Results-Significant associations were found between hospital admissions for all respiratory diseases, all cardiovascular diseases, chronic obstructive pulmonary diseases, and heart failure and the concentrations of all four pollutants. Admissions for asthma, pneumonia, and influenza were significantly associated with NO 2 , O 3, and PM 10 . Relative risk (RR) for admissions for respiratory disease for the four pollutants ranged from 1.013 (for SO 2 ) to 1.022 (for O 3 ), and for admissions for cardiovascular disease, from 1.006 (for PM 10 ) to 1.016 (for SO 2 ). Those aged >65 years were at higher risk. Significant positive interactions were detected between NO 2 , O 3 , and PM 10 , and between O 3 and winter months. Conclusions-Adverse health eVects are evident at current ambient concentrations of air pollutants. Further reduction in air pollution is necessary to protect the health of the community, especially that of the high risk group. (Occup Environ Med 1999;56:679-683)

We studied transmission patterns of severe acute respiratory syndrome (SARS) among medical students exposed exclusively to the first SARS patient in the Prince of Wales Hospital in Hong Kong, before his illness was recognized. We conducted a retrospective cohort study of 66 medical students who visited the index patient’s ward, including 16 students with SARS and 50 healthy students. The risk of contracting SARS was sevenfold greater among students who definitely visited the index case’s cubicle than in those who did not (10/27 [41%] versus 1/20 [5%], relative risk [RR] 7.4; 95% confidence interval [CI] 1.0 to 53.3). Illness rates increased directly with proximity of exposure to the index case. However, four of eight students who were in the same cubicle, but were not within 1 m of the index case-patient, contracted SARS. Proximity to the index case-patient was associated with transmission, which is consistent with droplet spread. Transmission through fomites or small aerosols cannot be ruled out.

From July 1992 to March 1993, we conducted a community-based prevalence survey of migraine and other types of recurrent headache by a telephone interview of 2,240 households with 7,356 persons aged 15 and above. 311 patients with recurrent headache were successfully interviewed. Of these, 101 were clinically validated. The overall prevalence rates were 1% for migraine, 2% for tension-type headache and 1% for unclassified headache. Adjusted for misclassification and non-response, the estimated prevalence rates for the three categories were 1.5, 3 and 0.4%, respectively. Agreement between clinical method and questionnaire interview was good for migraine, fair for tension-type headache and poor for unclassified headache. For all three types of recurrent headache, there was a female preponderance with a peak in the 25–44 age group. The prevalence of migraine was much lower than in Western communities but higher than that found in mainland China [1–8]. Common predisposing and aggravating factors for all three types of headaches as reported by the patients were mental stress, physical exertion and menstruation among females. Despite the low prevalence, the overall socioeconomic impact to a populous community is considerable.

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Aims: To explore the association of household gas cooking and respiratory illnesses in preschool children and their relation to outdoor air pollution. Methods: Cross-sectional study among households that used gas stoves for cooking in two housing estates with contrasting air qualities in Hong Kong. A structured questionnaire was administered to parents of 426 children aged 0-6 years on their exposure to gas cooking and passive smoking, and the prevalence of respiratory illnesses. Results: A total of 111 children (26.1%) were reported to have one or more respiratory illnesses (allergic rhinitis, asthma, bronchitis, sinusitis, and pneumonia). Of these, 21 (18.9%), 41 (36.9%), and 49 (44.1%) children were from households that cooked once, twice, and three times a day with gas. Hierarchical logistic regression models adjusting for socioeconomic, demographic, and indoor risk factors including passive smoking showed that household gas cooking was positively associated with respiratory illnesses. There was a dose-response relation between the frequency of gas cooking and the prevalence of respiratory illnesses in the estate with lower outdoor air pollution (OR = 6.1 and 3.2 respectively, for cooking three and two meals a day, compared to one meal a day). This relation was not observed in the more polluted estate. The association between the presence of a cigarette smoker in the household and the prevalence of respiratory illnesses was not significant. Conclusions: As gas cooking is common in urban households, the findings could have important public health implications.