2004年曾有瑞典學者 (Bornehag et al, 2004) 以病例--對照研究方法(Case-Control Study)探討鄰苯二甲酸與兒童氣喘(Asthma)及過敏症狀(Allergic Symptoms)的相關性。但該研究被 The European Council for Plasticisers and Intermediates (ECPI)認定為有錯誤，因為他們並未將一些眾所周知與兒童氣喘及其他呼吸相關疾病的重要因子納入考量。另外，在資料蒐集方面，病例組收案條件是: “須於初次受訪前12個月內至少在3種過敏性疾病 (氣喘、過敏性鼻炎(Allergic Rhinitis)或異位性皮膚炎(Atopic Eczema))中發生2種以上的症狀”，但當時有關居住環境中DEHP濃度的相關訊息無法獲得，而以收案後測得之濃度來分析，難以釐清兩者間因果關係。
Medical devices made from polyvinyl chloride (PVC) will add phthalates as the plasticizers to make the devices soft and pliable. The most widely used phthalate in medical devices is DEHP (di-ethyl-hexyl-phthalate). Many pediatric related literatures have demonstrated that the intensiveness of DEHP-containing product use in NICU (Neonatal Intensive Care Unit) neonates is associated with higher exposure to DEHP, as reflected in elevated urinary concentrations of MEHP (mono-2-ethylhexyl phthalate), which is one of the major urinary metabolites of DEHP.
In 2004, a group of Swedish scientists (led by Carl-Gustaf Bornehag) conducted a case-control study to explore the association between asthma and allergic symptoms in children and the use of phthalate plasticizers. However, the European Council for Plasticizers and Intermediates (ECPI) believes this study is flawed as it does not appear to take into consideration a number of key factors which are widely known and accepted as being significant contributors to asthma and other respiratory diseases. Furthermore, the authors indicate within the introduction that the cases and controls were actually selected from an early cross-sectional survey. Therefore, cases had at least two out of three symptoms of asthma, allergic rhinitis or atopic eczema at the start of the study, before any environmental samples were collected. This raises the real possibility that the phthalate-disease associations were a result of case status, rather than a cause.
Therefore, besides all information about the PVC medical devices, the parental and household allergic information will be recorded. The allergic symptoms we focus on are stomach symptom, allergic breathing passages, allergic rhinitis or atopic eczema. In this study, we try to figure out whether the potential hazardous of PVC medical devices have significant effects to allergic symptoms in neonates directly or not. The results of this study showed that the frequency of using PVC medical devices in NICU was significantly higher than NBC. However, the risks of four allergic symptoms in both units were no significant difference.