Limited agreement between written and video asthma symptom questionnaires.

The prevalence of asthma remains difficult to determine with precision with no absolute or "gold" standard for diagnosis. A recently developed video questionnaire for epidemiological studies with less reliance on understanding written questions provides another tool for determining prevalence and severity of asthma. This report from the International Study of Asthma and Allergies in Childhood (ISAAC) examines the agreement between the ISAAC video questionnaires on respiratory symptoms and reported asthma. Between December 1993 and April 1995, 4952 children aged 13-14 years in two Canadian communities completed sequentially the ISAAC written and video questionnaires at school. The agreement between responses to the two questionnaires for reported wheeze ever, current wheeze, wheeze on exercise, and nocturnal wheeze (the latter three questions relating to symptoms in the last 12 months), and to any combination of the latter three questions was examined in the full sample and in those reporting diagnosed asthma, using concordance and kappa coefficients as measures of agreement. The prevalences of wheeze ever, current wheeze, wheeze on exercise, and nocturnal wheeze were significantly lower based on responses to the video questionnaire compared with the written questionnaire in both regions in the full sample and in those labeled as having asthma. Although concordance between video and written questionnaires always exceeded 60% and often exceeded 70% for related questions, agreement measured by the kappa statistic for each question was only fair to moderate (kappa = 0.22-0.51). We conclude that the video questionnaire yields lower reported prevalence rates for asthma symptoms, and that there is limited agreement between responses to the two questionnaires that is not explained by issues of language, culture, or literacy.

Are wireless phones safe? A review of the issue.

Most wireless phones and their corresponding base stations operate at a very low power output and in the radiofrequency range of 800 to 2000 Megahertz. Current international guidelines protect against thermal biological effects in terms of the local or whole-body specific absorption rate (SAR). Potential non-thermal bio-effects resulting from the use of wireless phones are not established and laboratory (i.e., in vitro, in vivo) studies have shown conflicting results. Epidemiological studies of potential human health effects are few but are expected to emerge in the near future. Challenges to epidemiological research include difficult exposure assessment, selection of appropriate controls, potential confounding bias, and validation of outcome. Scientists, community advocacy groups, and public health professionals must be equipped to critically analyze the emerging evidence within a benefit/risk assessment framework.

Prevalence of asthma, rhinitis and eczema among children in 2 Canadian cities: the International Study of Asthma and Allergies in Childhood.

BACKGROUND: Wide variations in the prevalence of asthma, rhinitis and eczema have been reported between regions within Canada and between different countries. The International Study of Asthma and Allergies in Childhood (ISAAC) was developed to provide a standardized tool and methodology to ascertain the prevalence of asthma and allergies in different regions. Comparisons of prevalence rates across geographic regions and at different times may help to identify factors that contribute to the development of these conditions in individuals. METHODS: Two Canadian centres, Hamilton and Saskatoon, participated in the ISAAC. A standard questionnaire was distributed through schools and completed by 13- and 14-year-old children and by the parents of 6- and 7-year-old children. Prevalence rates and 95% confidence intervals were calculated for asthma, wheezing, rhinitis and eczema. RESULTS: The overall response rates were 75.1% among the children 6 and 7 years old and 68.6% among those 13 and 14 years old. Among the younger children, the lifetime prevalence of asthma was 17.2% in Hamilton and 11.2% in Saskatoon; the corresponding rates among the older children were 19.2% and 12.2% respectively. The prevalence of wheezing in the 12 months before the survey in the younger group was 20.1% in Hamilton and 14.1% in Saskatoon; in the older group it was 30.6% and 24.0% respectively. The prevalence of rhinitis in the 12 months before the survey was 28.6% in Hamilton and 22.6% in Saskatoon in the younger group and 45.8% and 33.8% respectively in the older group. The prevalence of eczema was slightly higher in Saskatoon in both age groups. INTERPRETATION: High prevalence rates of asthma, rhinitis and eczema exist among school children in Hamilton and Saskatoon, similar to rates in other Western countries. Further studies are required to determine the factors associated with the high rates in the 2 regions and possible reasons for the higher rates in Hamilton.

