[Breast-feeding and the mother's sentiment towards child rearing. Analysis of database on health checkups].

OBJECTIVES: This study aimed to identify the breast-feeding rate and associated factors and to get better understanding on the mother's sentiment towards child rearing due to differences in feeding methods. This information can be used as primary sources providing effective support through community-based health care for mothers and infants. METHODS: The study was carried out in Osaka city from April 2005 to December 2009. Data from the health-checkup records on infants aged 3-5 months were used after excluding any personal information. The data used included feeding methods (exclusive breast-feeding, mixed-feeding, and bottlefeeding), gestational age, multiple pregnancy status, gender, birth weight, use of an incubator, and birth year. Moreover, the data included the following maternal factors: planned or unplanned nature of pregnancy, smoking and drinking status during pregnancy, presence or absence of pregnancy-induced hypertension, maternal age at delivery, working status, presence or absence of financial anxiety, presence or absence of child-rearing support, presence or absence of individuals who can provide advice concerning child rearing, and sentiments of mothers during child rearing. RESULTS: From April 2005 to December 2009, 2552 infants underwent health checkups designed for infants. Of these, data on 2476 children, excluding 61 infants with unknown feeding methods and 15 infants aged 6 months, were used for analyses. The results showed that 56.6%, 28.7%, and 14.7% of children received exclusive breast-feeding, mixed-feeding, and bottle-feeding, respectively. Infant feeding methods were significantly associated with the birth year: in recent years, a decrease in the number of mothers who chose to bottle-feed their infants was observed. Furthermore, the feeding methods were associated with multiple births, birth weight, maternal smoking status during pregnancy, and maternal age at delivery. The results revealed that mothers who chose to breast-feed exclusively enjoyed child rearing at a significantly higher rate of 93.4%00, compared to 88.4%0 of mothers who chose to bottle-feed or mixed-feed. CONCLUSION: The study revealed that among infants aged from 3 to 5 months, 57% and 15% were exclusively breast-fed and bottle-fed, respectively; additionally, the proportion of bottle-fed infants declined every year. A significantly larger number of exclusively breast-feeding mothers enjoyed child rearing than the bottle-feeding or mixed-feeding mothers. These feeding methods were associated with multiple births, birth weight, maternal smoking status during pregnancy, and maternal age at delivery.

[An outbreak of tuberculosis in which environmental factors influenced tuberculosis infection].

OBJECTIVE: We encountered a contact group investigation in which differences in environmental factors, including the ventilation frequency and the airflow, led to differences in the infection risk. MATERIALS AND METHODS: The index case was diagnosed with tuberculosis after cough and sputum persisted for 9 months. The patient was an instructor working at vocational schools A and B. Sixty-six instructors/staff and 446 students had contact with this patient at the schools. The patient taught 24 regular courses and 21 short-term courses at the 2 schools after symptom onset through to the final day of work. RESULTS: In a contact investigation of instructors/staff, one person with latent tuberculosis infection (LTBI) was identified. Subsequently, 30 and 240 students with the closest contacts and those with 8-hour or longer contact with the index case, respectively, were examined. In School A, of the 162 students examined, one student developed tuberculosis, 7 were QFT-positive, one was QFT-doubtful, 147 were QFT-negative or judged as not infected (either QFT-negative, or a tuberculin skin test of erythema less than 20 mm, including past history of LTBI treatment or TB treatment), and 6 were not examined. In School B, of the 108 students examined, no one developed tuberculosis nor was QFT-positive, 4 were QFT-doubtful, 98 were either QFT-negative or judged as not infected, one was QFT-indeterminate, and 5 were not examined. Since the onset of tuberculosis and QFT-positivity occurred in only School A, the difference in the incidence of infection between the 2 schools, despite the levels of contact being similar, was assumed to be due to environmental factors. Thus, the ventilation frequency, which had been not reported initially, was reinvestigated. The frequency of air change was as low as 0.45-1/hour in School A, whereas it was better (3.57-7/hour) in School B. Moreover, the air flew from the instructor side toward students in School A, while it was reversed in School B. DISCUSSION: It was clarified that the ventilation frequency and airflow markedly influenced infection. It is important to investigate environmental factors on epidemiological investigations and to educate people regarding the importance of ventilation.

