CHILDHOOD ASTHMA IN FINLAND

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Does breast feeding help protect against atopic disease? Biology, methodology, and a golden jubilee of controversy

To help shed some light on the 50-year-old controversy concerning the possible protective effect of breast feeding on subsequent atopic disease, I developed 12 standards pertaining to both biologic and methodologic aspects of exposure (infant feeding), outcome (atopic conditions), and statistical analysis for studies of atopic eczema, asthma, allergic rhinitis, cow milk allergy, and other food allergy. Among the published studies on atopic eczema, the nine claiming a protective benefit of breast feeding performed less well than the 12 not making such a claim on "methodologic" standards relating to strict diagnostic criteria and blind ascertainment of outcome. The positive studies were somewhat stronger, however, on the "biologic" standards bearing on sufficient duration and exclusivity of breast feeding and on separate analysis of children at high risk. For the other atopic conditions, there were no important differences between positive and negative studies. In few negative or positive studies was there adequate control for confounding variables or examination of potential benefits relating to the severity or age at onset of atopic disease. To avoid another 50 years of unresolved controversy, future studies should improve both the biologic and methodologic aspects of their design and analysis.

Epidemiology of asthma in Denmark

The epidemiology of asthma in the Danish population is reviewed with reference to research on asthma in general populations, in general/family practice and in hospitals. The prevalence of asthma in Denmark is on the same order as found in national morbidity studies in Britain and the US. The two-peaked prevalence curve suggests that there are two different diseases: childhood asthma, provoked by allergy and temporarily stopping before adulthood, and adult asthma gradually increasing in prevalence until 60 to 70 years of age and due to hyperreactivity. In Denmark, asthma does not appear to be increasing in incidence. With the exception of the very young, seasonal variation is not pronounced and hyperreactivity is thus more dependent on irritants than on seasonally occurring allergens such as pollen. The concomitant prevalence of asthma and allergic rhinitis was similar to rates reported elsewhere. Problems and limitations of sources of data for epidemiologic studies are discussed.

Environmental allergens and morbidity in atopic and non-atopic families

148 newborns of non-atopic and 329 newborns of atopic parents were included in a five-year follow-up study of atopic diseases. The prevalence of atopic diseases at five years of age is compared to environmental factors, which may be involved in the development of atopic diseases. There was no significant correlation between the development of atopic disease and the following factors: the nature of the immediate environment (industrial, agricultural, rural, urban, arboreal, lake-district); building materials, heating systems and general state of repair of the houses, including its interior decoration; the presence of pets, plants, humidifiers or cigarette smoke. There was, however, one exception: in both family groups the avoidance of woollen garments and bed clothes before the outbreak of atopic symptoms was associated with the increased prevalence of asthma, allergic rhinitis and atopic dermatitis. The cause of this association remained uncertain. Children with atopic diathesis are known to frequently display skin intolerance to wool. Therefore, wool avoidance in a family may only indicate that the child was potentially atopic. Atopic children suffered from ear infections and vomiting more often than control children. The incidence of ear infections was also increased amongst children with a positive family history of atopy, even if no atopic disease was diagnosed in the child himself. Although breast fed infants tended to have less infectious diseases than those weaned early, ear infections were equally common in all feeding groups. This is further evidence, that in part of the cases of recurrent ear infections, atopy should be considered as a possible etiologic factor.

Seasonal variation of asthma and allergic rhinitis. Consultation pattern in general practice related to pollen and spore counts and to five indicators of air pollution

The seasonal variation of consultations on account of asthma and allergic rhinitis, and the relationship with air concentrations of pollen, spores, and lead, cadmium, dust, soot and sulfur dioxide was investigated in Danish general practice during a 1-year period 1977-78. A population of about 500,000 was studied. Among about 3000 asthmatics there were less consultations during spring than the rest of the year, but the seasonal variation of consultations with symptoms was rather small. The highest rate of consultations was in week 24, which is close to the peak of the grass pollen period. No relationship was found between asthma symptoms and concentrations of pollution indicators. Among about 5000 patients with allergic rhinitis the rate of consultations with symptoms increased at the start of the tree pollen season, still more at the start of the birch pollen season, and was very high during weeks 21-26 in the grass pollen season. Two thirds of all consultations for symptomatic allergic rhinitis took place within 10 weeks (Nos. 18-27). During the grass pollen season there was a relative preponderance of young patients, while during the birch pollen season older patients dominated. No connection was seen between rhinitis symptoms and pollution indicators. The different seasonal variation of asthma and allergic rhinitis indicates that the two patient categories differ as regards symptom-provoking factors. Allergic rhinitis is mainly precipitated by grass and birch pollen. The precipitating factors of asthma were not disclosed in this study, with the exception perhaps of some influence from pollen, and - among 0-4-year-old children - respiratory infections.

