Abstract：
BACKGROUND: Several studies found an association between periconceptional folic acid supplementation and the risk of childhood asthma. But the epidemiologic evidence is still inconsistent and the underlying biological mechanisms remain unclear.
METHODS: We conducted a hospital-based case-control study on childhood asthma with 548 cases and 816 normal controls in Shanghai, China. Mothers of the asthma children were asked about folic acid supplementation before and during pregnancy. Unconditional logistic regression models were employed to control for potential confounders.
RESULTS: Periconceptional folic acid supplementation was associated with an increased risk of childhood asthma after adjusting for potential confounders (adjusted OR = 1.28 [95% CI 1.14-1.43]). Moreover, the adjusted OR varied by the timing of starting folic acid supplementation: before gestation: 1.31 [95% CI 1.01-1.70]; in the 1st month of gestation: 1.09 [95% CI 0.96-1.23]; and after the 1st month of gestation: 1.90 [95% CI 1.56-2.30]. We further found that the adjusted OR was the highest when periconceptional folic acid supplementation lasted more than 6 months (< 4 months: 1.21 [95% CI 1.07-1.37]; 4-6 months: 1.06 [95% CI 0.88-1.27]; > 6 months: 1.75 [95% CI 1.35-2.27]).
CONCLUSIONS: Periconceptional folic acid supplementation was associated with an increased risk of childhood asthma in offspring. Further research on this issue is warranted.
METHODS: We conducted a hospital-based case-control study on childhood asthma with 548 cases and 816 normal controls in Shanghai, China. Mothers of the asthma children were asked about folic acid supplementation before and during pregnancy. Unconditional logistic regression models were employed to control for potential confounders.
RESULTS: Periconceptional folic acid supplementation was associated with an increased risk of childhood asthma after adjusting for potential confounders (adjusted OR = 1.28 [95% CI 1.14-1.43]). Moreover, the adjusted OR varied by the timing of starting folic acid supplementation: before gestation: 1.31 [95% CI 1.01-1.70]; in the 1st month of gestation: 1.09 [95% CI 0.96-1.23]; and after the 1st month of gestation: 1.90 [95% CI 1.56-2.30]. We further found that the adjusted OR was the highest when periconceptional folic acid supplementation lasted more than 6 months (< 4 months: 1.21 [95% CI 1.07-1.37]; 4-6 months: 1.06 [95% CI 0.88-1.27]; > 6 months: 1.75 [95% CI 1.35-2.27]).
CONCLUSIONS: Periconceptional folic acid supplementation was associated with an increased risk of childhood asthma in offspring. Further research on this issue is warranted.
摘要：
背景：一些研究发现，周觉叶酸补充与儿童哮喘的风险之间存在关联。但是流行病学证据仍然不一致，潜在的生物学机制仍不清楚。
方法：我们进行了一项以医院为基础的病例对照研究，在上海有548例儿童哮喘和816例正常对照，中国。哮喘儿童的母亲被问及怀孕前和怀孕期间补充叶酸的情况。采用非条件逻辑回归模型来控制潜在的混杂因素。
结果：在调整了潜在的混杂因素后，周觉叶酸补充与儿童哮喘风险增加相关(调整后的OR=1.28[95%CI1.14-1.43])。此外，调整后的OR值根据开始补充叶酸的时间而变化:妊娠前:1.31[95%CI1.01-1.70];妊娠第1个月:1.09[95%CI0.96-1.23];妊娠第1个月后:1.90[95%CI1.56-2.30].我们进一步发现，当补充叶酸持续6个月以上时，校正OR最高（<4个月：1.21[95％CI1.07-1.37]；4-6个月：1.06[95％CI0.88-1.27]；>6个月：1.75[95％CI1.35-2.27]）。
结论：周觉叶酸补充与后代儿童哮喘风险增加相关。有必要对此问题进行进一步研究。
方法：我们进行了一项以医院为基础的病例对照研究，在上海有548例儿童哮喘和816例正常对照，中国。哮喘儿童的母亲被问及怀孕前和怀孕期间补充叶酸的情况。采用非条件逻辑回归模型来控制潜在的混杂因素。
结果：在调整了潜在的混杂因素后，周觉叶酸补充与儿童哮喘风险增加相关(调整后的OR=1.28[95%CI1.14-1.43])。此外，调整后的OR值根据开始补充叶酸的时间而变化:妊娠前:1.31[95%CI1.01-1.70];妊娠第1个月:1.09[95%CI0.96-1.23];妊娠第1个月后:1.90[95%CI1.56-2.30].我们进一步发现，当补充叶酸持续6个月以上时，校正OR最高（<4个月：1.21[95％CI1.07-1.37]；4-6个月：1.06[95％CI0.88-1.27]；>6个月：1.75[95％CI1.35-2.27]）。
结论：周觉叶酸补充与后代儿童哮喘风险增加相关。有必要对此问题进行进一步研究。
