[A case-control study on risk factors that associated with severe hand-foot-mouth disease in Shanghai]

To explore the factors associated with severe hand-food-mouth disease (HFMD) case in Shanghai.

A total of 105 severe HFMD cases diagnosed from May to July, 2011 in Shanghai were enrolled as case group while another 210 mild HFMD cases were randomly selected as control group in the same period. All subject's parents or babysitters were asked to fill in the questionnaire in which including demography, ways of babysitting, behavior and the like. All HFMD cases were diagnosed by both clinical symptom and nuclear acid testing. Data was processed by EpiData (V3.0) and analyzed by SPSS (V17.0).

Factors as age, gender, Diaspora pattern, migrant, size of house, numbers of family member, numbers of children, frequency of seeing doctor, dishware that sharing with babysitter, food chewed by babysitter, dirty hand, EV71 virus type and diagnosis on HFMD in the fist visit to hospital were found associated with severe HFMD by univariate analysis.

through multivariate logistic regression showed that factors including: being the only male kid, more than 3 children in the family, dirty hands, unable to be diagnosed as HFMD in the first visit to the hospital, visiting doctor during the past 6 months for 2 and 3 times etc. could be kept in the model with statistical threshold of 0.05. Adjusted ORs and confidence intervals of them were 2.431 (1.317 - 4.487), 2.661 (1.332 - 5.315), 3.403 (1.871 - 6.191), 6.607 (3.011 - 14.500), 2.431 (1.111 - 5.321), 2.628 (1.137 - 6.071) respectively. Being Infected by EV71 was also found a very important risk factor compared with CoxA16 or other enteroviruses, and its adjusted OR was 5.614 (2.409 - 13.082).

It was necessary to implement molecular diagnosis for identifying the virus type of HFMD, together with improvement on the capacity of clinical diagnosis in order to diagnose the HFMD cases earlier. More attention should be paid to these HFMD cases with EV71 infection as well as prompting frequent visits to hospitals on those families with more children.