Development of asthma, allergic rhinitis and atopic dermatitis by the age of five years. A prospective study of 543 newborns

543 children were followed up from birth to 5 years of age. Children with a positive history of parents' atopy had a 51% occurrence of respiratory or dermal symptoms of atopy vs. a 19% occurrence among children with no family history of atopy. There was an association between asthma and allergic rhinitis while atopic dermatitis occurred equally in children with or without respiratory symptoms. The clinical course of atopic symptoms could not be correlated to the family history of atopy. The significance of date of birth, nasal eosinophilia and serum IgE levels seemed to be relatively low in atopic dermatitis while these parameters had a correlation to the development of respiratory atopies.

Prophylaxis of atopic disease by six months' total solid food elimination. Evaluation of 135 exclusively breast-fed infants of atopic families

One hundred and thirty-five infants of atopic parents were exclusively breast-fed for 6 months without any cow's milk based supplements. Of these infants 70 received no nourishment except breast milk during the 6 months, and 65 were started on solid foods at the age of 3 months. The diet of all the infants was similar during 6 to 12 months of age. The children were examined at the age of one year. In the exclusive breast milk group atopic eczema and food allergy were less frequent than in the solid food group. The results suggest that total solid food elimination for the first 6 months of life, in addition to exclusive breast milk feeding, is prophylactic for atopic disease in children who are at hereditary risk.

Asthma and allergic rhinitis in the same patients

This study from Danish general practice gives figures about the simultaneous prevalence of asthma and allergic rhinitis and the order of onset among 7662 patients, who during 1 year consulted for one or both of these diseases. Twenty-eight percent of patients with asthma consulted because they also had allergic rhinitis, and 17% of patients with allergic rhinitis consulted because they also had asthma. Age- and sex-distributions are presented. In 25% of patients with both diseases the onset of both diseases occurred within the same year, while in 35% the onset of asthma occurred first and in 40% allergic rhinitis. Among patients with both diseases, who did not have onset of both within the same year, more than 75% of them had onset of one disease within 2 years of the other.

Food allergy in Finnish children aged 1 to 6 years

Food allergy was studied in a total of 866 Finnish children aged 1, 2, 3 and 6 years in the Helsinki region. The diagnosis was based on history as well as on elimination and challenge performed at home concerning fish, citrus fruit and eggs. The prevalence of food allergy was 19% at one year of age, increased to a peak of 27% at three years, and thereafter decreased to 8% at six years of age. The most common allergenic foods were citrus fruit, tomato, eggs, strawberry and fish. A positive history of food allergy could be confirmed by challenge in about half of the cases in the younger age groups and in 100% at six years of age. The data indicate that food allergy is common in Finnish children.

Occurrence of atopic diseases in three generations

The incidence of asthma, hay fever and atopic dermatitis was assessed in three generations in 2820 families by a questionnaire. 35% of the families were atopic when the histories of parents and grandparents were included. 64% of atopic children had atopy in probands and the corresponding figure for non-atopic individuals was 31%. The highest prevalence of atopy was found in the parents' generation (13.5%) but it did not differ significantly from that of children (10.8%) when compared with grandparents (7.6%). The results suggested an increasing prevalence of children's atopic dermatitis in Finland since the 1950s. The influence of heredity was apparent. Few geographical differences were observed.

Serum IgE in infants and influence of type of feeding

Serum IgE in healthy infants was followed longitudinally during the first year of life and was related to heredity for allergy and type of feeding. During the first 6 months of life there were no significant differences of serum IgE levels in relation to presence or absence of heredity for allergy and type of feeding. IgE levels determined at the age of 12 months in infants who were weaned after the age of 6 months were significantly higher than in infants weaned before that age (P < 0.05). When the time periods had passed, following onset of cow's milk-feeding and complete cassation of breast-feeding, and were correlated to IgE at the age of 12 months, there were inverse significant correlations; i.e. the earlier the onset of cow's milk-feeding the lower the IgE and the later the cessation of breast-feeding the higher the IgE. This was particularly obvious as regards infants with heredity for allergy and a long duration of breast-feeding (r = -0.43; P < 0.01). Infants with heredity for allergy subjected to a hypoallergenic diet adhered to for 6 months had significantly higher IgE at the age of 12 months than infants with similar heredity but a normal diet (P < 0.05). The results indicate that serum IgE during late infancy is influenced by both genetic factors and the time of introduction of cow's milk formula in the diet and the time of cessation of breast-feeding.