[Comparative performance of tuberculin skin test and QuantiFERON TB-gold in contact investigations for tuberculosis].

OBJECTIVES: To evaluate the performances of the QuantiFERON TB-Gold assay (QFT) and tuberculin skin test (TST) and to examine how a latent tuberculosis infection (LTBI) should be diagnosed in contact investigations of children aged 6 to 17 years. METHODS: A total of 232 boys and girls aged 6 to 17 years who were in contact with 134 culture-confirmed pulmonary tuberculosis patients (index cases) were examined both with QFT and TST. Factors influencing the results of the tests and their interactions were evaluated with multivariate analyses. RESULTS: Two variables (whether household contact and with/without contact with a cavitary disease patient) were found to significantly predict a positive QFT result. Positive TST defined with erythema being either greater than 20 mm or 30mm correlated significantly with two variables (whether household contact and with/without contact with a smear positive patient). There was moderate agreement between QFT and TST (positivity defined as with erythema greater than 30mm), with kappa=0.49, for contacts aged 6 to 11 years. Among contacts aged 6 to 11 years, 14 had a negative QFT result and TST with erythema greater than 30 mm. Of these 14, 7 contacts (50%) of smear positive index case were not indicated for LTBI treatment. CONCLUSIONS: When diagnosing LTBI among contacts aged 6 to 11 years who show negative QFT and strong TST reactions, we should take into consideration the factors related with a higher probability to the risk of infection. Because a history of past BCG vaccination is more likely to affect TST results in those aged 12 to 17 years than in younger subjects, greater care must be taken when evaluating the TST of these contacts.

[Discussion on evidence for principle of tuberculosis contact investigation--from the experience in Osaka City].

Risk factors for tuberculosis transmission from patients to contacts were found to be younger age, presence of cavitary lesion in chest X-ray findings, shedding higher number of organisms, longer duration of respiratory symptoms, longer hours of contact, and smaller space of contact environment. It should be noted that even casual contacts identified by contact investigation developed tuberculosis later on. In the past contact investigation and subsequent latent TB infection (LTBI) treatment, preventive effects of tuberculosis was obvious, although there might be some over-diagnosis of LTBI with tuberculin skin testing (TST). Introduction of interferon-gamma release assay (IGRA) added to TST seems to increase specificity and reduce over-diagnosis of TB infection. However in case of outbreak investigation in schools, screening by TST is still effective and efficient. Only those case with 30mm or over of redness (equivalent of 15 mm of induration) of TST were tested with QFT, IGRA. If anyone shows positive QFT, test of QFT would be expanded to the contact with TST of less than 30 mm.

[Tuberculosis infection by tuberculin skin test or QuantiFERON and related factors in contact investigations].

OBJECTIVE: We investigated the factors related to secondary infections in contact group investigations. METHOD: From March, 2008 to February, 2009, a total of 457 tuberculosis (TB) notifications were reviewed by the Health Examination Committee of the Health Centers of Osaka City over indications of a contact investigation. A contact investigation was considered necessary for 92 cases with 620 contacts. For the contacts of these cases, the tuberculin skin test (TST) or/and QuantiFERON-TB 2nd Generation (QFT) was used. The contacts testing positive for QFT were classified as "infected". The contacts with "doubtful" QFT were classified as either "infected" or "non-infected" according to the QFT-positive rate of the group as a whole. Those with blisters in TST were classified as "infected". RESULTS: Among the total of 84 "infected" cases thus defined, 56 were QFT-positive, 17 were doubtful, and 11 had blisters with TST. On the other hand, among the total of 515 "uninfected" cases, 18 were doubtful on the QFT test, 323 were QFT-negative and 174 were cases with TST of erythema less than 30 mm without QFT test. The relationship between characteristics of index cases and whether a contact was infected or not was as follows: Severe chest X-ray findings, sputum smear positivity, and a cough persisting for more than two months were significantly associated with infection of the contacts. The closeness of contact was also significantly related with a higher risk of infection, so that contact with an index case for more than 100 hours, and contact in a space less than 100 square meters were more likely to cause transmission of infection. CONCLUSION: Severity of chest X-ray findings, degree of smear positivity and period of cough were confirmed to be important in judging whether investigations are necessary. The time and space of contact were also considered to be important factors. We should consider these factors comprehensively in order to decide on indications for a contact investigation.