Evaluation report on the causal association between humidifier disinfectants and lung injury / 한국역학회지

OBJECTIVES: As of November 2011, the Korean government recalled and banned humidifier disinfectants (HDs) from the market, because four case-control studies and one retrospective epidemiological study proved the association between HDs and lung injury of unknown cause. The report reviewed the causal role of HDs in lung injury based on scientific evidences. METHODS: A careful examination on the association between the HDs and lung injury was based on the criteria of causality inference by Hill and the US Surgeon General Expert Committee. RESULTS: We found that all the evidences on the causality fulfilled the criteria (strength of association, consistency, specificity, temporality, biologic gradient, plausibility, coherence, experiment, analogy, consideration of alternative explanations, and cessation of exposure), which proved the unknown cause lung injury reported in 2011 was caused by the HDs. In particular, there was no single reported case of lung injury since the ban in selling HDs in November 2011 as well as before the HDs were sold in markets. CONCLUSIONS: Although only a few epidemiological studies in Korea have evaluated the association between lung injury and the use of HDs, those studies contributed to proving the strong association between the use of the HDs and lung injury, based on scientific evidence.

Homocysteine in occlusive vascular disease: A risk marker or risk factor.

Homocysteine has emerged as a significant marker for occlusive vascular disease, but there has been some debate as to whether it is just an association (risk marker) or actually a causative factor (risk factor). To elucidate this, a retrospective statistical analysis was done of data generated in the course of our study on homocysteine and vascular disease. Homocysteine, lipid profile components and lipoprotein(a) were estimated in fasting blood samples drawn from 252 controls and 536 patients of occlusive vascular disease. The data were analyzed by SPSS version 17. Mean homocysteine levels were significantly higher (p<0.001) in all patients categories, as compared to controls. In fact, homocysteine level was the most significant biochemical risk factor for vascular disease. The odds ratios due to hyperhomocysteinemia varied from 3.170-4.153. When the cut-off was increased by 5 µmol/L, the odds ratio became almost three-fold. The prevalence of hyperhomocysteinemia increased by @20%, when the cut-off was reduced by 5 µmol/L. Statistical analysis of our data revealed that homocysteine conformed to Hill’s criteria of causation. Moreover, hyperhomocysteinemia was treatable by the administration of B-vitamins, even if the cause was genetic. Hence morbidity due to vascular disease could be reduced by identification and treatment of hyperhomocysteinemia.