Symptoms of chronic and allergic rhinitis and occurrence of nasal secretion granulocytes in university students, school children and infants

The prevalence of chronic and allergic rhinitis was studied in an unselected population sample consisting of 315 university students and 319 school children. History was taken by questionnaire, nasal appearance was examined by rhinoscopy, and a nasal smear was studied in all subjects. For comparison, nasal smears were also collected from 60 normal infants. Allergic rhinitis complaints were reported by 28% of the students and by 13% of the school children, with no significant difference in sex distribution. The cytological examination revealed secretion eosinophilia in 20% of the students, 28% of the school children, and 22% of the infants. Secretion eosinophilia correlated significantly with allergic rhinitis history, and with nasal mucosal swelling and nasal secretion seen on rhinoscopy. Nasal secretion neutrophilia, which occurred in 47% of the students, 79% of the school children and 97% of the infants, seemed to have an adverse effect on the reliability of secretion eosinophilia as an indicator of active nasal allergy. Possible reasons for the rising prevalence rates of allergic rhinitis are discussed.

Serum IgE in healthy infants fed breast milk or cow's milk-based formulas

A group of ninety-five infants was followed from birth to one year of age, and the total serum IgE concentration was studied. The infants were fed on breast milk, home-prepared cow's milk formula, or proprietary infant milk formula. Solid foods were introduced at 3.5 months of age. The breast milk group had lower IgE than the cow's milk group up to 4 months of age, i.e. until the end of exclusive milk feeding. The formula group had intermediate IgE values. The difference was not due to the presence of IgE antibodies to cow's milk in bottle-fed infants, since no such antibodies could be detected. After the introduction of solid foods the differences between the groups disappeared. Our data suggest that exclusive breast milk feeding can reduce total serum IgE concentration in early infancy. Reference values for unselected infants and for infants with no atopic manifestations are reported.

Perennial atopic rhinitis as an early stage of bronchial asthma

Etiologic factors and incidence of bronchial hyperreactivity as a 'stigma' of bronchial asthma were studied in 237 patients suffering from perennial atopic rhinitis. All pateints underwent detailed laryngologic and allergologic examiniation and pulmonary function tests at rest, after exercise, and after histamine inhalation. Most often the patients were sensitized tungal allergens. Bronchial hyperreactivity, typical of bronchial asthma, was observed in 48.52% of patients. Results were analysed statistically. It was concluded that early institution of causal therapy can cure the symptoms of rhinitis and prevent evolution of the disease into atopic bronchial asthma in patients already suffering from bronchial hyperreactivity.

Atopic allergy and immunoglobulins in children with adenoids and recurrent otitis media

From 274 adenoidectomized children 1-16 years of age two groups were selected: children with a history of recurrent otitis media and/or otosalpingitis (middle ear effusion) and those in which nasal obstruction was the main symptom. In all, 154 children were subjected to an allergy investigation including history, skin tests, eye tests, determination of IgE and RAST, blood eosinophils and immunoglobulins G, A and M. No increased incidence of immunoglobulin deficiency was found in either group in comparison with unselected children. A family history of atopic disease and/or otitis media was highly overrepresented, especially in the children with recurrent otitis media as the reason for the adenoidectomy. Atopic diseases had occurred in 24.4% of the children. Furthermore, in both groups there was a high incidence of positive skin and eye tests. An increased incidence of eosinophila, positive RAST tests and elevated IgE levels were also found. In all, 39.6% of the children had two or more laboratory findings characteristic of the atopic state but no significant difference was found between the two groups. Possible connections between atopic allergy and recurrent otitis media are discussed.

Dependence of immediate hypersensitivity on the month of birth

This report describes a retrospective study of 1421 patients allergic to pollens and 728 patients allergic to animal epithelia. In males, but not in females, the month-of-birth distribution differed significantly from that in the total population of Finland (P less than 0-01 in pollen allergy and P less than 0-05 in epithelium allergy). The phenomenon was most clearly apparent in boys aged 10-14 born in 1960-4 (P less than 0-01 in pollen allergy and P less than 0-001 in epithelium allergy). When the relative risk of immediate hypersensitivity was plotted as a function of the month of birth, a two-phasic curve with maxima in March-May and September-November was obtained for both pollen allergy and animal epithelium allergy. The results indicate that boys, but perhaps not girls, have a sensitive period early in life during which one or more environmental factor and seasonal variations in this factor influence the development of subsequent immediate hypersensitivity.

Serum IgE levels in healthy children quantified by a sandwich technique (PRIST)

Serum IgE was estimated in 226 healthy children aged 0-14 years without obvious atropic disease in their first degree relatives. A paper disc radioimmunoassay technique (PRIST) was used. A number of criteria for selection of cases were established. This led to the exclusion of forty-two potentially atopic children. The remaining group of 184 children is considered representative of normal children and may therefore be used for reference purposes. The IgE levels were found to be lower than in previous investigations, and this is attributed to the refined technique and the method of selection.