Hospital utilization of Saskatchewan people with fetal alcohol syndrome.

We describe the hospital utilization of 194 Saskatchewan persons with Fetal Alcohol Syndrome (88% Aboriginal), born between 1973-92. Complete provincial hospitalization data were obtained for 128 patients; partial data for 29 patients. Proportionately more persons missing data were adopted, not living with biological family members or were deceased. The hospital separation rates for the children with FAS, pooled from 1987-91, compared to the 1989-90 Saskatchewan rates were significantly higher (95% level of confidence) for males and females < 1 year, 1-4 years and 5-14 years of age. Relative to Saskatchewan Registered Indians, significantly higher hospitalization rate ratios were observed for males with FAS in all age groups and for females only age 5-14 years. Rate ratios for younger females may not have achieved significance because of missing data. Higher hospitalization rates in children with FAS may not be explained solely by factors associated with ethnicity.

Bone age and growth in fetal alcohol syndrome.

We have found delayed mean bone age in 63 children with fetal alcohol syndrome (FAS). The mean bone age Z-score for boys (n = 31) was -2.12 SDs and for girls (n = 32) was -1.62 SDs. This might suggest that they have potential for catch-up growth. However, experience with children with intrauterine growth retardation suggests that this will not be the case and that FAS children will be of reduced height at maturity. Further support for this assumption was gained from a sample of 26 patients who were followed until at least the age of 14 years for females and 16 years for males. There was no significant change in height Z-scores from early childhood to early adulthood, the mean score being -2.16 SDs and -2.11 SDs at mean ages of 4.83 years and 18.69 years, respectively. On the other hand, there were significant changes in weight and head circumference. The mean weight Z-score changed from -2.10 SDs to -1.14 SDs (p < 0.001). The head circumference mean Z-score in 16 patients was -3.13 SDs at a mean age of 2.79 years and -2.63 SDs at a mean age of 17.37 years (p = 0.013). Short stature can continue to be used as a diagnostic criterion for FAS beyond childhood.

Orienting medical education to community need: a review.

The literature on community-oriented medical education is reviewed. In response to major changes in the origin, expression and place of management of much illness, many medical schools are turning their attention increasingly to the community from whence to derive their curriculum and wherein to effect their teaching. The traditional hospital base of teaching is eroding, necessitating new, innovative approaches to medical education. Becoming community-oriented, or using community-based learning, offers potential benefits for the schools, the students, and the public. The experience of others demonstrates the necessity of enlisting community representatives as partners in the process of change. Institutional barriers are significant and careful planning is needed to overcome them.

Foetal alcohol syndrome in Saskatchewan: unchanged incidence in a 20-year period.

Despite major initiatives in public and professional education about foetal alcohol syndrome (FAS) in Saskatchewan in the last 20 years, its incidence rate has not fallen. The rate was 0.515 per 1,000 live births in 1973-1977 and 0.589 in 1988-1992. Two hundred and seven (207) cases were ascertained, the majority being patients of the Alvin Buckwold Child Development Program in Saskatoon. These individuals were severely handicapped: 72% had at least one malformation, the mean intelligence quotient was 67.8 (range 35-106) and 45.9% had a behaviour problem. Only 25.6% still lived with their biological parents when last seen, and only 27 of 108 cases were in a regular class at school without additional support being necessary. New approaches are needed to reduce the incidence of FAS. Emphasis should be placed on individual case-finding, counselling for high-risk women, and community development programs. We are currently attempting this through a provincial coordinating committee.

Increased asthma hospitalizations among registered Indian children and adults in Saskatchewan, 1970-1989.

