| ObjectiveRecent years, type 1 diabetes mellitus has become a common endocrinopathy in childhood.It appears urgently and has serious syndromes. If one suffers f-rom the type 1 diabetes,he will be treated with insuline for his left lifetime,which does harm to human living quality and natural life seriously. From the worldwide, about 100,000 children aging below fifteen are suffering from type 1 diabete seach year and the case number is going up. The incidence of type 1 diabetes has tended to rise since 1980s, especially fast in the people with low inc-idence rates, which implies that environmental factors may be critical in the disease happening,but the true reason is not clear. Shenyang is the place where the incidence rate of type 1 diabetes mellitus of child is very high and increaseevidently. It is the more important that the research about it is few in Shenya-ng,even few in China. In order to find the environmental risk factors of children type 1 diabetes and prevent them effectively, we investigated the environmentalrisk factors with the case-control study of childhood diabetes in Shenyang City.Materials and MethodsCases were forty children with type 1 diabetes who were in hospital follow-up in endocrine division in hospital China Medical Unviersity and Shenyang Women and Infants Hospital from years 2003 to 2005.Controls were one hundredand sixty children who selected from community in Shenyang who did not suffer from type 1 diabetes. 1:4 matched case control study was used to carry out th-is investigation.We asked the parent some questions about the disease of historyof children, passive smoking in pregnancy,birth weight,feeding fashion and soon,then filled in the questionnaire. Univariate and multivariate conditional logisiticregression models was used to analysis the possible environmental risk factors infecting type 1 diabetes in Shenyang.ResultsThe univariate conditional logisitic regression analysis showed age of pregnancy, passive smoking in pregnancy,birth weight,history of suffering from respiratory infection,feeding fashion,time of infant feeding of cow's milk(1-3months after birth),intestinal infection and the history of hypersusceptibility might increase the disease risk. The odds ratios(OR) and its 95% confidence interval(CI) were 4.816(1.142-20.287), 3.248(1.283-8.224), 1.512(1.158-5.447), 17.150(3.695-79.599), 3.73(1.654-8.474), 9.300(2.25-38.436), 4.267(1.51-12.061), 6.488(1.168-36.053) and 2.181(1.014-4.639). Based on the univariate conditional logisitic regression analysis, theresult of the multivariate conditional logisitic regressive analysis showed age of pregnancy, passive smoking in pregnancy, time of infant feeding of cow's milk(1-3months) and the history of suffering from respiratory infection had significant relationship with type 1 diabetes(P<0.05),OR and its 95% CI were 4.963(1.487-16.56), 2.394(1.01-5.212),5.801(1.336-25.179),17.532(2.195-140.05),respectively.DiscussionThe univariate conditional logisitic regression analysis showed the infection(newborn respiratory infection,children respiratory infection and intestinal infection) was the environmental risk factors causing type 1 diabetes. Children respiratory infection was chosen into the model by univariate conditional logisitic regre-esion analysis(P=0.006,OR=17.532, OR 95%CI=2.195-140.05),which showed children respiratory infection played a key role in type 1 diabetes occurrence.The study also showed that passive smoking history during pregnancy made impact on children type 1 diabetes(P=0.031, OR=2.394, OR 95%CI=1.010-5.212).The possible explaination was when mother smoked passively, the poison of tobaccos(such as tar,nicotin,carbon monoxide and benzene)came into blood and placenta, which lead toβ-cell damadged and thus type 1 diabetes occurred in the timeof fetation. This study showed that the earlier the time of infant feed withcow s milk(1-3months after birth), the more closely relationship with type 1 diabetes. The relative ratio of type 1 diabetes caused by feeding with cow's milk was 5.801(OR95%CI=1.336-25.179), which illuminated that the earlier time of infant feeding with cow's milk increased the risk of type 1 diabetes. In the case-control study, univariate logistic regression showed birth weight was an environmental risk factor(OR=2.512, OR95%CI=1.158-5.447).But because P value was bigger than 0.05 in the multiple logistic regression, after controlled other factors,ithad not found to be statistically associated with type 1 diabetes. By our logisticregression analysis, the age of pregnancy might be associated with type 1 diabetes. The survey discovered when the range of the age of pregnancy was 22～33, the age of pregnancy increased 3 years every time, the risk of type 1 diabetes increased 4.963 times. The reason had not yet been identified. According to the literature reported and the case-control study, the possible reason was that the larger pregnancy age caused the gene mutation during the formation of embryo aandβ-cell aberrance, thus created the occurrence of type 1 diabetes.ConclusionsThe age of pregnancy, passive smoking in pregnancy,beginning time of infant feeded with cow's milk and the history of suffering from respiratory infection were environmental risk factors of type 1 diabetes in Shenyang city. |
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