared with that in Wuxi areas (4.6 per 10,000 births). In four counties of Shanxi province, the prevalence rates of anencephaly, spina bifida, hydrocephaly, cleft palate alone and polydactyly were significantly higher than in Wuxi areas. The NTDs prevalence rate in four counties of Shanxi was 30.2 times higher than in Wuxi areas. When compared with previous surveillance data, the NTDs prevalence rate did not present obvious declining trend in high risk areas. The birth prevalence rate had a 31.8% decrease when births were calculated after 28 gestational weeks and compared with those from 20 gestational weeks.</p><p><b>CONCLUSION</b>NTDs remained to be the most common birth defect seen in Shanxi province. The birth prevalence rate of NTDs in some areas of Shanxi province was among the highest that ever reported in the world in comparison with data from other countries and regions. The current prevalence rate in high risk areas in Shanxi province did not clearly show a declining trend. Programs on surveillance and prenatal diagnosis were proved to have made big impact on the rates of major external birth defects.</p>