We investigated asthma morbidity in children and adults among Registered Indians in Saskatchewan using hospitalization data for 1970-1989. In Registered Indians, significant increases were observed in the asthma hospitalization rates from 1979 to 1989 in boys and girls under 4 years, boys aged 5-14 years, and female adults aged 15-34 years respectively. In children under 4 years, the asthma hospitalization rates increased from 12.7 per 1000 in 1979 to 21.7 per 1000 in 1989. Asthma hospitalizations were higher among Indian boys than girls in the age group 0-4 years but this was reversed in the age groups 15-34 and 35-64 years. When compared with other Saskatchewan populations, the Indian population in age groups 0-4 and 35-64 years had significantly increased risk for hospitalization for asthma. Even though asthma was reported to be rare among Indians before 1975, we observed increases in asthma morbidity in recent years among Indian children and young adults.

Role of cations and IgA in saliva-mediated aggregation of Pseudomonas aeruginosa in cystic fibrosis patients.

Oral colonization by Pseudomonas aeruginosa possibly precedes the pulmonary infection process in cystic fibrosis (CF) patients. As bacterial aggregates may play a role in establishment of pulmonary infections, involvement of IgA and cations in CF patient saliva-mediated aggregation of P. aeruginosa was investigated. For colonized patients, P. aeruginosa aggregation correlated with bacterial-specific and total salivary IgA. Cation or IgA depletion reduced P. aeruginosa aggregation by saliva from all patients. However, if cations were removed before IgA, and saliva was then reconstituted with calcium, only colonized patient saliva showed reduced aggregation. Aggregation by IgA-depleted saliva was augmented by reconstituting with original IgA. CF patient saliva-mediated aggregation of P. aeruginosa thus is cation-dependent and enhanced by bacterial-specific IgA. Characterizing the interactions among bacterial aggregating factor(s), cations, and antibodies in CF saliva will help clarify the link between P. aeruginosa oral colonization and pulmonary infections in CF patients.

Use of gastrointestinal and respiratory illness hospitalization rates as indicators of different social influences.

The hospitalization rates for gastrointestinal and respiratory illnesses in children under five years of age were examined on two Indian reserves in Northern Saskatchewan. The gastrointestinal illness rate was used as an index of waterborne disease, and the respiratory rate as an index of general health and of local customs affecting hospitalizations. The reserve rates were compared with those for other Saskatchewan status Indians and for other Saskatchewan residents. The risk ratios between the reserves and other Indians, and between the reserves and other Saskatchewan residents, were increased for both gastrointestinal and respiratory illnesses. The risk ratio of gastrointestinal rate divided by respiratory rate was greater for either reserve than for other Indians or other Saskatchewan residents. Waterborne illnesses were an even greater problem on the two study reserves than on other reserves. Comparing hospitalization rates for different illness groups is a useful method to compare the effect of different social factors.

The role of saliva in aggregation and adherence of Pseudomonas aeruginosa in patients with cystic fibrosis.

The aggregation and adherence activity of P. aeruginosa, mediated by whole saliva from cystic fibrosis (CF) patients and non-CF subjects, was investigated. CF saliva-mediated aggregation of P. aeruginosa was stronger than the activity of non-CF saliva. Likewise, P. aeruginosa adherence to buccal epithelial cells (BEC) of CF patients was stronger than to BEC of non-CF subjects. Adherence of non-mucoid P. aeruginosa to BEC of CF patients was increased by saliva, whereas the mucoid variant was not. CF patients colonized with P. aeruginosa showed higher adherence of the non-mucoid variant than non-colonized CF patients. CF patients with high saliva-mediated adherence of non-mucoid P. aeruginosa also had high salivary aggregation activity. Increased CF saliva-mediated aggregation activity may be linked to the increased non-mucoid P. aeruginosa adherence to BEC of CF patients.

Duplication of well-baby services.

Parents, community health nurses (CHNs) and physicians in Saskatoon were surveyed to determine if specific components of well-baby services provided by CHNs and physicians were duplicated. A response was obtained from 348 (81%) of the parents, 34 (89%) of the CHNs and 129 (87%) of the physicians. Results of the study indicate that there is extensive duplication of measurements taken by CHNs and physicians at the two, four, six, and twelve-month well-baby visits, especially that of height and weight. Content of well-baby care was also examined. The percentage of both physicians and CHNs who "usually or always" perform specific tasks at each well-baby visit was very high, particularly screening tests and inquiries about nutrition. Assessments and inquiries regarding development were performed less frequently, as were inquiries about safety issues.

Whole, submandibular, and parotid saliva-mediated aggregation of Pseudomonas aeruginosa in cystic fibrosis.

The aggregation of mucoid and nonmucoid Pseudomonas aeruginosa by submandibular, parotid, and whole saliva from patients with cystic fibrosis (CF) and non-CF subjects was investigated. There were significant differences (P less than 0.01) in aggregation of mucoid and nonmucoid variants of P. aeruginosa by submandibular and whole saliva from CF patients and non-CF subjects. However, the differences in the parotid secretion were not as pronounced. Patients with CF who were colonized with P. aeruginosa demonstrated a significantly higher (P less than 0.05) percent aggregation of the mucoid variants by the submandibular secretion and of both mucoid and nonmucoid variants by whole saliva, compared with corresponding secretions from patients with CF not colonized with this pathogen. The parotid saliva aggregation activity was not markedly different for the two groups with CF. From patients with CF, whole saliva demonstrated a higher percent P. aeruginosa aggregation than did the submandibular saliva. In non-CF subjects, however, the percent aggregation of P. aeruginosa by submandibular saliva was higher than that by whole saliva. Our results indicate that the sero-mucous products of the submandibular gland have a more significant role in P. aeruginosa aggregation than the serous secreting parotid cells and that the submandibular secretion is possibly responsible for the differences in oral colonization by this pathogen in subjects with and without CF.

Incidence of infantile hypertrophic pyloric stenosis in Saskatchewan, 1970-85.

We reviewed the incidence rates of infantile hypertrophic pyloric stenosis (IHPS) and pylorospasm in Saskatchewan from 1970 to 1985 and found a marked decrease in the rates after 1976. As expected, there was a preponderance of males among those with IHPS and among those with pylorospasm discharged from hospital between 1 and 3 months of age. No seasonal pattern was observed. We believe that the decrease in incidence rates was related to environmental influences, such as changes in the methods of feeding observed since 1977.

Infantile hypertrophic pyloric stenosis: a study of feeding practices and other possible causes.

We carried out a case-control study of the hospital charts of 91 infants with infantile hypertrophic pyloric stenosis (IHPS) to determine the feeding practices at the time of discharge from the neonatal nursery. We excluded infants whose feeding might have been influenced by confounding factors. The infants were matched with controls for gestational age. The mean birth weight of the IHPS group was 3501 g and of the control group 3543 g. The male:female ratio for the IHPS group was 5.5. The odds ratio of male predominance was 4. We found that bottle-feeding was 2.9 times more prevalent among the infants with IHPS than among the control subjects. We speculate that the recently observed decrease in the incidence of IHPS is due to the decline in bottle-feeding.

Fever in Children: Should it be Treated?

Fever, which is the regulation of body temperature at an elevated level, must be differentiated from hyperthermia. The pathogenesis of fever involves exogenous pyrogens acting on macrophages/monocytes to produce the endogenous pyrogen, interleukin-1, which acts on the thermoregulatory centre and also has important effects on the body's immune responses to infection. Fever by itself is rarely harmful, and there is no evidence that febrile seizures produce long-term sequelae. On the other hand, fever may be part of the body's innate protection against infection. The main reason for treating a fever in a child is to relieve discomfort. Acetaminophen should be the drug of first choice in treatment, and sponging, if used at all, should be employed only after acetaminophen has been given first. Education of parents about fever management can be helpful.

Role of sialic acid in saliva-mediated aggregation of Pseudomonas aeruginosa isolated from cystic fibrosis patients.

The mechanism of saliva-mediated aggregation of Pseudomonas aeruginosa in subjects with and without cystic fibrosis (CF) was investigated. Virtually all saliva from CF patients that we tested strongly agglutinated the Pseudomonas cells and was heat stable to 56 degrees C, whereas saliva from subjects without CF had a decreased aggregating ability and was heat sensitive. When saliva was treated with neuraminidase and proteases, and also when P. aeruginosa cells were treated with mixed gangliosides, there was a decrease in aggregating activities. However, neither the addition of the acid-hydrolyzed ganglioside nor the treatment of the P. aeruginosa cells by sugars had any effect on subsequent aggregating activities. Therefore, the release of sialic acid by enzymatic treatments of saliva, as well as the blockage of the sialic acid-binding sites on the cell wall by mixed gangliosides, resulted in the parallel loss of saliva-mediated aggregating activity of P. aeruginosa. The level of free sialic acid released by endogenous neuraminidase was higher in the saliva from CF patients than in that from the non-CF subjects examined. The increased aggregation of P. aeruginosa mediated by saliva from patients with CF seems to be directly related to the sialic acid content present, suggesting that this acid molecule acts as the salivary receptor for P. aeruginosa.

Characterization by pyocine typing and serotyping of oral and sputum strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients.

Oral and sputum isolates of Pseudomonas aeruginosa in patients with cystic fibrosis were investigated. Of the 17 patients studied, 12 patients (71%) yielded both mucoid and nonmucoid variants of Pseudomonas aeruginosa from sputum and (or) various oral ecological sites, such as buccal mucosa, tongue dorsum, dental plaques, and saliva. A total of 51 strains of mucoid and nonmucoid Pseudomonas aeruginosa were isolated from these patients and were phenotypically characterized by both pyocine typing and serotyping. Five patients (42%) were colonized or infected by a single strain of Pseudomonas aeruginosa, whereas 7 patients (58%) were cocolonized or coinfected by two or more phenotypically different strains of Pseudomonas aeruginosa. To understand the mechanisms involved in Pseudomonas aeruginosa colonization, it may be necessary to identify multiple isolates of Pseudomonas aeruginosa not only from the sputum but also from the various oral ecological sites and to further explore the role of the oral cavity in this colonization.

Interbacterial adhesion between Pseudomonas aeruginosa and indigenous oral bacteria isolated from patients with cystic fibrosis.

Interbacterial adhesion between strains of Pseudomonas aeruginosa and strains of indigenous oral bacteria, both of which were isolated from the oral cavity of cystic fibrosis patients, was investigated by the phenomenon of the coaggregation reaction. A total of 22 strains of P. aeruginosa were isolated from the oral cavity of 17 patients and examined for their abilities to coaggregate with 5 strains each of Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii. Coaggregation reactions were common between these oral bacteria and both the mucoid and nonmucoid variants of P. aeruginosa. All strains of P. aeruginosa were also able to agglutinate neuraminidase-treated or untreated human erythrocytes of blood types A, B, and O. Positive coaggregation reactions were further characterized by determining the effects of several sugars, and of heat and protease treatments of the bacteria. None of the coaggregtion reactions were inhibited by 0.05 M lactose, galactose, glucose, fucose, or mannose. All coaggregation reactions were dependent upon heat- and protease-sensitive components of the Pseudomonas. Thus, the interbacterial adhesions between P. aeruginosa and the oral bacteria studied appears to involve adhesins on the Pseudomonas cell, which bind to complementary receptors, on the cell surfaces of oral bacteria. The apparent prevalence and diversity of interbacterial adhesions between P. aeruginosa strains originating from the oral cavity of cystic fibrosis patients and strains of the indigenous oral bacteria suggest that some of these reactions may affect the extent to which P. aeruginosa colonizes in the oral cavity of cystic fibrosis patients, and thereby, influence susceptibility of the host to infection.